Week 3 Mutations-P2

Question 1

Cytogenetics

Answer 1

The study of chromosomes and their abnormalities

Question 2

The goal of cytogenetic analysis

Answer 2

To help diagnose / plan treatment,

Question 3

Meta centric, sub centric and acrocentric

Answer 3

M-Centre
S-Slightly off set
A-At the edges

Question 4

Karotype

Answer 4

Display of chromosomes / group

Question 5

Euploidy

Answer 5

Having correct no of chromosomes

Question 6

Polyploidy

Answer 6

Presence of abnormal amount of chromsomes e.g 2-3-4 more

Question 7

Aneuploidy

Answer 7

Missing or having an extra

Question 8

non-disjunction

Answer 8

Failure for chromosomes to split apart and go into new daughter cells

Question 9

How many steps does meiosis have

Answer 9

2

Question 10

Condiitons examples and chromosomes group involved

Answer 10

Downs 21
Edwards 18
Patua 13

Question 11

How can chromosomal mutations occur

Answer 11

deletions, inversions, translocations

Question 12

Name and explain the two types of chromosomal deletion

Answer 12

Terminal deletion - Single break, loss of the tip
Interstital deletion - Two breaks, loss of material

Question 13

Chromosome inversion

Answer 13

Two breaks of chromosome, inverts and moves into other pair

Question 14

Translocation

Answer 14

A portion of one chromosome is transported to the other

Question 15

Reciprocal translocation

Answer 15

exchange of segments between non-homologous chromosomes

Question 16

Robertsonian translocation

Answer 16

the long arms of two non-homologous, acrocentric chromosomes
fuse at the centromeres to form a single chromosome

Question 17

How do cancer cells arise

Answer 17

Genetic mutations like oncogenes, tumour suppressor genes or DNA repair genes, loss of cell cycle control

Cancer cells prevent apoptosis

Question 18

Cell cycle main two stages

Answer 18

Interphase and M phase

Question 18

Molecules used in these phases

Answer 18

CDK’s - uses target protein to speed production

Tumour suppressor - Stops cell cycle if not correct

Question 19

Checkpoints in the cell cycle

Answer 19

g1 - checks dna is ready for replication

g2 - checks if complete and error free

m - ensures chromosomes are aligned

Question 20

I phase

Answer 20

g1 - cell grows and produces necessary organelles

s phase - dna replication

g2 - prepares for mitosis and checks for errors

Question 20

M phase

Answer 20

Dividing into two daughter cells

Prophase - Chromosome condenses and spiral forms

Metaphase - Chromosomes align in the middle

Telephase - Nuclear envelope surrounds chromosome

Cytokinesis

Question 20

Oncogenes

Answer 20

Mutated forms of pro-oncogenes that causes uncontrolled cell proliferation

Question 20

How does an oncogene arise

Answer 20

Point mutation - nucleotide change causes protein to become resistant to regulation e.g RAS mutation

Gene amplification - Multiple copies = over expression e.g HER2 in BC

Chromosomal translocation - One chromosome is transferred to another, fuses with adjacent protein, e.g BCR fusion in leukemia

Question 20

Intrinsic pathway

Answer 20

Caused by intracellular stress e.g stress or dna damage, controlled by the mitochondria

stress signals activate bcl-2 proteins which releases cytochrome c

forms complex called apoptosome, releases capsase 3 and 7 = apoptosis