Paper 1 June 2021 Flashcards
Name two pieces of laboratory equipment the student could have used to prepare
cells to view using a microscope
any two from:
* (microscope) slide
* cover slip
* dye / stain
* (mounted) needle
* pipette / dropper
* scalpel
* forceps / tweezers
What is the function of the coarse focus?
to focus (the image / cells)
Suggest one reason why the student could not see any cells when looking through the eyepiece
- no cells in the field of view
- slide not in the correct
position - mirror not in correct position
- (objective) lens not clicked
into place
or
(objective) lens dirty - (student is) looking at a
(large) air bubble - (the microscope is) not
focussed
Compare the structure of a red blood cell with the structure of a plant cell. (6)
Differences:
* red blood cell has no nucleus or plant cell has a nucleus
* red blood cell has no cell wall or plant cell has a cell wall
* red blood cell is a biconcave disc or there are many different
shapes of plant cell
* red blood cell contains haemoglobin or plant cells do not contain
haemoglobin
* red blood cells do not contain chlorophyll or plant cells (may)
contain chlorophyll
* red blood cell has no chloroplasts or plant cell has chloroplasts
* red blood cell has no (permanent) vacuole or plant cell has
(permanent) vacuole
* red blood cells are (much) smaller than plant cells
Similarities:
both have:
* cytoplasm
* cell membrane
* pigments (although they are different)
ignore references to mitochondria and ribosomes
When placed into a beaker of water:
* a red blood cell bursts
* a plant cell does not burst.
Explain why the red blood cell bursts but the plant cell does not burst.
water enters (the cells) by
osmosis / diffusion
plant cell has a cell wall (which
prevents it from bursting)
Describe two aseptic techniques the student should have used.
- sterilise equipment / surfaces
(before use) - (use) sterilised agar
- secure lid of the Petri dish
with (adhesive) tape - only lift lid of Petri dish a little
(when setting up plate)
or lift lid of Petri dish at an
angle (when setting up plate)
Which antibiotic is the least effective?
Give a reason for your answer.
it kills the fewest bacteria
or
it has the smallest area where
no bacteria were growing
Suggest one way the student could improve the investigation. (aseptic/disinfectant)
- repeat and calculate a mean
- repeat and eliminate
anomalies - use a control disc
- use different types of bacteria
Explain the financial impact on the UK economy of an increasing number of people
who are obese.
costs the NHS / UK health
service / Government / hospitals
more money
(because need to pay for)
additional surgery / medication /
hospital stay to treat stroke /
diabetes
or
more time off work (if in hospital
/ unwell) (1)
(so) employer / Government
have to give financial support (1)
A person who is obese is more at risk of arthritis.
Arthritis is a condition that damages joints.
Suggest how arthritis could affect a person’s lifestyle.
- movement issues
- loss of job / income
- disability
- mental health impact of lack
of movement
or
mental health impact of pain - need to visit the doctor / take
medication regularly - may need surgery
A person who eats a diet high in saturated fat might become obese.
Name two health conditions that might develop if a person eats a diet high in
saturated fat.
Do not refer to arthritis in your answer
type 2 diabetes
CVD / CHD
or
heart attack / disease
or
stroke
What is the chemical equation for aerobic respiration?
6O2 + C6H12O6 6H2O + 6CO2
Name the sub-cellular structures where aerobic respiration takes place.
mitochondria / mitochondrion
Energy is released in respiration.
Give two uses of the energy released in respiration.
- movement / muscle
contraction - keeping warm
- active transport
- building larger molecules
Describe two differences between aerobic and anaerobic respiration in humans.
Do not refer to oxygen in your answer.
- anaerobic produces lactic
acid and aerobic does not - aerobic produces carbon
dioxide and anaerobic does
not - aerobic produces water and
anaerobic does not - aerobic occurs (mainly) in the
mitochondria and anaerobic
does not - anaerobic releases less
energy than aerobic
What are the two products of anaerobic respiration in plant cells?
carbon dioxide
ethanol
A scientist investigated respiration and photosynthesis using some pondweed and a
pond snail. The apparatus was left in a well-lit room for 5 days.
The data logger recorded the concentration of carbon dioxide continuously.
After 5 days, the scientist completely covered the boiling tube with black paper.
The data logger continued to record the concentration of carbon dioxide.
Explain why the concentration of carbon dioxide in the tube stayed the same between
day 0 and day 5.
pondweed takes in CO2 for
photosynthesis
snail and pondweed are
respiring producing CO2
Suggest why the concentration of carbon dioxide increased between day 5 and
day 10.
(no light so) no photosynthesis
or
plant is not taking in CO2
and
snail and plant are respiring and
so are releasing CO2
On day 10, the pond snail died.
Explain why the death of the pond snail caused the concentration of carbon dioxide to
increase after day 10.
snail is being decayed /
decomposed / broken down
(by) decomposers / bacteria (in
pond water / snail)
(therefore) respiration (of
decomposers / bacteria)
releases CO2
Amylase is a polymer of smaller molecules.
