year 10 science notes

8/14/2019 Year 10 Science Notes

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BY: Amal Vivek :D

Science Notes Yearly 2012Body Balance

Glossary

Coordinationthe functioning of interrelated body systems and organs working together to

enable proper functionality

The Five Senses

o Sight

o Smell

o Touch

o

Hearingo Taste

Sensory Receptors

Sensory receptors are nerve endings of the sensory nerve. They respond to internal and external

stimuli of an environment. They are what perceive light, taste, touch and so on in organisms. They

converted what they have detected from the stimuli and convert them into electrical impulses.

These signals are sent to the CNS via the PNS. The brain then coordinates a response to the signal

received. In emergencies, the signal stops at the spinal cord where a response isnt coordinated by

the brain but a signal is sent to the appropriate motor neurons as a reflex from the spinal cord. The

sensory receptors are:

Mechanoreceptorsrespond to mechanical stimuli such as sound a and distortions in

pressure for example touch, and pain; any deformation of a mechanoreceptors nerve

ending results in an electrical change (i.e. response)

PhotoreceptorsLight; convert light in to signals that stimulate biological processes

ChemoreceptorsRespond to chemical stimuli; Smell and Taste; also digestive and

circulatory systems; there are two types of chemoreceptors (distant and direct):

Distantfor example the nose receives smell from distant objects

Directfor example taste buds require direct contact for sensation

ThermoreceptorsTemperature; heat

Electroreceptorsdetect electricity in marine or amphibious organisms

Taste Vs. Flavour

Taste is one of the 5 senses that is picked up by sensory receptors. Flavour, however, is a

combination of a couple of senses.

Nervous System

The Nervous System is a network of cells called Neurons that coordinate the different parts of thebody. The Nervous system consists of two parts; Central and Peripheral:


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Central Nervous System (CNS)the central nervous system receives all the information

from the different parts of the body and integrates this. It is the largest part of the nervous

system composed of the Brain and Spinal Cord.

Peripheral Nervous System(PNS)the peripheral nervous system consist of the sensory

and motor components that act as a bridge between the environment and central nervous

system. These components send signals that it receives from stimuli to usually the brain part

of the CNS but sometimes in emergencies the spinal cord will stop the message and send it

back for a quick response. The PNS can be divided into two subdivisions:

Somatic Nervous System (SNS)the SNS is the part of the PNS that is

associated with voluntary movements and muscles.

Autonomic Nervous System (ANS)the ANS controls involuntary

movements and muscles like heart rate, digestion, salivation, perspiration,

pupil dilation, urination, sexual arousal and breathing. The ANS can be

further divided into:

Sympatheticused in fight or flight response (adrenaline) Parasympathetic - used in relaxation

Both these subdivisions involve reflex arcs. Somatic reflex arcs are ones that

occur from exterior stimuli affecting muscles such as the knee jerk or pulling

your hand away from a flame or hot surface. Autonomic reflex arcs are ones

that affect internal organs such as sweating. They both, however, do not

involve the brain.

Neurons

Sensory NeuronsCarry messages signals from the receptors to the spinal cord and brain. There are12 pairs of Cranial nerves that are the only nerves that send messages directly to the brain. The rest

of the 31 pairs are spinal verves

that send their message first to the

spine and are then sent to the

brain.

Relay NeuronsCarry messages

from one part of the central

nervous system to another. In

reflex actions, relay neurons carrymessages from the sensory

neurons straight to the motor

neuron bypassing the brain. Reflex

actions occur in emergencies

where quick action is required (e.g. when you touch something hot).

Motor Neuronsthe purpose of motor neurons is to carry signals from the CNS to the effectors (e.g.

muscles) that produce actions.


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The structure of each neuron:

Synapses

A synapse is a junction

between nerve cells.

Nerve cells dont meet

directly. There is a tiny

gap where they meetcalled a Synaptic Cleft.

Signals cross this gap

using chemicals called

Neurotransmitters.

Neurotransmitters are

stored in Synaptic

Vesiclesclustered at the tip of an axon. The crossing of impulses of a synaptic cleft takes

approximately 0.51 millisecond. One the action is complete, the neurotransmitters get absorbed

back into the vesicles or diffuse in to the cleft.

Nerves

Nerves are enclosed cable like bundles of neurons/axons (covered in a myelin sheath that protect

and speed up the responses) in the peripheral nervous system. They are the path that nerve

impulses follow. Nerves can be categorised into 3 groups:

Afferent (Sensory)From sensory receptors to spinal cords

Efferent (Motor)From CNS to motor neurons/effectors


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Mixed (Relay)Impulses travel both ways receiving sensory information

and conduct outgoing response to

the motor cells

Brain

Part of the Brain Function

Brain Stem This area connects to the spinal cord. It act as a relay centre for the

brain, but its main function is for involuntary actions such as

heartbeat, breathing and blood pressure

Medulla Oblongata Closest to the spinal cord; involved in involuntary actions; regulation

of heartbeat, breathing, blood pressure, coughing, sneezing, etc.

Located in the Brain Stem which leads to the Spinal Cord.

Midbrain Is a very small section that is commonly used in association for


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auditory and visual information. It also controls some body

movements and eye movements

Pons Pons has similar function to the midbrain. It is involved in sleep,

respiration, swallowing, hearing, taste, eye and facial movements,

and posture.

Cerebellum It is located in the lower back of the head. It is the second largeststructure in the brain and is composed of two hemispheres. It

controls complex motor functions such as walking, running, posture,

and general motor coordination.

