How do you think the Universe is put together?

In this class, we’ll look at the universe from a scientific POV

Biology is the Study of Life

• How do we know something is alive?

• Scientists have defined it this way:

Common features of all organisms: (characteristics of life)1. Cells: All living things are composed of cells. No life exists if it is not a cell. Basic

structural and functional unit of life. Genetic information is contained in DNA which is housed within the nucleus or cytoplasm of a cell.

2. Living things have a different molecular composition than nonliving things. However, there are many nonliving things which have similar elements as living things. The arrangements of the elements is particular to living things.

3. Living things maintain homeostasis. This is the most important element of biology and is the core of this class as we study humans. Homeostasis means maintaining a living environment for the cells to survive in. Ex: If you sat out in the cold in a bathing suit for 3 days, your body would not be able to adjust to this temperature for that long and you would die. Cells need special conditions in which to survive including: a temperature range, a pH range (acid/base balance), a water level, fuel (food) etc.

4. Growth and Development:• Growth: Occurs by an increase in cell size, cell number, or both.• Development: Changes that take place during an organism’s life.

5. Energy use and metabolism:

• All organisms must take in and transform energy to do work, to live.

• Metabolism: All chemical reactions and energy transformations essential for growth, maintenance, and reproduction.

• 6. Living things respond to their external environment. The only way that your body knows how to adjust itself using homeostatic methods is to know what the external environment is like. Your nervous system tells your brain what is going on outside (and inside) and your brain sends messages to systems to accommodate changes. (homeostasis)

• 7. Evolution. Populations change over many generations in a process known as evolution. Evolution explains why there are so many different forms of life on earth today. Ex: Wolves are the animal from which all dogs evolved. (many through human intervention)

Diversity of Life

• Scientists have over time made many different classification systems. There is controversy (or conversation) about how living things should be classified.

• For now, we are agreed upon three huge categories:• Bacteria, Archaea and Eukarya• Within those three Domains are 6 Kingdoms, 4

eukaryotic: Planta, Fungi, Animalia and Protists• And 2 Prokaryotic: eubacteria and archaebacteria

(which live in extreme environments)

Evolution

• This is biology’s unifying theme.• Theoretically, all life was derived from one initial

cell and over billions of years we now have millions of different species of organisms

Levels of Organization

Monera (includes Eubacteria and Archeobacteria)Individuals are single-celled, may or may not move, have a cell wall, have no chloroplasts or other organelles, and have no nucleus. Monera are usually very tiny, although one type, namely the blue-green bacteria, look like algae. They are filamentous and quite long, green, but have no visible structure inside the cells. No visible feeding mechanism. They

absorb nutrients through the cell wall or produce their own by photosynthesis.Protista

Protists are single-celled and usually move by cilia, flagella, or by amoeboid mechanisms. There is usually no cell wall, although some forms may have a cell wall. They have organelles including a nucleus and may have chloroplasts, so some

will be green and others won't be. They are small, although many are big enough to be recognized in a dissecting microscope or even with a magnifying glass. Nutrients are acquired by photosynthesis, ingestion of other organisms, or

both.Fungi

Fungi are multicellular,with a cell wall, organelles including a nucleus, but no chloroplasts. They have no mechanisms for locomotion. Fungi range in size from microscopic to very large ( such as mushrooms). Nutrients are acquired by

absorption. For the most part, fungi acquire nutrients from decaying material.Plantae

Plants are multicellular and most don't move, although gametes of some plants move using cilia or flagella. Organelles including nucleus, chloroplasts are present, and cell walls are present. Nutrients are acquired by photosynthesis (they all

require sunlight).Animalia

Animals are multicellular, and move with the aid of cilia, flagella, or muscular organs based on contractile proteins. They have organelles including a nucleus, but no chloroplasts or cell walls. Animals acquire nutrients by ingestion.

MONERA

I PROMISE THAT YOU WILL NEED TO KNOW THE 3 DOMAIN NAMES ON THE EXAM!

The Five Kingdoms of life are Bacteria, Archaea, Eucaryota, plants and animals

Let’s begin with the smallest unit of matter

• The Atom – the smallest unit of cohesive matter

Chemistry

• All of this information is critically important and you need to know all of it.

