Exam 3 – Dr. Sullivant Carbohydrate Metabolism Flashcards Preview

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Flashcards in Exam 3 – Dr. Sullivant Carbohydrate Metabolism Deck (60):
1

What are the body's energy sources?

Food intake (CHOs, fats, proteins)
Metabolism
ATP

2

Why is metabolism important?

All cells and tissues must have energy for survival/homeostasis, growth, reproduction, repair, and movement

3

What is the main energy source used by the body?

ATP

4

Where is ATP present?

In cytoplasm and nucleoplasm of all cells

5

What is ATP a combination of?

Adenine
Ribose
3 phosphate radicals

6

What is ATP obtained from?

CHO, proteins, and fats

7

Where does the important stuff/magic happen in ATP?

In phosphate radicals

8

What does the breaking of a phosphate molecule from ATP do?

Causes a band of energy release, which powers muslce

9

Why does ATP provide so much energy?

High energy bonds
Removal of each of the last 2 phosphate radicals liberates 12,000 calories of energy

10

ATP is involved in energy utilization. What does it do?

Active ion transport
Muscle contraction
Synthesis of molecules
Cell division and growth

11

ADP and Pi are involved in energy production. What do they do?

Help proteins, CHOs, and fats that are involved in oxidation

12

What do kinases do?

Add a phosphate

13

What do phosphatases do?

Remove a phosphate

14

What does phosphorylase do?

Splits a compound by adding phosphate

15

What are 90% of CHOs in the body used for?

ATP production

16

What are the final products of CHO digestion in the gut?

Fructose
Galactose
Glucose (80%)

17

What happens after fructose and galactose absorption from the GI tract?

They are rapidly converted to glucose in the liver via glucose phosphatases; therefore, glucose is the final common pathway for transport/supply of CHO to all tissues

18

What is option 1 for the fate of glucose in the liver?

CHO is processed in the liver, then glucose formation, then transport out of liver to needy tissues for energy use
1. Glucose has to go through a cell membrane
2. Glucose foes through a series of reactions inside the cell to produce ATP (glycolysis, TCA)
3. Hydrogen atoms that are released concurrently yield even more ATP (glycolysis, TCA)

19

What is option 2 for the fate of glucose in the liver?

CHO processed in the liver, then glucose formation, the glycogenesis (energy storage)

20

What is glycogen?

A large polymer of glucose

21

What is option 3 for the fate of glucose in the liver?

Glycogenolysis in the liver

22

What is glycogenolysis?

Breakdown of stored glycogen in times of energy needs

23

What produces ATP?

Glucose entry into the cell
Glycolysis
Citric acid cycle
Chemiosmotic mechanism
Pentose phosphate pathway
Glycogenesis
Glycogenolysis

24

Glucose is too large to pass through cell membranes. What allows it pass?

Facilitated diffusion

25

How does facilitated diffusion allow glucose to move into most cells?

A specialized "carrier protein" in the cell membrane binds with glucose
Glucose transporter "GLUT" are on the outside and release it intracellularly
Glucose moves from an area of high concentration to lower concentration

26

What is insulin?

An anabolic hormone secreted by pancreatic β cells

27

What does insulin do?

Speeds the process of facilitated diffusion, which makes it a more effective and efficient process

28

Where can glucose transport occur without insulin?

RBC
Brain
Liver

29

What is the rate of CHO utilization by most cells controlled by?

Rate of insulin secretion

30

Look at figure 67-3

Look at figure 67-3

31

What is a GLUT 1 transporter?

RBCs

32

What are GLUT 2 transporters?

Liver
Pancreas
GI tract
Kidney

33

What is a GLUT 3 transporter?

Brain

34

What are GLUT 4 transporters?

Muscle
Fat

35

What is the first step once glucose is in the cell?

It must be "locked" in the cell
Phosphorylation via glucokinase or hexokinase
Glucose becomes Glucose 6 phosphate via glucokinase and ATP

36

What is glycolysis?

The splitting of glucose to form 2 pyruvic acids molecule

37

How does glycolysis occur?

Via 10 successive chemical reaction inside the cell
Does not require oxygen

38

What does phosphofructokinase (PFK) do?

Converts fructose-6-phoppate to fructose-1,6-diphosphate

39

What does ATP do to PFK?

Inhibits it

40

What does ADP do to PFK?

Activates it

41

What is the initial energy source for glycolysis?

Phosphofructokinase

42

What is the net gain of ATP from glycolysis?

2 ATP

43

What is the first step to using glucose for energy?

Conversion of pyruvic acid from glycolysis into 2 molecules of acetyl CoA
No ATP formed
4 H+ atoms released for later oxidation

44

What is the second step to using glucose for energy?

TCA cycle
Acetyl CoA is degraded into CO2 and H+ atoms in the mitochondria
Requires oxygen

45

What does the Kreb's cycle start with? What does it produce?

Acetyl CoA
ATP

46

How many ATP are produced in the citric acid cycle?

2 (1 per Acetyl CoA)

47

What is the fate of hydrogen atoms?

Most combine with NAD+ to form NADH+

48

What will happen with NADH+?

It will enter into multiple oxidative chemical reaction that form lots of ATP

49

What is the 3rd step for using glucose for energy?

Oxidative phosphorylation

50

What is oxidative phosphorylation?

The oxidation of hydrogen atoms released from all the previous stages of glucose metabolism

51

How much of the ATP that comes from glucose metabolism is formed from oxidative phosphorylation?

90%

52

How many ATP come from oxidative phosphorylation?

30

53

List the amount of ATP and where they come from

Glycolysis: 2
TCA cycle: 2
Oxidative phosphorylation: 30
Total: 34
4 remaining H+ atoms go on to produce 4 more ATP
Total: 38 per glucose molecule

54

Why does glycolysis occur?

As means to produce some energy when oxygen is low or unavailable

55

What is an alternative pathway for glucose?

Pentose phosphate pathway

56

What is the pentose phosphate pathway responsible for?

About 30% of glucose breakdown in liver and more in fat cells

57

What is the pentose phosphate pathway?

Cyclical process in which one molecule of glucose is metabolized per revolution of cycle

58

What does the pentose phosphate pathway yield?

CO2
H+ atoms
5 carbon sugar, D-ribulose

59

What can glucose be stored in? As what?

Liver and muscle as glycogen

60

How does glycogenolysis occur?

Via phosphorylation, catalyzed by enzyme phosphorylase

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