AQA A-level Biology paper 1 Exam Questions And
Answers Verified 100% Correct
what is the function of SER? - ANSWER synthesises, stores and transports lipids and
carbohydrates
what is the function of RER? - ANSWER provides a large surface area to synthesise
proteins and glycoproteins
provides a transport pathway for materials throughout the cell
what is the function of golgi apparatus? - ANSWER add carbs to proteins to form
glycoproteins
produce secretory enzymes
secrete carbohydrates
transport, modify and store lipids
form lysosomes
what is meant by 'organ'? - ANSWER a combination of tissues that are coordinated to
perform a variety of functions.
What is the first stage in binary fission? - ANSWER the circular DNA molecule
replicates and both copies attach to the cell membrane.
plasmids also replicate
how do viruses replicate? - ANSWER they attach to their host cell with their attachment
proteins.
nucleic acids are injected into host cell.
the genetic info contains "instructions" for the host cells metabolic processes to start
producing the viral components, which are assembled into new viruses.
What is the role of phagocytes? - ANSWER Injest pathogens. Places antigens from
pathogen on its cell surface membrane, so it becomes an antigen presenting cell.
What is the role of a T helper cell? - ANSWER Receptors attach to antigens on antigen
presenting cell. This attachment activates T cells to divide rapidly by mitosis and form a
clone of genetically identical cells.
,What is the role of T cells? - ANSWER a. develop into memory cells
b. stimulate phagocytosis
c. stimulate B cells to divide and secret their antibody
d. activate cytotoxic T cells
describe humoral immunity - ANSWER B cells take up antigens and present them. B
cells activated by T-helper cells and form plasma cells. Plasma cells secrete antibodies
and form memory cells.
what is passive immunity and how is it produced? - ANSWER produced by the
introduction of antibodies into individuals from an outside source.
immunity is acquired immediately but not lasting e.g. anti-venom.
what is active immunity and how is it produced? - ANSWER produced by stimulating
the production of antibodies by the individuals own immune system. contact with
pathogen/s needed. immunity takes time to develop
natural active immunity - ANSWER results from an individual becoming infected with a
disease under normal circumstances.
long term
body produces its own antibodies
artificial active immunity - ANSWER involves inducing an immune response in an
individual
WITHOUT them suffering the symptoms of the disease.
e.g. vaccinations
memory cells produced
what are the features of a successful vaccination programme? - ANSWER 1. vaccine
must be economically available in sufficient quantities
2. must have few side effects
3. available means of producing, storing and transporting the vaccine
4. must be possible to produce herd immunity
why can vaccinations not be effective? - ANSWER 1. immunity may not be induced in
people with defective immune systems
2. individuals may develop disease after the vaccination but before their immunity
levels are high enough to prevent it.
, 3. pathogen may mutate frequently, so vaccines cant prevent them from harming
people 4. certain pathogens conceal themselves from the body's immune system e.g.
by hiding within cells
5. individuals may object to vaccinations due to religious, ethical or medical reasons
what are antibodies made up of? - ANSWER 4 polypeptide chains:
- 2 are 'heavy chains' -
2 are 'light chains'
variable (binding) region
What kind of cell does HIV infect? - ANSWER T helper cell
features of specialised gas exchange surfaces - ANSWER - a large surface area to
volume ratio
- very thin therefore short diffusion pathway
- selectively permeable
- a transport system
How is mass transport carried out in an insect? - ANSWER Insect pump muscles in
abdomen, squeezing gases through trachea.
The gas exchange system in an insect... - ANSWER Spiracles > trachea > tracheoles >
diffusion of gases into cells.
Why is there fluid in the end of the tracheoles? - ANSWER Water potential of cells
lowered during exercise. Fluid drawn into cells. Shortens diffusion distance for gas
exchange.
describe and explain the countercurrent exchange principle - ANSWER -the blood and
the water flow in opposite directions
-Maintains maximum diffusion gradient across all of gill.
how does the structure of a plant leaf link to gas exchange? - ANSWER -all cells are
close to stomata, and therefore surface, therefore a short diffusion pathway
-inter-connecting air spaces in the mesophyll so that gases can readily contact
mesophyll cells
describe and explain why plant stomata links to gas exchange and its benefits -
ANSWER stomata are like minute pores, on the underside of leaves.
each has guard cells, which control the rate of gas exchange
Answers Verified 100% Correct
what is the function of SER? - ANSWER synthesises, stores and transports lipids and
carbohydrates
what is the function of RER? - ANSWER provides a large surface area to synthesise
proteins and glycoproteins
provides a transport pathway for materials throughout the cell
what is the function of golgi apparatus? - ANSWER add carbs to proteins to form
glycoproteins
produce secretory enzymes
secrete carbohydrates
transport, modify and store lipids
form lysosomes
what is meant by 'organ'? - ANSWER a combination of tissues that are coordinated to
perform a variety of functions.
