topic 2 exam questions Flashcards
U. marinum cells ingest bacteria and digest them in the cytoplasm.
Describe the role of one named organelle in digesting these bacteria.
Lysosomes;
Fuse with vesicle;
(Releases) hydrolytic enzymes;
Give two structures found in all prokaryotic cells and in all eukaryotic cells
Cell(-surface) membrane;
Ribosomes;
Scientists have found that the rate of plasmid replication is faster in cells growing in a culture with a high concentration of amino acids than in a culture with a lower concentration of amino acids.
Suggest one explanation for the faster rate of plasmid replication in cells growing in a culture with a high amino acid concentration.
(Amino acids used in) protein synthesis;
Accept for ‘protein synthesis’, translation
(So) more enzymes (for DNA/plasmid replication)
(Amino acids used in) respiration;
(So) more energy/ATP (for DNA/plasmid replication);
Eukaryotic cells produce and release proteins.
Outline the role of organelles in the production, transport and release of
proteins from eukaryotic cells.
DNA in nucleus is code (for protein);
Ribosomes/rough endoplasmic reticulum produce (protein);
Accept rER for ‘rough endoplasmic reticulum’
Mitochondria produce ATP (for protein synthesis);
Golgi apparatus package/modify;
Contrast how an optical microscope and a transmission electron
microscope work and contrast the limitations of their use when studying
TEM use electrons and optical use light;
TEM allows a greater resolution;
(So with TEM) smaller organelles / named cell structure can be
observed
OR
greater detail in organelles / named cell structure can be
observed;
TEM view only dead / dehydrated specimens and optical (can)
view live specimens;
TEM does not show colour and optical (can);
TEM requires thinner specimens;
TEM requires a more complex/time consuming preparation;
TEM focuses using magnets and optical uses (glass) lenses;
Explain why the solution the biologist used was ice-cold, buffered and the
same water potential as the liver tissue (step 1).
Ice-cold – Slows / stops enzyme activity to prevent digestion of
organelles / mitochondria;
Buffered – Maintains pH so that enzymes / proteins are not
denatured; .
Same water potential – Prevents osmosis so no lysis / shrinkage of
organelles / mitochondria / C;
Give two ways in which the nucleotides in DNA are different from the
nucleotides in RNA.
DNA contains thymine and RNA contains uracil;
DNA contains deoxyribose and RNA contains ribose.
Describe how you could make a temporary mount of a piece of plant tissue
to observe the position of starch grains in the cells when using an optical
(light) microscope.
Add drop of water to (glass) slide;
Obtain thin section (of plant tissue) and place on slide / float on
drop of water;
Stain with / add iodine in potassium iodide.
Lower cover slip using mounted needle.
