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Unit 3
past paper bio
55 cards
Cards (181)
Describe what happens during fertilisation
sperm and egg nuclei fuse/ gamete nuclei fuse
What is formed in fertilisation
diploid zygote
what is meant by chromosome complement
zygote has two sets of chromosome
Most features of an individual phenotype are
polygenic and show continuous variation
Which term describes the type of variation in which a characteristic is controlled by more than one gene?
continuous
State the type of variation shown by tongue-rolling.
discrete
Explain what is meant by the term homozygous.
(both) alleles are the same/identical
State a feature of the cell membrane which allows the movement of only some substances into the cell.
selectively permeable/ contains proteins
Describe the effect of osmosis on a leaf cell if it was placed in pure water
The cell would become turgid
Describe the effect of osmosis on a red blood cell if it was placed in pure water.
cell would burst
What is the definition of diffusion
movement of molecules from a higher concentration to a lowe concentration
What is the definition of active transport
Movement of moelcules/ions from a low to a high concentration against a concentration gradient
Enzymes such as lactase are biological
catalysts.
Explain the role of enzymes in living cells.
speed
up chemical
reactions
name the substance of which enzymes are made.
proteins
/
amino acids
Explain why the fermenter must be sterilised using aseptic techniques before it is used.
To ensure there are no other
bacteria
present
The fermenter is controlled to provide optimum conditions. Name one factor which can be controlled.
temperature/ pH
Explain why muscle cells require many mitochondria
requires a lot of
energy
for
movement
/
contraction
name one substance produced by a cell carrying out
aerobic
respiration.
carbon dioxide/
water
/ (2)
ATP
A muscle cell will carry out fermentation when oxygen is not available. Describe the fermentation pathway in muscle cells. (3)
glucose
converted into
pyruvate
pyruvate converted to lactic acid
2ATP produced
function of cytoplasm
site of chemical
reactions
the bases in a strand of DNA make up the code for the production of proteins. The DNA for every individual person varies.
Describe how this code differs from person to person.
sequence/order of bases
what is a source of new alleles in a population
mutations
It is a biotic factor and causes a decrease in prey numbers. is what factor
predation
Function of
sensory
neuron
carries/sends message/impulses/signal from sense organ
relay
neuron/
CNS
/spinal cord
function of
motor neuron
carries/sends message/impulse/signal from
CNS
to muscle/
effector
function of
relay neuron
carries/sends message/impulse/signal from
sensory
to motor neuron/within
CNS
describe how information is passes along a neuron
electrical impulse
most features of an individuals phenotype are controlled by more than one gene
polygenic
describe the structures and processes involved as water moves through plants from soil to the air
Water is absorbed by
root hairs
by
osmosis
/
diffusion
(1)
(Water) travels upwards in the
xylem
(1)
(water) travels to the
stomata
and
diffuses
out
describe two features of these sturctures which improve the efficiency of gas exchange
large
surface area
thin
walls/ walls are
one cell
thick
rich blood supply
/
dense capillary network
moist
describe how mucus and cilia work together to prevent bacteria getting into the lungs
Dirt/dust/
microrganisms
are trapped in the
mucus
Cilia
move these up and away from the
lungs
why is nitrates important to plants
needed to make
proteins
name a site of mitosis in
plants
meristem/root tip
when writing percentage change for increase you must include...
+
suggest why the eggs were blotted dry before reiweighed
to remove
excess water
on the
eggs
so it wont alter
mass
describe one difference between passive and active transport
passive transport moves
down
a concentration whereas active transport goes
against
a concentration gradient
DNA contains genetic material which controls the synthesis of chemical made from amino acids. Name the chemical synthesised
protein
Give description of what mRNA is
Messanger RNA
is an
order
/
sequence
of
bases
(which determine
base
/
sequence
of
amino acids
)
wheres is mRNA made
nucelus
name two products used in second stage of photosynthesis
hydrogen
and
ATP
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