Cerebrum The cerebrum is the largest part of the brain. It associated with

conscious thought, movement and sensation. It is made up of 2

halves each controlling opposite sides of the body (i.e. left half of

cerebrum controls right side of body and vice versa). The cerebrum is

then divided in to 4 sections called lobes:

Frontal Lobecontrols attention, behaviour, abstract

thinking, problem solving, imagination, emotion, intellect,

coordinated movements, physical reactions, and personality Parietal Lobecontrols some movements, orientation,

perception of internal stimuli, and some language, reading,

and visual functions

Temporal LobeControl auditory and visual memories, and

some language functions

Occipital Lobeat the back of the head and controls vision

Grey Matter Vs. White Matter

The CNS is composed of two types of matter:

Grey MatterThis is the major part of the CNS consisting of neuronal cell bodies,

neuropil (dendrites and un-myelinated axons), glial cells, and capillaries.

White matterthis is the minor part of the CNS that consist of only myelinated

axons and not that many un-myelinated axons.

The difference is that grey matter contains neural cell bodies where white matter

does not. White matter also contains myelinated axons unlike grey matter.


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Endocrine System

The endocrine system is a system of glands that secrete hormones into the blood stream to regulate

the body. The word endocrine derives from the Greek words endo meaning inside and crinismeaning secrete. The endocrine system is similar to the nervous system except that its responses

rather than being instantaneous are prolonged and last much longer. Hormones are substanes

(chemical mediators) that are released from endocrine tissue into the bloodstream where they

travel to their targeted tissue in pursuit of a response. They generally result in changes in mood,

growth and development, tissue function, and metabolism.


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Negative Feedback

Negative feedback is used in regulating blood sugar levels in order to keep the body in homeostasis
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Parkinsons Disease

Parkinsons disease is a progressive, degenerative brain disease that causes trembling, stiffness, slowness of

movement and a loss of fine motor control.

The disease destroys neurons in an area of the brain called the substantia nigra. Without these dopamine-

producing cells, the brains ability to control movement is progressively reduced.

Neuroscience Australias Research:

Because much of the damage to the brain in Parkinsons disease occurs over several years before symptoms

become noticeable, early diagnosis is a critical issue, particularly as more effective treatments become available.

Lead byAssoc Prof Kay Double,we are currently developing several methods to diagnose Parkinsons disease

earlier than is currently possible, including a novel blood test and atechnique using ultrasound to identify a change in

the appearance of the substantia nigra.

We are also looking atwhy specific cells are more vulnerable to death in Parkinsons disease ,the role of copper in

Parkinsons disease,andthe regulation of an enzyme involved in dopamine production.

We are conducting research to gain abetter understanding of the formation of new neurons in healthy ageing.Such

knowledge is important for current research which aims to develop novel therapeutic approaches for

neurodegenerative disease based upon stimulating the formation of or transplanting new neurons into the human

brain.

The disease progresses at different rates and in different patterns in each person. Lead byProf Glenda Halliday,we

are determiningwhether genetic factors contribute to these differences.In particular, we are looking at a gene called

LRRK2, which has been identified as causing Parkinson's disease in some people. Our research is identifying the

proteins that interact with LRRK2 to cause Parkinson's disease. These proteins may be amenable to future

therapeutic manipulation.
http://www.neura.edu.au/research/themes/double-grouphttp://www.neura.edu.au/research/themes/double-grouphttp://www.neura.edu.au/research/themes/double-grouphttp://www.neura.edu.au/research/projects/ultrasound-imaging-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/ultrasound-imaging-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/ultrasound-imaging-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/ultrasound-imaging-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/differential-expression-proteins-human-brainhttp://www.neura.edu.au/research/projects/differential-expression-proteins-human-brainhttp://www.neura.edu.au/research/projects/differential-expression-proteins-human-brainhttp://www.neura.edu.au/research/projects/copper-changes-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/copper-changes-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/copper-changes-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/copper-changes-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/regulation-tyrosine-hydroxylasehttp://www.neura.edu.au/research/projects/regulation-tyrosine-hydroxylasehttp://www.neura.edu.au/research/projects/regulation-tyrosine-hydroxylasehttp://www.neura.edu.au/research/projects/neurogenesis-healthy-ageinghttp://www.neura.edu.au/research/projects/neurogenesis-healthy-ageinghttp://www.neura.edu.au/research/projects/neurogenesis-healthy-ageinghttp://www.neura.edu.au/research/themes/halliday-grouphttp://www.neura.edu.au/research/themes/halliday-grouphttp://www.neura.edu.au/research/themes/halliday-grouphttp://www.neura.edu.au/research/projects/parkinsons-disease-and-related-syndromeshttp://www.neura.edu.au/research/projects/parkinsons-disease-and-related-syndromeshttp://www.neura.edu.au/research/projects/parkinsons-disease-and-related-syndromeshttp://www.neura.edu.au/research/projects/parkinsons-disease-and-related-syndromeshttp://www.neura.edu.au/research/themes/halliday-grouphttp://www.neura.edu.au/research/projects/neurogenesis-healthy-ageinghttp://www.neura.edu.au/research/projects/regulation-tyrosine-hydroxylasehttp://www.neura.edu.au/research/projects/copper-changes-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/copper-changes-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/differential-expression-proteins-human-brainhttp://www.neura.edu.au/research/projects/ultrasound-imaging-parkinson-s-diseasehttp://www.neura.edu.au/research/projects/ultrasound-imaging-parkinson-s-diseasehttp://www.neura.edu.au/research/themes/double-group


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Physics

Newton and His Three Laws

Sir Isaac Newton was an English Physicist who discovered gravity and the three laws of motion. He is

considered the most influential science that ever lived. He discovered gravity when an apple fell on

his head. His three laws of motion are:

i. The Law of INERTIAthis law states that an object will remain stationary or at a

constant velocity unless acted upon by a force.

ii. The relationship between the mass of an object, the acceleration and force applied

is F = mawhere:

a.