What is the first stage in binary fission? - ANSWER the circular DNA molecule
replicates and both copies attach to the cell membrane.
plasmids also replicate
how do viruses replicate? - ANSWER they attach to their host cell with their attachment
proteins.
nucleic acids are injected into host cell.
the genetic info contains "instructions" for the host cells metabolic processes to start
producing the viral components, which are assembled into new viruses.
What is the role of phagocytes? - ANSWER Injest pathogens. Places antigens from
pathogen on its cell surface membrane, so it becomes an antigen presenting cell.
What is the role of a T helper cell? - ANSWER Receptors attach to antigens on antigen
presenting cell. This attachment activates T cells to divide rapidly by mitosis and form a
clone of genetically identical cells.
,What is the role of T cells? - ANSWER a. develop into memory cells
b. stimulate phagocytosis
c. stimulate B cells to divide and secret their antibody
d. activate cytotoxic T cells
describe humoral immunity - ANSWER B cells take up antigens and present them. B
cells activated by T-helper cells and form plasma cells. Plasma cells secrete antibodies
and form memory cells.
what is passive immunity and how is it produced? - ANSWER produced by the
introduction of antibodies into individuals from an outside source.
immunity is acquired immediately but not lasting e.g. anti-venom.
what is active immunity and how is it produced? - ANSWER produced by stimulating
the production of antibodies by the individuals own immune system. contact with
pathogen/s needed. immunity takes time to develop
natural active immunity - ANSWER results from an individual becoming infected with a
disease under normal circumstances.
long term
body produces its own antibodies
artificial active immunity - ANSWER involves inducing an immune response in an
individual
WITHOUT them suffering the symptoms of the disease.
e.g. vaccinations
memory cells produced
what are the features of a successful vaccination programme? - ANSWER 1. vaccine
must be economically available in sufficient quantities
2. must have few side effects
3. available means of producing, storing and transporting the vaccine
4. must be possible to produce herd immunity
why can vaccinations not be effective? - ANSWER 1. immunity may not be induced in
people with defective immune systems
2. individuals may develop disease after the vaccination but before their immunity
levels are high enough to prevent it.
, 3. pathogen may mutate frequently, so vaccines cant prevent them from harming
people 4. certain pathogens conceal themselves from the body's immune system e.g.
by hiding within cells
5. individuals may object to vaccinations due to religious, ethical or medical reasons
what are antibodies made up of? - ANSWER 4 polypeptide chains:
- 2 are 'heavy chains' -
2 are 'light chains'
variable (binding) region
What kind of cell does HIV infect? - ANSWER T helper cell
features of specialised gas exchange surfaces - ANSWER - a large surface area to
volume ratio
- very thin therefore short diffusion pathway
- selectively permeable
- a transport system
How is mass transport carried out in an insect? - ANSWER Insect pump muscles in
abdomen, squeezing gases through trachea.
The gas exchange system in an insect... - ANSWER Spiracles > trachea > tracheoles >
diffusion of gases into cells.
Why is there fluid in the end of the tracheoles? - ANSWER Water potential of cells
lowered during exercise. Fluid drawn into cells. Shortens diffusion distance for gas
exchange.
describe and explain the countercurrent exchange principle - ANSWER -the blood and
the water flow in opposite directions
-Maintains maximum diffusion gradient across all of gill.
how does the structure of a plant leaf link to gas exchange? - ANSWER -all cells are
close to stomata, and therefore surface, therefore a short diffusion pathway
-inter-connecting air spaces in the mesophyll so that gases can readily contact
mesophyll cells
describe and explain why plant stomata links to gas exchange and its benefits -
ANSWER stomata are like minute pores, on the underside of leaves.
each has guard cells, which control the rate of gas exchange