A. Matter1. Matter takes up space and has mass. That’s what we’re taught, right? Is this really true? Consider the FACT that 99.99999999% of atoms are empty space! What? Think about it.2. All living and nonliving matter is composed of 92 naturally-occurring basic elements (Periodic Table)3. Elements cannot be broken down to substances with different chemical or physical properties.4. Six elements (C, H, N, O, P, S) make up 98% of living things.

B. Atomic Structure

1. Chemical and physical properties of atoms (e.g., mass) depend on the subatomic particles. (electrons, protons and neutrons)a. Different types of atoms, such as hydrogen cesium etc. contain specific numbers of protons, neutrons, and electrons. b. Protons and neutrons are in nucleus of atoms; electrons move around nucleus.c. Protons are positively charged particles; neutrons have no charge; both have about 1 atomic mass unit of weight.d. Electrons are negatively charged particles.

https://www.youtube.com/watch?v=lP57gEWcisY

2. The atomic mass (weight) of an atom is about equal to the sum of its protons and neutrons.3. All atoms of an element have the same number of protons, the atom's atomic number.

Number of protons plus number of neutrons (average)

Pick your favorite element from the table.  Turn and tell your lab partner what it is, how many protons, electrons and neutrons it has, and what it's atomic weight is.

C. Isotopes

1. Isotopes are atoms with the same number of protons but differ in number of neutrons; e.g., a carbon atom has six protons but may have more or less than the usual six neutrons.

Carbon 14  - Break it Down!

Carbon- 12 is the most common form of carbon, it has 6 protons, 6 electrons, and 6 neutrons It is called Carbon 12 because that is its weight  (6 + 6 )Carbon 14 has 2 extra neutrons, its weight is 14  (6 + 8 ); it is an isotope of carbon

2. A carbon with eight rather than six neutrons is unstable; it releases rays and subatomic particles and is a radioactive isotope.

Sample Question:A 200 g sample of muskopfonian is left in a container from 8:00 AM one morning until 8:00 AM the next day. If the final mass of the sample  was 50 g, what is the half-life of muskopfonian??

Answer:

200 x .5 = 100100 x .5 = 50

It halved twice in 24 hours, the half life is the 12 hours.

3. Low levels of radiation such as radioactive iodine or glucose allow researchers to trace the location and activity of   the atom in living tissues; therefore these isotopes are called tracers (used in CAT scans)

4. High levels of radiation can cause cancerous tissues and destroy cells; careful use of radiation in turn can sterilize products and kill cancer cells.

Elements

• A particular type of atom distinguished from another type by the number of protons in the nucleus

E. Electrons and Energy

1. Electrons occupy an orbital at some level near or distant from the nucleus of the atom.2. An orbital is a volume of space where an electron is most likely to be found; the first orbital contains no more than two electrons.3. The more distant the orbital, the more energy it takes to stay in the orbital.

*When atoms absorb energy during photosynthesis, electrons are boosted to higher energy levels*.The innermost shell of an atom is complete with two electrons; all other shells are complete with eight electrons.The octet rule: The outer shell is called the “Valence” shell and it’s electrons are called Valence electrons. All atoms attempt to complete their valence shell so that it contains 8 electrons. This “pull” is what causes chemistry to happen.

How to draw an atom

• First draw a circle to represent the nucleus

• Then, put + for each proton and a tiny 0 for neutrons

• Then draw rings for the electrons

++oo

Lewis and Bohr Diagrams

• Follow simple rules:• Take the number of protons for the atom you

wish to represent, say 5• In the first orbit, place 2 dots to represent the

first two electrons• In the next orbit, place the remaining electrons

up to 8 maximum• There, that simple!

DRAW IT!     QUICK!!1. Draw six protons in the nucleus of the atom. 2. Draw six neutrons in the nucleus of the atom.3. Draw two electrons in the first energy level and label them with their charge.4. Draw four electrons in the second energy level and label them with their charge.5. What element is it!? __________  (the future of the human race depends on it!)

• The outer ring, energy level or orbit is called the valence level and their electrons are called valence electrons

• There are many ways to represent atoms and molecules. Two of the most common are Lewis structures and Bohr diagrams

Quick Check

• At this point make sure that you understand atoms, protons, neutrons and electons

• You understand the arrangement of electrons in energy levels

• You understand the Valence level and how to draw diagrams of atoms

2.2 Elements and Compounds

A. Compounds

1. When two or more different elements react or bond together, they form a compound (e.g., H2O).

2. A molecule is the smallest part of a compound that has the properties of the compound.

3. Electrons possess energy and bonds that exist between atoms in molecules contain energy.

B. Ionic Bonding

1. Ionic bonds form when electrons are transferred from one atom to another.2. Losing or gaining electrons, atoms participating in ionic reactions fill outer shells, and are more stable.3. Example: sodium with one less electron has positive charge; chlorine has extra electron that has negative charge. Such charged particles are called ions.4. Attraction of oppositely charged ions holds the two atoms together in an ionic bond.