F= Applied Force

b. m = Mass of an object

c. a = Acceleration

iii. For every action, there is an equal and opposite reaction

Glossary

Distance is a scalar measure of the total distance

an object has travelled

Displacement - is a vector measurement of how far

an object is out of place from its original positionand direction in which it has gone. For example, in

the diagram to the right, if an object travelled from

A to B via C, the distance would be 140m, but its

displacement would be 100m North-East.

Scalar quantities describe by a numerical value

alone (i.e. distance travelled)

Vector quantities described by a numerical value and a direction

Velocity Velocity is again a vector measurement measured by the formula

and refers to the rate at which an object changes position.

Speed Speed is a scalar measurement which is measured by

and refers to how

fast an object is moving rather than how far an object has moved in a certain amount of time.

Instantaneous Speedthe speed of an object at certain point in time

Average SpeedThe speed of an object over a span of time

Acceleration a vector measurement that measures the rate at which an object changes its velocity.

It is measured by the formula


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This formula can be presented algebraically as

where the terms correspond with the words

in the previous formula.

Acceleration will change when you are turning even if you have not lost or gain any

speed due to the change in direction.

Motion motion is not always in a straight line as when acceleration comes at an angle to motion, it

results in a turning

Distance-Time Graphs

Distance-time graphs show the relationship between time and distance


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The Unit of Acceleration

The unit of acceleration is Metres per second per second. This is general written as either or

More Equations

Acceleration due to gravity is -9.8m/s2

v = final velocity

u = initial velocity

s = displacement

a = acceleration

t = time

These equations are used to show the relationship between displacement, velocity, time andacceleration.

Cars and Physic

Breaking Distance

When calculating breaking distance, you can assume that the final velocity is 0m/s, therefore you

can manipulate the above equations to tell you the displacement and distance and time when

breaking.

Formula for braking distance is

Starting and Stopping

When starting a car from a resting position, it first has to overcome static friction. Static friction is

the interlocking of irregularities in surfaces. Static friction will be overcome when the car reaches the

threshold of motion. After this point, the car is affected by a constant kinetic friction.

Stopping a car is not immediate when you press the brakes due to momentum and inertia the car

continues to move forward. It is stopped by the frictional force between the brake pads and the

tyres. There are many variables involved in stopping a car such as the slope it is on, individual

starting time, type of tyres and so on.


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Acceleration

Acceleration has nothing to do with speeding up as it is measured by velocity not speed. A car going

at a constant speed but turning is changing its magnitude and therefore is an accelerating object.

Acceleration has an inverse relationship with mass.

Reaction Time

On average, for drivers in emergencies, the time taken to react is 1.5 seconds which will mean an

extra 25m approximately when travelling at 60km/h.

Ap pl ic at io n of Newt on s Laws

Seat Belts

Everything in a car has its own separate inertia. Seatbelt protect people from inertia that is active in

a car. When a car comes to an abrupt stop, everything inside continues to move forward due toinertia. In the event of an accident, a seatbelt protects people from flying through the front

windscreen.

Moving Space Inertia

???

Tangential Motion of Cars

The tangential motion of cars occurs due to inertia and inward force. The inward force of the cars

door moves towards the direction you are turning, but as, due to inertia, we are still going in astraight line, we feel like we are being thrown in the opposite directions, is the reason why cars flip

over.

The Apparent Ease of which Satellites Orbit Earth

The only force that acts upon a satellite is gravity. This is due to the fact that most satellites are

orbiting earth at a point high enough that it is outside the atmosphere. If gravity wasnt in effect on a

satellite, the satellite would continue in its straight trajectory on the tangent to Earth. But since

gravity is in effect, the satellite is pulled away from its path and orbits Earth. The reason that a

satellite doesnt fall to the surface is because of the speed its travelling at. Earth is round, and so

every 8000m the Earth curves 5m downwards. So at a certain speed, the satellite will fall at the same

rate as the earth. 5m every 8000m.

Contact and Non-contact Forces

A force is a pull, push or twist that changes the speed, direction or shape of an object

Contact Forces

o Friction

o Resistance/Drag

o Appliedo Tensional


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Non-contact Forces

o Magnetic

o Nuclear

o Gravitational

Objects always have more than one force acting upon them stated by Newtons third law, for every

action, there is an equal and opposite reaction. To find the overall effect of all the forces in effect on

an object (called the Resultant Force) you add forces working in the same direction and subtract

forces working in opposite directions.

Net Force

This shows the effect of net force. It determines in which direction the displacement will occur.

Acceleration occurs when there is a net force. When there is no net force, the forces will be balance

and the object will either be at rest or at a constant speed.

Qualitative Relationship between Force, Acceleration, and Mass

Force and Acceleration

Force and accelerations relationship is directly proportional. Provided that mass stays constant,

doubling force will result in acceleration also doubling. This works vice versa that halving force will

result in acceleration halving.

Mass and Acceleration

Mass and acceleration have a inversely proportional relationship. Provided that force is constant,

doubling the mass will result in halving the acceleration. Halving the mass will result in doubling the

acceleration.

Friction Vs. Motion

Friction opposes motion as it is an unbalanced force that is what changes inertia. A ball rolling on the

ground would keep rolling unless acted upon by a force which in this case is kinetic friction. As

energy cannot be created or destroyed, the kinetic energy of the rolling ball is turned into heat

energy from the friction which intern causes the ball to stop rolling as all the kinetic energy as been

converted.


