Chapter 4

Question 1

Cellular respiration equation

Answer 1

C6H12O6 + 6O2 –> 6CO2 + 6H2O

Question 2

Two major pathways of glucose catabolism

Answer 2

anaerobic fermentation
–> occurs in absence of oxygen
–> reduces pyruvic acid to lactic acid
aerobic respiration
–> occurs in the presence of oxygen
–> oxidizes pyruvic acid to CO2 and H2O

Question 3

where does glycolysis occur?

Answer 3

cytoplasm

Question 4

glycolysis

Answer 4

1. priming
   –> glucose phosphorylated twice, converted to fructose 1,6 diPhosphate
   Cost: 2 ATP
2. cleavage to form 2 PGAL
   Fructose 1,6 diphosphate is broken into 2 PGAL
3. Oxidation and dephosphorylation of 2PGAL
   2 PGAL produce 4 ATP, 2 NADH and 2 pyruvic acid
4. oxygen: pyruvic acid enters intermediate step/ mitochondria
   no oxygen present: PA is converted to lactic acid

Question 5

NET gain of ATP during glycolysis

Answer 5

Need 2 ATP during priming
Make 4 ATP during “cleavage”
NET Gain = 2 ATP

Question 6

NAD+ and FAD electron carriers

Answer 6

two coenzymes that carry electrions in the form of hydrogen atoms to harvest ATP at the end of the process

Question 7

NAD+

Answer 7

nicotinamide adenine dinucleotide
–> derived from niacin (B vitamin)
–> NAD+ + 2 H –> NADH + H+

Question 8

FAD

Answer 8

flavin adenine dinucleotide
–> derived from riboflavin
–> FAD + 2H –> FADH2

Question 9

anaerobic fermentation

Answer 9

lactic acid leaves the cells that generate it and travels to the liver via the blood
–> when oxygen becomes available the liver oxidizes it back to pyruvic acid
–> oxygen required for this is part of the reason we breathe more vigoursly after exercising

Question 10

aerobic respiration

Answer 10

most of ATP is generated in mitochondria
requires oxygen
pyruvic acid enters the mitochondria and is oxidized by aerbic respiration
Two steps:
1. matrix reactions: their controllign enzymes are in the fluids of mitochondrial matrix
2. membrane reactions: their controlling enzymes are bound to the membranes of the mitrochondrial Cristae

Question 11

The matrix reaction intermediate step

Answer 11

prepares pyruvic acid to enter citric acid cycle
1. decarboxylation– CO2 removed from pyruvic acid to make a C2 compound
2. convert C2 cimpound to aceitic acid (NAD+ removes hydrom atoms from the C2 compound becomes NADH)
3. acetyl group binds to coenzyme A (results in acetyl coA)

Question 12

Where does citric acid cycle occur

Answer 12

matrix of mitochondria

Question 13

Intermediate step products, electron carriers

Answer 13

2 acetyl Co-A, 2 NADH

Question 14

citric acid cycle

Answer 14

1. Acetyl-CoA enters cycle and forms citric acid—start of cycle
2. Water is removed and citric acid molecules rearranged
3. Hydrogen atoms are removed and accepted by NAD+ to form
   NADH
4. CO2 is removed
5. Previous step repeats, making NADH and removing another
   CO2
6. Phosphorylation of guanosine diphosphate (GDP) converts it
   to guanosine triphosphate (GTP) (Quickly transfers Pi group to ADP to make ATP)
7. Two hydrogen atoms are removed and accepted by FAD to
   make FADH2
8. Water is added
9. Two final hydrogen atoms are removed and transferred to
   NAD+ to make NADH
10. Reaction generates oxaloacetic acid, which is available to start
    the cycle again

Question 15

The membrane cristae reactions. Membrane reactions have 2 purposes:

Answer 15

1. oxidizes NADH and FADH2 and transfers energy to ATP
2. Regenerates NAD+ and FAD

Question 16

Where does electron transport chain occur?

Answer 16

inner mitochondrial membrane

Question 17

Electron transport chain on membrane

Answer 17

–>Hydrogen atoms from NADH and FADH2 are
split apart. Transfer from coenzymes to the
chain
–>Protons pumped into the intermembrane space
–>Electrons travel in pairs (2 e−) along the
transport chain
–>Each electron carrier becomes reduced
when it receives an electron pair and oxidized
again when it passes the electrons along to the
next carrier

Question 18

What is the final electron accept in electron transport chain?

Answer 18

Oxygen, if there was no oxygen cells produce too little ATP to sustain life

Question 19

chemiosmosis

Answer 19

the kinetic energy of passing hydrogen ions generates ATP

Question 20

glycogenesis

Answer 20

synthesis of glycogen, stimulated by insulin, chains glucose monomers together
–> releases glucose between meals
–> stimulated by glucagen and epinephrine
–> liver cells can release glucose back into blood

Question 21

glycogensis (anabolic or catabolic)

Answer 21

anabolic

Question 22

gluconeogensis

Answer 22

synthesis of glucose from non-carbohydrates, such a glycerol and amino acids
–> occurs mainly in liver and later kidneys

Question 23

gluconeogenesis (anabolic or catabolic)

Answer 23

synthesis of glucose from noncarbohydrates such a glycerol and amino acids

Question 24

glycolysis (anabolic or catabolic)

Answer 24

catabolic

Question 25

glycogenolysis

Answer 25

the hydrolysis of glycogen to release free glucose or flucose 1-phosphate

Question 26

glycogenolysis (anabolic or catabolic)

Answer 26

catabolic

Question 27

triglycerides

Answer 27

stored in adipocytes, turnover of lipid molecules every 2 to 3 weeks, released into blood, transproted and either oxidized or redeposited in other fats cells

Question 28

lipogenesis

Answer 28

synthesis of fats from other types of molecules

Question 29

examples of lipogenesis

Answer 29

-->amino acids and sugars used to make fatty acids and glycerol -->PGAL can be converted to glycerol -->Acetyl-CoA used to make fatty acids

Question 30

lipolysis

Answer 30

breaking down fat for fuel

Question 31

Free amino acids can be converted to glucose, fat or direct used as fuel. As fuel amino acids must be ________. What remains?

Answer 31

deaminated (removed of NH2) Keto acid and may be converted to pyruvic acid, acetyl-CoA or oen of acids of citric acid cycle. Used to synrhesis glucose in gluconeogenesis

Question 32

what happens when an amino acids is deaminated?

Answer 32

its amino group is transferred to a citric acid cycle intermediate, converting it to glutamic acid