AQA GCSE Biology Paper 1 Practice Test
Questions And Answers
Give two ways that the villi in the small intestine are adapted for absorbing digested
food - answer 1) A single layer of surface cells
2) A very good blood supply to assist quick absorption
Explain how the leaves are adapted to maximise the amount of carbon dioxide that gets
into their cells - answer 1) The exchange surface in a leaf is covered in stomata which
the carbon dioxide diffuses through
2) The leaf has a flattened shape which increases the area of its exchange surface,
therefore it's more effective
3) The walls of the cells inside the leaf act as another exchange surface
4) The air spaces inside the leaf increase the area of the exchange surface which
increases the chance for carbon dioxide to enter the cells
What affects the rate of diffusion? - answer Concentration gradient - the steeper the
gradient, the faster the rate
Temperature - the higher the temperature, the faster the rate (the particles have more
energy thus move around faster)
Surface area - the larger it is, the faster the rate
Diffusion distance - the shorter the distance, the faster the rate
Examples of active transport - answer Plants = Root hairs absorb minerals and water.
Each branch of a root will be covered in tiny hairs, therefore increasing the surface area
for the absorption of minerals and water. The concentration of minerals is usually higher
in the root hair cells than in the soil around them, therefore they can't use diffusion for
this process.
Animals = Glucose is taken in from the gut and from kidney tubules.
How are alveoli in the lungs specialised to maximise the diffusion of oxygen and carbon
dioxide? - answer -an enormous surface area
-a moist lining for dissolving gases
-very thin walls
-a good blood supply
How do fish respire? - answer -Water enters the fish through the mouth and passes out
through the gills
-During this process, oxygen diffuses from the water into the blood in the gills and
,carbon dioxide diffuses from the blood into the water
How are fish adapted for gas exchange? - answer -Each gill is made up of lots of
gill filaments which create a large surface area for the exchange of gases -Gill
filaments are covered in lamellae which increase the surface even more
-The lamellae have lots of blood capillaries to speed up diffusion
-The lamellae have a thin surface layer of cells to minimise the diffusion distance -Blood
flows through the lamellae one way and water flows over in the opposite direction which
maintains a higher concentration gradient between the blood and the water
-The concentration of oxygen in the water is always higher than that in the blood to
maximise the amount of oxygen diffusion from the water into the blood
Microscopy Practical - Preparing the Slide - answer 1) Add a drop of water to the
middle of a clean slide
2) Cut up an onion & separate it out into layers. Use tweezers to peel off some
epidermal tissue from the bottom of one of the layers
3) Using the tweezers, place the epidermal tissue into the water on the slide 4)
Add a drop of iodine solution - a stain used to highlight objects in a cell by adding
colour to them
5) Place a cover slip on top - stand the cover slip upright on the slide, next to the water
droplet. Then, carefully tilt & lower it so it covers the specimen. Try not to get any air
bubbles under there - there'll obstruct your view
Microscopy Practical - Using a Light Microscope - answer 1) Clip the slide you've
prepared onto the stage
2) Select the lowest-powered objective lens
3) Use the coarse adjustment knob to move the stage up to just below the objective
lens 4) Look down the eyepiece. Use the coarse adjustment knob to move the stage
downwards until the image is roughly in focus
5) Adjust the focus with the fine adjustment knob, until you get a clear image of what's
on the slide
Microscopy Practical - Drawing Observations - answer 1) Draw what you see under the
microscope using a pencil with a sharp point
2) Make sure your drawing takes up at least half of the space available & that it is drawn
with clear, unbroken lines
3) Your drawing should not include any colouring or shading
4) If you are drawing cells, the subcellular structures should be drawn in proportion