Name the type of smaller molecule.
amino acid(s)
Name the three parts of the human digestive system that produce amylase.
salivary gland
pancreas
small intestine
Explain how amylase breaks down starch.
Answer in terms of the ‘lock and key theory’.
starch / substrate binds to active
site (of enzyme)
(because) shape of active site
and substrate are
complementary
a chemical reaction occurs to
produce smaller molecules
or
bonds between the (starch)
molecules are broken to
produce smaller molecules
Name two control variables the student used in the investigation.
- time before mixing (starch
and amylase) solutions - volume / 5 cm3 of starch
(solution) - volume / 1 cm3 of amylase
(solution) - volume / 1 drop of mixture
added to spotting tile - volume / 2 drops of iodine
(solution)
Why did the student leave the starch solution and amylase solution for 5 minutes
before mixing them?
to allow the solutions to reach
the same temperature as the
water
or
to allow both solutions to reach
5 °C
What conclusion can be made about the effect of temperature on amylase activity
between 20 °C and 65 °C?
as temperature increases,
(amylase / enzyme) activity
increases, to 35 °C after which
activity decreases
Explain the results at 5 °C and at 80 °C. (did not become yellow/brown)
(iodine is not yellow-brown
because) starch is still present
or starch has not been broken
down
at 5 °C amylase / starch /
molecules have low (kinetic)
energy
(therefore) there are fewer
(enzyme-substrate) collisions
at 80 °C the amylase has been
denatured
(so) the starch can no longer fit
The student investigated the effect of temperature on amylase activity.
Describe how the student could extend the investigation to determine the effect of a
different factor on amylase activity.
keep temperature constant
(but) change named factor and
test a range of values of named
factor
Water is taken in by the roots, transported up the plant and lost from the leaves.
Which scientific term describes this movement of water?
transpiration stream
Which change would decrease the rate of water loss from a plant’s leaves?
increased humidity
Compare the structure and function of xylem tissue and phloem tissue. (6)
Structure
* xylem is made of dead cells
and
phloem is made of living cells
* phloem cells have pores in their end walls
and
xylem cells do not have pores in their end walls
* xylem is hollow or xylem does not contain cytoplasm
and
phloem contains cytoplasm
* xylem contains lignin
and
phloem does not (contain lignin)
- both made of cells
- both tubular
Function
* xylem transports water / mineral ions
and
phloem transports (dissolved) sugars
* xylem is involved in transpiration
and
phloem is involved in translocation
* xylem transports unidirectionally
and
phloem transports bidirectionally
- both transport liquids / substances throughout the stem / leaves /
roots / plant
The rate of water loss at midnight was much lower than at 12:00
Explain why.
(less water loss at night)
stomata are (almost completely)
closed
(because) it’s cooler / colder
or
(because) there’s less / no light
Describe what happens to cells when a tumour forms.
cells grow / divide abnormally /
uncontrollably
What evidence is there in Figure 11 to suggest that the tumour in the lung
is malignant?
has spread to other parts /
organs of the body
or
has spread to the liver / lung
or
has formed a secondary tumour
Some types of cancer can cause the numbers of blood components in a person’s
body to fall to a dangerously low level.
A person with one of these types of cancer may experience symptoms such as:
* tiredness
* frequent infections
* bleeding that will not stop after the skin is cut.
Explain how a very low number of blood components in the body can cause
these symptoms.
Tiredness
* fewer red blood cells
* so less haemoglobin
* so less oxygen transported around the body
* so less (aerobic) respiration can take place
* so more anaerobic respiration takes place
* less energy released for metabolic processes
or less energy released so organs cannot function as well
* lactic acid produced (during anaerobic respiration) causes
muscle fatigue
Frequent infections
* fewer white blood cells / phagocytes / lymphocytes
* so fewer antibodies produced or less phagocytosis
* so fewer pathogens / bacteria / viruses killed
Bleeding
* fewer platelets
* so blood does not clot as easily
It is dangerous for a patient with blood group A to receive red blood cells from a donor
with blood group B.
Explain why.
anti-B antibodies in patient /
receiver / recipient
will bind to type B antigens on
person’s / donor’s red blood
cells
(so) red blood cells clump
together and are wider than
capillaries
or
(so) red blood cells clump
together and block capillaries
(so) cells have reduced supply
of oxygen / glucose
or
(so) cells can’t respire
Explain why blood group O red blood cells can be given to patients with any blood group.
no antigens (on type O red
blood cells)
(so) antibodies cannot bind
(to the antigens / red blood
cells)
A person has a tumour blocking the tube leading from the gall bladder to the
small intestine.
Explain why this person would have difficulty digesting fat.
no / less bile reaches the small
intestine
(so) less / no emulsification of
fat
(so) smaller surface area for
lipase to break down fat
pH of small intestine is not
neutralised / alkaline
(so) lipase is not at its optimum
pH to break down fat
