cell structure Flashcards
some mucus secreting cells were immersed in a solution of radioactive amino acids. every five seconds some of the cells were removed and their organelles were seperated and analysed. the radioactivity of the diff organelles were measured for each five second interval ( golgi apparatus, ribosomes, rough endoplasmic reticulum and vesicles.
(a) in which would radioactivity appear first. explain your answer (2)
(b) after 5 mins the golgi apparaturs had become radioactive. which other organelle(s) would be radioactive by this time ? (2)
(c) what is the cuntion of the vesicles ? (1)
- (a) ribosomes, because this is where proteins synthesis occur
- (b) the rough endoplasmic reticulum and some vesicles
- (c) transports substances in and out of cells and between organelles
give three functions of a cell’s cytoskeleton (3)
- enables cell’s movement
- strengthens the cell
- suuports the cell’s organelles
give 3 reasons why staining is used in preperation of microscope slides ? (3)
- to observe specific organelles
- to differentiate between different types of cells
- to distinguish between different tissues
state what light microscopes, TEM’s and laser scanning confocal microscopes are used to observe (3)
light microscope: whole cells + tissues
TEM: organelles
laser scanning confocal microscopes: object at certain depth within cells
what 2 prts of a microscope are used to magnify the specimen ? (2)
- objective lens
- eyepeice lens
what term is used to describe the detailed structure of celss visible only with an electron microscope ?
ultra structure
explain why the microscope was set to the lowest magnification
easier to focus
name the structure within cells consisting of microtubules and microfilaments
cytoskeleton
the student had easten cereal and not cleaned her teeth before making her cheeck cell slide. plaque bacteria and peices of fibrous plant material were visible on the slide. suggest how the bacterial and plant cells could be distinguished from th cheek cells (2)
- bacterial cells are clustered
- but plant cells have a known structure
suggest 1 stage during the secretion of a protein that requires energy
exocytosis
give 3 peices of evidence for the endosymbiotic theory (3)
- mitochondria contains ribosomes smaller than those in cytoplasm
- mitochondria are similar size to bacteria
- chloroplast have their own circular DNA
describe roles of cytoskeleton (5)
- movement of cilia
- movement of chromosomes
- exocytosis
- suppot + shape
- holds organelled in place
explain why the details of mitochondria cant be seen very clearly under a light microscope (3)
- mitochondria too small
- resolution not high
- wavelength of light too long
give 3 advantages of staining specimens to be seen under a microscope (3)
- easier to see more detail
- recognise organelles
- recognise diff compounds
do plant cells contain chloroplast ?
yes
