Human genome

Question 1

How many chromosomes in a human?

Answer 1

23 homologous pairs = 46

Question 2

from whom do you inherit your mitochondrial DNA

Answer 2

Your mother

Question 3

What are the two arms of a chromosome called?

Answer 3

P (short) and Q

Question 4

What is a telomere?

Answer 4

protective cap on the end of a chromosome

Question 5

What characteristic does telomere DNA have?

Answer 5

repetitive

Question 6

what are the names of the two sorts of bands on a chromosome and what are their characteristics?

Answer 6

G-light:
gene rich, Guanine and Cytosine rich, early replicating,
G-dark:
gene poor, Adenine and Thymine rich, late replicating

Question 7

what does the centromere do?

Answer 7

keeps sister chromatids together,
attaches sc’s to microtubules

Question 8

what is it called when all the chromosomes are displayed in size order?

Answer 8

karyotype

Question 9

what sort of chromosomes are the 22 paris of not sex-chromosomes

Answer 9

autosomes

Question 10

What is an abnormal number of chromosomes called?

Answer 10

Aneuploidy

Question 11

From which end is DNA read?

Answer 11

5 prime

Question 12

What is found at the 5 prime end?

Answer 12

free phosphate group

Question 13

Name a translation start codon

Answer 13

aug

Question 14

What do you find at the 3 prime end?

Answer 14

free OH group

Question 15

Name some non-coding elements of DNA

Answer 15

Introns, promoters, enhancers (regulate transcription)

Question 16

Name the mechanisms of 5 abnormal chromosome structures

Answer 16

Deletion, inversion, duplication, translocation, Robertsonian translocation

Question 17

What is a feature of Gliobastoma Multiforme

Answer 17

Many de novo translocations

Question 18

name 3 autosomal aneuploidy conditions and specify their chromosomes

Answer 18

trisomy 21 Down Syndrome
Trisomy 18 Edwards Syndrome
trisomy 13 Patau Syndrome

Question 19

What is Turner syndrome?

Answer 19

X chromosome missing or partially missing

Question 20

What is Klinefelter syndrome

Answer 20

XXY male

Question 21

Name 3 features of Down Sydrome

Answer 21

Muscle hypotonia
Upwards slanting eyes
Single palmar crease

Question 22

Why does Down Syndrome increase chance of early onset dementia?

Answer 22

APP is on gene 21

Question 23

What is mosaic Down syndrome?

Answer 23

Only some cells have the trisomy. Effects can be less than full trisomy

Question 24

Name some features of Edwards syndrome

Answer 24

multiple malformations
clenched hands with overlapping fingers
very poor prognosis

Question 25

How rare is Patau syndrome?

Answer 25

1/5000 live births

Question 26

Name 2 features of Klinefelter syndrome

Answer 26

tall
poorly developed secondary sexual characteristics
infertile

Question 27

Name 2 features of Turner syndrome

Answer 27

short, primary amenorrhoea, congenital heart disease (20%), webbed neck

Question 28

What is the likelihood of a girl with Turner syndrome being carried to term?

Answer 28

1%

Question 29

When is amniocentesis carried out?

Answer 29

15-18 weeks

Question 30

what is chorionic villus sampling?

Answer 30

transabdo or transcervical sampling of placental tissue

Question 31

what is the neck fluid test looking for?

Answer 31

Nuchal translucency

Question 32

What is X-ist

Answer 32

long non-coding RNA in the X-chromosome. Inactivates one of the X chromosomes

Question 33

Where is Xist found

Answer 33

X Inactivation Centre on the X chromosome

Question 34

What does Xist do to the X chromosome and how

Answer 34

deactivates its transcription by causing the chromatin to wind very tight.

Question 35

Describe the Y chromosome

Answer 35

few genes, many repeat sequences

Question 36

what is the SRY?

Answer 36

Sex determining region of teh Y chromosome