Unit 14: Control and Coordination
Define the term sensitivity. (2)
(the ability to) detect / sense,changes in the environment/stimuli;
to respond/ react (to thosechanges);
State the function of the jelly coat that surrounds egg cells.
to prevent more than one sperm fertilising the egg / stops other sperm entering ;
Which statements about mitosis are correct?
1 Mitosis produces genetically identical cells.
2 Mitosis produces genetically different cells.
3 Mitosis produces gametes.
4 Mitosis produces body cells
A. 1 and 3
B. 1 and 4
C. 3 and 4
D. 2 and 3
B. 1 and 4
Which is likely to decrease as an animal population increases?
A. consumers
B. food shortage
C. pollution
D. producers
D. Producers
Polluted water can be purified at sewage treatment works.
State one reason why it is necessary to treat polluted water before it is used as drinking water.
prevent (spread of named water borne) diseases /infections ; remove/kill, (named) pathogens
Ovulation is controlled by the release of a hormone.
The hormones responsible for the changes in a girl's body when puberty takes place are the
same as the hormone that controls ovulation.
Name this hormone, State how hormones travel around the body.
Name: Oestrogen;
Mode: (in the) blood/ bloodstream/
plasma ;
Describe the advantages of cross-pollination.
any two from: allows, variation/genetic diversity ;plant more likely to survive(named) environmental change;
resistance to disease;(ability to) evolve;ref. to fitness; AVP;
In some plants, H is the dominant allele for hairy stems and h is the recessive allele for smooth stems.
A pair of these plants produce 37 offspring, 18 with hairy stems and 19 with smooth stems.
What are the most likely genotypes of the parents?
A. HH X HH
B. Hh X Hh
C. Hh X hh
D. HH X hh
C. Hh X hh
Ammonium ions are an important part of the nitrogen cycle. They can be converted into nitrate ions, which are used by plants and protoctists such as diatoms.
State the name of the process of converting ammonium ions into nitrate ions.
Nitrification
Fertilisers, herbicides, and insecticides can all pollute water.
List two other sources of water pollution.
any two from:(named) factory waste /chemicals; pesticides ;acid rain;oil/petrol ;(named) rubbish / litter/AW ;(named component of) sewage; nuclear waste ;AVP ;
Reflex actions allow the body to respond rapidly to changes in the external environment.
Outline the pathway in a reflex arc in response to shining a bright light into the eye.
any three from:
stimulus/light (detected by)
retina/rod/cone/receptor;
reference to (electrical) impulse/ electrical signal ;
sensory neurone → relay /connector, neuron → motor neurone ;
reference to
synapses between neurones ;
effector/(circular) muscles (in the iris), contract / respond;
One purpose of seed banks is to reintroduce plant species into their natural environment.
A survey was done to find out why some reintroduction programmes are not successful.
Some of the seeds in the reintroduction programmes did not germinate.
State the conditions that are necessary for seeds to germinate.
(3)
any three from:
water;
oxygen;
suitable/optimum, temperature;
AVP;
Two tall sunflower plants were crossed. 25% of the offspring produced were dwarf.
Explain how it is possible for two tall parent plants to have this percentage of dwarf offspring.
the allele for dwarfism is,
recessive /t;
both parents are heterozygous
(so do not express the allele)
In a food chain, mice are primary consumers that feed on corn and the snakes are secondary consumers that feed on mice.
The total biomass of the snakes is much less than the total biomass of the mice.
Explain why the total biomass of the snakes is less than the total biomass of the mice.
Use the term energy in your answer.
any three from:
1. snakes occupy a higher trophic level than mice ;
2 (most of the) energy is lost between the trophic levels ;
3. examples of energy loss ;;
5 not enough energy to sustain larger biomass (of snakes) at higher trophic levels / AW
Some farmers spray their crops with insecticides to kill pests such as aphids.
Explain the benefits of killing pests.
reduced / no, damage to crops;ora
increased, yield / quality (of the
crop);ora
more, income / profit ;ora
because more, sugar / amino
acids, available for growth ;ora
reduced disease transmission /
AW ;ora
Explain the effects of the hormone released when a person is in a dangerous situation on the following organs:
1. Heart
2. Liver
3. Lungs
4. Eyes
Heart: increased, pulse /heart, rate/beat;
Liver: conversion of glycogen to glucose/ increased blood glucose(concentration);
Lungs: increase, (rate) /depth, of breathing;
Eyes: dilated pupils / radial muscles (in iris) contract;
Mutations are always inherited in single-celled organisms that reproduce asexually but are not always inherited in organisms that reproduce sexually.
Explain why.
any four from: mutations are found in the DNA; asexual reproduction offspring are, genetically identical to /clones of, the parent / AW ;
(so) any existing mutations (in parent DNA) will be inherited /AW ;
sexual reproduction (usually)involves two parents ;
mutation will only be in one of the parents ;
mutation will only be in some of the gametes ;
meiosis does not result in genetically identical cells ;
Insulin is a protein made by cells in the pancreas.
