Protein

Question 1

Which compounds are contained in protein?

Answer 1

C, H, O, N

Question 2

What are the building blocks of protein?

Answer 2

Amino acids

Question 3

What is the chemical structure of protein?

Answer 3

Amino group NH2, Carboxylic group COOH and a unique side group which differentiates each amino acid - R group.

Question 4

Name the essential amino acids

Answer 4

Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine

Question 5

Name the conditionally essential amino acids

Answer 5

Arginine
Cysteine
Glutamine
Glycine
Proline
Tyrosine
Carnitine
Taurine
Ornithine

Question 6

Name the non-essential amino acids

Answer 6

Alanine
Aspargine
Aspartic Acid
Citrulline
Glutamic Acid
Proline
Serine
Selenocysteine

Question 7

What is the difference between oligopeptide and polypeptide?

Answer 7

Oligopeptide has several amino acids and polypeptide has 50 amino acids and more.

Question 8

In a normal weight person what percentage accounts for protein?

Answer 8

17%

12kg in 70kg man

Question 9

Name the functions of proteins

Answer 9

1. As building materials for growth and maintenance e.g skin, muscles and GI tract cells.
2. As enzymes e.g digestive enzymes.
3. As hormones e.g thyroid, insulin, melatonin, dopamine
4. As immunoproteins e.g immunoglobulins and antibodies.
5. Transport proteins e.g albumin, transferrin, R-protein.
6. As acid-base regulators e.g protein have a negative charge and hydrogen have a positive charge maintaining an acid base balance in the body.
7. As regulators of fluid balance e.g proteins attract water. Can cause oedema, kidney disease.

Question 10

What are conjugated proteins?

Answer 10

Proteins joined to non-protein components e.g glycoproteins (proteins bound to carbohydrates found in mucus and connective tissue) and Proteoglycans which make up extracellular matrix that surrounds tissues and organs.

Question 11

What is protein synthesis?

Answer 11

In response to stimuli/messages, cells synthesise proteins according to the genetic information provided by the DNA in the nucleus of each cell. DNA dictates the order in which amino acids must be linked together to form a given protein.

Question 12

What are the endogenous sources of protein and how much does it account for in our body?

Answer 12

desquamated mucosal cells
digestive enzymes
glycoproteins
These proteins are digested and the amino acids absorbed and may total to about 70g or more of protein per day.

Question 13

What are the exogenous sources of protein?

Answer 13

All whole foods contain protein including fruit. These include:
animal products: meat, fish, poultry and dairy (excluding butter and sour cream which are composed of fat).
plant products: grains, legumes, beans, nuts, seeds and vegetables.

Question 14

What is transamination?

Answer 14

If a particular non-essential amino acid is not available in the body, it can make it from another.

Question 15

Which vitamin is needed in the synthesis of some non-essential amino acids?

Answer 15

B6 Pyridoxine

Question 16

What is protein in the body available as?

Answer 16

tissue components

Question 17

What is deamination?

Answer 17

When amino acids are broken down, they are stripped off their nitrogen and used for energy either immediately or stored as fat for later use.

Question 18

Explain the process of what happens to ammonia

Answer 18

The liver converts in into a less toxic compound called urea (urea cycle) and returns urea to the bloodstream. The kidneys filter urea out of the blood and amino nitrogen ends in urine. The remaining carbon fragments of amino acids may be used to produce glucose, ketones, cholesterol or fat.

Question 19

List the amino acids used in the urea cycle and whether they are essential or not?

Answer 19

Citrulline (non-essential)
Arginine (conditionally essential)
Ornithine (conditionally essential)

Question 20

How do you work out the RDA for protein?

Answer 20

Multiply weight in kg by 0.83 which gives you the amount of protein in grams.

Question 21

What are the health effects of excessive protein?

Answer 21

1. Osteoporosis (adult bone loss) due to an increase in calcium excretion.
2. Weight gain - protein rich foods are often fat rich.
3. Kidney disease - high protein intake increases the work of the kidneys (deamination, ammonia, urea).

Question 22

What are the health effects of protein deficiency in developed countries?

Answer 22

1. Acute kwashiorkor (recent food deprivation) - children who are thin for their height, low albumin levels and swelling of abdomen (oedema).
2. Chronic Marasmus (long term food deprivation) - children who are short for their age and don’t get enough calories and protein.

Question 23

Which other groups of people may become protein deficient?

Answer 23

1. children
2. teenagers
3. older people
4. Anorexia nervosa sufferers
5. recovering patients
6. homeless people

Question 24

Name the amino acid linked to enhancing epithelial tight junctions? What food sources which might help.

Answer 24

Glutamine
cabbage juice
Bone broth (especially beef bones)

Question 25

List 3 transport proteins and their specific vitamins or minerals that aid transport.

Answer 25

1. Transferrin - iron
2. Albumin - calcium
3. R-protein - B12