Paper 4 Theory (Extended)

1(a) (group of) organisms that can reproduce ;
to produce fertile offspring ;

2

1(b) pinna(e) / external ears ;
mammary glands / milk glands / production of milk / lactating /
suckling / breast feeding / nipples /
diaphragm ;
(three) bones in the middle ear ;
(four) different types of teeth / two sets of teeth ;
sweat glands ;
enucleated red blood cells ;
uterus / placenta / navel / AW ;

2

1(c) select, parent(s) / sheep / AW, with, fine / thin, hairs (in wool)
OR
use Merino sheep from South Africa and NZ sheep ;
cross them together / use artificial insemination / IVF / AW ;
measure /  the hairs in the wool of all the offspring ;
select offspring with, fine / thin, hairs (in wool) ;
cross / , offspring together ;
continue / repeat, selection and/or breeding ;
over many generations ;


5 max 4 if no reference to quality of wool

1(d) features are, adaptive / adaptations (for environment) ;
caused by , the, environment / surroundings ;
competition between individuals for (named) resource(s) ;
reference to named selective agent(s) ;
slow(er) ;
increase in fitness ;
explained: ability to survive AND reproduce (in natural environment) ;
maintains (genetic) variation / less (genetic) variation in
selective breeding ;
random mating ;


2(a) carbon dioxide is, raw material / substrate / reactant / AW ;
concentration of carbon dioxide is higher outside leaf than inside (so
carbon dioxide diffuses into the leaf) ;


2(b) subtract the concentration of carbon dioxide at the end from the
concentration at the start / AW ;
divide by the time (taken) / per unit time ;
ref. to taking (rate of) respiration into account ;


2(c)(i) light intensity ;
water (supply) ;
humidity ;


2(c)(ii) increases and, reaches a plateau / remains constant / ‘levels off’ ;
increases (between 10 °C) to 30 °C / levels off at 30 °C ;
any comparative use of figures for rate with units at least once ;


2(c)(iii) 36 ;;

2(c)(iv) temperature is the limiting factor (over whole range) ;

increased temperature increases, kinetic energy / KE, (of molecules) ;
increases rate of diffusion of carbon dioxide (into leaf) ;
temperature, influences / affects, (activity of) enzymes ;
idea of more (effective) collisions between substrate molecules and
enzymes (in plant) / more enzyme-substrate complexes formed ;
more carbon dioxide is, fixed / used in photosynthesis / converted into
sugar ;
carbon dioxide (concentration) is not limiting ;


2(c)(v)

B shows that:
rate of photosynthesis is, higher / continues to increase, if carbon
dioxide is increased (at all temperatures  ;

2(d) prediction:
rate of photosynthesis, remains constant / decreases / slows ;
any explanation one from:
enzymes / active sites, are denatured (at high temperatures) ;
stomata close, so, little / no, carbon dioxide can enter leaves ;
plant is adapted to survive at high temperatures ;

3(a) accommodation ;
antagonistic ;
peripheral ;
optic ;
brain ;


3(b) involves, proteins / carriers / pumps (in neurone membrane) ;
(named) ion(s) bind to, proteins / carriers / pumps, to move ions  ;
move ions, against concentration gradient / from low to high
concentration ;
using energy ;
e.g. change in shape of carrier (protein)


3(c) general marking point
neurotransmitters move across, synapse / gap / junction /;
atropine
neurotransmitter cannot, bind to / enter / reach, receptors ;
therefore no impulses (along, next / postsynaptic, neurone) /
no impulses reach the CNS ;
no sensitivity to stimuli / feels no pain / painkiller ;
no, contraction of muscle / response ;
depressant ;
eserine
neurotransmitter stays in, synapse / synaptic gap ;
neurotransmitter can bind to receptor (rather than stay in synapse) ;
continuously stimulates the, next / postsynaptic, neurone ;
(more) impulses are sent (in, next / postsynaptic, neurone) ;
repeated, contraction of muscle / response ;
stimulant ;

3(d) anabolic steroids increase, muscle mass /;
gives athletes unfair advantage / ref. to cheating / unethical / immoral ;
(named), side effect / effect on health ;
can be banned from taking part in sport if found using them ;
ref. to illegality ; ; e.g. can lose sponsorship / loss of reputation /

4(a) tissue ;
cell structure ;
cell ;
organ ;


4(b)

name of structure function letter on Fig. 4.1
testis

production of
sperm / produces or
releases testosterone

C ;
sperm duct transports sperm but not urine D ;
urethra

passage for urine and
seminal fluid through the
penis

A ;

prostate gland

secretes / produces,
seminal fluid / nutrient-rich
fluid / alkaline fluid / AW

E ;

scrotum
/ scrotal sac contains testes B ;

4(c)
X on testis / label line on testis with X ;



4(d)(i) one set of chromosomes
4(d)(ii) 23

6(a)(ii) growth ;
producing cells ;
increase length of shoot / elongation of shoot ;


6(b) dividing cell / cell division / mitosis, needs (lot of) energy ;
carry out aerobic respiration ;
provide / release, energy ;
(for) a named function in dividing cells ;
e.g. movement of chromosomes
making cell wall
making new (named) molecules (e.g. protein / DNA)
making (named) organelle(s)

6(c)(i) auxin ;

6(c)(ii) auxin

/ hormone:
made in the, shoot / stem, tip ;
moves away from the tip ;
moves to / collects on, lower side of stem ;
stimulates cell elongation ;
stem, bends / grows, upwards ;


6(d) plants have different, structures / parts / specialised cells ;
idea that different parts / specialised cells, have different,
functions / roles / features ;
idea that specific proteins are required in, parts / specialised cells ;
genes code for proteins ;
therefore some genes, are required / are not required ;
; e.g. idea that waste of (named) resource(s) if all genes
expressed