Changes in chromosome structure

Question 1

deletion

Answer 1

where chromosomes have missing parts due to chromosomal segrments which lack the centromere breaking off

Question 2

deletion- where chromosomes have missing parts- detail

Answer 2

-a deletion is the loss of art of one chromosome arm -deletions can be small, only covering a part of one gene -deletion can be large, with chromosomes missing pieces large enough to be visualised on a karyotype

Question 3

karyotype

Answer 3

a test to identify and evaluate the size, shape and number of chromosomes in a sample of a body cell

Question 4

deletions can be small

Answer 4

only covering a part of one gene

Question 5

deletions can be large

Answer 5

with chromosomes missing pieces large enough to be visualised on a karyotype

Question 6

when chromosomes have mixed up pieces

Answer 6

inversion and translocations

Question 7

inversions

Answer 7

chromosomal segment is lost and rotated 180 degree and then reinserts in the same position

• all the same genes are the same but the order is inverted
• inversions are balanced rearrangements- no loss or gain of genetic material -meiosis

Question 8

inversions can lead to

Answer 8

deletions or duplication

Question 9

how are inversions created

Answer 9

to create an inversion, a segment of the chromosome is cut out, flipped and reinserted into he chromosome in the opposite orientation in the same place

Question 10

translocation

Answer 10

a rearrangment involving a part of one chromosome that has broken off and reattached to a DIFFERENT part of the chromosome or to a non-homologous chromosome

Question 11

reciprocal translocation

Answer 11

usually an exchange of material between nonhomologous chromosomes. -usually harmless and can be found in prenatal tests

Question 12

robertsonian translocation

Answer 12

(ROB) is a rare form of chromosomal rearrangement that, in humans, generally occurs in the five acrocentric chromosome pairs, namely 13, 14, 15, 21 and 22. Other Robertsonian translocations can occur, but do not lead to a viable fetus

Question 13

duplications

Answer 13

chromosomes can have extra fragments from homologous chromosomes

-duplications of sequences of DNA already present

Question 14

what do duplications play an important role in

Answer 14

duplications play an important role in the evolution own the genome

Question 15

reciprocal translocation

Answer 15

2 fragments switch places on non homologous chromosomes