Module 2.1.2 Biological Molecules

Question 1

What are the 3 Monosaccharides?

Answer 1

Glucose
Galactose
Fructose

Question 2

What are the 2 types of glucose?

Answer 2

Hexose form - Alpha & beta

Question 3

What are the 2 types of galactose?

Answer 3

Hexose form - Alpha & beta

Question 4

Is Fructose a pentose or hexose?

Answer 4

Pentose due to the shape but still has 6 carbons

Question 5

What are the 3 disaccharides?

Answer 5

Maltose
Sucrose
Lactose

Question 6

How are disaccharides bonded?

Answer 6

Glycosidic bonds

Question 7

What is maltose made up of and what bonds do they form?

Answer 7

2 alpha glucose + 1:4 glycosidic bonds

Question 8

What is sucrose made up of and what bonds do they form?

Answer 8

Alpha glucose & fructose + 1:2 glycosidic bonds

Question 9

What is lactose made up of and what bonds do they form?

Answer 9

Beta glucose & Beta galactose + 1:2 glycosidic bonds

Question 10

What is a disaccharide?

Answer 10

2 monosaccharides linked together with glycosidic bonds

Question 11

What is a polysaccharide?

Answer 11

Many monosaccharides linked together via glycosidic bonds

Question 12

What are the 3 polysaccharides?

Answer 12

Starch
Cellulose
Glycogen

Question 13

What is starch & what bonds is it linked by?

Answer 13

A polymer of alpha glucose linked by 1:4 glycosidic bond

Question 14

What are the 2 different types of starch?

Answer 14

Amylose & Amylopectin

Question 15

What is the difference between amylose & amylopectin?

Answer 15

Amylose - helical (1:4 glycosidic bond)
Amylopectin - branched (1:4 + 1:6 glycosidic bond (at point of branch))

Question 16

What is cellulose and what is it linked by?

Answer 16

A polymer of beta glucose (1:4 glycosidic bond) - linear chains cross linked via hydrogen bonds

Question 17

What is glycogen & what bonds is it linked by?

Answer 17

A polymer of alpha glucose (1:4 + 1:6 glycosidic bonds (at point of branch))

Question 18

What is glycogen and what bonds is it linked by?

Answer 18

A polymer of alpha glucose + (1:4 & 1:6 glycosidic bonds (at point of branch))

Question 19

What type of reaction makes glycosidic bonds?

Answer 19

A condensation reaction (water is released)

Question 20

What are the properties of water?

Answer 20

The oxygen in water is more electronegative than the hydrogen (the atoms spend more time orbiting oxygen)
Oxygen is slightly negative + hydrogen is slightly positive (unequal share of electrons)
Water is non polar (allows the molecules to form hydrogen bonds between the slightly positive hydrogen & slightly negative oxygen of the different water molecules)
Water is cohesive (the forces between water molecules) & adhesive (the forces between the water molecules & the surface it is attached to)
The hydrogen bonds are weak between the oxygen & hydrogen molecules but water forms many - strong
Density (ice is less dense so nutrients in the water below can still circulate)
Transparent
Has a high specific heat capacity

Question 21

What are the different important functions of water?

Answer 21

Water is a solvent (polar substances can dissolve e.g. glucose but not non polar)
Water is a medium for chemical reactions
Water is a transport medium -> (animals - blood plasma, plants - (xylem for mineral ions & water), (phloem for dissolved sugars)
Water is a coolant (sweat - evaporation)
Water is a habitat (aquatic organisms)
Is a major component of all cells & has important roles in cells (e.g cytoplasm - animal & plant cells)
Has a role in synthesising & breaking down biological molecules (condensation & hydrolysis reactions)

Question 22

What is an amino acid?

Answer 22

The monomers that make up proteins

Question 23

What are amino acids made from?

Answer 23

An amine group
A Carboxyl group
A variable ‘R’ group
A hydrogen

Question 24

How many amino acids are there?

Answer 24

20

Question 25

What makes amino acids different from eachother?

Answer 25

The R group

Question 26

What is the bond that joins two amino acids together?

Answer 26

A peptide bond

Question 27

What is a dipeptide?

Answer 27

Two amino acids joined by a peptide bond

Question 28

What is a polypeptide?

Answer 28

3 or more amino acids joined together by peptide bonds

Question 29

What are the different structures of a protein?

Answer 29

Primary Secondary Tertiary Quaternary

Question 30

What is the primary structure of a protein?

Answer 30

The sequence of amino acids in the protein

Question 31

What is the secondary structure of a protein?

Answer 31

The shape of the amino acid Can either be an alpha helix or beta pleated sheet (determined by hydrogen bonding)

Question 32

What is the tertiary structure of a protein?

Answer 32

The 3D shape of the protein Either fibrous or globular

Question 33

What is a globular protein & an example?

Answer 33

A spherical protein that is soluble in water & usually takes a metabolic role in the body Haemoglobin -> water soluble globular protein consisting of 2 alpha helices & beta pleated sheets that each contain a haem group (prosthetic group) -> carries oxygen around the body

Question 34

What are fibrous proteins and what is an example of one?

Answer 34

Thin & long proteins that usually have structural roles in the body Collagen -> fibrous protein that is strong & found in bones, cartilage & connective tissue & the main component of tendons

Question 35

What is the quaternary structure of a protein?

Answer 35

When a protein has multiple polypeptide chains & is held together by hydrogen bonding, disulphide links or ionic bonds Can also contain prosthetic groups (E.g. in haemoglobin)

Question 36

What is the reaction that synthesises the formation of a peptide bond?

Answer 36

Condensation reaction

Question 37

What is the name of the reaction that synthesises the breakdown of a polypeptide into amino acids?

Answer 37

Hydrolysis reaction

Question 38

What does a hydrolysis reaction need?

Answer 38

Water

Question 39

What does a condensation reaction release?

Answer 39

Water molecule

Question 40

What are lipids only soluble in?

Answer 40

Organic solvents e.g. alcohol

Question 41

What are the 2 types of lipid?

Answer 41

Saturated & unsaturated

Question 42

What is a saturated lipid & where would they be found?

Answer 42

Found in animal fats A lipid that doesn’t contain double carbon bonds

Question 43

What is an unsaturated lipid and where is it found?

Answer 43

Found in plants Contains double carbon bonds (Kinked)

Question 44

What are tryglycerides?

Answer 44

Lipid molecules that contain 1 molecule of glycerol & 3 fatty acid molecules

Question 45

What bonds join triglycerides together & in what reaction?

Answer 45

Ester bonds in a condensation reaction