Biology_Ch6-8_Flashcards

Question 1

6.1 - What is energy?

Answer 1

The ability to promote change or do work.

Question 2

6.1 - What is the difference between potential and kinetic energy?

Answer 2

Potential energy is stored energy due to structure or position, while kinetic energy is energy associated with movement.

Question 3

6.1 - What is the first law of thermodynamics?

Answer 3

Energy cannot be created or destroyed, only transformed or transferred.

Question 4

6.1 - What is the second law of thermodynamics?

Answer 4

Every energy transfer increases the entropy (disorder) of the universe.

Question 5

6.1 - How does free energy determine the direction of a chemical reaction?

Answer 5

Reactions proceed in the direction that leads to a decrease in free energy (negative ΔG).

Question 6

6.1 - What are exergonic and endergonic reactions?

Answer 6

Exergonic reactions release energy (ΔG < 0); endergonic reactions require energy input (ΔG > 0).

Question 7

6.1 - How does ATP hydrolysis drive endergonic reactions?

Answer 7

By coupling with ATP hydrolysis, the overall ΔG becomes negative, allowing the reaction to proceed.

Question 8

6.2 - How do enzymes lower activation energy?

Answer 8

By stabilizing the transition state and reducing the energy needed for the reaction.

Question 9

6.2 - What is substrate specificity and induced fit?

Answer 9

Enzymes bind specific substrates and change shape to improve binding (induced fit).

Question 10

6.2 - What is competitive inhibition?

Answer 10

Inhibitor binds to the enzyme’s active site, preventing substrate binding.

Question 11

6.2 - What is noncompetitive inhibition?

Answer 11

Inhibitor binds to a different site on the enzyme, changing its shape and reducing activity.

Question 12

6.2 - What factors influence enzyme activity?

Answer 12

Temperature, pH, cofactors, coenzymes, and inhibitors.

Question 13

6.3 - What is a metabolic pathway?

Answer 13

A series of chemical reactions catalyzed by enzymes to transform molecules.

Question 14

6.3 - Difference between catabolic and anabolic reactions?

Answer 14

Catabolic breaks down molecules for energy; anabolic builds complex molecules.

Question 15

6.3 - How do catabolic reactions help in biosynthesis and energy production?

Answer 15

They provide building blocks and energy intermediates like ATP and NADH.

Question 16

6.3 - What is a redox reaction?

Answer 16

A chemical reaction where electrons are transferred between molecules.

Question 17

6.3 - What are three types of metabolic regulation?

Answer 17

Gene regulation, cellular regulation (e.g., hormones), and biochemical regulation (e.g., feedback inhibition).

Question 18

6.4 - What are the four stages of aerobic respiration?

Answer 18

Glycolysis, pyruvate breakdown, citric acid cycle, oxidative phosphorylation.

Question 19

6.5 - What are the three phases of glycolysis?

Answer 19

Energy investment, cleavage, energy liberation.

Question 20

6.5 - What are the net products of glycolysis?

Answer 20

2 ATP, 2 NADH, 2 pyruvate.

Question 21

6.5 - What is the principle behind PET scans in tumor detection?

Answer 21

Cancer cells consume more glucose, which is traceable using radioactive glucose analogs.

Question 22

6.6 - What happens to pyruvate in the mitochondrial matrix?

Answer 22

It is oxidized to acetyl-CoA, releasing CO2 and producing NADH.

Question 23

6.7 - What is the citric acid cycle?

Answer 23

A metabolic cycle that oxidizes acetyl-CoA to CO2 and generates NADH, FADH2, and ATP.

Question 24

6.7 - What are the products of the citric acid cycle?

Answer 24

3 NADH, 1 FADH2, 1 GTP (or ATP), and 2 CO2 per acetyl-CoA.

Question 25

6.8 - How does the electron transport chain (ETC) create an H+ gradient?

Answer 25

Electrons move through ETC complexes, pumping H+ into the intermembrane space.

Question 26

6.8 - How does ATP synthase work?

