practise questions Flashcards
explain how the inner membrane is adapted to its function?
the inner membrane has folds that form cristae and this has a large surface area
give the functions of both types of endoplasmic reticulum?
SER synthesises lipids and process them
RER folds and processes proteins made at the ribosomes
what is the function of the lysosome?
they release digestive enzymes that breakdown pathogens and unwanted cell organelles
what is the cell wall made of in plants and in fungal cells?
polysaccharide cellulose
cells of multicellular organisms may undergo differentiation. what is meant by differentiation?
cells become specialised and change to carry out a particular function
palisade cells are the main site of photosynthesis. explain one way in which a palisade cell is adapted for photosynthesis?
chloroplast move to trap and absorb light. it has lots of chloroplast to trap and absorb lights
describe the structure of epithelial tissues in humans and relate this structure to the different functions of these tissues?
epithelial cells has a thin layer of cells which is flattened. they are involved in the exchange and absorption of gases and are an efficient barrier to the external environment
name one feature of a chloroplast and explain how this enables the chloroplast to function
has a watery stoma that contain stacks of folded membrane, this enables it to form grana and is where photosynthesis takes place. it also contains enzymes
describe four essential steps required when streaking an agar plate with bacteria
- heats the incubating loop with a Bunsen burner until it is red to ensure it is sterilised
- replace the agar dish slip
- streak the loop across surface of the plate
- lift lid of agar plate
compare the advantages and disadvantages of using ultrasound and x-ray scanner to view internal structures of a human patient, and explain how this makes them suitable for viewing different structures?
ultrasound has no radiation, can be used on moving structures and produce 3 images. Dis - cannot be used on diagnosing problems in lung, images have limited detail and has limited use in detection of breast cancer
x-rays can see structures of different densities clearly. and produce high quality images. Dis - exposure to radiation which causes tissue damage. screening is dangerous to radiographer, not suitable for pregnancy.
explain how gel electrophoresis separates the fragments of DNA?
separates DNA based upon its size, electric field is applied to gel and the DNA is negatively charged
describe how gel electrophoresis can be carried out?
chamber must have a buffer solution, this can conduct electricity
the electric current is then turned on, so the negatively charged DNA moves towards the positive end
once it is done you can visualise the results as the DNA fragments will be a fluorescence blue colour
