3.2.1 Cell Structure Flashcards
Why do epithelial cells of the small intestine have large amounts of mitochondria?
They carry out aerobic respiration which provides lots of ATP for active transport. Active transport allows the small intestine to absorb small molecules
How are plants cell adapted for photosynthesis?
The contain chloroplasts which absorb light and convert the energy from the sun into chemical energy
Describe how you can make a temporary slide using plant tissue
Put a drop of water in middle of slide
Separate thin layer of tissue with scalpel and place on water
Put a drop of iodine solution on the plant tissue
Use a mounted needle to place a cover slip over the sample
How can you identify and image created by a transmission electron microscope?
2D image
High resolution and magnification
Black and white
Can see internal structures of the cell
Advantages of electron microscopes
High magnification and resolution because electron beams allow cells to be seen in great detail
Disadvantages of electron microscopes
Very expensive
Artefacts frequently get into the sample
Can only view dead cells as sample must be in vacuum
Not in colour
Sample can be damaged by electrons
When carrying out cell fractionation, why is the cell homogenised? the resulting suspension filtered? the suspension kept cold? isotonic solution used?
To break the membrane and release what’s inside
To get rid of any debris
To stop enzyme activity
To prevent osmosis so the cell organelles aren’t damaged
Which organelles have double outer membranes
Nucleus, mitochondria, chloroplasts
Contrast how an optical microscope and a transmission electron microscope work + contrast their limitations
TEM uses electrons + optical light
TEM allows greater resolution
TEM can only view dead specimens + optical can view live
TEM doesn’t show colour but optical can
TEM requires thinner specimens
TEM requires more complex prep
