topic 1 biological molecules

Question 1

suggest method to measure quantity of reducing sugar in solution {2}

Answer 1

.filter/dry precipitate
.measure mass

Question 2

describe test to show solution contains non reducing sugar {3}

Answer 2

.Heat with HCl
.nuetralise with alkaline
.heat with benedicts solution, form red precipitate

Question 3

describe how amino acid join so COOH and NH2 at either end {2}

Answer 3

.COOH join NH2 form peptide bond .so there’s free COOH and NH2 at either end

Question 4

State and explain the property of water that help to buffer change in temp {2}

Answer 4

. high specific heat capacity
. takes bare energy to change temp

Question 5

Give two ways in which the hydrolysis of ATP is used in cells {2}

Answer 5

1. provide energy for other reactions 2. add phosphate to substance AND make it more reactive

Question 6

Give two ways in which ATP is a suitable energy source for cells to use {2}

Answer 6

. releases energy instantly
. can rapidly re-synthesise
. phosphorylates other compounds AND make them more reactive
. does not leave cells

Question 7

Give two properties of water that are important in the cytoplasm of cells and explain how {4}

Answer 7

1. Polar molecule - .Acts as a solvent
2. solvent - .Metabolic reactions occur faster in solution

Question 8

Explain how cellulouse molecules are adapted for their function in plant cells {3}

Answer 8

.Unbranched & long
.linked by H bonds to form fibrils .give strength to cell walls

Question 9

Explain 5 properties making water important for organisms {5}

Answer 9

1. metabolite- in condensation/hydrolysis
2. solvent- so metabolic reactions occur
3. high specific heat capacity- buffers change in temperature
4. large latent heat of vaporisation- provides a cooling effect via evaporation
5. cohesion betw water molec- supports columns of water in plants 6. cohesion- surface tension for smol organisms

Question 10

Describe the structure of DNA {5}

Answer 10

.polymer of nucleotides
.nucleotide formed from deoxyribose,phosphate grp and nitrogenous base;
.phosphodiester bonds between nucleotides
.double helix held by H bond
.hyd bond between AT & CG

Question 11

Describe test for protien {2}

Answer 11

.add buiret reagent
.turns purple

Question 12

Describe induced fit model of enzyme action and how enzyme acts as catalyst {3}

Answer 12

.catalyst reduces activation energy .enzyme substrate complex forms .active site slightly change to be complimentary to substrate/break bonds in substrate

Question 13

Describe how phosphodiester bond formed betw 2 nucleotides in DNA {3}

Answer 13

.condensation reaction
.betw phosphate & deoxyribose .catalysed by DNA polymerase

Question 14

Describe how ester bond is formed in phospholipid {2}

Answer 14

.condensation reaction by removing water
.ester bond between glycerol and fatty acid

Question 15

Describe how an ATP molecule is formed from its component molecules {4}

Answer 15

1. condensation reaction
   2.of adenine and ribose sugar
2. and 3 phosphates
   4.using ATP synthase

Question 16

Describe chemical reactions in conversion of polymers to monomers, and monomers to polymers. Give 2 examples of polymers & their monomers & bonds? {5}

Answer 16

.monomers to polymers= condensation, forming chemical bond by removing water
.polymer to monomer= Hydrolysis, breaking chemical bond between monomers by using water
.Cellulouse = made of beta glucose monomers, glycosidic bond
.Protien= made of amino acids, peptide bond

Question 17

Describe and explain 2 features of starch that make it a good storage molecule {2}

Answer 17

.Branched=glucose readily released by hydrolysis
.Insoluble=doesnt affect water potential
.Coiled=compact many molec in small area

Question 18

Describe test for lipid in food {2}

Answer 18

.Dissolve food in ethanol, then add water
.white emulsion

Question 19

Describe how ATP is resynthesised in cells {2}

Answer 19

. During respiration
. from ADP and phosphate
. by ATP synthase