16. Energy Balance and metabolism

Question 1

how many calories per mole are released in the body by ATP–>ADP + Pi reaction?

Answer 1

-12,000 cal/mol released

Question 2

Are glucose, galactose, fructose all interconvertable?

Answer 2

yes, all hexoses are

Question 3

How is glucose transported into tissue cells?

Answer 3

active sodium-glucose co-transport

Question 4

What does insulin do to glucose absorption?

Answer 4

increases absorption by 10x

Question 5

Where can glucose phosphorylation be reversed, so glucose can leave the cells?

Answer 5

liver, intestinal cells, renal system

Question 6

What are teh roles of glucokinase, phosphorylase, and phosphatase in the glycolysis pathway?

Answer 6

1. glucokinase: phosphorylates glucose to prevent leaving cells
2. phosphorylase: converts glycogen to usable form
3. phosphatase: removes P only present in renal, intestinal, and liver cells

Question 7

What factors activate phosphorylase?

Answer 7

1. epinephrine

2. glucagon

Question 8

What are the end products of glycolysis?

Answer 8

1. pyruvic acid 2 molecules
2. 4 hydrogen ions
3. 2 ATP molecules (net)

Question 9

What are the final products of converting pyruvic acid into acetyl-CoA?

Answer 9

1. acetyl-CoA (2)
2. hydrogen ion (4)
3. carbon dioxide (2)

Question 10

What are the final products from pyruvic acid to lactic acid?

Answer 10

lactic acid and NAD+

-requires lactic dehydrogenase

Question 11

Where does the citric acid cycle occur and what are the final products?

Answer 11

1. mitochondrial matrix
2. (16) hydrogen ion
3. (2) ATP
4. (4) carbon dioxide

Question 12

Where do the hydrogen ions from TCA move?

Answer 12

to oxidative phosphorylation on the mitochondrial cristae

and others migrate to form NADH

Question 13

What are major components of oxidative phosphorylation?

Answer 13

1. flavoprotein
2. iron sulfide proteins
3. ubiquinone
4. cytochrome A3 (donate electrons to oxygen)

Question 14

What are the specific number of ATP from entire ox phosp process?

Answer 14

1. (2) glycolysis
2. (2) TCA
3. (34) ETC

Question 15

The pentose phosphate pathway mostly is used for fat synthesis, but can provide immediate source of glucose. HOw?

Answer 15

1. five glucose can be resynthesized from 6 molecules

2. hydrogen ions are bound to NADP+ not NAD+

Question 16

What role does NADPH have in biosynthesis?

Answer 16

1. converts acetyl-CoA into fatty acid chains

2. occurs when glucose store cells are saturated and glucose is then converted to fat

Question 17

What ways can glucose be converted to triglycerides?

Answer 17

1. glycolytic pathway to form fatty acid to form trigs
2. pentose phosphate pathway to form fatty acid to form trigs
3. directly from alpha-glycerophosphate

Question 18

How are triglycerides absorbed in the intestines?

Answer 18

1. converted to monoglycerides and fatty acids
2. can then be reformed in lymph as chylomicron
3. Apoprotein B added to chylomicron surface is important

Question 19

Which tissues produce lipoprotein lipase in order to remove chylomicrons from blood?

Answer 19

1. adipose
2. skeletal
3. heart

Question 20

What does lipoprotein lipase do to allow triglyceride absorption into tissue?

Answer 20

hydrolyzes trig to release fatty acid and glycerol

Question 21

Can all the normal energy requirement of the body be provided by oxidation of fatty acids, without utilizing carbs or proteins as energy sources?

Answer 21

yes

Question 22

What will increase the utilization of fats for energy?

Answer 22

starvation mode, diabetes mellitus

Question 23

What type of lipoproteins are synthesized by intestinal cells?

Answer 23

chylomicrons

Question 24

What lipoproteins are synthesized by the liver?

Answer 24

VLDL, IDL, LDL, HDL

Question 25

What is the function of VLDL in blood?

Answer 25

1. transport from liver to adipose tissue | 2. high [triglyceride], cholesterol and phospholipid

Question 26

What is the function of LDL?

Answer 26

high [cholesterol] and phospholipids

Question 27

What is the function of HDL?

Answer 27

1. high [protein] and low [cholesterol, fatty acid]

Question 28

What are the principal functions of the liver in regard to lipid metabolism?

Answer 28

1. degrade fatty acids to energy 2. synthesis of triglycerides 3. synthesis of lipids from fatty acids, mainly cholesterol and phospholipids

Question 29

Under what conditions are large quantities of triglycerides appearing in the liver?

Answer 29

1. starvation stage early 2. diabetes mellitus 3. any situation where fats, not carbs, are main energy source

Question 30

Beta-oxidation occurs in the mitochondria to convert fatty acids to what?

Answer 30

acetyl-CoA where it binds with oxaloacetic acid

Question 31

What are the products of one molecule of stearic acid undergoing beta-oxidation?

Answer 31

(9) acetyl-CoA molecules, (146) ATP molecules

Question 32

Fatty acids that are degraded in the liver produce energy that is not used for metabolism. What is acetoacetic acid converted into?

Answer 32

beta-hydroxybutyric acid and acetone

Question 33

What body conditions will favor ketosis?

Answer 33

1. starvation 2. diabete mellitus 3. fatty diet

Question 34

What are the benefits of storing fat rather than carbohydrates?

Answer 34

1. more efficient. more storage than carbs | 2. 2.5x amount of energy of same amount of carbs

Question 35

Why are fats poorly synthesized during insulin deficiency?

Answer 35

1. decreased delivery of glucose to cells, reduces amount of NADPH and Acetyl-CoA required for fat synthesis 2. reduced glucose in cells reduces availability of alpha-glycerophosphate

Question 36

Why are carbohydrates preferred over fats for energy?

Answer 36

1. triglycerides are in equilibrium with soluble fatty acids, but fatty acids will shift equilibrium to form more trigs. 2. fatty acid synthesis is faster than degradation when carbs in excess

Question 37

What are the processes of athersclerotic plaque development?

Answer 37

1. vascular endothelium damage 2. monocytes and LDL accumulate at site of injury 3. Monocytes enter intima become macrophages 4. macrophages ingest lipoproteins 5. fatty streak develop and grow surrounding fibrous and smooth muscle tissue

Question 38

How does damaged vascular endothelium contribute to athersclerotic plaques?

Answer 38

1. increase adhesion molecules | 2. decrease NO, and anti-adhesive signaling molecules

Question 39

How do monocytes contribute to athersclerotic plaque formation?

Answer 39

1. cross endothelium, form macrophages | 2. enter the intima

Question 40

What role do macrophages have in athersclerotic plaque formation?

Answer 40

1. ingest lipoproteins 2. become foam cells 3. form visible fatty streaks

Question 41

What happens to fatty streaks to become athersclerotic plaque?

Answer 41

1. coalesce and increase in size

Question 42

What is the threat of having large atherosclerotic plaques present in blood vessels?

Answer 42

1. occlusion | 2. become fibrotic or calcified

Question 43

What generally causes athersclerosis?

Answer 43

1. increased LDL | 2. familial hypercholesterolemia