List two characteristics of a mutant allele
List the 4 chromosome structure mutations
ANS Rare and random
ANS translocation/ inversion/ deletion
/duplication
List 3 mutagenic agents
What type of mutation alters the
chromosome number?
ANS UV light / Xrays / chemicals
ANS non disjunction
List 4 gene mutations
What type of mutation causes Down's
syndrome
ANS substitution/
inversion/insertion/deletion
ANS non disjunction
What is changed by in a gene by a gene
mutation?
Explain how the mother causes the child to
be a Down's syndrome child
ANS the sequence of bases in a gene
ANS non disjunction during meiosis produces
an egg with 24 chromosomes instead of 23
What type of substance would be altered by
a gene mutation?
List the chromosomes in a cell of a Down's
syndrome male.
ANS The sequence of amino acids in a
protein
ANS 45 + XY
Why would a gene mutation be bad for a
metabolic pathway
What can happen to an infertile hybrid plant
to produce a new species
ANS Enzymes that control the metabolic
pathway will not be made
ANS Complete non disjunction that doubles
the chromosome number
What is a plant called, that is produced by
complete non disjunction?
What is the ploidy of a gamete cell?
ANS polyploid plant
ANS Haploid
List 3 features of a polyploid plant
What is the ploidy of the mother cell that
can carry out meiosis?
ANS increased vigour / stronger/ bigger /
greater yield of crop
ANS Diploid
How many cell divisions occur during
meiosis?
Where in a mammal does meiosis occur?
ANS 2
ANS ovary / testes
How can meiosis increase variation?
When does the crossing over of alleles occur
in meiosis?
ANS crossing over of alleles at chiasma /
independent assortment of chromosomes
ANS During the 1st cell division
What type of cells are produced by meiosis?
Explain the difference between the
arrangement of chromosomes at the equator
during meiosis and mitosis.
ANS Gametes
ANS In meiosis the chromosomes go to the
equator with their homologous partners.
Where will meiosis occur in a flowering plant
Explain the term allele
ANS ovary / anther
ANS different forms of a gene
What does the term true bred mean?
ANS the genes are homozygous for a
characteristic eg (AA) or (BB)
If a cross between an unlinked pair of genes
produce a ration of 9 :3 : 3 :1. What ratio
would have been produced if the genes were
linked?
ANS 3 : 1
What is meant by a carrier female?
ANS The women carries a gene for a
genetic condition but does not show it in the
phenotype.
What does a mutagenic agent do?
ANS Increases the rate of mutations
How many cells are produced by mitosis?
ANS 2 diploid cells
What is the definition of a species?
Why have resistant bacteria increased in
the population?
ANS Organisms that can produce fertile
young
ANS Antibiotics have killed the non
resistant bacteria so they have decreased in
population.
If there was pollution in the environment
why would dark moths be best suited.
List the 3 isolation mechanisms (barriers)
ANS They are camouflaged against dark
bark and eaten less by birds.
ANS geographical / ecological /
reproductive
Why do light moths increase in an rural
area?
What is the role of isolation barriers in the
formation of a new species.
ANS camouflaged against light bark so
eaten less by birds and reproduce more
young
ANS Stop population breeding together
(prevent gene flow between populations)
What does I Must Not Smoke stand for
In the case of the peppered moth what is
causing the selection pressure?
ANS Birds eating the moths they can see
easily
What have bacteria become resistant to?
ANS Antibiotics
ANS Isolation of population/ Mutations
occur/ Natural selection occurs / Speciation
or new species formed
List 3 ways to conserve endangered species
ANS Cell banks/ wild life reserves /
captive breeding
What must the parents have in selective
breeding.
Name the enzymes that can join DNA back
together
ANS The same desirable characteristcs.
ANS Ligase enzymes
State what an animal has been selectively
bred for.
What is the name of the chromosome
removed from bacteria during genetic
engineering?
ANS Cattle for meat or milk/ greyhound
dogs for speed (any suitable answer)
ANS Plasmid
State what plants have been selectively
bred for
Name two substances that is produced by
genetically engineered bacteria.
ANS Sunflower plants for greater yield of
oil / greater resistance to disease / greater
yield of crop
ANS Insulin /growth hormone
Explain hybridisation.
ANS Parents are selected to be true bred
for a different desirable characteristics
List two techniques that can locate a gene.
ANS Gene probe / characteristic banding
patterns
What is better about genetic engineering
that selective breeding?