5) Include a title & write down the magnification that it was observed under
6) Label the important features of your drawing using straight, uncrossed lines
What happens during binary fission? - answer 1) The circular DNA & plasmid(s)
replicate
2) The cell gets bigger & the circular DNA strands move to opposite poles of the cell
, 3) The cytoplasm begins to divide & new cell walls begin to form
4) The cytoplasm divides & two daughter cells are produced. Each daughter cell has
one copy of the circular DNA, but can have a variable number of copies of the
plasmid(s)
What is binary fission? - answer A type of simple cell division used by prokaryotic cells
to reproduce & split into two
What conditions do bacteria need to divide? - answer 1) Warm environment
2) Lots of nutrients
What is the mean division time? - answer The average amount of time it takes for one
bacterial cell to divide into two
How do you make an agar plate? - answer Hot agar jelly is poured into shallow Petri
dishes. When the jelly's cooled & set, inoculating loops can be used to transfer the
microorganisms to the culture medium. Alternatively, a sterile dropping pipette &
spreader can be used to get an even covering of bacteria. The microorganisms then
multiply
Investigating the Effect of Antibiotics on Bacterial Growth - Method - answer 1) Place
paper discs soaked in different types of antibiotics on an agar plate that has an even
covering of bacteria. Leave some space between the discs
2) The antibiotic should diffuse into the agar jelly. Antibiotic-resistant bacteria that
aren't affected by the antibiotic will continue to grow on the agar around the paper
discs, but non-resistant strains will die. A clear area will be left where the bacteria have
died - an inhibition zone
3) Make sure you use a control - a paper disc that has not been soaked in an
antibiotic. Instead, soak it in sterile water so you can be sure that any difference
between the growth of bacteria around the control disc & around one of the antibiotic
discs is due to the effect of the antibiotic alone 4) Leave the plate for 48 hours at 25°C
5) The more effective the antibiotic is, the large the inhibition zone will be
Avoiding Contamination - answer 1) The Petri dishes & culture medium must be
sterilised before use (heating to a high temperature), to kill any unwanted
microorganisms
2) If an inoculating loop is used to transfer the bacteria to the culture medium, it
should be sterilised first by passing it through a hot flame
3) After transferring the bacteria, the lid of the Petri dish should be lightly taped on -
stops any microorganisms from the air getting it
4) The Petri dish should be stored upside down - stops drops of condensation
falling onto the agar surface
Questions And Answers
Give two ways that the villi in the small intestine are adapted for absorbing digested
food - answer 1) A single layer of surface cells
2) A very good blood supply to assist quick absorption
Explain how the leaves are adapted to maximise the amount of carbon dioxide that gets
into their cells - answer 1) The exchange surface in a leaf is covered in stomata which
the carbon dioxide diffuses through
2) The leaf has a flattened shape which increases the area of its exchange surface,
therefore it's more effective
3) The walls of the cells inside the leaf act as another exchange surface
4) The air spaces inside the leaf increase the area of the exchange surface which
increases the chance for carbon dioxide to enter the cells
What affects the rate of diffusion? - answer Concentration gradient - the steeper the
gradient, the faster the rate
Temperature - the higher the temperature, the faster the rate (the particles have more
energy thus move around faster)
Surface area - the larger it is, the faster the rate
Diffusion distance - the shorter the distance, the faster the rate
Examples of active transport - answer Plants = Root hairs absorb minerals and water.
Each branch of a root will be covered in tiny hairs, therefore increasing the surface area
for the absorption of minerals and water. The concentration of minerals is usually higher
in the root hair cells than in the soil around them, therefore they can't use diffusion for
this process.
Animals = Glucose is taken in from the gut and from kidney tubules.
