Biology Exam 2

Exam 2 study guide- Being on this study guide does not guarantee that topic will be on the exam.

1)    Explain the structure of the fluid mosaic model; what is it used to show, and what is included

Structure of plasma membrane; made out of phospholipid bilayer embedded with diverse proteins.

2)    Define the following term-

            Diffusion- Passive transport; down a concentration gradient, spreading out of particles on either side of a semi-permeable membrane until equilibrium is reached

            Osmosis- Diffusion of water, all the same as diffusion

            Active Transport- moving against concentration gradient; requires energy (ATP)

            Passive Transport- moving down a concentration gradient; does not require energy (ATP)

            Facilitated Diffusion- passive transport of polar or charged molecules using transport proteins.

            Endocytosis- similar to into; transport of large molecules INTO the cell, photocytosis and receptor mediated endocytosis; plasma membrane engulfs and pinches off to bring into cell via a vacuole/vesicle

            Exocytosis- similar to exit; transport of large molecules OUT of the cell

            Exergonic- releases energy; potential energy of the reactants is larger than the potential energy of the products

            Endergonic- requires input of energy; the potential energy of the products is larger than the potential energy of the reactants.

            Phosphorylation- the addition of a phosphate group to compound (ADP and ATP)

3)    Compare the tonicity terms; isotonic, hypertonic, hypotonic and what happens to both animal and plants cells in each

Hypotonic – lower solute level; water into cells; NET WATER GAIN; animal cell lyse, plant cells are normal

Isotonic – equal solute levels; water goes in and out of the cell; NO NET WATER GAIN OR LOSS; animal cells are normal, plant cells are flaccid

Hypertonic – higher solute levels; water leaves cell; NET WATER LOSS; animal cells and plant cells are both shriveled.

4)    What are the functions of enzymes?

Speed up chemical reactions

Lower activation energy

Fit specific substrates

Do NOT get used up in chemical reactions

5)    Compare where competitive and noncompetitive enzyme inhibitors bind to the enzyme and what it does to the active site for the substrate.

Competitive – block the active site so the substrate cannot bind to the active site

Noncompetitive – bind elsewhere on enzyme (NOT active site), active site changes shape, substrates cannot fit active site.

6)    Define the following term and/or identify their importance to cellular respiration or photosynthesis:

Carbon Fixation- first step of Calvin cycle, takes carbon from carbon dioxide binds to RuBP (facilitated by RuBIsCO)

Calvin Cycle- light independent reactions of photosynthesis; four steps – carbon fixation, reduction, release of G3P, regeneration of RuBP; uses ATP and NADPH from light reactions and uses carbon dioxide, production of glucose

ATP synthase- enzyme that catalyzes the phosphorylation of ADP to ATP, in both photosynthesis and cell respiration

Oxygen- final electron acceptor of oxidative phosphorylation (aerobic cellular respiration)

Water- split during light reactions of photosynthesis; producing electrons needed by photosystem 2

Electron Transport Chain- in BOTH photosynthesis and cellular respiration; series of REDOX reactions that produces H+ gradient that drives the phosphorylation of ADP to ATP

Carbon Dioxide- needed for carbon fixation step of CALVIN CYCLE; product of cell respiration

Photosynthesis- production of glucose; light reactions and Calvin cycle; light energy plus carbon dioxide plus water to produce glucose and oxygen; conversion of light energy to chemical energy

Glycolysis- first part of cellular respiration; occurs in cytosol, does NOT require oxygen; breaks down glucose into 2 pyruvates

Photosystem I- light reactions of photosynthesis; receives electrons from ETC; requires photon of light (photoexcited electrons); reduce NADP+ to NADPH

Photosystem II- light reactions of photosynthesis; receives electrons from splitting of water; requires photon of light (photoexcited electrons); sends electrons to ETC

NADP+ - final electron acceptor from photosystem I (light reactions of photosynthesis / photorespiration)

Redox Reaction- reaction where electrons are transferred – something gets reduced or gains electrons, and anther gets oxidized or loses electrons (LEO says GER) or (OIL RIG)

7)    Identify the steps of the Calvin Cycle in the order they occur and what the end products are

1.    Carbon fixation

2.    Reduction

3.    Release of one molecule of G3P

4.    Regeneration of RuBP

Products = Glucose, NADP+, and ADP

8)    Identify the main stages of Cellular Respiration, where those steps occur, the products of each step.

Stage 1: Glycolysis; cytosol; does NOT require oxygen; takes glucose and breaks down into 2 pyruvates; 2NADH; net 2ATP

In MITOCHONDRIA

Stage 2: pyruvate oxidation and citric acid cycle

Pyruvate oxidation produces: CO2, 2 NADH, 2 Acetyl CoA

Citric acid cycle produces: 6 NADH and 2 FADH2 (from 2 acetyl CoA) and net 2 ATP

Stage 3: oxidative phosphorylation (ETC and chemiosmosis); produces about 28 ATP

1 glucose molecule going through cell respiration gives us about 32 ATP total

**3 NADH and 1 FADH2 if only ONE acetyl CoA

9)    Compare the overall type of reaction, end products, and primary function of Cellular Respiration and Photosynthesis

Photosynthesis – endergonic; end products are O2 and Glucose (C6H12O6); converts light energy to chemical energy

Cell (aerobic) respiration – exergonic; end products heat, CO2, and water; produce ATP for cell functions

10)  Identify the 2 main stages of Photosynthesis, the individual processes of each, where those steps occur, the products of each step.

Light reactions – thylakoids (chloroplasts)

a)    Photosystem 2; gets electrons from water; photon of light; sends its photoexcited electrons to ETC

b)    Electron transport chain; gets electrons from photosystem 2; series of redox reaction to produce H+ gradient (ATP synthase to phosphorylate ADP to ATP)

c)    Photosystem 1; gets electrons from ETC (electron transport chain); photon of light; send its photoexcited electrons to reduce NADP+ to NADPH

Products: NADPH and ATP (go to Calvin cycle); O2

Photosystems function is to produce photoexcited electrons

            Calvin Cycle – stroma (thick fluid) of chloroplasts

(1)  Carbon fixation

(2)  Reduction

(3)  Release of G3P

(4)  Regeneration of RuBP

Products: Glucose, NADP+, ADP

11)  Identify the chemical equation for photosynthesis; what type of energy reaction it is; specify what is happening to Carbon chemically; color coordinate where the product oxygen originates from in the reactants, and where the carbon in glucose comes from (this is also where the majority of the organic mass comes from)

Light + 6CO2 + 6H2O              C6H12O6 + 6O2

Endergonic

Carbon is reduced

Organic mass from atmosphere

12)  Identify the chemical equation for Cellular Respiration; what type of energy reaction it is; specify what is happening to Carbon chemically.

C6H12O6 + 6O2             6CO2 + 6H2O + heat

Exergonic

Carbon is oxidized