exam questions Flashcards
(18 cards)
give two reasons why sexual reproduction causes variation in the offspring 2 marks
gametes are not identical
there is mixing of genetic information
describe a method to investigate how the distance from the river affects the number of different plant species in the field 4 marks
measure the transect at right angles to the river
place quadrat at intervals
count the different plant species in the quadrat at the specific distances
repeat for 2 more transects
Describe how the hormones given to women during IVF treatment interact with other hormones to prepare the body for pregnancy. 3 marks
the hormones FSH and LH used in IVF cause an increase in progesterone and oestrogen
oestrogen maintains the uterus lining
uterus lining is prepared for the embryo to be implanted
explain the role of adrenal glands in responding to a decrease in the body temperature 5 marks
adrenal glands produce adrenaline to increase heart rate so more faster delivery of oxygen and glucose to the brain because oxygen is needed for respiration to move muscles to increase the body temperature
Explain how the thyroid gland controls the response to a decrease in body temperature by negative feedback. 3 marks
decreasing body temperature causing the thyroid gland to produce thyroxine which increases metabolic rate so increasing the temperature decreases the production of thyroxine
Microorganisms in the soil recycle carbon from the leaves so that the carbon is used
for new plant growth.
Explain how. 4 marks
leaves are broken down
respiration by decomposers
respiration releases carbon dioxide
carbon dioxide is used in photosynthesis
Water pollution is a problem for humans and wildlife.
Explain how human activities are polluting rivers, lakes and seas. 6 marks
increase in population- sewage causes algae to grow
algae blocks light causing plants to die and too decompose
leading to a lack of oxygen in the water
need to produce food for the growing population
fertilisers are used on farms to increase the crop yield
cause algae to grow- lack of oxygen in the water
Explain how the two hormones (insulin and glucagon) keep the blood glucose concentration
within the normal range for 3 hours after a meal. 6 marks
when blood glucose concentration is high after a meal insulin is secreted causing glucose to enter cells
glucose is converted into glycogen in the liver
this causes blood glucose concentration to return to normal so insulin secretion decreases
when blood glucose concentration is low glucagon is released which causes the break down of glycogen in the liver
blood glucose concentration returns to normal so glucagon secretion decreases
give two uses of peat taken from peat bogs 2 marks
compost
burning
describe two ways to increase biodiversity in the UK 2 marks
reduce pollution
plant trees
which domain are fungus in
eukaryota
what is the three domain system
based on the DNA
the three domains are
Archaea-simple bacteria
prokaryota - true/ modern bacteria
eukaryota - includes plants and animals
Describe the sequence of hormone interactions in the menstrual cycle.
Name where each hormone is produced. 5 marks
FSH from the pituitary stimulates an egg to mature
FSH stimulates oestrogen from the ovaries
oestrogen causes the thickening of the uterus
oestrogen inhibits FSH but stimulates LH from the pituitary
the high levels of LH stimulate release of the egg
Describe how carbon from the atmosphere is cycled through living organisms.
[6 marks]
carbon dioxide is taken in through the stomata - used in photosynthesis
plants are eaten by animals which use the carbon compounds to make other carbon compounds
when plants and animals die they are decomposed by microorganisms which use the carbon compounds to make other carbon compounds
plants respire and releases carbon dioxide into the atmosphere
name the two main organs involved in the CNS 2 marks
brain
spinal cord
neurones: 3 marks
neurones carry information in the form of electrical signals called nerve impulses
what happens in a nervous response?
stimulus: a change in the environment is detected
receptor: special cells detect the stimulus
sensory neurone: carries the electrical impulse from the receptor to the central nervous system
relay neurone: passes the impulse across the cns
effector: responds (e.g muscle contracts to move your hand away)
process of IVF
FSH and LH are giving to the woman to stimulate her ovaries to produce multiple eggs instead of just one
eggs are collected from the ovaries
sperm is collected from the male partner
fertilisation happens in the lab
(the eggs and the sperm are mixed together in a dish)
embryos develop
one or two embryos are inserted into the womb
