2.1.1 Cell structure and microscopy Flashcards
What is the function of the cell surface membrane?
To separate what is inside of the cell from its environment.
What are plant cell walls made of?
cellulose
Purpose of plant cell wall
Support the cell
purpose of lysosomes
Contain digest enzymes to digest invading cells.
Where are the two places that ribosomes can be found?
Cytoplasm
RER
Function of ribosomes
protein synthesis
Function of RER
Folds and processes proteins.
Function of smooth ER
Synthesised and processes lipids.
What are vesicles?
Small fluid filled sacks found in cytoplasm.
Function of a vesicles.
Transport substances in and out of cell
Function of Golgi apparatus.
Sorts and packages molecules for transport around the cell
function of mitochondria
ATP production
What happens at the chloroplasts?
photosynthesis
What are centrioles?
Hollow cylinders containing micro tubules.
Function of centriole?
Formation of spindle fibres in cell division.
What is the liquid found in the cytoplasm?
Cytosol
Function of cytoplasm
Site of chemical reactions.
Function of nuclear membrane.
-separates nucleus from the rest of the cell
What is the role of the nucelus?
Controls the cells activities.
what is a eukaryote?
a cell that has a nucelus
What is a prokaryote?
A cell which does not have a nucleus
What are plasmids?
Small circles of DNA that are found in bacteria and used to copy DNA during Genetic Engineering.
Can ribosomes be observed under light microscopes?
No
Definition of resolution
The ability of a microscope to distinguish between two separate points.
Define magnification
How many times larger an image is compared to the object being observed.
Maximum resolution of light microscope.
200nm
Magnification of light microscope
X1500
Disadvantages of light microscope.
Cannot see small organelles.
Maximum resolution of electron microscope
0.2 nm
Magnification of electron microscope
X1,500,000
Two types of electron microscopes
scanning and transmission
Why do some parts of the image appear darker when using an electron microscope?
Denser parts of the specimen absorb more electrons so they appear darker in image.
Advantages of transmission electron microscopes.
High resolution
Disadvantages of TEM’s
Thin specimens have to be used.
Why can live specimens not be used when using TEM’s and SEM’s?
There is a vacuum inside electron microscopes so water must be removed so cells must be dead,
Advantages of SEM’s
Thick specimens can be used.
Disadvantages of SEM’s
Colour images not produced.
Advantages of lazer scanning confocal microscope
Clear image
Disadvantage of LSCM’s
Can cause photo damage.
What can light microscopes be used for.
Observing eukaryotic cells, their nuclei, possible mitochondria and chloroplasts.
What can not be seen by light microscopes?
Small organelles such as ribosomes, lysosomes, endoplasmic reticulum.
Maximum magnification of light microscope ?
X1500
How do electron microscopes form an image?
Using a beam of electrons.
Maximum resolution of electron microscope.
0.2nm
Name two features of plant cells that are not features of animal cells.
Cellulose cell wall
permanent vacuole
chloroplasts
Name one structure present in animal cells that is not present in animal cells
Centrioles
