lecture 4- Gene regulation

Question 1

what are liver cells specialised for?

Answer 1

storage and metabolism of carbohydrates

Question 2

name the cells of retina and what the do roughly

Answer 2

• receptor cells contain rods and cones- containing rhodopsin which is sensitive to light

neurons to transmit signals to brain

pigment epithelium- nourishes rods and cones

Question 3

name the different peptide chains in haemoglobin and when they are active

Answer 3

alpha- before and after birth
beta- largely after birth
delta- after birth

gamma- largely before birth
epsilon- before birth

Question 4

describe gene regulation in bacteria in absence of lactose.

Answer 4

regulatory gene codes for regulatory protein (made on ribosomes in cytoplasm) which binds to operator gene and overlap promoter gene. RNA polymerase cannot bind to promoter gene, hence promoter cannot switch genes for lactose, and lactose enzyme genes are switched off.

Question 5

describe gene regulation in presence of lactose in bacteria

Answer 5

lactose presence diffuses into bacteria and binds to regulatory protein changing its shape and cannot bind to operator gene which frees promoter gene, rna polymerase can bind to promoter and can now switch on the enzymes to make lactose and so bacteria can make lactose.

Question 6

how is the regulatory protein able to control gene regulation in bacteria?

Answer 6

regulatory protein has the same shape that fits the site of the operator gene in DNA of bacteria

Question 7

what is cancer?

Answer 7

an abnormal mass of tissue resulting from uncontrolled cell division.

Question 8

what is glioblastoma?

Answer 8

a malignant brain tumour which is invasive and causes considerable local tissue destruction

Question 9

what is retinoblastoma?

Answer 9

tumour developing from cells in the retina

Question 10

which 4 structures can malignant melanoma develop from?

Answer 10

may develop from mole on eyelid

from conjunctiva

iris

choroid

Question 11

when does retinoblastoma look like a white swelling?

Answer 11

in early stages

Question 12

how can retina be detached during retinoblastoma?

Answer 12

the tumour can spread behind retina

Question 13

how can retinoblastoma become solidified?

Answer 13

may become calcified as calcium salts are deposited in it.

Question 14

which age group is retinoblastoma frequently seen in?

Answer 14

children

Question 15

can retinoblastoma affect the optic nerve

Answer 15

yes

Question 16

how can you treat retinoblastoma

Answer 16

removal of much of the eye and optic nerve

Question 17

what kind of gene is responsible for retinoblastoma?

Answer 17

a dominant gene