paper 1

Question 1

what is the role of starch

Answer 1

store of glucose for energy

Question 2

what is structure of amylose

Answer 2

long unbranched
angles of glycosidic bonds give it a coiled structures (compact)

Question 3

structure of amylopectin

Answer 3

long and branched
side branches allow enzymes that breakdown the molecule to have easy access
glucose release quickly

Question 4

features of starch

Answer 4

insoluble not affecting water potential so doesn’t swell making it good for storage

Question 5

structure of glycogen

Answer 5

lots of side branches compact and good for storage

Question 6

cellulose structure

Answer 6

long unbranched chains of beta glucose
straight chains joined by H-Bonds forming microfibrils
structural support provided

Question 7

what are the properties of triglycerides

Answer 7

mainly used as energy storage molecules
long hydrocarbon tail of FA contains lots of chemical energy- released when broken down
because of these tails lipids contain twice as much energy per gram as carbs

insoluble in water doesn’t affect WP so water doesn’t enter by osmosis
Bundle together forming droplets, tails face inwards and shield themselves with glycerol heads

Question 8

properties of phospholipids

Answer 8

make up bilayer of CM controlling what leaves and enters cell
heads are hydrophilic
tails are hydrophobic
meaning water soluble substances cant easily pass through
membrane acts as a barrier

Question 9

what does a functional protein have

Answer 9

1 or more polypeptide chains

Question 10

what is the role of hydrogen bonds in protein structure

Answer 10

form bond between partially neg oxygen and partially pos nitrogen make it coil or fold more (secondary structure)

Question 11

what is the role of ionic bonds in protein structure

Answer 11

tertiary structure
more bond form between different parts go polypeptide chain, further coiling and folding the chain

Question 12

what is the role of disulphide bridges in protein structure

Answer 12

form whenever 2 molecules of aa cysteine come close together, sulphur of one bonds to sulphur of the other S=S

Question 13

structure of enzyme relating to function

Answer 13

spherical tightly folded polypeptide chains
soluble and have a role in metabolism

Question 14

structure of antibodies relating to function

Answer 14

involved in immune response
2 light chain and 2 heavy chains
variable regions

Question 15

structure of structural proteins relating to function

Answer 15

physically strong
consist of a long-polypeptide chains lying in parallel with cross-links

Question 16

how many pp chains does collagen have

Answer 16

3
tightly coiled

Question 17

what can enzymes do (not basic definition)

Answer 17

enzymes catalyse a wide range of intra/extracellular reactions that determine structures and functions from cellular to whole organism
involve in hydrolysis and DNA replication

Question 18

what bonds form between 2 nucleotides

Answer 18

phosphodiester bond

Question 19

is rna short of long

Answer 19

short

Question 20

what is pi used for

Answer 20

when inorganic phosphate is released during hydrolysis of atp can be used to phosphorylate other compounds and make them more reactive

Question 21

inorganic ions occur….

Answer 21

in solution in the cytoplasm and bodily fluids of organisms
some in high conc and some in low

Question 22

iron inorganic ions

Answer 22

Fe2+
haemoglobin large protein that carries o2 around the body in RBC’s
made up of 4pp chains with fe2+ at the centre
fe2+ binds to oxygen in Hb when fe2+ binds to oxygen fe3+ until o2 released

Question 23

hydrogen ions inorganic ions

Answer 23

ph is calculated based on the conc of h+ in environment
more h+ means its more acidic
enzyme controlled reactions affected by pH

Question 24

sodium ions inorganic ions

Answer 24

glucose and amino acids need a bit of help crossing CM
glucose/AA transport into a cell (co-transport)

Question 25

phosphate ions inorganic ions

Answer 25

attached to another molecule DNA, RNA and ATP have phosphate allowing nucleotide to join yp to form polynucleotides

Question 26

nucleus structure and function

Answer 26

jelly-like nucleoplasm nucleolus nuclear envelope nuclear pore chromatin control cell activities (by controlling transcription of DNA) pores allow substances t9 move between cytoplasm and nucleus

Question 27

prokaryotic features

Answer 27

much smaller smaller ribosomes cell wall contains murine (glycoprotein)

Question 28

what does the xylem do

Answer 28

cohesion tension theory, water and dissolved mineral ions moves from the roots to the stem and leaves

Question 29

what does the phloem do

Answer 29

carry organic substances (sucrose) source to the sink

Question 30

structure of xylem

Answer 30

hollow tubes formed from dead cells joined one way and no end walls lignin providing structural support for plant

Question 31

whats cohesion

Answer 31

water molecules attracted to others by hydrogen bonding

Question 32

whats a transpiration stream

Answer 32

water and dissolved mineral ions through xylem vessels from roots to leaves

Question 33

whats transpiration

Answer 33

evaporation of water from plants surface especially leaves

Question 34

whats cohesion tension theory

Answer 34

1) water transpires from leaves, decreasing water potential in leaf cells so water drawn out xylem by osmosis 2) creating tension more water down up through xylem as h2o cohesive due to hydrogen bonding, water moves as a continuous column 3) allows more water to enter roots by osmosis (water potential at roots decreases)

Question 35

increased light intensity effect on transpiration

Answer 35

increases stomata open due to more co2 for photosynthesis increased water vapour leaving

Question 36

increased humidity effect on transpiration

Answer 36

decreases as decreased conc gradient of water vapour in and out so slower diffusion in and out

Question 37

increased temp effect on transpiration

Answer 37

increases h2o has increased KE so more h2o evaporates increasing conc gradient of water vapour so faster diffusion

Question 38

increased wind effect on transpiration

Answer 38

increases h2o removed from around stomata increasing conc gradient and increased diff rate

Question 39

whats source

Answer 39

where sucrose produced

Question 40

whats sink

Answer 40

where sucrose needed (roots as they cant photosynthesise)

Question 41

phloem structure

Answer 41

column with sieve tube elements containing no nucleus and few organelles they are living cells that are elongated and join to the end to form long tubes companion cells carry out living functions for sieve cell (energy for AT)

Question 42

what maintains conc gradient in phloem

Answer 42

enzymes conc gradient of solutes between source and sink by regulating conc of solutes at sink by hydrolysis them

Question 43

mass flow hypothesis

Answer 43

source: sucrose AT from cells in source into phloem by companion cells, which have mitochondria decreased water potential at phloem water enters phloem by osmosis and high hydrostatic pressure at phloem (volume of water increase) sink: sucrose AT out phloem into sink cells water potential of sink cells decrease so water enters by osmosis decreased hp at sink overall pressure gradient pushes solutes to sink

Question 44

ringing trees

Answer 44

removing section of the bark (which contains phloem) so solutes accumulate above the removed area as no phloem for them to flow through to sink creating a bulge pressure applies from above sucrose accumulates

Question 45

radioactive tracers

Answer 45

plant supplied with co2 containing radioactive c14, often done in air tight container radioactive carbon incorporated into glucose when plants photosynthesise covering glucose to sucrose (moved by translocation) movement traced using radioactive tracers (black)

Question 46

evidence against mass flow hypothesis

Answer 46

organic materials have to reach sink to flowers so how can sap move up and down plant at the same time sucrose rate of movement doesn't change no matter how steep conc gradient is