ANS guaranteed product / quick / produce
large quantities of product
Explain the term somatic fusion.
ANS
2 plant protoplast cells fuse together
Name the enzymes that can cut DNA.
How are protoplasts cells produced?
ANS endonuclease enzymes
List two ways the new species formed by
somatic fusion has been improved.
ANS greater resistance to disease or
greater yield of crop
ANS remove cell wall using cellulase enzyme
What is over come by somatic fusion?
ANS Sexual incompatibility
What problem does a fish have if it lives in a
fresh water environment?
What problem does a fish have if it lives in
sea water?
ANS Gains too much water by osmosis
ANS loses too much water by osmosis
Describe the number and size of the
glomerulus in the nephrons of a fresh water
fish.
Describe the number and size of the
glomerulus in the nephrons of a salt water
fish.
ANS Many and large glomeruli
ANS Few and small glomeruli
What process occurs at the glomerulus?
What volume and concentration of urine
would the salt water fish produce?
ANS Filtration of substances out of the
blood
ANS Small volume of concentrated urine.
What volume and concentration of urine
would the fresh water fish produce?
Which way would the salt move in a salt
water fish?
ANS Large volume of dilute urine.
ANS The salt would move from the fish to
the sea water
Which way would the salt move in a fresh
water fish?
What does the sea water fish do to over
come the problem of losing too much water?
ANS The salt would move from the fresh
water into the fish.
ANS Gulps in sea water
What process happens at the chloride
secretory cells in a fish?
What is the name given to balancing the
water concentration in an organism?
ANS active transport
ANS Osmoregulation
What would happen to the filtration rate in
a fresh water fish?
ANS the filtration rate would increase
What would happen to the filtration rate in
a sea water fish?
ANS the filtration rate would decrease
What can migratory fish do ?
ANS Change the filtration rate and the
active transport of salt in sea water and
then in fresh water.
List 4 physiological adaptations in a desert
rat.
ANS Dry nasal passages / small and few
glomeruli so low filtration rate / Long loop
of Henle to reabsorb lots of water /
concentrated urine / no sweating
List 2 behavioural adaptations of a desert
rat.
ANS Come out at night when it is cooler.
Live in a cooler moist burrow during the hot
day
What does foraging mean?
Explain the term intrAspecific competition
ANS To find food
ANS Competition between the sAme
species
Explain the term economics of foraging
behaviour.
List 3 benefits of co-operative hunting.
ANS Energy used foraging for food is less
than the energy gained from eating the
food.
ANS Less fighting as reduced competition
Energy used for foraging is reduced
More chance of catching bigger prey
All members get food
Describe the foraging behaviour of bees.
ANS A few bees go and find the food and
then go back to hive and use a waggle dance
to tell the rest how to go directly
Why do ants leave a chemical trail to the
food?
ANS As this cuts down the energy used by
the rest of the ants getting to the food.
Why is the chemical trail to the ants food
short lived?
List 3 benefits of Dominance hierarchy
ANS Less fighting as reduced competition
All members get food
Most experienced animal is most
dominant so better chance to survive
What does dominance hierarchy mean?
ANS Each member of the group has a fixed
rank or position within the group
List 3 benefits of Territorial behaviour.
ANS As the food will run out and the trail
will be useless
What type of competition is between the
red squirrel and grey squirrel?
ANS Interspecific competition
ANS Reduced competition for food so less
fighting
Territory provides food for pair or group
Size of territory regulate number of
offspring produced
List 3 ways animals as individuals cope with
danger
ANS Avoidance behaviour / make
themselves bigger / produce a smell /
Play dead / use colour / roll into a ball
List 3 ways a social group can cope with
danger
ANS can mob the predator / confuse the
predator/ share look out duties / can form a
circle / put young & weak in centre of circle
Explain habituation behaviour
ANS When an animal has learned the
stimulus is harmless so stops reacting to it
Why is habituation beneficial to the animal?
ANS Stops wasting energy reacting to a
harmless stimulus
List 4 structural defence mechanism
ANS Stings / large teeth / claws /
protective shell / colour to camouflage
Explain how water enters a root hair cell
List 3 factors that can increase the
transpiration rate.
ANS Water moves from the hypotonic soil
water into the root hair cell by osmosis
ANS Increasing the temperature / wind
speed / light intensity OR decreasing the
humidity
Explain how water moves across the cortex
of the root
Why is the transpiration stream important
to a plant?
