M+C lecture 3

Question 1

describe endosymbiotic theory

Answer 1

cells engulfing another bacterium with advantageous features e.g. aerobic or photosynthetic

Question 2

describe secondary endosymbiosis

Answer 2

ingestion of cyanobacteria by algae a couple of times creating more than one membrane to form plastids with 3/4 membranes which are very common in algae

Question 3

what does mitochondrial DNA encode?

Answer 3

rRNAS, tRNAs and 13 out of 85 components of the oxidative phosphorylation system

Question 4

what does chloroplast DNA encode?

Answer 4

some rRNAs and tRNAs, ribosomal proteins, RNA polymerase sub units and some genes for photosynthesis

Question 5

where does mitochondrial inheritance come from?

Answer 5

mainly the egg which contains 10x more mitochondrial DNA than the sperm

Question 6

how many signal sequences are needed for polypeptides to pass through thylakoid membranes?

Answer 6

2 because plant cells have 2 membranes

Question 7

what is the enzyme rubisco needed for and where is it synthesised?

Answer 7

needed for carbon fixation in photosynthesis and synthesised by both the nucleus and plastid DNA

Question 8

how are mitochondria and chloroplasts able to produce enough energy to express proteins?

Answer 8

loads of internal membranes increase the surface area for oxidative phosphorylation