Explain the role of the mRNA molecule that is synthesized from the gene coding for Insulin.
any three from:
mRNA, is a copy of the gene (for insulin) ;transfers instructions from, DNA/ nucleus, to, cytoplasm /ribosome / ;passes through ribosome;
sequence of bases determines the order of amino acids
Snap bean plants are legumes which have root nodules that contain nitrogen-fixing bacteria.
Suggest the advantage to farmers of having snap bean plants that have a large number of root nodules.
any one from:
farmers, do not have to add (nitrogen) fertiliser /use less fertiliser ;
idea of increased yield / more profit per hectare ;
(snap beans / beans / plants) grow, faster / better;
Food shortages that result in famine can be caused by many factors.
Describe how drought can contribute to famine.
any three from:
1. drought is a lack of, water /
rainfall ;
2. destruction of, crops ;
3. seeds / plants, can’t germinate;
4. soil erosion / desertification ;
5. plants need water for photosynthesis ;
6. plants wilt ;
7. less, food/water, for livestock;
Explain the advantages of coordinating the response to a dangerous situation using both the nervous system and the endocrine system.
nervous system, responds quickly / immediately;ora
idea that(nerve) impulses travel to, (specific) muscles / (adrenal)glands/effector(s) ;
effects of endocrine system are long-lasting;ora
hormones/adrenaline travels throughout the body / allows multiple (target) organs to respond (to the same signal);
idea that less energy required than to have nerves going to every, cell/tissue;
stimulate both voluntary and involuntary responses(simultaneously);
more effective / enhanced, response (than using one system alone)
The placenta provides a large surface area for the ............................................... of oxygen and carbon dioxide between maternal and fetal blood. Dissolved nutrients also pass across the placenta. Examples of dissolved nutrients are: ............................................... acids,............................................... and ............................................... . Antibodies pass from the maternal blood giving natural ...............................................immunity to the baby for some infections that the mother has had or has been vaccinatedagainst. Each different type of vaccine contains one or more ...............................................taken from the ............................................... that causes the disease.
1 diffusion / exchange;
2 amino / fatty;
3&4 ;;max. two from:glucose(named) vitamins(named) minerals / ions/ salts glycerol fatty acids amino acids
5 passive ;
6 antigens ;
7 pathogen / (micro)organism
AAbnormal red blood cells occur because of a mutation in the gene for haemoglobin.
The allele for the normal form of haemoglobin is HbA.
The allele for the abnormal form of haemoglobin is HbS.
Determine the probability of two heterozygous parents having a child who does not have the HbS allele.
1/4 (25%)
parental phenotypes
unaffected / sickle trait / (sickle)
carrier / AW x unaffected /
sickle trait / (sickle) carrier ;
Parents: HbAHbS X HbAHbS
Gametes: HbA HbA
HbS HbS
Offsprings: HbAHbA
HbAHbS
HbAHbS
HbSHbS
Researchers investigated the effect of adding cattle manure (cattle faeces) to fields where snap bean plants, Phaseolus vulgaris, were grown. Cattle manure contains some protein.
Explain how protein in the cattle manure is converted to the type of ions that plants can absorb.
any five from
1. protein, broken down / digested / decomposed, to amino acids ; by decomposers / fungi /bacteria in terms (in context of breakdown of manure / protein);
2 ref to use of proteases ;
3 deamination (of amino acids / proteins) /described;
4 production of, ammonia / ammonium ions / NH3/NH4+;
5 ammonium (ions), converted to, nitrite / nitrate (ions) / NO3-/ NO2-;
6 ref. to, nitrification /nitrifying bacteria ;
7 AVP ; e.g., nitrite to nitrate ion
Complete the sentences by writing the missing words in the spaces.Carbon dioxide is a greenhouse gas. Greenhouse gases trap .................................................in the atmosphere. Water vapour is the most common greenhouse gas in the atmosphere.Another greenhouse gas is methane which is released from .................................................and ................................................. . Carbon dioxide and methane released from humanactivities over the past 200 years have contributed to the .................................................greenhouse effect.Other atmospheric pollutants can cause acid rain. One of these is................................................. which is a waste gas from some power stations.One source of pollution in both aquatic and terrestrial ecosystems is................................................. plastics.
gap 1:
heat OR long-wave/infra-red, radiation ;
gaps 2 and 3, any two from paddy fields/rice farming (named) animals / livestock decay / decomposition (by bacteria) rubbish tips / landfill sewage/dung / feces (natural) gas extraction/fracking melting tundra waterlogged soil/swamp/ marsh biomass burning / forest fires/peat fires;;
gap 4:enhanced ;
gap 5:sulfur dioxide /sulfur trioxide/nitrogen oxide(s);
gap 6:non-biodegradable /micro- / non-recyclable /single-use ;