AP Biology Unit 3

3.1 & 3.2 Enzyme Structure and Catalyst

What are enzymes

They are catalytic proteins that speed up the rate of chemical reactions (without being consumed)

3.3 Environmental Impacts on Enzyme Function

What is denaturation?

It occurs when an enzyme’s protein structure is disrupted, eliminating it's ability to catalyze reactions

What bonds are being broken during denaturation?

Hydrogen bonds

Can denaturation ever be reversed?

Only if it is mild

What are some contributing factors to denaturation?

1) Temperature: too much heat or not enough heat

2) pH levels: too acidic or too basic levels

3) Concentration levels: too much of or too little of substrate & product

4) Inhibitors: competitive and noncompetitive

What do inhibitors do?

They alter the shape and productivity of an enzyme

3.4 Cellular Energy

All living systems need energy, and energy input must exceed energy loss for survival.

3.5 Photosynthesis

What characteristic of a leaf allows for the passage of gasses?

The stomata

Photosynthesis Equation

CO2 + H2O ——> C6H12O6 + O2

Autotrophs vs Hetertrophs

Autotrophs: produce their own food

Heterotrophs: Rely on other organisms for food

Chlorophyll

Green light reflecting, light absorbing pigment in plants

Photons

Light energy that is absorbed by pigments

Three pigments found in plants

Chlorophyll A, Chlorophyll B, and Carotenoids

Chlorophyll A

Main protein pigment found in all plants and algae

Chlorophyll B

Funnels sunlight energy to Chlorophyll A

Carotenoids

Accessory pigments that funnel sunlight energy to Chlorophyll A (red, orange, or yellow)

What is the primary purpose of photosynthesis?

To use ATP and NADPH to make sugar using CO2

Two reactions in photosynthesis

1) Light Dependent/Light Reaction

2) Light Independent/ Dark Reaction/ Calvin Cycle

Components of the thylakoid membrane

PSI, PSII, ATP Synthase

Steps of Light Reaction

1) Sunlight powers H2O to split across the thylakoid membrane

2) O diffuses, and H ions move into the cell

3) While the hydrogens move into the thylakoid lumen and form a protein gradient…

4) Electrons are dropped off and travel through PS I and II

5) To create NADPH, the electrons are released from the photosystems

6) To create ATP, the hydrogens are released through ATP synthase

*Recall that there are ADP’s floating around the thylakoid membrane that help make these*

We now have our intermediates

Steps of Calvin Cycle

1) Begins with 3 molecules of CO2

2) Enzyme rubisco changes CO2 shape

3) ATP and NADPH power the cycle and fixate CO2s into 3 carbon sugars

4) End of cycle: ATP is present, and rubisco is reset

5) Cycle occurs twice, so that 6 carbon sugars (glucose) are made

Cellular Respiration

Organisms break down glucose from carbohydrates for energy

Cellular Respiration Equation

C6H12O6 + O2 (+ATP) —> CO2 + H2O + ATP

What are the two main pathways of cellular respiration?

Aerobic and Anaerobic Respiration

3 Components of Aerobic Respiration

1) Glycolysis

2) Krebs Cycle

3) Electron Transport Chain

Explain the process of glycolysis

1) Energy from glucose is released

2) ATP (from ADP), NADH (from NAD+), and Pyruvate (from 3 oxygens)

3) Pyruvate is fixed into acetyl coA

4) Acetyl coA travels to the matrix to begin Krebs Cycle

True or False: Every single organism goes through glycolysis

True

Explain the process of the Citric Acid Cycle

OXYGEN MUST BE PRESENT

1) Acetyl coA creates ATP (from ADP), and electron carriers NADH (from NAD+) and FADH2 (from FADH)

2) At the end of the cycle, CO2 waste is formed

Describe the process of the Electron Transport Chain

1) EC’s NADH and FADH2 transfer electrons along