Exam 3 – Dr. Sullivant Protein Metabolism

Question 1

What methods of protein metabolism occur in the liver?

Answer 1

Breakdown of amino acids
Formation of urea for removal of ammonia from body fluids
Formation of virtually all plasma proteins
Manipulation of amino acids and synthesis of other stuff from amino acids

Question 2

What is the breakdown of amino acids in the liver for?

Answer 2

Energy

Conversion to CHO and fats

Question 3

What is ammonia formed by in the liver?

Answer 3

Deamination

Gut bacteria

Question 4

What is protein used for?

Answer 4

Energy
Gluconeogenesis/ketogenesis
Enzymes
Transport proteins
Structural support
Muscles

Question 5

What is one of the major transport proteins?

Answer 5

Albumin

Question 6

What are amino acids?

Answer 6

Building block of proteins

Question 7

What do all amino acids have?

Answer 7

An acidic group and a nitrogen atom attached

Question 8

How many AA are in the body?

Answer 8

Approximately 20

Question 9

How are AA arranged?

Answer 9

Into chains via peptide linkages to form proteins

Question 10

What is the average protein size?

Answer 10

400 AA

Question 11

How long does protein digestion in the GI tract take?

Answer 11

About 2-3 hours

Question 12

What is the final breakdown product of protein digestion?

Answer 12

Amino acids

Question 13

Once in the blood stream, how quickly are amino acids absorbed by cells?

Answer 13

5-10 minutes

Question 14

What does a quick absorption of amino acids do?

Answer 14

Prevents any build-up of circulating AA

Question 15

What do amino acids require to diffuse through a cell wall?

Answer 15

Facilitated diffusion or active transport

Question 16

What happens to amino acids that make it to the kidneys?

Answer 16

They are mostly resorbed by the proximal convoluted tubule

Question 17

What is the fate of amino acids in the cell?

Answer 17

Turnover is rapid

They are quickly used up to make proteins

Question 18

What can happen to most intracellular proteins?

Answer 18

They can be degraded rapidly to yield AA

Question 19

What does the body prefer as its main energy sources?

Answer 19

CHO and fats

Question 20

What is used as energy sources after a couple of weeks of starvation?

Answer 20

Amino acids

Question 21

Where is growth hormone from?

Answer 21

Pituitary gland

Question 22

Where is insulin from?

Answer 22

Pancreas

Question 23

What do growth hormone and insulin do?

Answer 23

Increase formation of tissue protein

Question 24

What do glucocorticoids from adrenal gland do?

Answer 24

Increase plasma concentration of AA

Increase protein production in the liver

Question 25

How do glucocorticoids increase plasma concentration of AA?

Answer 25

By breaking down extrahepatic proteins to provide AA for energy

Question 26

What does testosterone do?

Answer 26

Increases protein deposition in tissues

Question 27

What does thyroxine do?

Answer 27

Increase the rate of protein synthesis or increase the rate of protein degradation for energy

Question 28

What are the protein functions?

Answer 28

Plasma proteins Essential and non-essential amino acids Source of energy

Question 29

What are the different plasma proteins?

Answer 29

Albumin Globulins Fibrinogen

Question 30

What does albumin do?

Answer 30

Provides oncotic pressure Transporter Involved in healing

Question 31

What do globulins do?

Answer 31

Immunity and enzyme functions

Question 32

What does fibrinogen do?

Answer 32

Polymerizes into fibrin to form blood clots

Question 33

What are essential amino acids?

Answer 33

Cannot be synthesized and therefore must be in the diet

Question 34

What are non-essential amino acids?

Answer 34

Synthesized by the body from keto-acids, which are precursors to the AA

Question 35

What is the process of amino acids being synthesized from kets-acids called?

Answer 35

Transamination

Question 36

What are aminotransferase enzymers derived from?

Answer 36

Vitamin B6, pyridoxine

Question 37

What are the essential amino acids for both dogs and cats?

Answer 37

``` Arginine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine ```

Question 38

What is the essential amino acid that only cats need?

Answer 38

Taurine

Question 39

What does the degradation of protein occur in the liver by?

Answer 39

Deamination

Question 40

What happens to an amino group when proteins are used for energy?

Answer 40

It is transferred to another molecule or released in form of ammonia

Question 41

What are deaminated protein end-products used to do?

Answer 41

Synthesize glucose and fats

Question 42

What can protein breakdown products be used for?

Answer 42

Gluconeogenesis or ketogenesis

Question 43

Where does the urea cycle occur?

Answer 43

Liver

Question 44

What does the urea cycle do?

Answer 44

Controls ammonia levels in the body | Prevent hepatic encephalopathy

Question 45

What is the process of the urea cycle?

Answer 45

Ammonia from deamination becomes urea and then it goes through renal excretion