cell structure and microscopy Flashcards
describe the role of one named organelle in digestion of bacteria (3)
- lysosomes
- fuse with vesicle
- release hydrolytic enzymes
explain why its not possible to see small structures using a optical microscope (2)
- resolution is too low
- as wavelength of light is too long
give 3 organelles present in all prokaryotic and eukaryotic cells
- ribosomes
- cytoplasm
- cell membrane
describe how a sample of chloroplasts can be isolated from leaves (4)
- break open cells and filter
- in cold, isotonic, buffered solution
- spin in centrifuge and remove nuclei
- spin at faster speed, chloroplasts settle out
outline the role of organelles in the production, transport and release of proteins from eukaryotic cells (4)
- DNA in nucleus is code for protein
- ribosomes produce proteins
- mitochondria produce ATP for protein synthesis
- Golgi apparatus package proteins
- vesicles transport proteins
give an advantage of viewing specimens using a transmission electron microscope rather than scanning electron microscope (1)
has a higher resolution
can view internal structures
name an organelle found in both a chloroplast and prokaryotic cell (1)
70s ribosome
describe 3 properties of solution used in separating cells (3)
- cold to reduce enzyme activity
- buffered to prevent denaturing of enzyme
- same water potential to prevent bursting of organelle
contrast how an optical and transmission microscope work and contrast their limitations (6)
- TEM use electrons, optical use light
- TEM allows greater resolution
- TEM can see smaller organelles
- TEM only view dead specimens, optical can view live specimens
- TEM does not show colour, optical shows colour
- TEM requires thinner specimens
- TEM focuses using magnets and optical uses glass lenses
why are no organelles visible in red blood cells (1)
cytoplasm is filled by haemoglobin
name 3 structures in a eukaryotic cell that cannot be viewed using an optical microscope
- ribosome
- endoplasmic reticulum
- lysosome
describe how to make a temporary mount of a piece of plant tissue to observe the position of starch grains when using an optical microscope (4)
- add drop of water to glass slide
- obtain thin section of plant tissue and place on slide
- stain with potassium iodide
- lower cover slip using mounted needle
name 2 structures found in ALL bacteria that are not found in plant cells (3)
- murein cell wall
- circular DNA
- 70s ribosomes IN CYTOPLASM
name 2 features of HIV particles that are not found in bacteria
don’t include attachment protein (2)
- capsid
- RNA genome
- reverse transcriptase
- lipid envelope
give 3 structures found in all prokaryotic cells and all eukaryotic cells
- cell membrane
- cytoplasm
- ribosomes
name the biological molecule in the cell membrane of a bacterium cell
phospholipids
name the biological molecule in the murein cell wall of bacteria
peptidoglycan
Describe how HIV is replicated (4)
- attachment proteins on HIV bind to RECEPTOR molecules on the T cell
- virus injects it’s nucleic acid into host cell
- reverse transcriptase converts RNA into DNA
4.host cell makes viral proteins, they are assembled and released, the cell bursts
is RNA present in: bacteria
virus
yes in bacteria and virus
is a cell wall present in:
bacteria
virus
yes in bacteria
no in virus
are enzyme molecules present in:
bacteria
virus
yes in bacteria and virus
is a capsid present in:
bacteria
virus
no in bacteria
yes in virus
describe and explain a difference between images produced by a transmission and scanning electron microscope
SEM produces 3D image whereas TEM produces 2D image
because electrons are deflected with SEM but pass through with TEM
a student determined the size of a cell from a photograph using a ruler and calculator and gave the answer in micrometres,
describe how (2)
- measured length of structure and divided by magnification
- multiplied by 1000 from mm