BCH 204

Question 1

What are the four main roles of dietary protein?

Answer 1

1. It is an essential structural component of all cells
2. Maintains production of important secretions ( enzymes and hormones)
3. Synthesizes plasma proteins
4. Source of energy

Question 2

What is the main function of carbohydrate in a diet?

Answer 2

Energy production

Question 3

What are the roles of carbohydrate in diet?

Answer 3

1. Energy production
2. High carbohydrate diet encourages synthesis of enzymes such as glucokinase and other enzymes of the HMP shunt
3. Low CHO diet encourages synthesis of gluconeogenesis, fatty acid oxidation and amino acid catabolism enzymes

Question 4

What storage form of carbohydrate is affected by diet and exercise ?

Answer 4

Glycogen

Question 5

What enzymes are up regulated in high carbohydrate diet ?

Answer 5

Glucokinase, HMP enzymes, triacylglycerol synthesis enzymes

Question 6

What enzymes are upregulated in low carb diets?

Answer 6

Gluconeogenesis, amino acid catabolism and fatty acid oxidation enzymes

Question 7

Which macronutrient is more efficient at protein sparring: carbs or fats?

Answer 7

Carbs - carbohydrates

Question 8

What is the protein sparing effect of carbohydrates ?

Answer 8

Carbohydrates are used for ATP production allowing proteins to perform its other jobs in building and repair of tissues

Question 9

What do essential fatty acids help maintain?

Answer 9

Cell membrane structure, integrity and function, synthesis and transport of prostaglandins, fat metabolism

Question 10

List 3 roles of lipid in the diet.

Answer 10

Energy source, membrane structure, stored as triacylglycerol

Question 11

What is nitrogen fixation ?

Answer 11

Conversion of nitrogen gas to ammonia by nitrogen fixing bacteria eg Azobacter

Question 12

What diseases are associated with high fat intake ?

Answer 12

Atherosclerosis and Cardiovascular Disease

Question 13

What enzyme present in bacteria helps it convert nitrogen to ammonia ?

Answer 13

Nitrogenase

Question 14

What is the order of nitrogen cycle?

Answer 14

Nitrogen fixation( by nitrogen fixing bacteria e.g azobacter) ➡️ nitrification ( by nitrifying bacteria eg nitrosomonas converts ammonia to nitrites, nitrobacter converts nitrites to nitrates ➡️ nitrates are used by plants and converted to amino acids and protein➡️ consumed by animals including humans.

Question 15

How do humans obtain nitrogen ?

Answer 15

By eating plant and animal protein

Question 16

What is positive nitrogen balance?

Answer 16

Nitrogen intake > nitrogen excretion
( In pregnant women and children )

Question 17

What causes negative nitrogen balance ?

Answer 17

Senescence/ aging , illness, starvation

Question 18

Which fiber is a polymer of glucose and affects stool bulk ?

Answer 18

Cellulose

Question 19

What is dietary fiber ?

Answer 19

Plant components that cannot be digested by human enzymes and affect digestive health

Question 20

What is the function of pectin ?

Answer 20

Slows gastric emptying, decreases blood glucose levels and lowers serum cholesterol

Question 21

Which fibers are water soluble and digestible

Answer 21

Pectin and gum

Question 22

Which fibers are insoluble and non digestible

Answer 22

Cellulose and lignin

Question 23

What is the function of pectin ?

Answer 23

Slows gastric emptying, decreases blood glucose levels and lowers serum cholesterol

Question 24

Which fiber is partially digestible and insoluble ?

Answer 24

Hemicellulose

Question 25

Which fiber binds cholesterol and carcinogens?

Answer 25

Lignin

Question 26

What is the effect of dietary fiber on sugar absorption ?

Answer 26

Slows down sugar absorption

Question 27

List the dietary fibers had their chemical nature

Answer 27

Cellulose ➡️glucose polymer Hemicellulose ➡️ pentoses, hexoses, ironic acid Lignin ➡️aromatic alcohols Pectin ➡️partially esterified rhamnogalactouronan Gum➡️ rhamnose, galactose, xylose , arabinose

Question 28

What are the sources of the dietary fiber

Answer 28

Cellulose - unrefined cereals, wheat Hemicellulose - unrefined cereals, some fruits and vegetables Lignin - woody part of vegetables Pectin - fruits Gum - dried beans, oats

Question 29

How does dietary fiber reduce colon cancer risk

Answer 29

By binding carcinogens, reducing intracolonic pressure thereby speeding the transit of carcinogens

Question 30

What is the biological value (BV) of protein

Answer 30

It is the ration of nitrogen retained to nitrogen absorbed. It shows how efficiently absorbed protein has been used

Question 31

What is Net protein Utilization

Answer 31

It measures the percentage of protein ingested that is retained in the body . It denotes the nutritional quality and availability of protein

Question 32

What is the formula for Net Dietary Protein Value

Answer 32

NDPV = Intake of Nitrogen x6.25 x NPU

Question 33

What does NDPV denote

Answer 33

The quality and quantity of dietary protein

Question 34

What does the Protein Efficiency Ratio (PER) measure

Answer 34

Weight gain per gram of protein consumed . It evaluates the protein quality

Question 35

What is chemical score

Answer 35

The essential amino acid of protein compared to that of egg protein