Genetics

Question 1

what direction is DNA replicated?

Answer 1

5’ to 3’

Question 2

what is a chromosome made of?

Answer 2

DNA strand that has associated with proteins

Question 3

what happens in G1 of the cell cycle?

Answer 3

cellular contents, apart from the chromosome, are duplicated

Question 4

what happens in S of the cell cycle?

Answer 4

DNA replication

Question 5

what happens in G2 of the cell cycle?

Answer 5

cell undergoes its second growth period and assembles the materials needed for mitosis

Question 6

what happens in M of the cell cycle?

Answer 6

mitosis

Question 7

in meiosis, one diploid cell becomes…

Answer 7

4 haploid

Question 8

in mitosis, one diploid cell becomes

Answer 8

2 diploid

Question 9

when does crossing over occur?

Answer 9

meiosis

Question 10

in splicing, what is removed from pre mRNA?

Answer 10

introns (non coding)

Question 11

what is a polymorphism?

Answer 11

Any variation in the human genome that does not cause a disease in its own right. It may however, predispose to a common disease

Question 12

what is a mutation?

Answer 12

A gene change that causes a genetic disorder. (a disease causing mutation)

Question 13

what are the parts of a chromosome?

Answer 13

telomere
short arm (p)
centromere
long arm (q)
telomere

Question 14

what is an acrocentric chromosome?

Answer 14

the short arm (p) is too small to see

Question 15

what is a metacentric chromosome?

Answer 15

both arms are the same length

Question 16

what is aneuploidy?

Answer 16

whole extra or missing chromosome

Question 17

what is a Robertsonian Translocation?

Answer 17

two acrocentric chromosomes stuck end to end (only occurs with 13, 14, 15, 21, 22)

Question 18

trisomy 21

Answer 18

down’s syndrome

Question 19

trisomy 18

Answer 19

Edward syndrome

Question 20

45 X

Answer 20

Turner syndrome

Question 21

47 XXY

Answer 21

Klinefelter syndrome

Question 22

what are Reciprocal Translocations?

Answer 22

an exchange of genetic material between non homologous chromosomes (can be balanced or unbalanced)

Question 23

symptoms of Digeorge Syndrome

Answer 23

• tetralogy of fallout
• thymus problems
• learning difficulties

Question 24

what is Somatic Mosaicism

Answer 24

two populations of genetically different cells within an individual

Question 25

what can her2 amplification cause?

Answer 25

breast cancer

Question 26

what is the Philadelphia chromosome?

Answer 26

a gene translocation in chromosome 22 of cancer cells

Question 27

7 types of mutations in DNA

Answer 27

``` wild type stop missense insertion deletion (out of frame) deletion (in frame) triplet expansion ```

Question 28

what is Penetrance?

Answer 28

The likelihood of having a disease if you have a gene mutation

Question 29

pattern of X-Linked Recessive Inheritance?

Answer 29

for females - half male children affected, half female children carriers for males - no male children affected, all female children carriers

Question 30

what is X inactivation?

Answer 30

one copy of the x chromosome in females is inactivated

Question 31

what is methylation and what does it do?

Answer 31

methyl groups added to DNA, it prevents transcription

Question 32

what is imprinting?

Answer 32

variation in gene expression, depending on which parent you inherit the gene from

Question 33

what happens in Angelman's syndrome?

Answer 33

mother's copy of UBE3A is methylated and does not work

Question 34

what is Heteroplasmy?

Answer 34

Different daughter cells contain different proportions of mutant mitochondria (similar to mosaicism)

Question 35

who is mitochondrial DNA inherited form?

Answer 35

mother

Question 36

what is epigenetic variation?

Answer 36

Functional modifications to the genome that do not involve a change in the nucleotide sequence

Question 37

where are the checkpoints in the cell cycle?

Answer 37

Between G2 and M | Between G1 and S

Question 38

how many copies of a tumour suppressor gene are required to be mutated for control to be lost?

Answer 38

2

Question 39

variation occurs via meiosis by..

Answer 39

Crossing over | Independent segregation of homologous chromosomes

Question 40

what is a telocentric chromosome?

Answer 40

The centromere is located at the terminal end of the chromosome