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NewtonsThird Law and Rocket Propulsion

For every action, there is an equal and opposite reaction

This is the theory behind rocket propulsion. Due to combustion in a rocket engine, there is a high

outflow of energy in the form of gasses pushing into the ground at high speeds that flows through arear nozzle. This has an opposite reaction of thrust pushing the rocket upwards.

Car Crashes

During a car crash, there are many stages as shown in the above timeline. The major force involved

in car crashes is kinetic energy. The force of the crash depends on the speed and mass of the car.

The force of a crash is measured as deceleration. The best way of reducing the impact of the crash is

to slow down the process of decelearation. This is because of the directly proportional relationship

involved in force and acceleration. The most pressure is felt around 75 milliseconds in the a crash.


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Reducing Impact

There are two ways of reducing impact:

Active Safetythis is where there are certain things in place to prevent a crash

Passive SafetyThis is to reduce impact during a crash

Active safety features Passive safety features

Anti-skid brakes

Stop lights

Mirrors

Fog lights

Demisters

Power steering

Bumper bars

Air bags

Padded dash

Crumple zones

Seat belts

Collapsible steering column

Head rests

Child restraint capsules

Recessed door handles Laminated wind screen

Mass Vs. Weight

Mass is the amount of matter an object is made up of.

Weight is the effect of gravity on that mass

Universal Gravitation

The formula:

Newtons law of Universal Gravitation states that every point mass in the universe attracts every

other point mass with a force that is directly proportional to the product of their masses and

inversely proportional to the square of the distance between them.


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Chemistry II

Compounds

Atoms of elements bod together to produce new substances called Compounds. These reactionsoccur when two or more atoms chemically bond resulting in a unique compound chemically and

physically different to the parent atoms. An example of the uniqueness of compounds from their

parent cells is table salt. Table salt, which is totally safe to eat, is produced from sodium (Na (S)) and

chlorine (Cl(g)) that are two dangerous elements. Sodium reacts so violently with water, it results in

flames, and chlorine is extremely poisonous used as a weapon in WWII.

There are two main types of bonding:

Ionic

Covalent

Ionic Bonding

Ionic compounds are held together by

electrostatic forces. These forces are

due to the transferring of negatively

charged electrons. One of the atoms in

the reaction loses an atom making it

positively charged and another atom in

the reaction gains that lost ion making

it positively charged. The charges of

different atoms are shown ---------------

These charges determine how the

electrons will be lost or gained. For a

reaction to occur the charges must add

up to 0. For example Sodium is in group

1, so its charge is +1, and Chlorine is in group 7, which has a charge of -1. +1 + -1 = 11 = 0. This

proves that the charges must add up to 0. The features of Ionic Bonds are:

Form between metals and non-metals

When naming the bond, the metal always comes first

These compounds dissolve easily in water and other polar solvents

In solution, they can conduct electricity

Tend to form crystalline solids with high melting points

The solids that are made from the reaction are formed together with multiple molecules

that have a crystalline/repeating pattern calle a crystal Latt ice.


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Covalent Bonding

Covalent bonding occurs

when two non-metals want

to bond. Covalent bonding,

unlike ionic bonding where

there is a complete transfer

of electrons, is where two

atoms share atoms. It occurs

between to negatively

charged ions. As both non-

metals want to gain

electrons they will merge

and share their electrons as

shown in the diagram -----

This occurs as the ions are

trying to fill their shells in

order to achieve a neutrally

charged state. Some atoms

are required to share

multiple electrons to fill

their shell. This means

sometimes they require to share more than 1 pair of electrons resulting in Multiple Bonds.

There are to subtypes of Covalent Bonding:

Non-Polaroccurs when the attraction between the atoms are equal. The first two

examples in the diagram above are examples of non-polar bonds. This is because

both atoms require the same amount of atoms to fill their shell.

Polaroccurs when the attraction is not equal between the atoms. The second two

in the diagram above are polar bonds. In the carbon dioxide example, the carbon

atom requires more electrons to fill its shell than the oxygen.

Properties of covalent bonds:

Exist as gases, liquids, or solids with low melting points as their attraction is weakerthan ionic bonds

Do not conduct electricity

Insoluble in water

Precipitation Reactions

These occur when an insoluble solid is formed when two solutions are mixed.

Solubilityis the amount of solute that can be dissolved in a solvent

Soluteis the substance that is dissolved

Solventis the liquid in which the solute is being dissolved


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Solute + Solvent = Solution

To predict a precipitation reaction, you check if any of the products of the reaction are insoluble

using the solubility rules.

Simplified Solubility Rules

All nitrates are soluble

All group 1 metal compounds are soluble

All chlorides (except silver, lead, and mercury) are soluble

All sulphates (except silver, calcium, barium, and mercury) are soluble

All carbonates (except group 1 metals) are insoluble

All hydroxides ( except group 1 metals) are insoluble

Double Replacement

The general equation:

AB + CD AD + CB

Example:

Copper (II) Nitrate and Sodium Phosphate Copper (II) Phosphate and Sodium Nitrate

CuNO3 + NaPO4 CuP04 + NaNO3

To find the subscript to write chemical formula, use the criss-cross method:


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Ac id s and Base s

Acids and Bases:

Indicators

Indicators are chemicals that are used to measure pH or acidity. The universal indicator is the most

common and effect way of testing pH. It changes colour depending the acidity/pH level.

Examples of Common Acids and Bases

Acids Bases

Contains Contains hydrogen in

combination with other non

metal elements, for example,

hydrochloric acid (HCI).

Contain hydroxide (OH) in

combination with metal

elements, for example sodium

hydroxide (NaOH).

