Nutrition Chapter 9

Question 1

What do cells use energy for?

Answer 1

1. building compounds
2. contracting muscles
3. conducting nerve impulses
4. pumping ions

Question 2

What is ATP?

Answer 2

adenosine triphosphate
the main form of energy the body uses
does mechanical, chemical and osmotic work

Question 3

What are anabolic pathways?

Answer 3

building larger, more complex compounds from smaller ones

Question 4

What are catabolic pathways?

Answer 4

break down compounds into small units

Question 5

What are intermediates?

Answer 5

compounds formed in the steps of the metabolic pathway

Question 6

How is a substance oxidized?

Answer 6

when it loses 1 or more electrons

when it gains oxygen or loses hydrogen

Question 7

How is a substance reduced?

Answer 7

when it gains 1 or more electrons

when it loses oxygen or gains hydrogen

Question 8

What is cellular respiration?

Answer 8

The process of of oxidizing food molecules to obtain energy.

Question 9

What are the stages of aerobic cellular respiration?

Answer 9

1. glycolysis
2. transition reaction
3. citric acid cycle
4. electron transport chain (oxidative phosphorylation)

Question 10

What happens in glycolysis?

Answer 10

glucose broken down to form pyruvate
6-C glucose –> 2, 3-C pyruvates
uses and produces ATP
can be reversed, but requires energy

Question 11

What happens in the citric acid cycle?

Answer 11

pyruvate –> acetyl CoA
requires several B vitamins
generates NADH, FADH2, GTP, CO2
irreversible

Question 12

What happens in the electron transport chain?

Answer 12

series of carrier molecules move hydrogen ions and electrons
oxidative phosphorylation
NADH, FADH2 converted to ATP
H2O generated

Question 13

Where does energy metabolism occur?

Answer 13

in the cell - cytoplasm and mitochondria

Question 14

What are the sources of glucose for glycolysis?

Answer 14

1. dietary CHO
2. glycogen stores
3. endogenous biosynthesis
4. lactate (anaerobic)

Question 15

What happens in lipid metabolism?

Answer 15

triglycerides are broken into glycerol and fatty acids
glycerol –> pyruvate
fatty acids –> acetyl CoA (lipolysis)

Question 16

What is lipolysis?

Answer 16

The breakdown of lipids.
lipids are cleaved at the beta bond and progressively broken into 2 C molecules
triggered by hormone sensitive lipase

Question 17

How are ketones formed?

Answer 17

acetyl CoA molecules combine, ketones are products of incomplete fatty acid oxidation
results from low CHO intake or insufficient insulin
acetyl CoA can’t enter the TCA cycle

Question 18

When does ketosis occur?

Answer 18

fasting, diabetes
fasting - lack of glucose from CHO, fatty acids flood the liver, TCA cycle stops w/o oxaloacetate
diabetes - acetyl CoA builds up, more ketones, causes blood to become acidic, diabetic coma

Question 19

How is protein metabolized?

Answer 19

amino acids become part of pyruvate, TCA cycle or acetyl CoA depending on side chain
in order to be used as fuel, AAs must be reanimated
ketogenic and glucogenic amino acids

Question 20

How is metabolism regulated?

Answer 20

enzymes
hormones
blood glucose concentration
ATP concentration
mostly occurs in the liver

Question 21

What happens in feasting?

Answer 21

store a little glycogen and a lot of fat

lipogenesis - build fat

Question 22

What happens in fasting?

Answer 22

body draws on glycogen and fat stores for energy

stores last about 24 hours w/o strenuous activity

Question 23

What happens in starvation?

Answer 23

after glycogen stores are used up
body begins to break down protein from AA to produce glucose –> lost muscle mass and organs shrink
eventually, to preserve tissue, fatty acids start being converted to ketones for energy
ketosis keeps you alive
adaptation keeps you alive for up to 2 months