4.3 Whole Body Metabolism

Question 1

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

Answer 1

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

Question 2

What is the primary, readily mobilized source of energy?

Answer 2

Glycogen in the liver and muscle

Question 3

Other sources of glucose-like carbohydrates

Answer 3

Recycled lactic acid
Glycerol from triglycerides
Amino acid “skeletons”

Question 4

Gluconeogenesis

Answer 4

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

Question 5

Do fatty acids go through gluconeogenesis?

Answer 5

NO they go to ketone bodies

Question 6

When are proteins catabolized for energy?

Answer 6

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

Question 7

Amino acids must undergo_________ to remove the amino group

Answer 7

Deamination

Question 8

What is the amino group excreted as?

Answer 8

Urea in the kidneys

Question 9

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

Answer 9

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

Question 10

What are triglycerides catabolized into? Where?

Answer 10

Fatty acids and glycerol in adipocytes

Question 11

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

Answer 11

It is a carb so it enters glycolysis

Question 12

Beta Oxidation

Answer 12

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

Question 13

Does beta oxidation require oxygen?

Answer 13

Yes

Question 14

Why is beta oxidation important?

Answer 14

It preserves carbohydrate reserves for the brain

Question 15

What happens to fatty acids during starvation?

Answer 15

They go to the liver and become ketone bodies

Question 16

Downside to ketone bodies being produced

Answer 16

Ketoacidosis

• Drops blood pH
• Ketones can be toxic

Question 17

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

Answer 17

Intensity of activity
Duration
Starvation

Question 18

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

Answer 18

High intensity (because they sustain inefficient cellular respiration)

Question 19

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

Answer 19

Lower intensity

Question 20

Duration

Answer 20

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

Question 21

Starvation

Answer 21

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

Question 22

What do tissue proteins do during starvation?

Answer 22

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

Question 23

What types of food molecules can you make ATP from?

Answer 23

Virtually any

Question 24

Essential nutrients

Answer 24

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

Question 25

Nutrients for survival

Answer 25

``` Minerals Vitamins Proteins Lipids Water ```

Question 26

Are carbohydrates essential nutrients?

Answer 26

Technically they are not

Question 27

Main carbohydrate function

Answer 27

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

Question 28

Starch

Answer 28

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

Question 29

Fiber

Answer 29

Carbs that can't be digested down to glucose

Question 30

Insoluble fiber

Answer 30

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

Question 31

Soluble fiber

Answer 31

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

Question 32

Simple sugars like table sugar have a _____ glycemic index

Answer 32

High

Question 33

Why do table sugars have a high glycemic index?

Answer 33

They are so quickly absorbed in the small intestine

Question 34

Cycle initiated by high glycemic index foods

Answer 34

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

Question 35

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

Answer 35

20 | 10

Question 36

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

Answer 36

Amino Acid

Question 37

Two essential fatty acids

Answer 37

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

Question 38

Can plants make cholesterol?

Answer 38

NO

Question 39

Most vitamins are ________

Answer 39

Enzyme cofactors

Question 40

How many vitamins are there?

Answer 40

13

Question 41

What matters in terms of osteoporosis?

Answer 41

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

Question 42

What do acidic foods do to iron absorption?

Answer 42

Promote absorption in intestine