Properties

-Acids have a sour taste

- Acids turn blue litmus paper

red

-Acids conduct electricity in

water solution

- Bases taste bitter

- Bases have a soapy feel

- Bases turn red litmus paper

blue

Common Uses Pain relievers, flavouring, and

preserving food, herbicide, car

batteries, herbicide, vitamin

supplements and brick and

metal cleaners.

Oil and grease dissolver,

soaps, washing powder,

cooking and neutraliser


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pH Sc al e

The pH scale is used to measure acidity.

Classification Substances Properties Litmus colour change

Acid (1 pH) White vinegar, soda

water, lemon juice

-Tastes sour

-Attacks and dissolves

some reactive metals

- Attacks limestone

-Does not react withfats

Blue-purple to red

Neutral (7 pH) Water - No taste

-Does not react with

most metals

-Does no react with

fats

Remains blue-purple

Base (14 pH) Ammonia solution,

washing soda

solution, baking soda

solution, lime water

-Tastes bitter

-Does not attack

metals

-Reacts slowly with

fats

Blue-purple to blue


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Tracks Through Time

Darwins Natural Selection

Darwin is considered one of the most influential scientists of all time, particularly due to his work on

his theory Natural Selection. He established that all species have evolved from common ancestors.

Certain traits either become more or less common due to changes in environments requiring

adaptation. Certain species died out as they could not adapt quick enough. The basic process of

natural selection is as follows:

Members of a single species show variation in their characteristics, some of which is passes

from parent to offspring Some members of a species will die before they reproduce The surviving members if a species possess the characteristics that best enable them to survive

in their present environment Over time, organisms become better suited to their current environment

Natural selection is one of the cornerstones in modern day

biology. Changes are caused by:

Changes in the physical environment

Changes in the chemical environment

Competition (survival of the fittest)

To help prove his theory, Darwin used a group of about 15species of passerine birds from the Galapagos Islands known as

Darwins Finches. He described the most distinguished feature,

the beak, on each of the species. He concluded that each birds

beak was suited to its preferred choice of food and evolved due

to natural selection. The theory of natural selection has been

applied to prove many other biological theories and findings. The

term used for the unlimited applicability of his theory has been called Universal Darwinism.

Ad ap ta ti on s

Through adapting and evolving to suit the ever-changing environment, organisms have been able tosurvive through ice ages, giant meteors and other harsh conditions. Adaptation is a key aspect to

survival and promotes the wellbeing of species in their environment (eg. Giraffes long neck to eat

leaves at the top of trees is an adaptation to suit its environment. There are two types of

adaptations:

Structural (Physical)

Behavioural

Physiological


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Structural Adaptations are anatomical developments that allow a species to survive in its

environment. Examples:

Giraffes neck

Kangaroos pouch,hind legs

Porcupines spines

Chameleons ability to change colour

Behavioural Adaptations are actions that organisms have learnt to do in order to increase its chance

of survival. Examples:

Form groups, packs, herds to avoid attacks from predators

Some have learnt to use tools like humans, chimpanzees

Some are active only during certain times of the days, for example many desert dwelling

animals are active at night to avoid the heat

Some animals use intimidation to avoid predators

Physiological Adaptations are internal functions that have developed in order to increase chance of

survival. Examples:

Some orchids release the scent of a female bee to become pollinated

Echidnas have sticky saliva to trap ants

However, some feature of organisms may be leftover adaptations from ancestors that lived in

different environments and may be useless in their current environment. An example of this is the

appendix in humans which the reason for is still unknown.

More Natural Selection

Natural selection can also be caused within species due to variations. As not all individuals in a

species are the same, some may naturally be more suited to certain conditions. For example, some

individuals within a species may tolerate the cold better and over several generations, the change

will be notices as the offspring of these

individuals will survive more while the

other offspring may not reach breedingage. As natural selection becomes

noticeable over several generations, it is

easier to observe certain organisms like

bacteria or insects. The picture to the left

can help in understanding the process of

natural selection. Which moth would

survive in each environment?


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Convergent evolutionis when organisms that begin from different

organisms evolve into similar ones. This can occur due to:

Living in similar environments

Having similar habitats and lifestyles

Natural selection has to do with this form of evolution. This is

because those adaptations which resulted in similarities have been selected for. These organisms

have analogous structures (structures that look similar but which have come from different

ancestors).

The final form of evolution isparallel evolution. This occurs where related species evolve similar

features while separated from each other. The result is organisms that look alike and have common

ancestry but are found in different location.

Evidence for Evolution

The main evidence for evolution comes frompalaeontology(the study of fossils). The fossil record

allows palaeontologists to study over 3500 million years of fossil evidence and developments of life.

Fossils are preserved evidence of past life which is used to examine evolution. It is thought that life

began around 3500 million years ago by single-cell anaerobic organisms that slowly evolved into

photosynthesizing bacteria and algae which release oxygen creating an atmosphere. This created

some form of safety against harsh radiation for newer forms of organisms to develop.

Comparisons of theAnatomyalso provide evidence of

evolution in various organisms. Homologous structuresare

fundamentally similar structures where the differences

reflect adaptations to different environmental conditions.


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Comparisons of organism embryos show many similarities as well, further proving evolution to be a

correct theory. The embryos and there developmenthave been significantly linked to the process of

evolution.

Human Evolution

Humans belong to the order of the primates and are most closely related to chimpanzees. The most

recent group of primates to evolve are known as the Hominoids. These include lesser apes

(Gibbons), great apes (Gorillas, Chimpanzees and Orang-utans) and humans. The oldest fossils of a

Homo sapiento be discovered are in Ethiopia

and dates back to about 195,000 years ago.

