GIM 6 - chromosomal basis of inheritance

Question 1

what is cytogenetics

Answer 1

study of chromosomes

Question 2

what is autosomes

Answer 2

chromosome 1-22

23 = sex chromosomes

Question 3

when is chromosome most visible?

Answer 3

in metaphase in mitosis

Question 4

at what phases do G-banding test at ?

Answer 4

metaphase in mitosis

Question 5

at what phases do molecular cytogenetic test at ?

Answer 5

all phases and stages

Question 6

what does karyotype mean?

Answer 6

using G-banding and sort out from the largest chromosome to the smallest

Question 7

what are the telomere

Answer 7

the endings of the chromosome bands

Question 8

what are the 2 large subdivision for chromosome bands

Answer 8

P & Q

Question 9

how many smaller subdivisions are there for the p band

Answer 9

2

Question 10

how many smaller subdivisions are there for the q band

Answer 10

3

Question 11

what are the different types of cytogenetic abnormality

Answer 11

numerical & structural

Question 12

what does diploidy mean

Answer 12

2 copies of each chromosome

Question 13

what does aneuploidy

Answer 13

gain (trisomy) or less (monosomy)

Question 14

what does aneuploidy

Answer 14

gain whole sets (triploidy or tetraploidy)

Question 15

what does mosaicism mean

Answer 15

diploidy & aneuploidy

Question 16

where can numerical abnormality arise

Answer 16

gametogenesis - meiosis, fertilisation, early cleavage

Question 17

what can increase in maternal age do?

Answer 17

increase aneuploidy

Question 18

how is meiotic error arise?

Answer 18

chromosome non-disjunction, chromatid non-disjunction

Question 19

what syndrome can trisomy 18 lead to?

Answer 19

Edwards Syndrome

Question 20

what are some clinical features for Edwards Syndrome

Answer 20

Head: microcephaly; low set ears; micrognathia; ears low set; cleft lip and palate

Hands & feet: Clenched hands, overlapping fingers; Rockerbottom feet

Severe mental retardation

Question 21

what are some examples of organ malformation in trisomy 18

Answer 21

umbilical/inguinal hernia
congenital heart disease
congenital kidney abnormalities

Question 22

what is the cause of patua syndrome

Answer 22

trisomy 13

Question 23

what causes Turner’s syndrome

Answer 23

45,X

Question 24

what causes Klinefelter’s syndrome

Answer 24

47,XXY

Question 25

what are some clinical features for Turner’s Syndrome

Answer 25

Reproductive, Lymphatic, Skeletal abnormaliteis

Question 26

how is Klinefelter Syndrome commonly presented

Answer 26

infertility & hypogonadism

Question 27

what errors can arise in fertilisation?

Answer 27

polyploidy, molar pregnancy

Question 28

what is molar pregnancy

Answer 28

double paternal, no maternal

Question 29

what happens in double maternal genes instead of paternal and maternal

Answer 29

very small placenta - small baby

Question 30

what happens in double paternal genes instead of paternal and maternal

Answer 30

huge placenta

Question 31

what does maternal and paternal genome code for?

Answer 31

M - foetus

P - placenta

Question 32

what problem can arise in early cleavage?

Answer 32

mosaicism