How are alveoli in the lungs specialised to maximise the diffusion of oxygen and carbon
dioxide? - answer -an enormous surface area
-a moist lining for dissolving gases
-very thin walls
-a good blood supply
How do fish respire? - answer -Water enters the fish through the mouth and passes out
through the gills
-During this process, oxygen diffuses from the water into the blood in the gills and
,carbon dioxide diffuses from the blood into the water
How are fish adapted for gas exchange? - answer -Each gill is made up of lots of
gill filaments which create a large surface area for the exchange of gases -Gill
filaments are covered in lamellae which increase the surface even more
-The lamellae have lots of blood capillaries to speed up diffusion
-The lamellae have a thin surface layer of cells to minimise the diffusion distance -Blood
flows through the lamellae one way and water flows over in the opposite direction which
maintains a higher concentration gradient between the blood and the water
-The concentration of oxygen in the water is always higher than that in the blood to
maximise the amount of oxygen diffusion from the water into the blood
Microscopy Practical - Preparing the Slide - answer 1) Add a drop of water to the
middle of a clean slide
2) Cut up an onion & separate it out into layers. Use tweezers to peel off some
epidermal tissue from the bottom of one of the layers
3) Using the tweezers, place the epidermal tissue into the water on the slide 4)
Add a drop of iodine solution - a stain used to highlight objects in a cell by adding
colour to them
5) Place a cover slip on top - stand the cover slip upright on the slide, next to the water
droplet. Then, carefully tilt & lower it so it covers the specimen. Try not to get any air
bubbles under there - there'll obstruct your view
Microscopy Practical - Using a Light Microscope - answer 1) Clip the slide you've
prepared onto the stage
2) Select the lowest-powered objective lens
3) Use the coarse adjustment knob to move the stage up to just below the objective
lens 4) Look down the eyepiece. Use the coarse adjustment knob to move the stage
downwards until the image is roughly in focus
5) Adjust the focus with the fine adjustment knob, until you get a clear image of what's
on the slide
Microscopy Practical - Drawing Observations - answer 1) Draw what you see under the
microscope using a pencil with a sharp point
2) Make sure your drawing takes up at least half of the space available & that it is drawn
with clear, unbroken lines
3) Your drawing should not include any colouring or shading
4) If you are drawing cells, the subcellular structures should be drawn in proportion
5) Include a title & write down the magnification that it was observed under
6) Label the important features of your drawing using straight, uncrossed lines
What happens during binary fission? - answer 1) The circular DNA & plasmid(s)
replicate
2) The cell gets bigger & the circular DNA strands move to opposite poles of the cell
, 3) The cytoplasm begins to divide & new cell walls begin to form
4) The cytoplasm divides & two daughter cells are produced. Each daughter cell has
one copy of the circular DNA, but can have a variable number of copies of the
plasmid(s)
What is binary fission? - answer A type of simple cell division used by prokaryotic cells
to reproduce & split into two
What conditions do bacteria need to divide? - answer 1) Warm environment
2) Lots of nutrients
What is the mean division time? - answer The average amount of time it takes for one
bacterial cell to divide into two
How do you make an agar plate? - answer Hot agar jelly is poured into shallow Petri
dishes. When the jelly's cooled & set, inoculating loops can be used to transfer the
microorganisms to the culture medium. Alternatively, a sterile dropping pipette &
spreader can be used to get an even covering of bacteria. The microorganisms then
multiply
Investigating the Effect of Antibiotics on Bacterial Growth - Method - answer 1) Place
paper discs soaked in different types of antibiotics on an agar plate that has an even
covering of bacteria. Leave some space between the discs
2) The antibiotic should diffuse into the agar jelly. Antibiotic-resistant bacteria that
aren't affected by the antibiotic will continue to grow on the agar around the paper
discs, but non-resistant strains will die. A clear area will be left where the bacteria have
died - an inhibition zone
3) Make sure you use a control - a paper disc that has not been soaked in an
antibiotic. Instead, soak it in sterile water so you can be sure that any difference
between the growth of bacteria around the control disc & around one of the antibiotic
discs is due to the effect of the antibiotic alone 4) Leave the plate for 48 hours at 25°C
5) The more effective the antibiotic is, the large the inhibition zone will be
Avoiding Contamination - answer 1) The Petri dishes & culture medium must be
sterilised before use (heating to a high temperature), to kill any unwanted
microorganisms
2) If an inoculating loop is used to transfer the bacteria to the culture medium, it
should be sterilised first by passing it through a hot flame
3) After transferring the bacteria, the lid of the Petri dish should be lightly taped on -
stops any microorganisms from the air getting it
4) The Petri dish should be stored upside down - stops drops of condensation
falling onto the agar surface