Answer 26

It uses the H+ gradient to rotate and catalyze ATP formation from ADP and Pi.

Question 27

6.8 - How was ATP synthase shown to be a rotary machine?

Answer 27

Experiments attached fluorescent actin filaments and observed rotation.

Question 28

6.9 - How are carbohydrate, fat, and protein metabolism connected?

Answer 28

They feed into glycolysis and the citric acid cycle at various points.

Question 29

6.10 - What is anaerobic respiration?

Answer 29

Respiration using a final electron acceptor other than oxygen.

Question 30

6.10 - How does fermentation allow ATP synthesis without oxygen?

Answer 30

It regenerates NAD+ by reducing pyruvate to lactic acid or ethanol.

Question 31

7.1 - What is the overall photosynthesis equation?

Answer 31

CO2 + H2O + light → C6H12O6 + O2

Question 32

7.1 - How does photosynthesis power the biosphere?

Answer 32

By producing organic molecules and oxygen used by most organisms.

Question 33

7.1 - What is the structure of a chloroplast?

Answer 33

Double membrane organelle with thylakoids, stroma, and grana.

Question 34

7.1 - What are the two stages of photosynthesis?

Answer 34

Light reactions and the Calvin cycle.

Question 35

7.2 - What are pigments?

Answer 35

Molecules that absorb light; chlorophyll a, b, and carotenoids are examples.

Question 36

7.2 - What does PSII produce?

Answer 36

O2, ATP, and NADPH.

Question 37

7.2 - What is cyclic photophosphorylation?

Answer 37

An alternative light reaction path that produces ATP but not NADPH or O2.

Question 38

7.3 - How does PSII produce O2?

Answer 38

By splitting water molecules (photolysis).

Question 39

7.3 - What is the energy flow from PSII to NADP+?

Answer 39

Electron loses energy as it moves through carriers to NADP+.

Question 40

7.4 - What are the three phases of the Calvin cycle?

Answer 40

Carbon fixation, reduction, and regeneration of RuBP.

Question 41

7.4 - How does carbon in CO2 differ from carbohydrate carbon?

Answer 41

CO2 carbon is oxidized; carbohydrate carbon is reduced.

Question 42

7.5 - What is photorespiration?

Answer 42

A process where RuBisCO fixes O2 instead of CO2, reducing efficiency.

Question 43

7.5 - How do C4 and CAM plants reduce photorespiration?

Answer 43

They spatially (C4) or temporally (CAM) separate carbon fixation from the Calvin cycle.

Question 44

8.1 - What are the two reasons for cell signaling?

Answer 44

Responding to environment and communication with other cells.

Question 45

8.1 - What are five ways cells communicate?

Answer 45

Direct contact, paracrine, autocrine, endocrine, and contact-dependent signaling.

Question 46

8.1 - What are the three stages of signaling?

Answer 46

Receptor activation, signal transduction, and response.

Question 47

8.2 - What happens during receptor activation?

Answer 47

Ligand binds receptor, causing a conformational change and activation.

Question 48

8.2 - What is dissociation constant (Kd)?

Answer 48

A measure of receptor-ligand binding affinity; lower Kd = higher affinity.

Question 49

8.3 - What are the three cell surface receptors?

Answer 49

Enzyme-linked receptors, G-protein-coupled receptors, and ligand-gated ion channels.

Question 50

8.4 - What are intracellular receptors?

Answer 50

Receptors within the cell that bind hydrophobic ligands like steroids.

Question 51

8.5 - How does a receptor tyrosine kinase work?

Answer 51

Ligand binding leads to dimerization, phosphorylation, and signal transduction.

Question 52

8.6 - How do GPCRs work?

Answer 52

Ligand activates receptor → G protein activates → second messengers produced.

Question 53

8.6 - Why use second messengers like cAMP?

Answer 53

They amplify signals and allow fast, distributed responses.

Question 54

8.7 - What is crosstalk in signaling?

Answer 54

Interaction between different signaling pathways to fine-tune responses.