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APBiology

Critical Concepts

The CarbohydratesEnergy

Structure

The Lipids

Fatty Acids

Phospholipids

Steroids

Proteins

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Protein Structure Proteins

Because their shape is held together by weak hydrogen bonds, proteins are easily denatured by heat, acids/bases or shaking.

Enzymes

Active Site

If it happens in a cell, an enzyme does it!

S1 + S2 New Material + EnzymeE

Enzyme Substrate Complex

Membranes are Great Examples of Form and Function

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Transport Occurs Through Membranes

Active=Energy=ATP 3 Na out:2 K in; Outside is more + than before

ATP Stores Energy and Phosphate

Nucleic Acid Structure is Similar to ATP

DNA Nucleotide

DNA and RNARNA usually 1 strand

DNA usually a double helix

DNA in nucleus

RNA in both nucleus and cytoplasm

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DNA and RNA DNA

"It has not escaped our attention that the specific pairing we have postulated immediately suggests a possible copying mechanism for the

genetic material."

Telomeres: Is old age necessary?Each time the RNA primer is used on a new chain ready to be replicated it is ‘deleted’ and

replaced by the corresponding DNA sequence. However, the point of the primer is to give the DNA polymerase a place to start at because it can’t start a chain and it can only add to a chain on

its 3’ side. So what happens when the primer is removed at the start of the chain on the 5’ end? The polymerase can’t get to where it needs to go to add that section back on. Thus, in multi-cellular organisms’ replication, each daughter strand gets shorter and shorter as more replications occur (single-celled organisms have circular shaped DNA to solve this problem). What is the significance of this fact? Well, it has been shown that DNA is shorter in cells that come from older

people and in cells that have divided many times. Perhaps you can see the correlation now: it is possible that the DNA erosion in cells that comes about from regular replication may cause old age.

However, nature has also provided a solution to the problem of aging in the germ cell lines and in gametes, the cells in humans used to produce offspring. Both these types of cells, given

everything they need, are believed to live forever. All eukaryotic cells have telomeres at the ends of their DNA strands. Instead of eroding the genetic material, replication erodes these repetitions of a nucleotide sequence, typically TTAGGG in humans. In germ cell lines and

gametes, the enzyme telomerase speeds up the lengthening of the telomeres which quickly regain their original length from before replication. Telemorase isn’t in the body’s somatic cells, or

regular body cells, only in gametes and germ cell lines. Interestingly, scientists have also found telomorase in somatic cancerous cells, which may explain their incredible lifespan. The implications of such biotechnological research are apparent: not only could telomere mapping find

a cure for cancer, it could solve the problem of aging altogether.

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Cell Processes

Important Processes to Know• Transport (Passive

and Active)• Mitosis• Meiosis• Photosynthesis• Respiration• DNA Replication• Protein Synthesis

(Transcription & Translation

Transport of Materials

•Passive Transport: NO ATP

Diffusion

Osmosis

•Active Transport: ATP

Pumps

Motor Proteins

Motor proteins “walking” along actin, carrying a vesicle inside the cell

Organelles Responsible:

Membrane (ports and channels as well as direct)

Smooth Endoplasmic Reticulum

Golgi Body

Cell Organelles Responsible

Contractile vacuole

In Paramecium

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Mitosis

• For growth and repair• Two identical cells• Everywhere in animals (well almost)• Meristem in plants

Meiosis

• Produces sperm or egg (haploid cells)• One egg: 3 polar bodies• Two divisions• Independent Assortment and crossing

over very important in creating variation

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Cell cycleThe cell cycle is the cyclical process by which

a cell that has just divided grows, replicates its DNA, and then divides again. In eukaryotes, it is generally considered to have four phases:

G1 - the first gap phase, during which the cell grows to a threshold size. The cell actively takes up materials from its environment to form new organelles and cytoplasm.

S - during which the cell replicates its DNA and MTOCs (microtubule organising centres: i.e. centrioles, centrosomes, etc.)

