Biological molecules

Question 1

Define: “Anabolism”

Answer 1

Synthesis of small particles into larger molecules

Question 2

Define: “Catabolism”

Answer 2

Breakdown of larger molecules to smaller particles

Question 3

Give 4 examples of micromolecules

Answer 3

Amino acids, Fatty acids, Monosaccharides, Nucleotides

Question 4

Give 4 examples of macromolecules

Answer 4

Proteins, Lipids, Carbohydrates, DNA/RNA

Question 5

Give 3 examples of monosaccharides

Answer 5

Glucose, Fructose, Galactose

Question 6

Give 3 examples of disaccharides

Answer 6

Sucrose, Lactose, Maltose

Question 7

Give 4 examples of polysaccharides

Answer 7

Glycogen, Starch, Cellulose, Inulin

Question 8

State the general formula of carbohydrates

Answer 8

Cn(H2O)n

Question 9

State the general formula of monosaccharides

Answer 9

(CH2O)n

Question 10

State the difference between alpha-gluclose & beta-glucose

Answer 10

Alpha-glucose has its hydroxide group below the first carbon atom, while beta-glucose has its hydroxide group above the first carbon atom.

Question 11

State 2 roles of monosaccharides in living organisms

Answer 11

Source of energy in respiration (glucose) & building blocks for larger molecules.

Question 12

Explain how monosaccharides (glucose) are good sources of energy.

Answer 12

Due to its large number of CH bonds, when broken up, it releases energy (ATP)

Question 13

Explain the difference between a condensation reaction and hydrolysis in monosaccharides

Answer 13

Condensation: How 2 monosaccharides join together to form disaccharides
Hydrolysis; Addition of water, reverse of condensation—breaks up a disaccharide to form 2 monosaccharides

Question 14

Which polysaccharide(s) make up starch?

Answer 14

Alpha-glucose amylose and amylopectin

Question 15

State the difference between amylopectin and amylose

Answer 15

Amylose: A polysaccharide joined by many 1,4-linked alpha glucose molecules. (Spring-like structure)
Amylopectin: A polysaccharide joined by many 1,4-linked alpha glucose molecules & 1,6- linked alpha gluclose molecules (Branched-structure due to 1,6 linkages)

Question 16

Which polysaccharide(s) make up glycogen?

Answer 16

Alpha-glucose amylopectin

Question 17

Which polysaccharide(s) make up cellulose?

Answer 17

Beta-glucose, 1-4 beta linkages

Question 18

List the properties of cellulose (4)

Answer 18

Very high tensile strength, provides support, responsible for cell expansion, freely premeable
OR
> Higher tensile strength

> freely permeable

> mechanical strength

> inelastic

Question 19

List 3 lipids

Answer 19

Triglyceride, phospholipids, and cholesterol

Question 20

Describe the structure of Triglycerol

Answer 20

3 fatty acids that link to a glycerol molecule, forming an ester bond.

Question 21

State the properties of lipids (6)

Answer 21

Hydrophobic, non-polar, energy reserves, insulation against loss of heat, buoyance, metabolic source of water

Question 21

Explain why lipids are good for storage (3)

Answer 21

doesnt dissolve in water/bodily fluids, doesnt affect osmotic balance, has higher calorific values than carbohydrates

Question 22

Describe the structure of phospholipids

Answer 22

2 fatty acids and one phosphate group attaches to the glycerol, phosphoester bond between phosphate and glycerol and ester bond between the amino acids and glycerol.

Question 23

Explain why unsaturated lipids (plants) are healthy.

Answer 23

Dissolves easily / lower melting point

Question 24

state the role of proteins (Forms: __) (5)

Answer 24

Haemoglobin, antibodies, makes up all enzymes, keratin (makes hair, surface layer of skin, nails), Collagen (makes up our bones and wall of arteries)

Question 25

State the name of the bond between amino acids that form proteins.

Answer 25

Peptide bond

Question 26

Describe the structure of an amino acid

Answer 26

Amine group - R group - carboxylic acid (NH2 - R - COOH)

Question 27

(In proteins) Explain what a 'primary structure' is

Answer 27

A simple strand structure joined by peptide bonds. ( a.a - a.a - a.a - a.a )

Question 28

(In proteins) Explain what a 'secondary structure' is

Answer 28

Composed of two structures: Alpha-Helix : Polypeptide chain coiled due to the attraction of molecues, forming a helix shape. Beta-Pleated sheet : polypeptide; a much looser, straighter shape.

Question 29

(Proteins) Give examples of where alpha-helix is found and where beta-pleated sheet is found.

Answer 29

Alpha-Helix : hemoglobin and myoglobin Beta-pleated sheet: silk protein

Question 30

(In proteins) Explain what a 'tertiary structure' and the 3 bonds that can be found in it and where

Answer 30

The secondary structure coils and folds to form 3-dimensional shapes that contains hydrophobic interactions between R groups. Four bonds included: -Disulphide bonds (Between cysteine molecules) -Hydrogen bonds (R) -Ionic bonds (R)

Question 31

(In proteins) Explain what a 'quaternary structure' is with one example

Answer 31

A 4 unit structure, each unit containing a different combination of amino acids. E.g. Haemoglobin

Question 32

Explain the difference between globular proteins and fibrous proteins, as well as 2 examples for each.

Answer 32

Globular: Protein whose molecules are spherical/ball-shaped (tertiary structure) (Curls up so non-polar, hydrophobic R groups point into the center of the molecule, while the polar, hydrophylic R groups remain on the outside) E.g., hemoglobin, myoglobin Fibrous: Proteins with long strands, insoluble Fibrous: Protein with long strands, insoluble and have structural roles (quaternary structure) E.g., keratin, collagen

Question 33

Describe the structure of water

Answer 33

Unshared negative electrons on oxygen give it a slight negative charge

Question 34

State 5 properties of water

Answer 34

1) High specific heat capacity 2) High latent heat of evaporation 3) Cohesive 4) Good solvent 5) Less dense when solid

Question 35

What is the monomer of protein

Answer 35

Amino acids

Question 36

What is the monomer of lipids

Answer 36

Fatty acids (and glycerol)

Question 37

What is the monomer of carbohydrates

Answer 37

Monosaccharides

Question 38

What is the monomer of DNA/RNA/Nucleic acids

Answer 38

Nucleotides

Question 39

Why is it important to have 2 types of glucose (alpha & beta)? (List 2-3)

Answer 39

Greater chemical variety, alpha glucose is respiratory, beta glucose is structural

Question 40

Why are phospholipids arranged the way they are in cell membranes?

Answer 40

Polar heads mix with water; non-polar tails do not. Thus, heads face water on both sides with tails to middle

Question 41

In an amino acid, what does the R-group represent?

Answer 41

Rest of the molecule/side chain

Question 42

Give an example of an R-group (2)

Answer 42

Hydrogen, Methyl group (CH3)

Question 43

What is the molecular formula for amylose?

Answer 43

C6H10O5