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Principles of disease (Ross Lilley) > chromosome abnormalities, mutations and analysis > Flashcards

Flashcards in chromosome abnormalities, mutations and analysis Deck (37)
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1

types of chromosome abnormalities

-numerical
-structural
-mutational

2

aneuploidy

the presence of an abnormal number of chromosomes in a cell

3

trisomy

disorder characterised by the presence of the three homologous chromosomes instead of two

4

down syndrome cause

3 copies of chomosome 21 (trisomy 21)

5

down syndrome characteristics

characteristic facial features (flattened, upward slanting eyes)
IQ less than 50

6

patau syndrome cause

3 copies of chromosome 13 (trisomy 13)

7

Patau syndrome characteristics

multiple dysmorphic features (eg. cleft lip and palate)
very few survive beyond first year

8

Edwards syndrome cause

3 copies of chromosome 18 (trisomy 18)

9

edwards syndrome characteristics

severe developmental problems such as small head, heart, kidney and breathing problems.
Many don't live past first birthday.

10

turner syndrome cause

one X chromosome

11

turner syndrome characteristics

females of short stature and infertile, neck webbing and widely spaced nipples.

12

flinefelter syndrome cause

sex chromosomes XXY

13

klinefelter syndrome characteristics

tall statue and long limbs.
male but infertile, small testes and half exibit gynaecomastia
mild learning difficulties.

14

balanced chromosome rearrangements

structural chromosome abnormalities that don't lead to the loss of genetic information

15

unbalanced chromosome rearrangements

structural chromosome abnormalities that lead to the loss of genetic information

16

acrocentric chromosome

chromosome in which the centromere is located near to the end of the chromosome

17

metacentric chromosomes

chromosomes with their centromere in the middle of the chromosome

18

balanced translocation

a section of a chromosome breaks off from two non-homologous chromosome and they are swapped.

19

unbalanced translocation

occurs when one parent has normal chromosomes and one has chromosomes that have undergone a balanced translocation. This causes the loss of genetic information.

20

deletion

chromosome breaks in two place and the section in between is removed. Then the two sections join back together

21

inversion

the chromosome breaks in two places then the section cut out inverts and is reinserted into chromosome

22

pericentric inversion

inversion that occurs with centromere in the inverted section

23

paracentric inversion

inversion that occurs when the section of the chromosome that inverts does not contain the centromere

24

germline mutation

A gene change in a body's reproductive cell (egg or sperm) that becomes incorporated into the DNA of every cell in the body of the offspring

25

somatic mutation

An alteration in DNA that occurs after conception. Somatic mutations can occur in any of the cells of the body except the germ cells (sperm and egg) and therefore are not passed on to children

26

polymorphism

natural variation in the genome of organisms of the same species

27

types of mutation

Silent
Missense
Nonsense
Frameshift – deletion / insertion

28

sillent mutation

point mutation in which the substitution of a base pair has no effect on the amino acid the codon it is part of codes for

29

missense mutation

point mutation in which the substitution of a base pair causes the coding of a different amino acid in a protein

30

nonsense

point mutation in which the substitution of a base pair causes the the formation of as stop codon in the wrong place, this causes the protein chin produced to be truncated.