Section 1: Biological molecules

Question 1

what is a condensation reaction

Answer 1

joining 2 molecules together
monomer to polymer
larger molecule is formed
covalent bond
water is released

Question 2

what is a hydrolysis reaction

Answer 2

polymer to monomer
breaking down larger molecule into a smaller one
water molecule is used

Question 3

how many carbons are in a alpha glucose

Answer 3

six

Question 4

what is the ratio of carbon : hydrogen : oxygen in glucose

Answer 4

c : 2h : o
1 : 2 : 1

Question 5

what is the name of two monosaccharides joined together

Answer 5

disaccharide

Question 6

glucose x 2 is what disaccharide?

Answer 6

maltose

Question 7

glucose + galactose is what disaccharide?

Answer 7

lactose

Question 8

glucose + fructose is what disaccharide?

Answer 8

sucrose

Question 9

what bond forms between 2 monosaccharides

Answer 9

glycosidic bond when it forms a disaccharide

Question 10

what does the prefix glyco mean

Answer 10

sugar (carbohydrates)

Question 11

name function, location and structure of starch (in plants)

Answer 11

polysaccharide storage molecule
long straight chain amylose molecules and branched amylopectin
stored in chloroplasts in membrane bound starch grains
can be broken down into glucose for respiration to release energy

Question 12

describe function, location and structure of glycogen (in animals)

Answer 12

polysaccharide storage molecules
more branched amylopectin
shorted 1-4 amylose chains
can be broken down into glucose for respiration to release energy
more compact , forms glycogen granules in places like liver and muscle cells

Question 13

Describe the function, location and structure of cellulose

Answer 13

B-glucose , straight un-branched, parallel Hydrogen bonds with cross linkage makes it strong micro-fibrils form fibres , plant cell walls prevents from bursting

Question 14

What are the features of lipids

Answer 14

Made up of carbon oxygen hydrogen
Insoluble in water
Soluble in organic solutions

Question 15

What are the roles of lipids

Answer 15

energy source : more energy released than carbs + releases water when oxidised
Waterproofing: waxy lipid cuticle, oily skin secretion
Insulation: slow conductors of heat so retain body temperature well
Protection: around delicate organs

Question 16

What are the adaptations of lipids that make it good for their roles

Answer 16

High ratio of bonds to carbon atoms make it excellent energy source
Low mass to energy ration excellent storage molecule
Large, non polar and insoluble doesnt effect water potential so wont diffuse or osmosis out of cells
Important water source due to high H:O ratio

Question 17

What is the reaction forming a triglyceride? state equation and bond

Answer 17

Glycerol + 3 fatty acids —> triglyceride + 3 water
condensation reaction
ester bond formed

Question 18

What does a phosphate and 2 fatty acids make

Answer 18

Phospholipid

Question 19

Describe features of phospholipid and their uses

Answer 19

Polar molecule : forms bilayer and barrier due to hydrophilic head and hydrophobic tail
Structure allows them to form glycolipids

Question 20

How would cellulose give something strength

Answer 20

Straight un branched chain
Many hydrogen bonds and cross linkage
Chains lie side by side (micro) fibrils

Question 21

Give two feature and explain why starch is a good storage substance

Answer 21

Insoluble : water isnt drawn out or into cells by osmosis/ doesnt effect water potential
Coiled : Very compact lots can be stored
Large : wont diffuse out cells
Branched : multiple ends acted on by enzymes rapidly

Question 22

What is the difference between a globular and fibrous protein

Answer 22

Globular are spherical and soluble
Fibrous are elongates and not water soluble

Question 23

What proteins are globular

Answer 23

Enzymes
Hormones
transport
Antibodies

Question 24

What proteins are fibrous

Answer 24

Keratin
Collagen
Myosin, actin

Question 25

What are four factors effecting enzyme action

Answer 25

Temperature
PH
Substrate concentration
Enzyme concentration

Question 26

What are buzz words to use in an enzyme question

Answer 26

Acts as catalyst
Lowers activation energy
Enzymes substrate complex
Induced fit

Question 27

Describe structure of an amino acid

Answer 27

Amino group (-NH2)
Carboxylate group (-COOH
R group
Hydrogen (-H)

Question 28

Primary structure description

Answer 28

Polymerisation
Peptide bonds -OH and -H
Long polypeptide chain
Specific order

Question 29

Secondary structure description

Answer 29

3-D shape
Hydrogen bonds -NH and -COOH
A helix or b pleated sheets

Question 30

Tertiary structure

Answer 30

Disulphide bridges
Ionic bonds
Hydrogen bonds

Question 31

Quaternary structure description

Answer 31

Multiple polypeptide chains together for example haemoglobin has 4

Question 32

What is a prosthetic group and give example

Answer 32

Prosthetic groups are non-peptide (non-protein) compounds that mostly attach to proteins and assist them in different ways.

Such as Haemgroup (Fe containing) in Haemglobin

Question 33

What are nucleotides made up of

Answer 33

Phosphate group, pentose sugar and nitrogen base

Question 34

How would heat effect the tertiary structure

Answer 34

Will damage the ionic H or disulphide bonds and break the shape

Question 35

How may a change in the primary structure of a globular protein result in a change of three-dimensional structure

Answer 35

Sequence of amino acid changes
Different places where bonds are
different folding into tertiary

Question 36

How does temperature effect enzyme action

Answer 36

temp falls = less kinetic energy = less frequent collisions = rate of reaction decreased

Question 37

How does ph effect enzyme action

Answer 37

Alters shape
Bonds break
Active site deformed
cant form e-s complex
Rate of reaction decrease

Question 38

Describe 5 features of DNA

Answer 38

Double helix provides strength
Phosphodiester backbone protects from chemicals
THe Higher the C-G pairings more stable the DNA because C-G has 3 hydrogen bonds
Very stable and can be passed on generation to generation
Base pairings ensure this
Large and carry’s lots of information

Question 39

When does DNA replication happen

Answer 39

Nuclear division
Cytokinesis

Question 40

Describe DNA replication briefly

Answer 40

Semi-conservative
DNA helicase break H bonds linking bases
Double helix separates
Both strands act as templates
Free nucleotides attach to bases
DNA polymerase join agacent nucleotides together

Question 41

What bonds do DNA helicase and polymerase break and form

Answer 41

DNA helicase hydrolyse hydrogen bonds
DNA polymerase form phosphodiester bonds

Question 42

What is ATP made up of

Answer 42

Nitrogen base
Ribose
3 phosphates

Question 43

What are the uses of ATP

Answer 43

Metabolic processes - making starch from glucose
Movement - muscle contraction
Active transport - changes shape of carrier proteins
Secretion - needed to form lysosomes
Activation of molecules - addition of phosphate to glucose at start of glycolysis

Question 44

Why is ATP a good energy source

Answer 44

Releases less energy than glucose in more manageable quantities
Hydrolysis of ATP to ADP is immediate energy source only requires one reaction unlike glucose
ATP —> ADP + Pi is reversible

Question 45

What are the 5 features of water and the mnemonic

Answer 45

Metabolite (hydrolysis)
Solvent (dissolves gasses, enzymes, wastes)
High heat capacity (due to hydrogen bonds)
Large latent heat of vaporisation (evaporation of sweat very effective)
Cohesion (tendency of molecules sticking together ex. xylem tube)
My sofa has large cushions

Question 46

Does water have a charge

Answer 46

No however is dipolar as Oxygen has slight negative change and hydrogen has a slight positive charge so 2 water molecules are often attracted to each other hydrogen bonds between water molecules and covalent bonds betweeen 2 hydrogen atoms and one oxygen atom.