AQA GCSE Combined Science Trilogy :
Biology Paper 1 questions and answers
Name the two types of cells - Ans>>Prokaryotic and Eukaryotic
What is a prokaryotic cell? - Ans>>A cell without a nucleus
Give an example of a prokaryote (Prokaryotic cell) - Ans>>Bacteria
What is a eukaryotic cell? - Ans>>cell with a nucleus
Give two examples of eukaryotic cells - Ans>>Plant & Animal cells
What three sub-cellular structures do plant cells have which animal cells do not? -
Ans>>Permanent vacuole, cell wall and chloroplasts
What is the function of the nucleus? - Ans>>Contains genetic materials that
controls the activities of the cell
What is the function of the cytoplasm? - Ans>>A gel-like substance where most of
the chemical reactions happen. It contains enzymes that control these reactions
What is the function of the cell membrane? - Ans>>Holds the cell together and
controls the passage of substances
What is the function of the mitochondria? - Ans>>These are where most of the
reactions for aerobic respiration take place. Respiration transfers energy that the
cell needs to work
What is the function of the ribosome? - Ans>>These are were proteins are made in
the cell through protein synthesis
What is the function of the cell wall? - Ans>>To strengthen and support the cell
What is the function of the vacuole? - Ans>>Contains cell sap (a weak solution of
sugar and salts), it keeps the cell turgid
What is the function of the chloroplast? - Ans>>This is where photosynthesis takes
place, which makes food for the plant. They contain a green substance called
chlorophyll which absorbs the light required for photosynthesis
What do bacterial cells have instead of a nucleus? - Ans>>A single circular strand of
DNA that floats freely in the cytoplasm, and some may also contain one or more
small rings of DNA called plasmids.
How many mm are in um? - Ans>>1000
What do light microscopes use to work? - Ans>>Light and lenses to form an image
of a specimen. They let us see individual cells and large sub cellular structures such
as nuclei
,What is the formula triangle for magnification? - Ans>>
What do electron microscopes use to work? - Ans>>Electrons instead of light to
form an image. They have a much higher magnification than light microscopes
How are electron microscopes better than light microscopes? - Ans>>They allow us
to see much smaller things in greater detail since they have a higher magnification
and resolutions. For example, using an electron microscope, we can see the internal
structure of mitochondria and chloroplast
Describe the steps to prepare a slide [Required Practical] - Ans>>1) Add a drop of
water to the middle of a clean slide
2) Cut up an onion and separate it out into layers. Use tweezers to peel off some
epidermal tissue from the bottom of one the layers
3)Using the tweezers, place the epidermal tisse into the water on the slide
4) Add a drop of iodine solution. Iodine solution is a stain which is used to highlight
objects in the cell by adding colour to them
5) Place a cover slip on top. To do this, stand the cover slip upright on the slide,
next to the water droplet. Then carefully tilt and lower it so it covers the specimen.
Try not to get any air bubbles underneath it - they'll obstruct your view of the
specimen
Describe the steps needed to use a light microscope to look at your slide [Required
Practical] - Ans>>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
6) If you need to see the slide with greater magnification, swap to a higher-powered
objective lens and refocus
What is cell differentiation? - Ans>>Cell differentiation is the process by which a cell
changes to become specialised for its job.
What is cell specialisation? - Ans>>The process of cells as they develop depending
on their location in a tissue or organ.
What is a stem cell? - Ans>>A type of undifferentiated which are able to become
any type of cell
How are sperm cells specialised? - Ans>>For reproduction: they have a long tail
and a streamlined head to help it swim to the egg, there are lots of mitochondria in
, the cell to provide the energy needed and it also carries enzymes in its head to
digest through the egg cell membrane
How are nerve cells specialised? - Ans>>For rapid signalling: these cells are long to
cover more distances and have branched connections at their ends to connect to
other nerve cells and form a network throughout the body
How are muscle cells specialised? - Ans>>For contraction: these cells are long so
that they have space to contract and have lots of mitochondria to generate the
energy needed for contraction
How are root hair cells specialised? - Ans>>For absorbing water and minerals: they
grow into long "hairs" that stick out into the soil. This gives the plant a large surface
area for absorbing water and mineral ions from the soil
How are phloem and xylem cells specialised? - Ans>>For transporting substances:
phloem cells form phloem tubes and xylem cells form xylem tubes which transport
substances such as food and water around plants - the cells are joined end to end.
Xylem cells are hollow in the centre and phloem cells have few sub cellular
structures, so that stuff can flow through them
Define the term chromosome - Ans>>Coiled up lengths of DNA molecules, they
contain your genetic information
How many pairs of chromosomes are there in humans? - Ans>>23
What is mitosis? - Ans>>Part of the cell cycle where one set of new chromosomes is
pulled to each end of the cell forming two identical nuclei during cell division
What is the purpose of mitosis in multicellular organisms? - Ans>>For growth,
development and repair
What is the end result of mitosis? - Ans>>2 identical daughter cells
What are stages of growth and DNA replication during mitosis? - Ans>>1) In a cell
that's not dividing, the DNA is all spread out in long strings
2) Before it divides, the cell has to grow and increase the amount of sub cellular
structures such as mitochondria and ribosomes
3) It then duplicates its DNA - so there's one copy for each new cell. The DNA is
coped and forms X-shaped chromosomes. Each 'arm' of the chromosome is an
exact duplicate of the other.
What are the stages of mitosis? - Ans>>Once its contents and DNA have been
copied, the cell is ready for mitosis:
4) The chromosomes line up at the centre of the cell and cell fibres pull them apart.