The oldest organism that is thought to be a

common ancestor for modern day appeared

approximately 25 million years. The picture tothe right are two species that are thought to be

common ancestors


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Genetics

Mendels Work

Mendel, known as the father of genetics, was the most successful in proving how characteristics are

inherited. He proved it by growing garden peas. The traits he examined were:

Seeds that were round or wrinkled

Seeds that were yellow or green

Pods that were smooth or constricted

Pods that were green or yellow

Stems that were long or short


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Al lel es

Alleles refer to the different forms of the same gene. A capital case letter refers to a dominant allele

whereas a lower case letter refers to a recessive allele. In the case of Mendels experiment, punnet

squares can be used to show how he formed his results.

Punnet squares for the green or yellow pods.

Let G represent green

Let y represent yellow (notice the change to lower case representing a reciessive

allele)

Parent 2 Parent 1 -> G y

G GG yG

y Gy yy

Above is an example of punnet squares. As you can see, there is a 3:1 (Green:Yellow)

probability ratio. The dominant gene will appear when there are paired, only when two

recessives are paired together, will it show.

GG/yyare called Homozygous as both alleles are the same

Gy/yGare called Heterozygousas the two alleles are different

The appearance produced by a genotype is called the Phenotypeof the organism. The

genotypes GG and Gy would both be green since G is a dominant allele while yy would by

yellow. Hence there are two possible phenotypes: Green (GG & Gy) or Yellow (yy)

Meiosis & Mitosis

Meiosis and mitosis are different methods of cell division.

Mitosis is the process where both halves of the chromosome split in the cells nucleus into two

identical sets in two separate nuclei. The result of mitosis is two daughter cellsthat receive

duplicates of the chromosomes in the parent cell. Each daughter cell is the exact replica of the

parent cell.


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Meiosisoccurs in the cells of the ovaries and testes (gametes). The process of meiosis is the opposite

of fertilisation as meiosis involves creating gametes with only 1 set of 23 chromosomes whereas

fertilisation is when to gametes combine to create a cell with 2 sets of chromosome (total = 46).

There are two important differences between mitosis and meiosis:

During the process of

meiosis, the

chromosomes may

undergo a

recombination

The outcome of meiosis is four genetically unique haploid cells, compared with the two

genetically identically diploid cellsproduced from mitosis

Fertilisation

Fertilisationis the fusion of two

gametes to produce new organisms.

In animals the female gamete is

known as ovumand in males is

known as sperm. The combination

leads to the development of an

embryo.

Note:

Each characteristic is generally controlled by two or more genes. Very rarely does one gene control

one characteristic. This is why so many variations exists, including height, weight, eye colour, hair

colour and so on.

Pedigrees

Pedigreesare representative of a family tree:

Circles for female

Squares for males

Shaded dark for one who

has a genetic condition

Shaded grey for one who

is a carrier with no

symptoms

Unfilled signify the

unaffected


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Adenine will always pair

with Thymine

Guanine will always pair

with Cytosine

Example:

o A - G

o G - A

o A - G

o C - T

o T - C

o A - G

o CT

Uracil takes the place of

Thymine in RNA

(Ribonucleic Acid)

DNA

Genes are built from DNA (Deoxyribonucleic Acid)that forms a helical (double helix) structure.

DNA is a molecule that is made up of smaller units called

Nucleotides(also an essential part of RNA) that are strung

together in a row. Each nucleotide has three parts:

A Phosphate molecule

A Sugar molecule

A structure called a Nucleobase (Nitrogenous Base)

o Adenine

o Thymine

o Guanine

o Cytosine

o Uracil

In the reproduction of DNA, the two strands that make the

double helix structure unwind. The strands are separated as

the leading strand and the lagging strand. DNA polymerase

replicates each of the strands to duplicate them. The leading

strand is synthesised continuously whereas the lagging strand

is synthesised discontinuously (with gaps). Synthesis comes

as a result of the DNA Polymerase which is an enzyme that

acts as a catalyst (a chemical that helps speed up chemical

reactions) for nucleobases joining the separated strands.


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mRNA

Messenger RNA is a copy of DNA and acts of a gene by having a sequence complementary to one

strand of DNA and identical to the other strand. The mRNA carries information stored in the DNA

from the nucleus to the cytoplasm where the ribosomes can make it into proteins like hair and

fingernails.

Watson and Crick

The discovery of DNA by Watson and Crick was the foundations for heredity as we know it. It

contains the patterns for constructing proteins in the body and various enzymes. The impact of the

paper in which the structure of the double helix was proposed immediately showed connections and

similarities between parent and child. The discovery was key in further research of molecular and

biochemical biology. It led to many other things like protein synthesis and other key aspects of

biology.


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Mutations

Mutations are the accidental changes in genomic sequences. These random sequences can be

defined as sudden and spontaneous changes in a cell. Mutations are caused by radiation, viruses,

transposons and mutagenic chemicals as well as errors in DNA replication.

Advantages Disadvantages

Resulted in the X-MEN

May enable the mutant organism to

withstand there environment better and

takes effect through natural selection

Can result in resistance to certain

diseases/infection, for example

resistance to HIV is becoming more

common

Can result in genetic disorders

Can result in hereditary diseases

Can result in cancer

Some inherited genetic disorders include:

Cystic Fibrosis

Sickle Cell Anemia

Tay-Sachs Disease

Phenylketonuria

Colour Blindness

Most inherited genetic disorders are recessive, which means that a person must inherit two copues

of the mutated gene to inherit a disorder. This is one reason that children of close relatives are morelikely to inherit a genetic disorder; two genetically similar adults are more likely to give a child two

copies of a defective gene. Sickle Cell Anemia is a recessive genetic disorder that is harmful when

both recessive genes are present but when only one cell is present, it can protect the possessor from

malaria.

