1 - Biological Molecules

Question 1

What is a mole?

Answer 1

A unit for measuring a substance

Question 2

What is a molar solution?

Answer 2

The amount of solution that contains one mole of solute in each litre of solut

Question 3

What does one mole contain?

Answer 3

The same amount that there is of carbon atoms in carbon-12

Question 4

Condensation reaction

Answer 4

A reaction that produces water

Question 5

Hydrolysis reaction

Answer 5

When polymers are broken down by the addition of water

Question 6

α-glucose

Answer 6

2 hydrogen on the top, two hydroxides on the bottom

Question 7

β-glucose

Answer 7

1 hydrogen, then a hydroxide on the top, one hydroxide and one hydrogen on the bottom (alternate ways)

Question 8

General formula of monosaccharides

Answer 8

(CH2O)n

n can be any number from 3 - 7

Question 9

Glucose + Glucose –>

Answer 9

Maltose

Question 10

Glucose + Fructose –>

Answer 10

Sucrose

Question 11

Glucose + Galactose –>

Answer 11

Lactose

Question 12

What are monosaccharides joined by?

Answer 12

Glycosidic bonds formed by condensation reactions

Question 13

Where is starch found?

Answer 13

In animal cells

Question 14

What is starch made from

Answer 14

α-glucose homopolypeptide

Question 15

Structure of starch

Answer 15

Made up of chains of alpha glucose molecules linked by glycosidic bonds that are formed by condensation reactions

Question 16

How starch is related to its function

Answer 16

Insoluble - doesn’t effect water potential – water isn’t drawn in by osmosis
Large – doesn’t diffuse out of cells
Compact – lots can be stored in a small space
When hydrolysed forms α-glucose – easily transported and readily used in respiration
Branched form has many ends – each can be acted on by enzymes simultaneously meaning glucose monomers are realised very quickly

Question 17

Why does starch have a curved structure?

Answer 17

It forms α 1-4 glycosidic bonds

Question 18

Why is starch insoluble?

Answer 18

Forms α 1-4 glycosidic bonds. This gives it a curved structure, meaning all it OH groups are on the inside, making it insoluble

Question 19

Where is glycogen found?

Answer 19

Animal cells, bacteria cells, but never plant cells

Question 20

Structure of glycogen

Answer 20

Made up of chains of alpha glucose molecules linked by glycosidic bonds that are formed by condensation reactions
(shorter chains, but is more highly branched than starch)

Question 21

How is glycogen suited to its function

Answer 21

Insoluble – does not draw water out by osmosis
Insoluble – does not diffuse out of cells
Compact – lots can be stored in a small space
More highly branched that starch – more enzymes can work simultaneously so it can be broken down into glucose monomers more readily.

Question 22

What is the function of starch and glycogen?

Answer 22

Energy storage

Question 23

What is the function of cellulose?

Answer 23

Provides support and rigidity

Question 24

What is the structure of cellulose?

Answer 24

Has straight unbranched chains. These run parallel to each other, allowing hydrogen bonds to form cross-linkages between adjacent chains

Question 25

How is cellulose structure linked to its function?

Answer 25

Made from β-glucose – can from long, straight, unbranched chains
Cellulose chains run parallel to one another and are cross-linked with hydrogen bonds – adds strength
Molecules are grouped to form microfibrils – provides yet more strength

Question 26

What are triglycerides made from?

Answer 26

1 glycerol and 3 fatty acids

Question 27

What er phospholipids made from?

Answer 27

1 glycerol, 1 phosphate molecule, and 2 fatty acids

Question 28

How do you know if a lipid is saturated or unsaturated?

Answer 28

Saturated have no C=C bonds

Unsaturated have C=C bonds

Question 29

What holds glycerol and fatty acids together?

Answer 29

Ester bonds

Question 30

What do phospholipids form in water

Answer 30

A bilayer

Question 31

What part of the phospholipid id attracted to water

Answer 31

Head - hydrophilic

Tail - hydrophobic

Question 32

Why do phospholipids position themselves in this manner?

Answer 32

They are polar molecules

Question 33

Primary structure of proteins

Answer 33

The order of amino acids

Question 34

Secondary structure of proteins

Answer 34

A long polypeptide chain is twisted into a 3D shape of an α-helix. Hydrogen bonds form

Question 35

Tertiary structure of proteins

Answer 35

The α-helix folded and twisted even more complex (often specific) shape

Disulfide bridges (bonds) – strong
Ionic bonds – formed between carboxyl and amino groups. Weaker than disulfide bonds, easily broken by pH changes 
Hydrogen bonds – easily broken

Question 36

Quaternary structure of proteins

Answer 36

The combination of many different polypeptide chains and associated non-proteins.