G2 - the second gap phase, during which the cell condenses its genome and MTOCs begin to form a spindle which will later separate the chromosomes.

M - mitosis (or meiosis), during which the genome is passive, whilst the cytoskeleton actively moves the chromosomes about.

G0

Photosynthesis

• Transforms sunlight to ATP and ATP and CO2 to sugar

• Occurs in the chloroplasts• Uses red and blue wavelengths• C3 is the most common but C4 is a

modification for hot & dry

The Light Reactions

H2O

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H2O

O2

H+

e

Carbon Cycle

PGAL is the building block for carbon based molecules

Weak link

From Light Rx

From Light Rx

C4 Photosynthesis as an Adaptation to Heat

Rubisco is here

NO Rubisco here

Respiration

• Transforms energy stored in a carbon molecule to ATP

• Anaerobic: not efficient (2ATP), in cytoplasm, pyruvate (3C converted to C02either lactate, ethanol or acetyl co-A

• Aerobic: in mitochondria, 34 or 36 ATP, requires oxygen as an acceptor of H+ and e-

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Cell Respiration in Eukaryotes Occurs in the Mitochondria and in Three Stages

2 2

32 or 34

Krebs in the matrix; ETS in the membrane

Focus on the CO2 and NADH and FADH

Nucleus to Nucleotide

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DNA Makes RNA

Ribosome large and small units

mRNA

tRNA

Amino acids

DNA makes RNA (transcription); RNA makes protein (translation)

Functional Units

• Review the following information.• Use the CD from your text. Its animations

will help a lot.

Atom is the unit for matter. Know its structure

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Functional Unit of Life. Know: A) Prokaryote vs Eukaryote B) Plant vs Animal C) Function of these parts

Nephron is the functional unit of kidney. It filters nitrogen wastes, balances blood chemistry (homeostasis), and retain water. Know: A) the function of the Glomerulus, Bowman’s Capsule, nephron, collecting duct B) the adaptations of excretion of fish, birds, reptiles, mammals.

Neuron is the functional unit of the nervous system. Know: Dendrite, axon, myelin, synapse, neurotransmitters. Discuss how the sodium-potassium pump causes the electrical message. Discuss the neurotransmission in the synapse.

Evolution of the brain: toward the head (cephalization) and toward specialization. (Cerebellum is smaller compared to cerebrum as animal becomes more complex)

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Functional unit of the muscle, the sarcomere shortens during contraction. Know: Actin and myosin as the two proteins. Know that calcium and ATP are critical in their action.

Know the blood flow: Right side to lungs to left side. Pressure high in arteries, low in veins. Capillaries connect the two and are the areas where exchange occurs. Lymphatics collect the water that has “leaked out” (osmosis) and returns it to the blood (plasma)

Heart evolution: Chambers are “added” as the atria and ventricles are divided. Maintains pressure and prevents mixing.

The Leaf is a nearly perfect example of “Form and Function”

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The flower represents an important evolutionary advancement because it enlists the assistance of others in making its reproduction successful Ecosystems are functional

units of nature. Biodiversity is a keypoint in the ecosystem. The gene pool exists at the level of the population. Variation in the gene pool can be calculated using Hardy-Weinberg

Evolution and Population Genetics

Key Points

•Individuals don’t evolve, populations do.

•Adaptations are genetic, not aquired

• There’s a difference between genetic drift and speciation

• Speciation requires reproductive isolation

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As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form. Darwin, Introduction to “On the Origin…..

Darwin’s Theory

Overpopulation

VariationStruggle to Survive

Survival of Fittest

Increase in that gene in the gene pool

Allopatric Speciation

Sympatric Speciation

Barriers may be:

BehavioralTemporal

Geographical

Physiological

Types of Speciation

Natural Selection

Mutation

Factors that influence variation in the population Macroevolution

Three Domains

Classes of Vertebrates