Unit 2: Metabolic Processes

Question 1

first law in thermodynamics

Answer 1

energy cannot be created nor destroyed–only converted from one form to another

Question 2

activation energy

Answer 2

the amount of energy required to start a chemical reaction

Question 3

difference between exothermic and endothermic reactions

Answer 3

exothermic–give off more energy than they take; release heat (e.g. wood)
endothermic–give off less energy than they take; absorbs heat (e.g. ice pack)

Question 4

ATP

Answer 4

adenosine triphosphate; source of energy in living cells

Question 5

difference between reduction and oxidation

Answer 5

reduction–gain of electrons

oxidation–loss of electrons

Question 6

ATP and ADP can alternate through (___/___) reaction

Answer 6

hydrolysis/dehydration

Question 7

NAD+

Answer 7

nicotinamide adenine dinucleotide; molecule that moves electrons

Question 8

How does NAD+ become NADH?

Answer 8

It picks up 2 hydrogen atoms, takes a whole H + 1 e and releases a H+

Question 9

difference between substrate level phosphorylation and oxidative level phosphorylation

Answer 9

substrate level: forms ATP through an enzyme catalyzed reaction that directly transfers a P to ADP (glycolysis and citric acid cycle)
oxidative level: forms ATP indirectly using energy transferred through a series of redox reactions (electron transport/chemiosmosis)

Question 10

simple explanation of glycolysis

Answer 10

glucose molecule is broken down into 2 pyruvate molecules and energy is released

Question 11

simple explanation of pyruvate oxidation

Answer 11

pyruvate is oxidized by NAD+, releasing NADH, CO2 is lost, and an acetyl group is formed

Question 12

simple explanation of citric acid/Krebs cycle

Answer 12

series of reactions that transfer energy to ATP, NADH, FADH2, and releases CO2

Question 13

simple explanation of electron transport

Answer 13

NADH and FADH2 are oxidized, water is released, H+ gradient allows ATP to be created

Question 14

How is cellular respiration controlled? (list 3 ways)

Answer 14

1. phosphofructokinase is inhibited by ATP (fructose 6 phosphate cannot turn into fructose 1,6-biphosphate) and stimulated by ADP
2. phosphofructokinase also inhibited by citrate
3. NADH inhibits enzyme pyruvate decarboxylase, reducing amount of acetyl-CoA produced

Question 15

What does it mean when NADH levels are high?

Answer 15

electron transport chain is full and ATP production is at maximum

Question 16

What is photosynthesis + describe the chemical process in words.

Answer 16

The process by which chlorophyll containing organisms use the sun’s energy to produce glucose
(carbon dioxide + water + energy = glucose + oxygen)

Question 17

Where is the chlorophyll molecule usually found in the leaf?

Answer 17

Near the surface in the palisade layer

Question 18

Describe a chlorophyll molecule.

Answer 18

Porphryn ring whose movement of electrons allows for absorption of radiant energy and a phytol tail for anchoring

Question 19

Both mitochondria and chloroplasts contain their own ___, evidence that they once ____ _____.

Answer 19

Both mitochondria and chloroplasts contain their own DNA, evidence that they once existed separately.

Question 20

List the 3 distinct parts/stages of photosynthesis.

Answer 20

1. Capture light energy
2. Convert light energy into chemical energy (ATP, NADPH)
3. Storage of chemical energy in glucose (using ATP, NADPH)

Question 21

How do plants obtain energy from the glucose they make? How do they obtain energy without sunlight (e.g. at night)?

Answer 21

Cellular respiration

Question 22

light dependent reactions

Answer 22

first stage of photosynthesis where water is split as light energy is absorbed and transformed into chemical energy in ATP and NADPH

Question 23

dark reactions (aka light independent reactions aka Calvin cycle)

Answer 23

second stage of photosynthesis where ATP and NADPH is used to convert CO2 to glucose

Question 24

Where do light dependent reactions occur in photosynthesis?

Answer 24

thylakoid membranes

Question 25

Where do dark reactions occur in photosynthesis?

Answer 25

Calvin cycle occurs in the stroma of the chloroplast

Question 26

In what part of the mitochondria does each stage of cellular respiration occur?

Answer 26

Glycolysis - cytoplasm
Pyruvate oxidation and citric acid cycle - mitochondrial matrix
Electron transport - mitochondrial membrane

Question 27

3 goals of cellular respiration

Answer 27

1. Break bonds in glucose
2. Move electrons from glucose to oxygen
3. Trap free energy as ATP

Question 28

Facultative anaerobes will produce more ATP in the ___ of oxygen.

Answer 28

presence

Question 29

difference between alcohol fermentation and lactate fermentation

Answer 29

alcohol fermentation releases carbon dioxide, lactate fermentation does not

Question 30

T/F: Anaerobic respiration relies on organic compounds other than oxygen to act as the final oxidizing agents in the production of ATP

Answer 30

False; they rely on INORGANIC compounds to act as final oxidizing agents

Question 31

What are the products of pyruvate oxidation?

Answer 31

CO2, NADH, H+, acetyl Co-A

Question 32

What anaerobic ATP producing process can occur in nearly all animals?

Answer 32

lactate fermentation

Question 33

How does the folding of the mitochondria’s inner membrane benefit aerobic respiration?

Answer 33

Provides greater surface area for electron transport chain and ATP synthase = more copies of them = more ATP can be produced

Question 34

What is ferredoxin?

Answer 34

An electron acceptor in PSI

Question 35

____ have chloroplasts, and ____ have mitochondria.

Answer 35

Only green plant cells have chloroplasts, and all animal and plant cells have mitochondria.

Question 36

What are the 2 important products of PSI?

Answer 36

ATP and NADPH

Question 37

Out of the 6 glyceraldehyde 3 phosphate (G3P) molecules formed during the Calvin cycle, how many are turned into sugar?

Answer 37

One (but the cycle must repeat several times to make a carbon molecule because each turn only adds one carbon)

Question 38

Describe the steps of the Calvin cycle.

Answer 38

1. CO2 added to 5 carbon RuBP and the resulting 6 carbon molecule is unstable so it splits into 2, 3 carbon molecules called 3-phosphoglycerate.
2. After going through a series of reactions with ATP and NADPH, 3-phosphoglycerate is converted into glyceraldehyde 3 phosphate.

Question 39

Where does the Calvin cycle take place?

Answer 39

In the stroma of the chloroplasts

Question 40

What is photorespiration?

Answer 40

A phenomenon that occurs during hot dry days, when oxygen competitively inhibits enzyme rubisco instead of carbon dioxide, reducing the production of glucose

Question 41

How does an electron that has gained energy from light behave?

Answer 41

Three possible outcomes:

1. Return to ground state, releasing thermal energy or fluorescence
2. Transfer energy to neighbouring electron
3. Electron is accepted by an electron-accepting molecule

Question 42

p680 - PS II or I?

p700 - PS II or I?

Answer 42

PSII - p680

PSI - p700

Question 43

How many turns of the Calvin cycle is required to produce one molecule of glucose?

Answer 43

6 (3 turns will give 1 G3P, which is half a glucose)

Question 44

6 CO2 + 12 H2O + 12 NADP + 18 ADP = C6H12O6 + 6 H2O + 6 O2

Answer 44

correct equation for photosynthesis