genes and genetic disease

Question 1

what are the chromosomes in a cell

Answer 1

23 homologous chromosomes
22 autosome pairs
1 pair of sex chromosome xx or xy

Question 2

karyotype

Answer 2

• describes complete set of 46 chromosomes
• organized in pairs of homologous chromosomes according to shape size and number

Question 3

how do we get genetic disease

Answer 3

inherited
during development or throughout life

Question 4

single gene defect

Answer 4

monogenic

Question 5

several gene defect

Answer 5

polygenic

Question 6

combined effects of genes and environmental factors

Answer 6

multifactorial or complex disease

Question 7

gene mutations

Answer 7

permanent change to dna

Question 8

what causes mutations

Answer 8

errors in dna replication
external mutagens that damage dna

Question 9

single gene disorder
point mutation

Answer 9

single base in codon replaced
silent- no effect on aa
missense- codes for diff aa
nonsense-STOP codon aa not produced

Question 10

single gene disorder
frame shift mutation

Answer 10

insertion or deletion of single base
changes gene sequence

Question 11

how do chromosomal abnormalities cause genetic disease

Answer 11

change in chromosome number
structural abnormalities

Question 12

structural alterations

Answer 12

deletion or duplication of part of chromosome
inversion- rearrangement of part of chromosome
translocation- swap of chromosomes part

Question 13

change in chromosome number

Answer 13

due to non-disjunction in meiosis failure of sister chromatid separation
monosomy 2n-1 turners syndrome
trisomy 2n+1 down’s syndrome

Question 14

mendelian genetics describe

Answer 14

• traits inherited independently
• diff alleles dominant or recessive
• separation of homologous chromosomes at meiosis