Lecture 7: Proteins

Question 1

What happens to a protein when it is exposed to different environments, such as increased temperature

Answer 1

it unfolds into a single strand of amino acids, the normal protein becomes a denatured protein

Question 2

What two major pancreatic enzymes digest protein?

Answer 2

Chymotrypsin and trypsin

Question 3

Protein turnover

Answer 3

The process where all cells in the body continually break down proteins and build new ones

Question 4

What is the most abundant structural protein?

Answer 4

Collagen

Question 5

Enzymes

Answer 5

proteins that conduct specific chemical reactions, catalyst

Question 6

Hormones

Answer 6

proteins responsible for hormone synthesis, chemical messages produced by endocrine glands

Question 7

basic structure of amino acids

Answer 7

-Hydrogen

-Amino Group, N terminal (H2N)

-Acid Group, C terminal (C=O, C-OH)

-Side Chain, R group, unique to each
amino acid

Question 8

How are amino acids classified

Answer 8

20 amino acids –> 9 essential, 11 essential

Question 9

Structures of protein

Answer 9

Primary: Sequence of a chain of amino acids

Secondary: Hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern

Tertiary: Three-dimensional folding pattern of a protein due to side chain interactions

Quaternary: Protein consisting of more than one amino acid chain

Question 10

Process of gene expression

Answer 10

1. Transcription: genetic information copied using mRNA
2. mRNA leaves nucleus travels to cytoplasm
3. binds to ribosome, code is translated for specific order of amino acids
4. amino acids are added to growing chain and eventually produce a specific protein

Question 11

protein synthesis

Answer 11

translating the genetic information contained in mRNA into a functional protein. This process occurs in the cytoplasm of the cell

Question 12

Transamination

Answer 12

how your body converts non-essential amino acids to essential amino acids through transferring the amine group from an essential amino acid to a different acid group and side chain

Question 13

Food sources of protein

Answer 13

meat, poultry, legumes

Question 14

Role of protein in health

Answer 14

cell growth, repair, maintenance, fluid and electrolyte balance, acid-base balance

Question 15

AMDR for protein

Answer 15

10-35%, limit to 2g/kg BW

Question 16

Nutritional Implications of vegetarian diets

Answer 16

lower fat and energy intake, nutrient deficiencies

Question 17

Genetic conditions related to protein synthesis

Answer 17

PKU, sickle cell anemia, cystic fibrosis

Question 18

Marasmus vs. kwashiorkor

Answer 18

marasmus: low energy & protein intake, wasting of muscles, cannot be reversed, stunted physical & brain development, infants

kwashiorkor: food consumption but almost no protein intake, edema (water retention in belly), linked to early weaning, fatty liver, slow growth & development, toddlers, can be reversed

Question 19

What begins protein digestion in the stomach?

Answer 19

HCL & pepsin which dentures/unfolds protein

Question 20

What are polypeptides broken down into in the SI

Answer 20

amino acids, dipeptides, tripeptides

Question 21

Transport proteins

Answer 21

move products from protein digestion into mucosal cell

Question 22

How are amino acids absorbed?

Answer 22

Through mucosal cell that travels into the blood, to the liver which regulates distribution of amino acids

Question 23

Conditionally essential amino acid

Answer 23

Non-essential amino acid becomes essential.
For example, in patients with phenylketonuria (PKU), tyrosine must be provided by
the diet.

Question 24

What are proteins made up of?

Answer 24

amino acids, carbon, hydrogen, oxygen, nitrogen, some contain sulphur

Question 25

Gene

Answer 25

segment of deoxyribonucleic acid (DNA) that serves as a template for the synthesis (expression) of a particular protein

Question 26

Incomplete protein vs. complete protein

Answer 26

Incomplete protein (low quality):
-Generally plant based
-Lack at least one essential amino acid
-Lower digestibility

Complete Protein (high quality):
-Generally animal based
-Have 9 essential amino acids
-High digestibility

Question 27

Free radicals

Answer 27

unstable molecules that damages cell at DNA level which can lead to cancer

Question 28

High protein diets (consuming animal protein-rich diet)

Answer 28

contribute to calcium loss/bone loss, may increase blood acidity, progression of kidney disease and liver malfunction

Question 29

Consuming more plants can potentially reduce

Answer 29

cancer by neutralizing free radicals