Chapter 14: Digestion and some Chapter 15: Metabolism Flashcards Preview

Biochemistry Exam 2 > Chapter 14: Digestion and some Chapter 15: Metabolism > Flashcards

Flashcards in Chapter 14: Digestion and some Chapter 15: Metabolism Deck (54):
0

Mechanical and chemical breakdown; prep stage

  • proteins
  • -AAs
  • polysaccharides
  • sugars
  • fat
  • fatty acids

Digestion

1

Digestion will have no __________.

ATP Production

2

From AAs, sugars, fatty acids

-small amount of ATP production

Acetyl CoA Production

3

Citric acid cycle and oxidative phosphorylation

ATP Production (90% of energy generated)

4

Stomach

-pH 1-2, denaturation of proteins

-Pepsin (protease) breaks peptide bonds

-Protein fragments move to small intestine

5

Pepsin shows optimal activity in the _____, only one of few that can be active in these conditions.

Stomach

6

Small Intestine

  • low pH of food stimulates the release of secretin
  • secretin stimulates release of sodium bicarbonate from pancreas to neutralize pH of the food
  • Oligopeptides stimulate CCK -CCK causes secretion of digestive enzymes from pancreas and bile salts from gallbladder

7

Zymogens are...

Proenzymes secreted from pancreas as inactive precursors

8

Enteropeptidase activates...

Trypsinogen to Trypsin

9

Enteropeptidase is the only enzyme in the ________.

Small Intestine

10

Trypsin activates...

Remaining pancreatic zymogens

-only activated in SI and all at the same time

11

Zymogens start in the _______ form so that they cannot destroy the ______.

Inactive Pancreas

12

Pancreatic proteases hydrolyze proteins to _______ and small _______ in the intestines.

Animo acids and small oligopeptides (protein fragments)

13

Oligopeptides are cleaved into AAs and di- and tri- peptides by...

Intestinal peptidases

14

AAs are released into....

The blood for use by other tissues

15

Primary source of dietary carbohydrates are.....

Complex carbs (ie. starch - small amounts of glycogen)

16

Starch is digested by....

a-amylase

17

a-amylase cleaves

1,4-bonds NOT 1,6

18

Products of starch...

Maltose, maltotriose and limit dextrin (has a-1,6 bonds)

19

Maltose converted to glucose by... Maltotriose is digested by... Limit dextrin is digested by

Maltase a-glucosidase a-dextrinase to simple sugars

20

Disaccharides are...

Sucrose and Lactose

21

Sucrose

-present in vegetables, is cleaved to glucose and fructose by sucrase

22

Lactose

-present in milk is degraded by lactase into glucose and galactose

23

Monosaccharides are transported from intestinal cells into the bloodstream to be used as...

Fuel/generate energy

24

The major lipids in our diet are...

Triacylglycerols *form lipid droplets in the stomach*

25

Bile salts secreted by gallbladder insert into...

The lipid droplets, making them more digestible in SI Bile salts considered amphipathic

26

Lipases secreted by the pancreas, convert triacylglycerols into...

-2 fatty acids

-monoacylglycerol

27

Ionized fatty acids made by lipases form...

Micelles

28

Micelles prevent

exposure to water and are carried to intestinal cells for absorption

29

In intestinal cells, triacylglycerols are resynthesized and packed into lipoproteins called...

Chylomicrons

30

Chylomicrons transport triacylglycerols into the....

Lymph system

31

Cannot directly transport triacylglycerols, so they must be ______ before they can enter the mucosal cell

Degraded

32

Ability to maintain adequate but not excessive energy stores

Caloric homeostasis

33

Some health consequences of being obese:

Diabetes Coronary heart disease Cancers Stroke Hypertension (high blood pressure)

34

Short-term signals are active during

Only a meal

35

2 Types of Short-term signals

CCK - generate feels of satiety by acting on hypothalamus GLP-1

-acts like CCK on brain but also acts on pancreas too and potentiates insulin action

36

Long-term signals...

report on the overall energy status of the body

38

2 Types of Long-term signals

Leptin - secreted by adipocytes and produces feelings of satiety (long-term); reports on status of triacylglycerol or fat stores Insulin - secreted by pancreas - reports on status of blood glucose levels (carb availibility)

39

When you lack leptin or the leptin receptor, you...

Do not realize that you are full and will continue to eat --> obesity

40

List of proteins

  • Pepsin
  • Secretin
  • CCK
  • Zymogen
  • Enteropeptidase
  • Trypsin

41

List of carbs

  • a-amylase
  • malatase
  • a-glucosidase
  • a-dextrinase

42

List of lipids

  • Bile salts
  • lipases
  • chylomicrons

43

Long-term control of caloric homeostasis is regulated by:

Leptin and insulin

44

T or F: The gall bladder secretes bile salts to neutralize the low pH of the stomach.

False

45

T or F: Fats are a more efficient food source than glucose, because fats are more oxidized.

False

46

T or F: Muscle contains only enough ATP to power contraction for less than a second.

True

47

T or F: Activated carriers are common in biochemistry and often are derived from vitamins.

True

48

T or F: NADPH is used primarily for reductive biosynthetic pathways.

True

49

T or F: Coenzyme A is an activated carrier of two-carbon fragments.

True

50

Metabolic pathways that involve the oxidation of fuels to generate ATP are called ____________ pathways.

Catabolic

51

Which compound has the highest phosphoryl-group transfer potential? ATP or Phosphenolpyruvate

Phosphenolpyruvate

52

What is the relationship between anabolic and catabolic pathways?

Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.

53

The role of ATP in cellular metabolism

The free energy released by ATP hydrolysis may be coupled to an endergonic process via the formation of a phosphorylated intermediate.

54

What metabolite is NOT in a high-energy state and therefore cannot release free energy for ATP generation

Glycerol-3-phosphate