bio molecules

Question 1

one organelle in mucus secreting cell

Answer 1

Golgi apparatus package protiens

Question 2

what reducing sugars would you expect in chewing

Answer 2

maltose
salivary amylase breaks down starch

Question 3

lipid test

Answer 3

dissolve in alcohol
add water
white cloudy emulsion

Question 4

how do cells maintain constant shape

Answer 4

cant change shape
cell wall made of muerin

Question 5

chemical reactions to form polymer from monomer vice versa

Answer 5

condensation reaction
join monomers together, chemical bond releases h20
hydrolysis breaks chemical bond between monomers using water
AA - polypeptide - protein - peptide
alpha glucose - starch - glycosidic bond

Question 6

how can energy drink provide boost during running

Answer 6

contain carbs - rise BGC quick
increase glucose to muscles from respiration - faster respiration so more energy release
contains glucose so glucose can be absorbed faster

Question 7

why does maltase only break down maltose and at normal body temp

Answer 7

3d shape of enzyme - active site is comp to maltose
enzyme is a catalyst so lowers activation energy by forming e-s complex

Question 8

competitive inhibitor vs non comp inhibitor

Answer 8

inhibitor prevent enzyme substrate complexes forming
Competitive- inhibitor similar shape to substrate so bind to active site but can be overcome by adding more substrate
non comp - inhibitor bind to site on enzyme other than active site
changing shape of active site so cant be overcome by adding more substrate

Question 9

starch and cellulose similarities and differences

Answer 9

polysaccharides containing glucose carbon hydrogen and oxygen
glycosidic bonds 1.4
starch is alpha cellulose beta
1,6 branched but cellulose unbranched
starch cant form fibrils

Question 10

how are sieve cells adapted for mass transport

Answer 10

few organelles so easier flow

Question 11

how are companion cells adapted

Answer 11

mitochondria releases ATP 4 AT
ribosomes and RER 4 proteins carriers and enzymes

Question 12

non reducing sugar test

Answer 12

heat with acid
neutralise
heat with Benedict’s
red ppt

Question 13

milk after hydrolysis w lactate sweeter than cows lactose milk

Answer 13

lactose - hydrolysed to glucose and galactose so more sugars
sugars produced sweetener than lactose so Dif receptors stimulated

Question 14

after Benedict’s how to quantify sugar solution

Answer 14

filter and dry ppt and find mass

Question 15

how does use of colorimeter provide repeatability

Answer 15

quantitive
colour change subjective
standardised method

Question 16

reducing sugar test

Answer 16

Benedict’s to sample
heat in boiling water bath
brick red

Question 17

measuring quantity of sugar in solution

Answer 17

sugar dilutions of known conc
heat each sample with Benedict’s
use colorimeter to measure absorbance
plot calibration curve
conc x absorbance y
line of best fit
repeat Benedict’s with unknown sample and measure absorbance
read of calibration curve find conc associated with unknown samples absorbance

Question 18

how is triglyceride formed

Answer 18

1 glycerol
3 FA
condensation ad removal of 3 waters and add 3 ester bonds

Question 19

why are h bonds important in cellulose

Answer 19

hold cellulose molecules together
cross links
strong in large numbers

Question 20

why use animals instead of humans in tests

Answer 20

mammals react in same way as humans
smaller to keep in lab
can use in large numbers

Question 21

how can monitoring ph show lipase presence

Answer 21

lipid hydrolyses to fatty acids which lower ph of mixture
lipase increase rate of digestion of lipid and absorption of fatty acids

Question 22

how are fatty acids important in formation of new cells

Answer 22

make phospholipids in membrane more means more membranes
fatty acids - respire release energy so more triglycerides more energy released and energy used for cell production

Question 23

why does DNA polymerase move in opposite directions

Answer 23

DNA polymerase only bind to the 3′ end of a parental strand work in one direction build the new strand in the 5′ to 3′ direction only.
dna has antiparallel strands
arrangement of nucleotides on both ends are different
dna polymerase has a specifc shaped active site
so only binds to substrate with comp shape

Question 24

why’s it important 2 maintain constant blood ph

Answer 24

proteins and enzymes in blood sensitive to ph changes
which could change shape and tertiary structure so fewer enzyme and substrate complexes

Question 25

how does structure of proteins depends on amino acids it contains

Answer 25

structure determined by r group and position of AA
primary is the sequence of amino acids
2ndry h bonds
quaternary bonds between polypeptides
creates active site for enzymes

Question 26

similarities vs differences in dipeptides

Answer 26

have NH2 COOH
different r groups

Question 27

how does peptide bond form between amino acids

Answer 27

condensation between NH2 COOH

Question 28

Humans and grasshoppers have very similar percentages of each base in
their DNA but they are very different organisms.
Use your knowledge of DNA structure and function to explain how this is
possible.

Answer 28

different genes
triplets in different order
so different amino acids

Question 29

how does dna of virus differ from other organisms

Answer 29

no base pairing as a doesnt equal t
c doesnt equals g
so dna isn’t double stranded, it is single stranded

Question 30

structure of dna 5 marks

Answer 30

polymer of nucleotides
each nucleotide - phosphate, deoxyribose, nitrogenous base
phopshodiester bonds between nucleotides
double helix dna strands held by hydrogen bonds
hydrogen bonds and pairing between adenine and thymine - cytosine and guanine

Question 31

how are phosphodiester bonds formed between nucleotides

Answer 31

condensation reaction
between phosphate and deoxyribose
catalysed by DNA polymerase

Question 32

role of single stranded dna fragments and dna nucleotides

Answer 32

fragments - template determining order of nucleotides
nucleotides form comp base pairs

Question 33

how is atp formed by its component molecules

Answer 33

adenine ribose and 3 phosphates
condensation reaction via atp synthase

Question 34

why does length of muscle decrease as atp conc increases

Answer 34

more atp hydrolysed
more energy release
more muscle contraction

Question 35

atp as useful energy source

Answer 35

releases energy instantaneously
phosphorylates other compounds making them more reactive
rapidly resynthesised
it is also released in small bursts and only a single reaction
and it cant be stored

Question 36

At the end of a sprint race, a runner continues to breathe rapidly for some
time. Explain the advantage of this.

Answer 36

lactic acid build up
oxygen used to break down lactate
and convert it back to pyruvate or glucose

Question 37

5 properties of water

Answer 37

metabolise in condensation and hydrolysis

solvent so metabolic reactions can occur and faster

high specific heat capacity buffers changes in temp - gains and loses lots of heat w out changing temp

large latent heat of vaporisation cooling effect

cohesion so supports columns of water and surface tension

Question 38

role of phosphate sodium and iron ions in cells

Answer 38

phosphate affects osmosis and water potential
used to produce atp and phopshrylates other compounds making them more reactive

sodium - co transport of glucose and amino acids creating sodium conc gradient
affects wp

iron - hb binds with oxygen

Question 39

describe procedure to stop a reaction

Answer 39

boil or add strong acid denaturing enzymes
or add high conc inhibitor so no enzyme substrate complexes