OCR BIOLOGY STUDY AHEAD EXAM QUESTIONS AND
ANSWERS COMPLETE DOCS
Define magnification - How much larger a displayed image is compared with the original
object
Define resolution - The ability to distinguish between two points
Why is staining used? - - Some specimens are colourless
- It is useful to highlight different structures
- It increases contrast
What is the formula to calculate magnification from image size and actual size? - (The I AM
formula) Image size = Actual Size x Magnification
How do you calculate total magnification? - Total magnification = Eyepiece magnification x
Objective lens magnification
How is a light microscope set up? - Place the specimen on a slide, cover it with a cover slip,
illuminate with a lamp and view using the eyepiece
State 5 parts of an animal cell - Nucleus, cytoplasm, mitochondria, ribosomes and the cell
membrane
State 2 functions of the nucleus - - Controls the cell
- Contains genetic material - found in the form of chromosomes.
State the function of the cytoplasm - It is where most of the cell's chemical reactions take
place
State the function of mitochondria - They are the site of aerobic respiration
, State the function of ribosomes - State the function of ribosomes
State 3 organelles only found in plant cells - - Cellulose cell wall
- Permanent vacuole
- Chloroplasts
What is the function of the cell wall and what is it made of? - It provides strength and
support. It is made of cellulose
What is the function of the permanent vacuole and what does it contain? - It supports the
cell and contains cell sap (a solution of sugars and salts)
What is the function of chloroplasts? - They are the site of photosynthesis
Give 3 differences between prokaryotic and eukaryotic cells - - Prokaryotic cells have no
nucleus
- Prokaryotic cells have plasmid loops of DNA
- Prokaryotic cells have no mitochondria
Describe the image produced by an electron microscope - The image is black and white, it
can be 2D or 3D and it has a very high magnification and resolution
Why are electron microscopes better than light microscopes? - They produce images with
enough detail to see structures inside cells
Describe the structure of DNA - - It is a polymer made of many nucleotide monomers
- It is made of 2 strands in the shape of a double helix
ANSWERS COMPLETE DOCS
Define magnification - How much larger a displayed image is compared with the original
object
Define resolution - The ability to distinguish between two points
Why is staining used? - - Some specimens are colourless
- It is useful to highlight different structures
- It increases contrast
What is the formula to calculate magnification from image size and actual size? - (The I AM
formula) Image size = Actual Size x Magnification
How do you calculate total magnification? - Total magnification = Eyepiece magnification x
Objective lens magnification
How is a light microscope set up? - Place the specimen on a slide, cover it with a cover slip,
illuminate with a lamp and view using the eyepiece
State 5 parts of an animal cell - Nucleus, cytoplasm, mitochondria, ribosomes and the cell
membrane
State 2 functions of the nucleus - - Controls the cell
- Contains genetic material - found in the form of chromosomes.
State the function of the cytoplasm - It is where most of the cell's chemical reactions take
place
State the function of mitochondria - They are the site of aerobic respiration
, State the function of ribosomes - State the function of ribosomes
State 3 organelles only found in plant cells - - Cellulose cell wall
- Permanent vacuole
- Chloroplasts
What is the function of the cell wall and what is it made of? - It provides strength and
support. It is made of cellulose
What is the function of the permanent vacuole and what does it contain? - It supports the
cell and contains cell sap (a solution of sugars and salts)
What is the function of chloroplasts? - They are the site of photosynthesis
Give 3 differences between prokaryotic and eukaryotic cells - - Prokaryotic cells have no
nucleus
- Prokaryotic cells have plasmid loops of DNA
- Prokaryotic cells have no mitochondria
Describe the image produced by an electron microscope - The image is black and white, it
can be 2D or 3D and it has a very high magnification and resolution
Why are electron microscopes better than light microscopes? - They produce images with
enough detail to see structures inside cells
Describe the structure of DNA - - It is a polymer made of many nucleotide monomers
- It is made of 2 strands in the shape of a double helix
