AP Biology: Unit 3: Cell Energy Processes

Enzymes-

Proteins that catalyze chemical reactions and speed up biochemical processes

Active Site-

The zone of the enzyme that is specially designed to fit a substrate and allows an enzyme to break down a substance

How do enzymes work?

Enzymes work to catalyze chemical reactions by lowering the amount of activation energy required for a reaction to occur. A substance, or substrate, binds to the active site of an enzyme and breaks down the substance, resulting in the release of the end products

What affects enzymes-

Denaturation, caused by

Competitive Enzymatic Inhibition-

This kind of inhibition occurs when a substrate’s active site is blocked by the inhibitor

Non Competitive Enzymatic Inhibition-

This kind of inhibition occurs when instead of directly blocking the substrate by binding to the active site, it binds to the allosteric site, causing the active site’s shape so the substrate cannot bind

Coupling-

Chemical reactions that are linked together, typically one needs energy and one is releasing energy

Ex. ATP Hydrolysis with sodium potassium pump

Metabolism-

The sum of all chemical reactions occurring in an organism

Catoblism-

Refers to chemical reactions that break down molecules; Exergonic

Anabolism-

Chemical reactions that combine monomers to create polymers; Endergonic

Exergonic-

Release energy, spontaneous

Endergonic-

Absorbs energy, non spontaneous

Photosynthesis-

The process in which plants produce glucose

Photosystem II/Photolysis-

The first step in photosynthesis in which a complex breaks down water using light and creates the hydrogen gradient necessary to power the electron support chain

Inputs- H2O, light

Outputs- Electrons that are used in the ETC and Oxygen

Electron support chain-

Photons of light strike chlorophyll in Photosystem I, generating the electrons that move through the ETC and pump protons to help create the NADPH that goes to the Calvin Cycle

Inputs- Electrons, H+, NADP

Outputs- NADPH

ATP Synthase-

The first electron support chain that pumps protons feeds into the ATP synthase to produce ATP

Inputs- ADP from NADPH

Outputs- ATP

Calvin Cycle-

The NADPH, ATP and CO2 are all fed into the Calvin Cycle, which breaks them down and synthesize these molecules and produce 3 GP

Inputs- ATP, NADPH, CO2

Outputs- 3GP (glucose building blocks)

Cellular Respiration-

The process that which provides energy to the cell through the production of ATP in the mitochondria

Glycolysis-

The process in which glucose is broken down into pyruvate through oxidization. This occurs in two stages, the energy investment stage, in which 2 ATP molecules are invested to phosphorylate the glucose and break it down into 2 G3P molecules (pyruvate), and the energy payoff stage, in which oxidization in complete and the final products are two molecules of pyruvate, 2 molecules of NADH, and 2 ATP molecules

Inputs- glucose

Outputs- 2 ATP, 2 NADH, and 2 pyruvate, and the Acetyl Group that is transported

Krebs Cycle-

Pyruvate enters the mitochondria where enzymes of the krebs cycle complete the full oxidization of sugar into O2. This produces 2 ATP, CO2, and 2 Acetyl CoA. The acetyl group is converted into citric acid, producing 2 CO2, 3 NADH, and 2 ATP.

Inputs- Acetyl CoA

Outputs- 2 CO2, 3 NADH, 2 ATP, FADH (lots of electron carriers)

Electron Transport Chain-

This step occurs in proteins built into the cristae where the electrons fed along the transport chain help create the H+ gradient that powers the chain. Oxidative phosphorylation yields 36 ATP through aerobic respiration.

Inputs- NADH, H+, ADP, FADH2, O2

Outputs- NAD+, FAD, 36 ATP, H2O

Turgid-

When the stoma is open, the cell is turgid, or filled with water

Flaccid-

When the stoma is closed, the cell is flaccid, or lacking water

C3 Plants-

These are the vast majority of plants, and use RuBP to convert carbon into 3 compound phosphoglyceric acid to create glucose within their leaves

C4 Plants-

These make up only a few species of plants. They use phosphoenolpyruvate and convert CO2 into a 4 carbon intermediate within the mesophyll cells and bundle sheath cells

CAM Plants-

These plants are species of succulents, cacti, pineapple, or agave and use phosphoenolpyruvate carboxylase and conduct photosynthesis in 4 phases tied to available sunlight in which these plants collect CO2 during the day and fix it at night as a 4 carbon intermediate inside the vacuoles of cells