Biological Molecules

Question 1

Why can water form hydrogen bonds?

Answer 1

Because it’s a polar molecule

Question 2

What are the characteristics of water?

Answer 2

1) it’s an excellent solvent
2) it has a high specific heat capacity
3) it has a high latent heat of evaporation
4) it’s cohesive
5) can insulate large bodies of water

Question 3

How are monosaccharides joined together?

Answer 3

OH group from one monosaccharide and H from another are removed, forming a glycosidic bond

Question 4

What is the structure of alpha glucose?

Answer 4

Hexose sugar with both OH at the bottom

Question 5

What is the structure of beta glucose?

Answer 5

Hexose sugar with one OH at the top

Question 6

What is the structure of galactose?

Answer 6

Hexose sugar with both OH on top

Question 7

What is the structure of ribose?

Answer 7

Pentose sugar with one OH on top

Question 8

Which monosaccharides form sucrose?

Answer 8

Glucose + Fructose

Question 9

Which monosaccharides make maltose?

Answer 9

Glucose + Glucose

Question 10

Which monosaccharides form lactose?

Answer 10

Glucose + Galactose

Question 11

What is the composition starch?

Answer 11

• 10-30% amylose
• 70-90% amylopectin

Question 12

What is the structure of amylose?

Answer 12

Unbranched chains of alpha glucose in a helix shape (1-4 glycosidic bonds)

Question 13

How does structure of amylose help with its function?

Answer 13

It’s very compact so more of it can be stored in the cell

Question 14

What is the structure of amylopectin?

Answer 14

Branched chains of alpha glucose (1-4 and 1-6 glycosidic bonds)

Question 15

How does the structure of amylopectin help with its function?

Answer 15

It means it has an increased surface area so enzyme can break it down easier.

Question 16

What is the structure of glycogen?

Answer 16

Branched chains of alpha glucose (similar to amylopectin but more side branches)

Question 17

How does the structure of glycogen help with its function?

Answer 17

• It has a large surface area so enzymes can break it down easier.
• its more compact than amylopectin

Question 18

What is the structure of cellulose?

Answer 18

Unbranched chains of beta glucose

Question 19

How are microfibrils and microfibrils formed?

Answer 19

Hydrogen bonds between chains form marco and micro fibrils

Question 20

What is the structure of triglycerides?

Answer 20

One molecule of glycerol + 3 fatty acids

Question 21

How are the fatty acids bonded to the glycerol?

Answer 21

OH group on the fatty acid and the H on glycerol is removed to produce a molecule of water.
The reaction forms an ester bond.

Question 22

Which side of the triglyceride is hydrophobic and which side is hydrophilic?

Answer 22

The head is hydrophilic
The tail is hydrophobic

Question 23

What is the primary use of triglycerides?

Answer 23

Used as energy stores, the hydrolysis of triglycerides releases a lot of energy.

Question 24

What is the structure of phospholipids?

Answer 24

One molecule of glycerol bonded to two fatty acid tails and one phosphate head

Question 25

What is the function of phospholipids?

Answer 25

They form the phospholipid bilayer -> hydrophobic tails inside and hydrophilic heads outside

Question 26

What determines whether a lipid is saturated or mono/polyunsaturated?

Answer 26

The presence of C=C double bond.

Question 27

Where is cholesterol found, and what does it do?

Answer 27

Found in the cell membrane and strengthens it.

Question 28

How does cholesterol strengthen the cell membrane?

Answer 28

It pushes the hydrophobic tails of phospholipids closer together, making the membrane more rigid.

Question 29

What are proteins?

Answer 29

Polymers of amino acids joined together by peptide bonds

Question 30

What is the structure of a single amino acid?

Answer 30

Central carbon atoms surrounded by 4 groups. - amine group (NH2) - hydrogen atom - carboxyl group (COOH) - ‘R’ group

Question 31

What is the significance of the R group?

Answer 31

The identity of the R group influences how the amino acid reacts with other amino acids

Question 32

How does the peptide bond from?

Answer 32

The ‘H’ from the amine group and the ‘OH’ from the carboxyl group are removed

Question 33

What forms the primary structure in proteins?

Answer 33

Peptide bonds form a long chain (polypeptide)

Question 34

What forms the secondary structure of a protein?

Answer 34

Hydrogen bonds between nearby amino acids to form either an alpha helix or a beta pleated sheet

Question 35

What forms the tertiary structure in a protein?

Answer 35

More bonds form between the different R groups to give the protein a 3D structure.

Question 36

What bonds are formed in the teritary structure?

Answer 36

- Hydrogen bonds - Disulphide bonds - Ionic bonds - Polar interactions

Question 37

What forms the quaternary structure of a protein?

Answer 37

From interactions of multiple polypeptide chains.

Question 38

What is a prosthetic group?

Answer 38

Non-protein compounds which are required for protein function

Question 39

What is the structure of globular proteins?

Answer 39

- Spherical - hydrophobic amino acids tucked in } - hydrophilic amino acids expose out } therefore soluble

Question 40

What do globular proteins tend to be?

Answer 40

Enzymes or hormones

Question 41

What is a conjugated protein?

Answer 41

A globular protein with a prosthetic group attached to them.

Question 42

What is the structure of fibrous proteins?

Answer 42

- long and thin - their primary structure consists of a repetitive sequence of amino acids - they are strong and insoluble - less seneitive to change in enviroment

Question 43

What is the structure of collagen?

Answer 43

Consist of three polypeptide chains wrapped around each other in a helix shape to form a quaternary structure. It is held together by hydrogen bonds.