The two arms of each chromosome go to opposite ends of the cell
5) Membranes form around each of the sets of chromosomes. These become the
nuclei of the two new cells - the nucleus has divided
Biology Paper 1 questions and answers
Name the two types of cells - Ans>>Prokaryotic and Eukaryotic
What is a prokaryotic cell? - Ans>>A cell without a nucleus
Give an example of a prokaryote (Prokaryotic cell) - Ans>>Bacteria
What is a eukaryotic cell? - Ans>>cell with a nucleus
Give two examples of eukaryotic cells - Ans>>Plant & Animal cells
What three sub-cellular structures do plant cells have which animal cells do not? -
Ans>>Permanent vacuole, cell wall and chloroplasts
What is the function of the nucleus? - Ans>>Contains genetic materials that
controls the activities of the cell
What is the function of the cytoplasm? - Ans>>A gel-like substance where most of
the chemical reactions happen. It contains enzymes that control these reactions
What is the function of the cell membrane? - Ans>>Holds the cell together and
controls the passage of substances
What is the function of the mitochondria? - Ans>>These are where most of the
reactions for aerobic respiration take place. Respiration transfers energy that the
cell needs to work
What is the function of the ribosome? - Ans>>These are were proteins are made in
the cell through protein synthesis
What is the function of the cell wall? - Ans>>To strengthen and support the cell
What is the function of the vacuole? - Ans>>Contains cell sap (a weak solution of
sugar and salts), it keeps the cell turgid
What is the function of the chloroplast? - Ans>>This is where photosynthesis takes
place, which makes food for the plant. They contain a green substance called
chlorophyll which absorbs the light required for photosynthesis
What do bacterial cells have instead of a nucleus? - Ans>>A single circular strand of
DNA that floats freely in the cytoplasm, and some may also contain one or more
small rings of DNA called plasmids.
How many mm are in um? - Ans>>1000
What do light microscopes use to work? - Ans>>Light and lenses to form an image
of a specimen. They let us see individual cells and large sub cellular structures such
as nuclei
,What is the formula triangle for magnification? - Ans>>
What do electron microscopes use to work? - Ans>>Electrons instead of light to
form an image. They have a much higher magnification than light microscopes
How are electron microscopes better than light microscopes? - Ans>>They allow us
to see much smaller things in greater detail since they have a higher magnification
and resolutions. For example, using an electron microscope, we can see the internal
structure of mitochondria and chloroplast
Describe the steps to prepare a slide [Required Practical] - Ans>>1) Add a drop of
water to the middle of a clean slide
2) Cut up an onion and separate it out into layers. Use tweezers to peel off some
epidermal tissue from the bottom of one the layers
3)Using the tweezers, place the epidermal tisse into the water on the slide
4) Add a drop of iodine solution. Iodine solution is a stain which is used to highlight
objects in the cell by adding colour to them
5) Place a cover slip on top. To do this, stand the cover slip upright on the slide,
next to the water droplet. Then carefully tilt and lower it so it covers the specimen.
Try not to get any air bubbles underneath it - they'll obstruct your view of the
specimen
Describe the steps needed to use a light microscope to look at your slide [Required
Practical] - Ans>>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
6) If you need to see the slide with greater magnification, swap to a higher-powered
objective lens and refocus
What is cell differentiation? - Ans>>Cell differentiation is the process by which a cell
changes to become specialised for its job.
What is cell specialisation? - Ans>>The process of cells as they develop depending
on their location in a tissue or organ.
What is a stem cell? - Ans>>A type of undifferentiated which are able to become
any type of cell
How are sperm cells specialised? - Ans>>For reproduction: they have a long tail
and a streamlined head to help it swim to the egg, there are lots of mitochondria in
, the cell to provide the energy needed and it also carries enzymes in its head to
digest through the egg cell membrane
How are nerve cells specialised? - Ans>>For rapid signalling: these cells are long to
cover more distances and have branched connections at their ends to connect to
other nerve cells and form a network throughout the body
How are muscle cells specialised? - Ans>>For contraction: these cells are long so
that they have space to contract and have lots of mitochondria to generate the
energy needed for contraction
How are root hair cells specialised? - Ans>>For absorbing water and minerals: they
grow into long "hairs" that stick out into the soil. This gives the plant a large surface
area for absorbing water and mineral ions from the soil
How are phloem and xylem cells specialised? - Ans>>For transporting substances:
phloem cells form phloem tubes and xylem cells form xylem tubes which transport
substances such as food and water around plants - the cells are joined end to end.
Xylem cells are hollow in the centre and phloem cells have few sub cellular
structures, so that stuff can flow through them
Define the term chromosome - Ans>>Coiled up lengths of DNA molecules, they
contain your genetic information
How many pairs of chromosomes are there in humans? - Ans>>23
What is mitosis? - Ans>>Part of the cell cycle where one set of new chromosomes is
pulled to each end of the cell forming two identical nuclei during cell division
What is the purpose of mitosis in multicellular organisms? - Ans>>For growth,
development and repair
What is the end result of mitosis? - Ans>>2 identical daughter cells
What are stages of growth and DNA replication during mitosis? - Ans>>1) In a cell
that's not dividing, the DNA is all spread out in long strings
2) Before it divides, the cell has to grow and increase the amount of sub cellular
structures such as mitochondria and ribosomes
3) It then duplicates its DNA - so there's one copy for each new cell. The DNA is
coped and forms X-shaped chromosomes. Each 'arm' of the chromosome is an
exact duplicate of the other.
What are the stages of mitosis? - Ans>>Once its contents and DNA have been
copied, the cell is ready for mitosis:
4) The chromosomes line up at the centre of the cell and cell fibres pull them apart.
The two arms of each chromosome go to opposite ends of the cell
5) Membranes form around each of the sets of chromosomes. These become the
nuclei of the two new cells - the nucleus has divided
