Module 8

Question 1

What are the three main amino acid groups?

Answer 1

• Nitrogen containing amine group
• Carboxylic acid
• A side chain

Question 2

How many amino acids are there?

Answer 2

21

Question 3

What is a complete protein?

Answer 3

Foods with nine essential amino acids

Question 4

What are sources of complete protein and in-compete protein

Answer 4

• Complete = animal
• Incomplete = plant

Question 5

The amino acid that is lacking is called..

Answer 5

Limiting amino acid

Question 6

What are the steps for protein synthesis

Answer 6

1. RNA makes a copy of the DNA code for a particular gene
2. The RNA message has a code that controls the sequence of amino acid needed to build the specific protein. These amino acids are drawn from the amino acid pool

Question 7

How do primary structures arise

Answer 7

• Arise from adjacent amino acids bonding to each other
• Occurs through condensation reaction and leads to formation of a peptide bond

Question 8

What does peptide bonds lead to

Answer 8

• Polypeptide
• Not yet a protein it must fold into secondary, tertiary or perhaps quaternary structure

Question 9

How do secondary structures arise

Answer 9

• Hydrogen bonds between non-adjacent amino acids
• Formation of alpha helices and beta-pleated sheets

Question 10

How do tertiary structures arise

Answer 10

• Interactions between amino acids side chains
• Formation of polypeptide chain
• Might result in functional protein

Question 11

What are quaternary structures

Answer 11

• Several proteins with a tertiary structure to form a final protein
• Called a protein subunit

Question 12

What happens when a protein denatures

Answer 12

• Loses its folded 3D structure
• Loses its function

Question 13

What causes denature of protein

Answer 13

• Acid in our stomach, heat, agitation
• Once denatured it cannot be reversed

Question 14

Describe the protein digestion process

Answer 14

1. Mouth: no chemical digestion, only mechanical
2. Stomach: HCL denatures proteins; pepsin chemically digests protein
3. Pancreas: secretes pancreatic proteases, including chymotrysin and trypsin
4. Small intestine: majority of protein digestion; pancreatic proteases chemically digest protein
5. Large intestine: minimal protein digestion

Question 15

What are the functions for protein

Answer 15

• Body structure
• Transport
• Enzymes
• Movement
• Fluid balance
• Protection from disease
• Energy

Question 16

What is the protein body structure

Answer 16

• Bones, muscles, skin and every body organ contain protein

Question 17

What is the main structural protein

Answer 17

Collagen

Question 18

What is the other key structural protein

Answer 18

Elastin, permits elasticity

Question 19

Function of transport in protein

Answer 19

• Protein tracks in cells allow substances to walk along them, permitting transport around the cell
• Protein channels regulate movement into and out of the cell

Question 20

What is the blood protein and what does it do

Answer 20

• Hemoglobin
• Transports oxygen around the body

Question 21

Function of enzymes in protein

Answer 21

• Most enzymes are proteins
• Speed up rate of reactions

Question 22

Function of movement in protein

Answer 22

• Myosin and actin are found in muscle
• When myosin proteins attach to actin and kink their heads, muscle contraction occurs
• Allow our bodies to produce movement

Question 23

Function of fluid balance in protein

Answer 23

• Water is attracted to positive and negative charges of amino acids in blood proteins
• This draw water into the blood and out of the extracellular space
• If blood proteins are low, fluid can build up in the extracellular space leading to edema

Question 24

Protein protection from disease

Answer 24

• Collagen in skin helps restrict what can enter body
• If infectious agents enter, Y-shaped proteins called antibodies stick to these agents, promoting their removal and limiting the harm they can cause

Question 25

What is the first line of defence and second line

Answer 25

- First line, collagen in skin - Second line, antibodies

Question 26

Function of energy in protein

Answer 26

- Proteins provide 4 kcal/gram - Amino acids for energy is a wasteful process - Body prefers to use protein for its various other functions

Question 27

Synthesis of non-protein substances

Answer 27

- Creatine, DNA, RNA, dopamine and serotonin

Question 28

What is marasmus

Answer 28

- Occurs when energy and protein are deficient - Promotes anemia, dehydration, heart irregularities, body temperate dysregulation

Question 29

What is kwashiorkor

Answer 29

- Believed to occur when protein is deficient, but energy is sufficient - Evidenced by a distended, swollen abdomen and an otherwise slim appearance

Question 30

How can protein promote caloric deficit

Answer 30

- Promoting fullness - Contributing to carbohydrate and lipid metabolism - Requiring more energy to digest and absorb it

Question 31

Protein and muscle growth

Answer 31

- Protein muscle synthesis increases in the 24 hours following weight training - 10g of essential amino acids in the first 2 hours following exercise encourages muscle growth - Milk-based proteins, for instance, increases muscle strength and improves body composition

Question 32

Protein and bone health

Answer 32

- In bone, collagen forms a matrix that minerals (ex. Calcium) harden - However, high protein diets can promote calcium excretion - Overall, high protein diets do not seem to negatively affect bone health

Question 33

Protein and kidney health

Answer 33

- High protein diets tax the kidneys because they have more waste products to excrete - For those with reduced kidney function, consuming protein at the recommended intake level (0.8 g/kg), and not beyond it, is recommended

Question 34

Protein quality factors

Answer 34

- How well a protein is digested - How the types and quantities of amino acids in that protein source match the body's requirements.

Question 35

What is the PDCAAS

Answer 35

- Compares the amino acid content of a food against a standard amino acid profile. The highest score that can be achieved is 1.0

Question 36

What is the DIAAS

Answer 36

- Measures how well amino acids are digested in the ileum and more closely estimates the amount of amino acids absorbed by the body

Question 37

What is the PER

Answer 37

- How much weight an animal gains when consuming a specific amount of protein, divided by the amount of food it consumed

Question 38

What are branched-chain amino acids

Answer 38

- essential amino acids that have a branched side chain - They account for 35-40% of the dietary essential amino acids found in body protein - Have been shown to reduce muscle damage associated with weight training - Can be consumed from whole sources, do not have to come from supplements

Question 39

Animal source of protein

Answer 39

- Animal proteins have more total protein, a higher PDCAAS and are complete proteins - Also, they have vitamin B12 and are higher in vitamin D, iron, zinc and omega-3 fatty acids - However, they are also higher in saturated fat and are absent in fibre, phytochemicals - Also, processed animal products (ex. Deli meats, bacon) increase CVD risk/mortality

Question 40

Risk of vegetarian diets

Answer 40

- They are lower in vitamin D, omega-3 fatty acids, calcium, iron and zinc - Vitamin B12 is only found in animal products (with the exception of nutritional yeast) - Supplementation is recommended if these are not sufficient in diet

Question 41

Benefits of vegetarian diets

Answer 41

- Diets are high in fibre and phytochemicals and low in saturated fats - Vegetarians are more likely to have lower BMIs, total cholesterol and LDL - They are also at lower risk for heart disease, cancer and CVD mortality