4.3 Whole Body Metabolism Flashcards Preview

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Flashcards in 4.3 Whole Body Metabolism Deck (42):
1

Why don't our bodies take fat that we can do without and make it into sugar?

We cannot turn fatty acids into sugar, we do not have the enzymes

2

What is the primary, readily mobilized source of energy?

Glycogen in the liver and muscle

3

Other sources of glucose-like carbohydrates

Recycled lactic acid
Glycerol from triglycerides
Amino acid "skeletons"

4

Gluconeogenesis

Making glucose from any 'carbon skeletons' available (amino acids, glycerol, lactic acid, etc) to primarily feed the brain

5

Do fatty acids go through gluconeogenesis?

NO they go to ketone bodies

6

When are proteins catabolized for energy?

Only when carb supply is limited (starvation or very long term physical exertion)

7

Amino acids must undergo_________ to remove the amino group

Deamination

8

What is the amino group excreted as?

Urea in the kidneys

9

After deamination, what happens to the remaining C-skeleton?

Converted to a molecule that enters gluconeogenesis, glycolysis, pyruvate oxidation or Kreb's cycle

10

What are triglycerides catabolized into? Where?

Fatty acids and glycerol in adipocytes

11

What happens to glycerol after it is separated from the fatty acids?

It is a carb so it enters glycolysis

12

Beta Oxidation

Fatty acids are converted to acetyl-CoA (can enter Krebs) to generate ATP in various tissues (heart, muscle, etc)

13

Does beta oxidation require oxygen?

Yes

14

Why is beta oxidation important?

It preserves carbohydrate reserves for the brain

15

What happens to fatty acids during starvation?

They go to the liver and become ketone bodies

16

Downside to ketone bodies being produced

Ketoacidosis
-Drops blood pH
-Ketones can be toxic

17

What are the three factors that go into your body deciding which fuel your tissues burn?

Intensity of activity
Duration
Starvation

18

What type of activity are carbs favored for? (intensity)

High intensity (because they sustain inefficient cellular respiration)

19

What type of activity are lipids favored for? (intensity)

Lower intensity

20

Duration

Glycogen depletion leads to the use of alternate fuel sources (fatty acids and even amino acids if very long duration)

21

Starvation

Prolonged energy deprivation, by 4 days without eating 75% of fuel for the brain is ketone bodies

22

What do tissue proteins do during starvation?

Mobilize to save the brain and heart which are preserved to the last

23

What types of food molecules can you make ATP from?

Virtually any

24

Essential nutrients

Specific term used to describe molecules that must be food derived, your body cannot synthesize them itself

25

Nutrients for survival

Minerals
Vitamins
Proteins
Lipids
Water

26

Are carbohydrates essential nutrients?

Technically they are not

27

Main carbohydrate function

Provide energy and carbon skeletons to build other molecules (like amino acids)

28

Starch

When eaten as a part of whole grains, fruits and vegetables...takes time and energy to break down into absorbable glucose

29

Fiber

Carbs that can't be digested down to glucose

30

Insoluble fiber

Bulk that hastens movement through digestive tract
Activates stretch receptors in GI (makes you feel full)

31

Soluble fiber

Binds dietary fat and cholesterol, reduces their absorption in small intestine

32

Simple sugars like table sugar have a _____ glycemic index

High

33

Why do table sugars have a high glycemic index?

They are so quickly absorbed in the small intestine

34

Cycle initiated by high glycemic index foods

Blood sugar elevates
Insulin over-secreted
Too much sigh removed from blood
You feel hungry again

35

Proteins are made of ____ amino acids: ____ are essential and must be supplied in the diet

20
10

36

When consuming sufficient energy from multiple foods, it is virtually impossible to develop an ________ deficiency

Amino Acid

37

Two essential fatty acids

1) Alpha linolenic (canola, soy, flax)
2)Linoleic (Not an issue, lots of sources)

38

Can plants make cholesterol?

NO

39

Most vitamins are ________

Enzyme cofactors

40

How many vitamins are there?

13

41

What matters in terms of osteoporosis?

-Bone stress (exercise)
-Menopause
-Low protein diets
-Vitamin D plus calcium

42

What do acidic foods do to iron absorption?

Promote absorption in intestine