ANS between the cells by diffusion or
through the cells by osmosis across a
concentration gradient
ANS To cool the plant down and transport
water and minerals (nutrients) to the plant
What does the term cohesive forces mean?
What is the change in the turgor pressure
of the guard cells to open the stomata?
ANS Water molecules are attracted to
each other in the xylem vessels.
ANS Increased turgor pressure
What does the term adhesive forces mean?
What is the change in the turgor pressure
of the guard cells to close the stomata?
ANS Water molecules are attracted the
walls of the xylem vessel.
ANS Decrease in turgor pressure
What is meant by transpiration?
Why should an increase in humidity decrease
the transpiration rate of a plant?
ANS Water molecules evaporating from
the surface of the leaf
ANS The higher level of water molecules in
the air outside the leaf decreases the water
concentration gradient
How does water molecules leave the leaf?
Why do plant cells need water?
ANS the molecules diffuse through the
stoma and into the air.
ANS To keep them turgid for support and
some cells need it for photosynthesis
What is the term that describes a plant
that lives in a habitat which will produce a
high transpiration rate?
How does the waxy cuticle on the surface
of the leaf help a xerophyte.
ANS Xerophyte
ANS Acts as waterproof layer on the leaf.
What type of habitat will xerophytes live in?
Why should xerophytes have less stomata?
ANS Desert or windy exposed areas
(moorland)
ANS This reduces the water lost by
transpiration
Why do xerophytes have rolled leaves?
Why should leaves be reduced in size or
become spines?
ANS To trap water vapour and reduce the
transpiration rate?
ANS Less surface area for water to be lost
by transpiration.
Describe the types of roots that xerophytes
can have?
List two physiological adaptations of
xerophytes
ANS Long roots or superficial roots
ANS Reversed stomatal rhythm and quick
germination of seeds in rainy season
How do long roots help a xerophyte survive?
Where do hydrophytes live?
ANS Increase the chance of finding water
deep down
ANS partially or fully submerged in water
How do superficial roots help a xerophyte
survive?
List two adaptations of leaves if fully
submerged in water
ANS To absorb maximum water during the
rainy season.
ANS Air spaces / no stomata / finely
divided leaves
List two adaptations of the stem that
xerophytes can have.
Why should fully submerged leaves have air
spaces?
ANS Swollen stems to store water +
Folded stem to expand and contract as
water content changes
ANS store oxygen + buoyancy
If the leaves are floating leaves why does it
have air spaces?
What is the definition of the compensation
point in a plant?
ANS For buoyancy (NOT to store oxygen)
ANS When the light intensity increases to a
point where the rate of photosynthesis
equals the rate of respiration
Why are the xylem vessels in the centre of
hydrophyte stems?
ANS To allow the stem flexibility to move
with the water
Which plant will have the lowest
compensation point, a sun or a shade plant?
ANS A shade plant
Why should floating leaves have long leaf
stalks?
Describe the light intensity at which a shade
plants reaches its compensation point.
ANS To allow the leaf to be kept at the
surface as the water rises and falls.
What do plants compete for?
ANS Shade plants reach the compensation
point at a lower intensity of light compared
to a sun plant.
Which parts of the visible spectrum will a
sun plant absorb?
ANS Light / nutrients / water
ANS Blue and red regions
What type of competition occurs between
oak trees?
What is an unselective grazer?
ANS sAme species so intrAspecific
competition
ANS A herbivore that eats most plants
What type of competition occurs between
oak trees and pine trees?
ANS DiffErEnt species so intErspecific
competition
What will happen to the species diversity if
there is a low intensity of grazing
ANS species diversity decreases
What will happen to the species diversity if
there is a HIGH intensity of grazing
List the cellular substance made by plants
that isolate injured areas.
ANS species diversity increases
ANS Resin
What will happen to the species diversity if
there is a VERY high intensity of grazing
ANS species diversity decreases
If a selective grazers eats the dominant
plant what happens to species diversity?
ANS species diversity increases
Which toxic compound defends a plant
against being eaten by insects.
ANS Nicotine
Which toxic compounds defends a plant
mainly against micro-organisms?
ANS tannins
List 3 structural defences in plants.
What substance can a plant leaf produce
that could defend the plant from being
grazed.
ANS Stings / Thorns / Spines
ANS Cyanide
List 3 ways plants tolerate grazing
ANS low meristems / Deep root systems /
underground stems
List 3 toxic compounds made by the cells of
plants for defence.
ANS Tannins / nicotine / cyanide