A Level Biology Exam
With answers
- Sister chromatids are lined up at equator
- Spindle Fibres contract
- The chromatids separate from the centromere
- Move to opposite poles
- Genetically identical poles - answer-Describe and explain what happens during Anaphase
which ensures that two genetically identical cells are produced.
- Chromosome/DNA replication
- No separation - answer-Suggest an explanation for why the chromosome number doubles in
the early stages of mitosis.
- Chromosomes shorten/thicken
- Chromosomes form from chromatids
- Move to the equator and attach to the spindle
- Spindle fibres contract
- Chromosomes separate
- Each pole receives genetically identical info
- Nuclear envelope forms around
- Cell splits - answer-Describe the behaviour of chromosomes during mitosis and explain how
this results in the production of two genetically identical cells.
- Chromosomes more visible
- Chromosomes much thicker - answer-Describe why this diagram is an example of prophase?
- Circular DNA floating in cytoplasm
- Smaller ribosomes (70S) - answer-Give ONE piece of evidence that supports the theory that
mitochondria evolved from prokaryotic cells.
- Beta glucose has alternate 1-4 bonds meaning that it is straight and not bent.
- Long unbranched chains
- Joined by hydrogen bonds
- Forms microfibrils (Very strong) - answer-The structure of cellulose is related to its role in plant
cell walls. Explain how.
Making a slide:
- Create a thin layer/sample
- Stain the specimen
- push down on the blot using a cover slip. - answer-Describe how temporary mounts are made.
- Count all the cells in the field of view
- Count the number of chloroplasts
, - Divide the number of chloroplasts by the number of cells. - answer-Describe how the scientist
could have used the temporary mounts of leaves to determine the mean number of chloroplasts
in mesophyll cells of a leaf.
Releasing energy via aerobic respiration - answer-DETECT:
Mitochondria
- Water Potential - Diffusion - answer-DETECT:
Osmosis
Making a slide - answer-DETECT:
Temporary Mount
High resolution, Short wavelength - answer-DETECT:
Electron microscope
Quote Data - answer-DETECT:
Use information
Specific tertiary structure - answer-DETECT:
Protein channels/carriers
To prevent damage to the enzymes. - answer-Why do we use a buffer solution?
- The site of photosynthesis
- Produces sugars/ATP for the cell. - answer-What is the function of the chloroplast?
- Passive
- Concentration gradient - answer-DETECT:
Diffusion
- Against a concentration gradient
- Requires ATP - answer-DETECT:
Active Transport
- To allow light through
- To make the sample thinner - answer-Why do you firmly squash the root tip when making a
slide?
- As it gives you a 3D image. - answer-Give one advantage of using SEM rather than TEM.
- Active transport uses ATP to go against a concentration gradient
- Facilitated diffusion uses carrier and channel proteins
With answers
- Sister chromatids are lined up at equator
- Spindle Fibres contract
- The chromatids separate from the centromere
- Move to opposite poles
- Genetically identical poles - answer-Describe and explain what happens during Anaphase
which ensures that two genetically identical cells are produced.
- Chromosome/DNA replication
- No separation - answer-Suggest an explanation for why the chromosome number doubles in
the early stages of mitosis.
- Chromosomes shorten/thicken
- Chromosomes form from chromatids
- Move to the equator and attach to the spindle
- Spindle fibres contract
- Chromosomes separate
- Each pole receives genetically identical info
- Nuclear envelope forms around
- Cell splits - answer-Describe the behaviour of chromosomes during mitosis and explain how
this results in the production of two genetically identical cells.
- Chromosomes more visible
- Chromosomes much thicker - answer-Describe why this diagram is an example of prophase?
- Circular DNA floating in cytoplasm
- Smaller ribosomes (70S) - answer-Give ONE piece of evidence that supports the theory that
mitochondria evolved from prokaryotic cells.
- Beta glucose has alternate 1-4 bonds meaning that it is straight and not bent.
- Long unbranched chains
- Joined by hydrogen bonds
- Forms microfibrils (Very strong) - answer-The structure of cellulose is related to its role in plant
cell walls. Explain how.
Making a slide:
- Create a thin layer/sample
- Stain the specimen
- push down on the blot using a cover slip. - answer-Describe how temporary mounts are made.
- Count all the cells in the field of view
- Count the number of chloroplasts
, - Divide the number of chloroplasts by the number of cells. - answer-Describe how the scientist
could have used the temporary mounts of leaves to determine the mean number of chloroplasts
in mesophyll cells of a leaf.
Releasing energy via aerobic respiration - answer-DETECT:
Mitochondria
- Water Potential - Diffusion - answer-DETECT:
Osmosis
Making a slide - answer-DETECT:
Temporary Mount
High resolution, Short wavelength - answer-DETECT:
Electron microscope
Quote Data - answer-DETECT:
Use information
Specific tertiary structure - answer-DETECT:
Protein channels/carriers
To prevent damage to the enzymes. - answer-Why do we use a buffer solution?
- The site of photosynthesis
- Produces sugars/ATP for the cell. - answer-What is the function of the chloroplast?
- Passive
- Concentration gradient - answer-DETECT:
Diffusion
- Against a concentration gradient
- Requires ATP - answer-DETECT:
Active Transport
- To allow light through
- To make the sample thinner - answer-Why do you firmly squash the root tip when making a
slide?
- As it gives you a 3D image. - answer-Give one advantage of using SEM rather than TEM.
- Active transport uses ATP to go against a concentration gradient
- Facilitated diffusion uses carrier and channel proteins