Biotechnology

Genetically Modified Foods:

These are foods that have been produced from Genetically Modified crops and fish.

There is controversy over:

o Its safety

o Whether it should be labelled

o Whether it can help address world hunger

o Environmental effects

Transgenic Species:

These are organisms whose genes are altered through genetic engineering techniques

Organisms that have been genetically modified include:

o Bacteriao Yeast


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o Plants

o Fish

o Mammals

There is controversy over:

o Whether it is ethical

o Whether food produced from them is safe

o Whether medical practices (using insulin, vaccines, growth hormones, haemoglobin

produced by the GMOs) are safe

o Can create unwanted mutations resulting in uncontrollable circumstance like weed

growth.

o May accidently be release and end up competing with natural life

DNA Fingerprinting

Is used to identify people and typically used in forensics and parental testing

Some issues:

o Doesnt give a 100% match as there are some consistencies with peoples DNAs,

particularly in regards to families. Unlike fingerprints, it is not absolutely unique to

each individual.

o Not very accurate and prone to errors

Artificial Selection

This in contrast to Natural Selection where certain traits are bred intentionally.

Has resulted in superior agriculture

Mainly in domesticated animals, like dogs and racehorses Some issues:

o Has resulted in the negligence towards naturally selected breeds and their downfall

o Has resulted in a range of health issues like decreased life span

Cloning

Is the process of artificially producing genetically identical organisms from DNA fragments

Some issues:

o Very low success rate

o Problems can occur during the processo Cloning of embryos have been successful but none have yet been implanted into a

womans uterus. Possibility of health issues from these embryos.

o Can create psychological problems for the clone

Genetic Engineering

Is the direct manipulation of an organisms genome using biotechnology

Some concerns:

o Ethical, ecological and environmental issues

o Health risks

o Long-term environmental effects possible


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o Can be used to end world hunger

o Prevent and treat diseases

Human Genome Project

Is an international scientific research project in regards to DNA Aims:

o Identify all the approximately 2000025000 genes in human DNA

o Determine the sequences of the 3 billion chemical base pairs that make up human

DNA

o Store this information in databases

o Improve tools for data analysis

o Transfer related technologies to the private sector

o Address the ethical, legal, and social issues that may arise from the project

It can significantly improve the treatment and prevention of many human and genetic

conditions

Electricity

Currents

The flow of electricity through a conductor or conductive medium is known as an electric current.

Currents move through wires freely, losing very little

energy. This is similar to water travelling through a

pipe.


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Flow of Electricity vs. Flow o f Water

There are three important values used to measure circuits:

Currentis defined as the rate of flow of the moving charges/electrons. The unit for a

current isAmperes (I)which is measure by an ammeter

Voltageis the measure of how much energy (measured in volts):

Is available from the battery or

power pack to push current

through the circuit

Is used when current passes

through a load

Resistanceis the measure of how much a load

(e.g.) globe, motor, resistor) restricts and reducesthe flow of current. Resistance is measured in

Ohms (). In formulas, it is known as R.

The flow of water follows a very similar process. There is a

pump which drives the water around (current). The water

flows at a certain rate (voltage). The water wheel slows

down the force (resistor).

Resistance

Resistance occurs when a load

restricts the flow of current and

reduces the voltage. The load

changes the electrical energy

into other forms such as kinetic

or light.

Variables in resistance:

The length of the wire a current

travels across has a direct

relationship with amount of

resistance encountered by the

charge. After all, if resistance occurs as the result of collisions between charge carriers and the

atoms of the wire, then there is likely to be more collisions in a longer wire. More collisions mean

more resistance.


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The widthof the wire also affects the amount of resistance. Wider wires have a greater cross-

sectional area. Looking back at the water analogy, more water can travel through a wider pipe

resulting in a higher rate of flow (voltage). Same occurs with electricity. The wider the wire, the

more freely electricity can move around without losing voltage. The light globe works in this way;

the light struggles to pass through the extremely thin wires present inside a globe losing some of its

energy. This energy is turned into light and heat energy.

Ohms Law

Ohms Law describes the relationship between the current, voltage and resistance in a circuit.

Current is directly proportional to Voltage

Voltage = Current Resistance

o V = IR


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A magnetic field is created around

electrical currents

o Known as Electromagnetism

Series and Parallel Circuits

A series circuitoperates in a line

where the current is not split (as

shown on the right). In the image,

there are two globes in the same

circuit. This means that the globe will

glow dimmer than if there was only

one globe. If any one of the globes

fails to work, the other one will stop

working as well as the circuit breaks

Aparallel circuitis when youarrange the globes/load next to

each other yet not on the same

branch (as shown on the right). In

this type of circuit, the voltage is

split equally along all the branches

and if one of the loads fails to work,

the other one still works as the

circuit hasnt fully broken.

Electromagnetism


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AC and DC

The difference in these is in the way the electrons/charges act:

In Direct Current (DC)the electrons flow in one direction only (like water in a hose).

InAlternating Current (AC)the electrons shuttle back and forth along the wire (imaginewater flow constantly changing directions). This occurs as the voltage is constantly changing

from positive to negative to positive and so on. This is done through changes in the magnetic

field by putting rotating magnet along the wire. This form of current is generally used over

DC as it is safer, travels further distances and gives more power.

Electromagnets in Television

Electromagnets in televisions are responsible for creating the image. They control which pixel is

illuminated and what colour it is.