C. Covalent Bonding

1. Covalent bonds result when two atoms share electrons so each atom has octet of electrons in the outer shell.2. Hydrogen can give up an electron to become a hydrogen ion (H+) or share an electron to complete its outer shell of two electrons.3. Structural formulas represent shared atom as a line between two atoms; e.g., single covalent bond (H-H), double covalent bond (O=O)

Carbon has amazing bonding properties, as we will learn in the next chapter on BIOCHEMISTRY

D. Nonpolar and Polar Covalent Bonds

1. In nonpolar covalent bonds, sharing of electrons is equal.2. With polar covalent bonds, the sharing of electrons is unequal.a. In water molecule (H2O), sharing of electrons by oxygen and hydrogen is not equal; the oxygen atom with more protons dominates the H2O association.

              *The oxygen then assumes a small negative charge *

E. Hydrogen Bonding

1. A hydrogen bond is weak attractive force between slightly positive hydrogen atom of one molecule and slightly negative atom in another or the same molecule.2. Many hydrogen bonds taken together are relatively strong.3. Hydrogen bonds between complex molecules of cells help maintain structure and function.

Hydrogen bonds create surface tension.

2.3. Chemistry of Water

A. First Cells Evolved in Water

1. All living things are 70.90% water.2. Because water is a polar molecule, water molecules are hydrogen bonded to each other.3. With hydrogen bonding, water is liquid between 0 C and 100 C which is critical for life.

B. Properties of Water

1. The temperature of liquid water rises and falls more slowly than that of most other liquids..

a. Calorie is amount of heat energy required to raise temperature of one gram of water 1o C.b. Because water holds more heat, its temperature falls more slowly than other liquids; this protectsorganisms from rapid temperature changes and helps them maintain normal temperatures.

2. Water has a high heat of vaporization.

a. Hydrogen bonds between water molecules require a large amount of heat to break.b. This property moderates earth 's surface temperature; permits living �systems to exist here.c. When animals sweat, evaporation of the sweat takes away body heat, thus cooling the animal.

3. Water is universal solvent, facilitates chemical reactions both outside of and within living systems..

a. Water is a universal solvent because it dissolves a great number of solutes.b. Ionized or polar molecules attracted to water are hydrophilic.c. Nonionized and nonpolar molecules that cannot attract water are hydrophobic.

Solvents dissolve other substances (solutes) and do not lose their own properties.

If we use a simple and easy example, we can get a handle on the idea. Take a glass of warm water, put a teaspoon of table salt in it, and stir it. The salt will dissolve in the water and "disappear" from view. The water is the solvent here, the salt is the solute in this example, and the resulting salt water is a solution that we created. It's that simple.

C. Acids and Bases

1. Covalently bonded water molecules ionize; the atoms dissociate into ions.2. When water ionizes or dissociates, it releases a small (107 moles/liter) but equal number of H+ and OHions; thus, its pH is neutral.3. Water dissociates into hydrogen and hydroxide ions: 

4. Acid molecules dissociate in water, releasing hydrogen ions (H+) ions: HCl ¨ �H+ + Cl-.

5. Bases are molecules that take up hydrogen ions or release hydroxide ions. NaOH ¨ Na+ + OH-.�

See also:  Acid & Base Coloring

6. The pH scale indicates acidity and basicity (alkalinity) of a solution.

1) One mole of water has 107 moles/liter of hydrogen ions; therefore, has neutral pH of 7.2) Acid is a substance with pH less than 7; base is a substance with pH greater than 7.3) As logarithmic scale, each lower unit has 10 times the amount of hydrogen ions as next higher pH unit;

* Buffers keep pH steady and within normal limits in living organisms..

This art is technically incorrect as the electrons are actually much farther away from the nucleus than shown

The space-filling model does NOT show the double bond!

Using the pH scale shown, how does household bleach compare to household ammonia?