Biological molecules

Question 1

Example of monosaccharides

Answer 1

glucose, fructose, galactose

Question 2

How are monomers joined

Answer 2

by condensation reaction (eliminating a water molecule)

Question 3

Bond in disaccharides and polysaccharides

Answer 3

glycosydic

Question 4

Alpha glucose vs beta glucose molecule

Answer 4

OH on right on top for beta and bottom for alpha

Question 5

Maltose is formed from

Answer 5

2 glucose molecules

Question 6

Sucrose is formed from

Answer 6

glucose and fructose

Question 7

Lactose is formed from

Answer 7

galactose and glucose

Question 8

Glycogen and starch are made from

Answer 8

alpha glucose

Question 9

cellulose is formed from

Answer 9

beta glucose

Question 10

Glycogen structure and function

Answer 10

1,4 and 1,6 glycosydic bonds
Many branches- more ends for enzymes to react with so energy released more quickly
Compact
Insoluble- doesn’t change water potential of cells

Question 11

Amylose structure and function

Answer 11

made from alpha glucose
Unbranched
1,4 glycosydic bonds
Coiled and compact
insoluble- doesn’t affect water potential

Question 12

Amylopectin structure and function

Answer 12

1,4 and 1,6 glycosydic bonds
Branched
More ends so faster enzyme action
Insoluble- doesn’t affect water potential

Question 13

Cellulose structure and function

Answer 13

Unbranched chains of beta glucose
Very strong and exerts outward pressure- keeps cell turgid so doesn’t burst
Insoluble

Question 14

What are microfibrils

Answer 14

cellulose chains with hydrogen bnds between them

Question 15

What does benedict’s reagent test for

Answer 15

reducing sugars

Question 16

What are reducing sugars

Answer 16

all monosaccharides and some disaccharides (e.g maltose)

Question 17

What happens t benedict’s reagent during the reaction

Answer 17

The sugar donates an electron changing Copper (II) sulphate into copper (I) oxide. Must HEAT the solution.

Question 18

Positive test result for benedict’s

Answer 18

solution turns from blue to brick red

Question 19

Test for non-reducing sugar

Answer 19

Do benedict’s test, if it doesn’t work then:
Add HCl and heat in water bath. This hydrolyses the disaccharide bonds, turning them into monosaccharides.
Add sodium hydrogencarbonate (neutrilise or benedict’s won’t work).
Re-do

Question 20

What are lipids soluble in

Answer 20

organic solvents e.g alcohols

Question 21

Structure of triglycerides

Answer 21

one lipid molecule and three fatty acids
Joined by ester bonds in condensation reactions

Question 22

Do saturated or unsaturated lipids have higher mp

Answer 22

saturated as they are more tightly packed

Question 23

Structure and function of triglycerides

Answer 23

Many energy-storing c-h bonds
large and insoluble- doesn’t affect water potential
Release water when oxidised

Question 24

Phospholipid structure

Answer 24

hydrophilic head and hydrophobic tail so can form bilayer
polar

Question 25

Test for lipids

Answer 25

Add ethanol and shake positive- cloudy white emulsion

Question 26

Bond between amino acids

Answer 26

peptide

Question 27

Primary structure

Answer 27

sequence of amino acids

Question 28

secondary structure

Answer 28

shape of chain of amino acids- lpha helix or beta pleated sheet

Question 29

Tertiary structure

Answer 29

3D shape formed from twisting of folding disulphide bridges hydrogen bonds ionic bonds

Question 30

Globular vs fiborous proteins

Answer 30

Globular- compact (enzymes) Fibrous- long (keratin)

Question 31

Test for proteins

Answer 31

Biuret's reagent- tests for peptide bonds Will turn from blue to purple

Question 32

Induced fit model

Answer 32

Shape not exact fit- slightly moulds to fit

Question 33

Non-competetive inhibitors

Answer 33

bind at allosteric site

Question 34

Why is DNA a stable molecule

Answer 34

Phosphodiester backbone protects more reactive nitrogen group

Question 35

By what process is DNA replicated

Answer 35

semi-conservative replication

Question 36

Which enzymes are involved in DNA replication

Answer 36

DNA helicase and DNA polymerase

Question 37

ATP structure

Answer 37

ribose, adenine and three phosphates

Question 38

How does ATP release energy

Answer 38

ATP releases energy when hydrolysed into ADP and a phosphate molecule. This is catalysed by ATP hydrolase. Bonds between phosphate molecules are unstable so takes little energy to break them.

Question 39

Properties of ATP

Answer 39

broken down in a single step to release a manageable amount of energy

Question 40

# 7 Properties and function of water

Answer 40

Polar Good metabolite- e.g condensation reactions Solvent- gasses atc. can diffuse through it High heat capacity- minimal temperature fluctuations so good habitat (buffer) Large latent heat of vapourisation- provides cooling effect Strong cohesion- supports columns of water Good surface tension- animals etc. can land on its surface

Question 41

Purpose of Hydrogen ions

Answer 41

control pH

Question 42

Purpose of iron ions

Answer 42

in haemoglobin

Question 43

Use of sodium ions

Answer 43

used in co-transport of glucose

Question 44

Phosphate ions use

Answer 44

in ATP and DNA