Lecture 2: incomplete

Question 1

what order is a DNA sequence written?

Answer 1

5’ –> 3’

Question 2

what direction is DNA and RNA synthesised?

Answer 2

5’ –> 3’

Question 3

what is the sense strand in a gene?

Answer 3

The strand which ends up in the mRNA

Question 4

parent strand

Answer 4

strand of double helix which is used as a template to create the daughter strand during replication

Question 5

daughter strand

Answer 5

replicated strand of DNA from parent strand of double helix

Question 6

Okazaki fragments

Answer 6

short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication. formed on the 5’ –> 3’

Question 7

Centromere

Answer 7

the region of a chromosome to which the micro-tubules of the spindle attach

Question 8

Telomere

Answer 8

a region of repetitive nucleotide sequences at each end of a chromosome. Determines number of replication a cell undergo.

Question 9

what is the short arm of a chromosome also known as?

Answer 9

P

Question 10

what is the long arm of a chromosome also known as?

Answer 10

Q

Question 11

what is the telomeric sequence?

Answer 11

TTAGGG

Question 12

what is a normal human Karyotype?

Answer 12

46 chromosomes, inc. X and Y

Question 13

what is the structure of a telomere at the beginning of a chromosome?

Answer 13

initially double stranded but has a single stranded tail which loops around into a special structure.

Question 14

what enzyme replicates telomeres during development?

Answer 14

Telomerase

Question 15

where is telomerase inactive?

Answer 15

somatic cells

Question 16

what happens to telomeres with somatic cell division?

Answer 16

shorten, result in finite number of cell division to senescence.

Question 17

when is telomerase active?

Answer 17

short period during development.

Question 18

what is the activity of Telomerase like in cancer cells?

Answer 18

Telomerase reactivation allowing cancer cells to continue dividing.

Question 19

what is G-banding?

Answer 19

stained patterns on chromosomes. different for each chromosome.

Question 20

what are chromosome coordinates?

Answer 20

references to genes on a chromosome. universal/standard reference

Question 21

why are chromosome coordinates read from top to bottom?

Answer 21

chromosomes are linear

Question 22

what is dipoidy?

Answer 22

the state of having 2 sets of genes/chromosome

Question 23

what does diploidy occur?

Answer 23

maternal and paternal sets

Question 24

why is dosage of genes/chromosome important?

Answer 24

For many genes, 2 copies must be present for it to function adequately. For chromosomes, 2 copies must be present.

Question 25

what happens when there is an error in dosage of gene/chromosome?

Answer 25

haplo-insufficiency

Question 26

what is haplo-insufficiency?

Answer 26

a copy of a gene is lost = individual is haploid for that gene. this results in pathological insufficiency

Question 27

what chromosome is an exception of the diploidy rule?

Answer 27

X chromosome

Question 28

define pseudoautosomal

Answer 28

a region shared by the X + Y chromosomes consisting of similar genes.

Question 29

define Heterochromatin

Answer 29

repetitive DNA on Y chromosome which stains differently and mostly does not contain functional genes.

Question 30

what region on the Y chromosome is has a vital/specific function ?

Answer 30

SRY in the non-heterochromatin part of the Y chromosome

Question 31

what does the SRY gene do?

Answer 31

specify the formation of the Testis for development of male characteristics.

Question 32

why does the Y chromosome lead to a male fetus?

Answer 32

the SRY gene on the Y chromosome. this does not depend on the number of X or Y chromosomes.