Topic 3 Flashcards
DNA synthesis in bacterial cell cultures has been investigated.
Describe how DNA is organised in a bacterial cell.
large) circular DNA [1]
DNA not associated with histone proteins [1]
(small/several) plasmids [1]
Located inside the cytoplasm / not inside a nucleus [1]
Describe what happens to lysosomes once their contents have been digested
Lysosome fuses with cell (surface) membrane [1]
Contents of lysosome released from the cell / exocytosis [1]
Cells produce lactate during anaerobic respiration.
Lactate travels in the blood to the
liver.
Liver cells can absorb lactate from the blood.
Deduce what happens to the lactate in these cells
lactate is {oxidised to form / converted to} pyruvate [1]
(pyruvate is) converted to {glucose / glycogen} [1]
(pyruvate / glucose)
Give two functions of the Golgi apparatu
Modifies proteins [1]
Forms vesicles [1]
Removes (some) water from the protein / concentrates the {protein / glycoprotein} [1]
What are the similarities and differences between prokaryotic and eukaryotic cells
- eukaryotic have membrane bound organelles such as mitochondria and Golgi
- size of ribosomes is lager in prokaryotes (80 instead of 70)
- eukaryotic do not have plasmid in cytoplasm
Describe what happens to proteins following translation until they are released from cell
-proteins are folded in the RER
- proteins are packed into vesicles
-protein is then modified in the Golgi
-chemicals released
- exocytosis out
Explain why enzymes that are incorrectly folded can’t carry out their function
- if the protein is not folded correctly the tertiary structure (3d shape) would be different
- therefore the active site of the enzyme would not bind with the substrate and not be bale to form a enzyme substrate complex
-therefore it would not be bale to catalyse the reaction
Describe the acrosome reaction
-it fuses with cell surface membrane of thesperm cell
- digestive enzymes are relased
-these break down the zone pellucid
Describe the cortical reaction
-fusion of cortical granules and egg cell surface membrane
- results in thinking of zone pelludica
- therefore preventing other stem from entering - cant reach cell surface. Membrane
Describe how offspring from the same parents can be genetically different
-each zygote is formed from different gametes
-each gamete contains different combination of alleles
- different combinations are due to independent assortent and crossing over during meiosis
Describe how meiosis leads to genetic variation in the gametes produced
-independent assortment produces non identical gametes
- crossing over between Chromatids of chromosomes
Explain why DNA is replicated before mitosis begins
- to ensure that there is one copy of each chromosome one in each daughter cell
- this will ensure daughter cells are genetically identical
Order of mitosis
I - interphase
P - prophase
M - metaphase
A - anaphase
T - telaphse
Describe prophase
- nucleus breakdown
- spindle fibres formed
-chromesomes condense
Describe metaphase
-attach to spindle fibres
- aligned on the equator of the cell
