Midterm 1 - Lecture 3

Question 1

The 4 Energy Yielding Nutrients are:

Answer 1

• Carbs: 4 kcal/gm
• Protein: 4 kcal/gm
• Fat: 9 kcal/gm
• Alcohol: 7 kcal/gm

Question 2

Carbs are used in what metabolic process?

Answer 2

glycolysis (as glucose)

Question 3

Proteins are used in what metabolic processes?

Answer 3

Glycolysis, TCA, Urea cycle (as AA’s)

Question 4

Lipids are used in what metabolic processes?

Answer 4

Glycolysis (as glycerol)

TCA (as Ac-CoA)

Question 5

If glycolysis feeds into lactate dehydrogenase (anaerobic), what is produced?

Answer 5

lactic acid

Question 6

If glycolysis feeds into pyruvate dehydrogenase (aerobic), what is produced?

Answer 6

Ac-CoA+CO2 in mitochondria;
Irreversible process
NADH created in process
loses CO2 from Pyruvate to create Ac-CoA

Question 7

Inputs (reactants) of glycolysis

Answer 7

ADP, NAD+, glucose

Question 8

Outputs (products) of glycolysis

Answer 8

ATP, NADH + H+, Pyruvate

Question 9

Inputs (reactants) of pyruvate oxidation

Answer 9

pyruvate, CoA, NAD+

Question 10

Outputs (products) of pyruvate oxidation

Answer 10

CO2, NADH, Ac-CoA

Question 11

Inputs (reactants) of citric acid (tca) cycle

Answer 11

Ac-CoA, NAD+, FAD, ADP

Question 12

Outputs (products) of citric acid (tca) cycle

Answer 12

CoA, NADH + H+, FADH2, ATP, CO2

Question 13

Inputs (reactants) of respiratory chain

Answer 13

NADH + H+, FADH2, ATP, O2

Question 14

Outputs (products) of respiratory chain

Answer 14

NAD+, FAD, H2O, ATP

Question 15

Alpha vs Beta linkages in carbs

Answer 15

Alpha: Oxygen points down, CH2OH on same side
Beta: Oxygen points up, CH2OH alternates

Question 16

Conversion of glutamate to alpha-ketoglutarate via Glutamate dehydrogenase using H2O and NAD(P)+

Answer 16

• OOC-CH2-CH2-CH(NH3+)-COO- Glutamate

- OOC-CH2-CH2-CH(=O)-COO- alpha-KG

Question 17

Transamination of alanine and alpha-KG to pyruvate and glutamate (and reverse)

Answer 17

swapping of =O from pyruvate and NH3+ from glutamate

Question 18

Liver Functions (expanded)

Answer 18

Detoxification
Amino acid and fatty acid metabolism
Urea Cycle (ammonium elimination)
Glucose synthesis (gluconeogenesis)
Glycogen synthesis and storage
Alcohol metabolism
Synthesis of bile, cholesterol, lipids, blood proteins.

Question 19

Level of blood glucose maintained for brain function

Answer 19

blood glucose ~5 mM

Question 20

What are master signaling molecules that regulate energy metabolism?

Answer 20

Insulin

Question 21

How does insulin regulate metabolism?

Answer 21

Following nutrient consumption, insulin promotes carbohydrate uptake at key storage sites and
prompts the conversion of carbohydrate and protein to
lipids (a more efficient storage for calories)

Question 22

How does Insulin affect blood glucose?

Answer 22

Lowers blood glucose.

increase glucose uptake, glycogen synthesis-> decrease blood glucose.

Question 23

How does Glucagon affect blood glucose?

Answer 23

Increases blood glucose.

increase glycogen breakdown, glucose synthesis -> increase blood glucose.

Question 24

How does Glucagon regulate metabolism?

Answer 24

Glucagon and epinephrine, promote mobilization of stored triglycerides into free FA’s

Question 25

What are the two primary roles of malonyl CoA?

Answer 25

1. Provides 2 carbon units to FA’s to commit them to FA chain synthesis
2. Inhibits rate-limiting step of Beta-oxidation of FAs; FAs cannot enter the mitochondria for degradation

Question 26

What metabolic process is affected in Phenylketonuria patients (PKU)?

Answer 26

Conversion of Phenylalanine (essential AA) to Tyrosine (not usually essential AA) via phenylalanine hydroxylase is reduced or missing; Tyrosine becomes essential

Question 27

What happens to PKU patients with too much phenylalanine?

Answer 27

levels of phenylalanine and related deaminated forms build up in the body and harm the central nervous system; causes brain damage