Electromagnetic Spectrum

LOOK AT ASSIGNMENT!!

Ecosystems and Resources

Food Chains, Webs and Pyramids

Afood chainis linear sequence of species showing feeding patterns of an ecosystem

Afood webis a more complex for of a food chain as it is a web of many chains

There are three types offood pyramids:

o Pyramid of Numbersthis pyramid graphically presents the population of each level

of a food chain

o

Pyramid of Biomassshows the relationship between biomass and trophic level byquantifying the weight of the total number of organisms (grams per meter squared)

present in an ecological community

o Pyramid of Energythis pyramid is similar to the pyramid of biomass but rather

than graphing a snapshot in time, it measures the turnover of biomass over a period

of time

Ecosystems

Definition:

- An ecosystemis a community of living organisms and how they systematically interact withtheir non-living counterparts (i.e. their environmentsoil, air, water, etc.)


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Ab iotic vs . Bio ti c

Bioticmeans of or related to life, (prefix 'Bio' literally meaning life). Plants, animals, fungi,

protists and bacteria are all biotic or living factors and other stuff like competition, disease,

and overpopulation are all biotic factors.

Abioticare nonliving factors that affect living organisms. Environmental factors such as

habitat (pond, lake, ocean, desert, mountain, etc.) or weather (temperature, cloud cover,

rain, snow, hurricanes, etc.) are abiotic factors.

o Abiotic factors can be measured by many things like thermometers, barometers, etc.

Water Cycle

Describes the continuous flow of water on Earth.

Carbon Cycle

This is the biochemical process by which carbon constantly moves between the biosphere,

atmosphere, geosphere and oceans.


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Nitrogen Cycle

This is the cycle by which nitrogen is converted into its many forms

Ozone Layer

Ozone (O3) is a naturally occurring gas that formed a layer approximately 2030 km above

sea level. This layer is caused by Ultraviolet lights splitting the oxygen molecules into single

atoms which then join together in triplets forming ozone. This is a critical process as itprevents radiation from reach the Earths surface as the UV light is absorbed in the process.

The thickness of the ozone is measure by Dobson Units (DU). This thickness has gradually

depleted creating a large hole over Antarctica. This whole during summer time shifts over

Australia and New Zealand.

This whole can be fixed and is expected to do so by 2045.


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To help prevent climate change from getting worse, people and governments can look for

greener alternatives for everything

The Greenhouse Effect

The greenhouse effect occurs as greenhouse gases create a barrier/atmosphere around the earth.

These gases allow heat to enter but make it harder for it to escape (kind of like light and a tinted

window). Greenhouse gases provide a blanket that if too thin can cause Earth to freeze, and if too

thick can cause the Earth to become too hot to sustain life.

Fossil Fuelsare one of the largest contributors to excessive greenhouse emissions being

released into the atmosphere. Coal and other forms of fossil fuels are commonly burned to

produce energy and in this process, they release a lot of CO2

Other gases:

o Methane (CH4)

o Nitrous Oxide (N2O)

o CFCs (chlorofluorocarbons)

Human activity and demand has significantly increased the amount of greenhouse gases

released into the atmosphere each year. Demand for fossil fuels, land (deforestation), and

excessive use of cheap non-renewable resources have resulted in shitloads of greenhouse

gases accumulating in the atmosphere (about 13 billion tonnes each year).

By the end of this century, the average surface temperature is expected to go up by 1oC

4oC

Estimated increase in sea level0.5m

Many island nations will disappear

The more greenhouse emissions released into the atmosphere, the more volatile the

weather will become with changing temperatures, more storms and cyclones, etc.

Different pollutants come from different sources, for example CFCs come from aerosols,Methane comes from cow farts, nitrous oxide comes from car exhausts and so on.


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Bioaccumulation

Bioaccumulationis the process of toxins building up in an organisms body over time

o It occurs either when these toxins/pollutants are absorbed at a faster rate than at

which it is being lost or when a toxin cannot be metabolized

Causes of bioaccumulation:

o Human Activities

Pesticide and Herbicide use

Deforestation

Air Pollution (Emissions released by cars and factories,)

This can result in acid rain that can also cause bioaccumulation

o Natural pollutantsMercury is an example that affects many organism as it builds

up over time and can cause many health issues

Effects of bioaccumulation:

o

Can affect populationo Can threaten biodiversity in ecosystems

o Example: DDT is a chemical that causes bird egg shells to become thinner

o Chemicals/Toxins/Pollutants can effect more than one ecosystem (known as

Grasshopper Effect) as they can be moved to different ecosystems via wind, the

water cycle, etc.

Resource

A biological resource is a substance or object required by an organism for normal growth,maintenance, and reproduction. Resources can be consumed by one organism and, as a

result, become unavailable to another organism. For plants key resources are sunshine,

nutrients, water, and place to grow. For animals key resources are food, water, and territory.

Excessive use of these resources can make them unavailable for other species. It is

important to ensure moderation when using biological resources as many of them are also

non-renewable.

There are two types of resources:

o Renewable

This type is one that can be replenished or reproduced at a sustainable and

efficient rate (e.g. timber). The use of these must be managed in order to

ensure that they do not go beyond the natural worlds capacity to replenish

them

o Non-renewable

These are resources that cannot be replenished, grown, generated or be

used on a scale which can sustain its consumption rate (e.g. coal, oil, natural

gas). Once these resources are depleted, there is no more available in the

future.

To sustain and prolong the availability of non-renewable resources, measures should be put

in place to reduce usage to the bare minimum or a sustainable amount. Use of renewableresources is also very beneficial for the sustainability of non-renewable resources


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year 10 science notes

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