1.5 Principles of human nutrition

Question 1

What is metabolism?

Answer 1

The ensemble of catabolism and anabolism.

Tightly regulated by homes such as insulin and glucagon that regulate blood sugar levels, or growth hormone

Question 2

What is catabolism?

Answer 2

Chemical reaction that provides nutrients for the body to use

Question 3

What is anabolism?

Answer 3

Chemical reaction that provides energy storage when the body has enough energy.

Question 4

What are the 6 categories of nutrients?

Answer 4

Sugars, proteins, fats, vitamins, minerals and water

Question 5

What are macronutrients?

Answer 5

Chemical elements consumed in large quantities are used to generate energy and/or are involved in growth or repair

Question 6

What are micronutrients?

Answer 6

Chemical elements are required in small amounts. Important in human metabolism, acting as coenzymes or cofactors

Question 7

Examples of macronutrients

Answer 7

Carbohydrates, proteins, lipids and water

Calcium, sodium, potassium, potassium, etc

Question 8

Examples of micronutrients

Answer 8

Vitamins such as zinc, copper, iodine

Question 9

What are essential nutrients?

Answer 9

Essential nutrients are found in the diet and cannot be made from other molecules in the body.

Question 10

How many amino acids are essential out of the 20 in the body?

Answer 10

9 are essential; 2 fatty acids are essential; vitamins are also essentials and some minerals also play crucial roles in maintaining homeostasis

Question 11

What are non-essential nutrients?

Answer 11

Non-essential nutrients can be made from food or are synthesised through metabolic/ enzymatic reactions

Question 12

What are the main characteristics of carbohydrates?

Answer 12

• Main sources of energy. Essential for cell function.
• Readily available and release energy is fast
• Not the most efficient in terms of energy production (4 Kcal/g)

Question 13

What are monosaccharides?

Answer 13

Single units of carbohydrates they cannot be further digested or hydrolysed.

Question 14

What are the examples of monosaccharides?

Answer 14

Molecules of glucose, fructose and galactose

Question 15

What are oligosaccharides?

Answer 15

Carbohydrate chain made of more than 3 monosaccharides

Question 16

What is a triose?

Answer 16

Any group of monosaccharides that contain 3 carbons

Question 17

What is a 5-carbon ring sugar called?

Answer 17

Ribose

Question 18

What are hexoses?

Answer 18

6- carbon sugars.

They are either ketoses (contain a ketone group) or aldoses (contain an aldehyde group)

Question 19

What are hemi-acetal structures?

Answer 19

Sugars with at least 5 carbons easily form ring structures

Question 20

What are disaccharides?

Answer 20

Form when two monosaccharides combine

Question 21

What are examples of disaccharides?

Answer 21

Maltose (glucose+glucose), sucrose (glucose+fructose) and lactose (glucose+galactose)

Question 22

Are disaccharides soluble?

Answer 22

Yes

Question 23

What are polysaccharides?

Answer 23

When more than 10 units are combined.

Question 23

What are polysaccharides?

Answer 23

When more than 10 units are combined.

Question 24

What are examples of polysaccharides?

Answer 24

Starch, glycogen and cellulose

Question 25

What is a homopolysaccharide?

Answer 25

A polysaccharide containing only one type of monosaccharide

Question 26

What is a heteropolysaccharide?

Answer 26

A polysaccharide that contains different types of monosaccharides

Question 27

How is amylopectin formed?

Answer 27

Alpha 1-6 glycosidic bonds

Question 28

What are glycoaminoglycans?

Answer 28

Combine polysaccharides and proteins and are a part of the cell membrane

Question 29

What are lipids?

Answer 29

Heterogeneous group of compounds including, fatty acids (saturated or unsaturated), triglycerides, phospholipids, ketone bodies.

Question 30

What are the functions of lipids?

Answer 30

Metabolic messengers, regulators, providing some cushioning for internal organs or insulation, absorb lipid-soluble vitamins

Question 31

What is the structure of a fatty acid?

Answer 31

Fatty or hydrophobic carbon chain ending with an acidic COOH group

Question 32

What are saturated fatty acids?

Answer 32

All C-C bonds are single covalent bonds

Question 33

What are unsaturated fatty acids?

Answer 33

One or more C-C bonds are double

Question 34

What are cis-polyunsaturate fatty acids?

Answer 34

Bent configuration. Important for the good function of cell membranes.

Question 35

What are trans-fatty acids?

Answer 35

Hydrogen atoms on opposite sides of the carbon, making the molecule more linear. Present in dairy products and hydrogenated oils

Question 36

What is glycerol?

Answer 36

Glycerol is a 3-carbon type of alcohol. It has a hydroxyl group.

Question 37

What are proteins?

Answer 37

Structural elements of the cell: enzymes, hormones, receptors, channels, etc

Question 38

What are essential proteins?

Answer 38

Amino acids which can't be created in our body but can only be received from proper food or diet

Question 39

What are non-essential proteins?

Answer 39

Bodies can produce the amino acid, even if we do not get it from the food we eat.

Question 40

What is the structure of a protein?

Answer 40

Carboxylic acid group: COOH and an amine group NH2. Hence proteins have an N-terminal and a C-terminal R group defines the amino acid and the group can be non-polar, polar, acidic or basic

Question 41

What is a protein made of?

Answer 41

Combination of amino acids linked by peptide bonds

Question 42

What are the three structures of proteins?

Answer 42

- Primary structure: sequence of amino acids - Secondary structure: arrangement of protein chains - Tertiary structure: folding into a globular shape (enzymes, immunoglobins).Protein folding results from three different structural elements beyond primary structure. - Quaternary structure: more than one protein chain (Insulin (and pro-insulin) and haemoglobin)

Question 43

What is glycogenesis?

Answer 43

The synthesis of glycogen molecules from glucose units mostly in liver, small amount in skeletal muscle

Question 44

What is lipogenesis?

Answer 44

Synthesis of triglycerides by combining fatty acids and glycerol molecules Some fatty acids will be used to produce ATP via beta-oxidation and the excess will be re-combined with molecules of glycerol and stored as triglycerides

Question 45

What is gluconeogenesis?

Answer 45

Production of glucose from endogenous metabolites: pyruvate (lactate), glycerol and some amino acids (alanine and glutamine) in the liver

Question 46

What are the pathways involved in carbohydrate, lipid and protein metabolism?

Answer 46

Step 1: Digestion of sugars, lipids and proteins into monosaccharides, fatty acids+ glycerol and amino acids Step 2: further degradation leading to pyruvate and acetylCoA which are essential molecules for the production of ATP. Monosaccharides undergo glycolysis (creating pyruvate), fatty acids undergo beta-oxidation (producing acetylCoA), amino acids can be converted or degraded into various metabolites but only under conditions such as starvation Step 3: Kreb's cycle in mitochondria (main ATP production site)