errors in meiosis

Question 1

sources of genetic variation

Answer 1

• crossing over
• random alignment
• fertilization (random gametes)

Question 2

mistakes in meiosis

Answer 2

• too many/too little chromosomes
• errors in chromosomes leading to new traits
• zygote will inherit this error from the gamete

Question 3

mutation

Answer 3

• when DNA is damaged/changed so that the code carried by that gene changes
• not all mutations are expressed
• not all mutations are bad

Question 4

good mutation example

Answer 4

• lactose intolerance
• mutation allowed people to continue producing lactase throughout life instead of until 3 years old

Question 5

sexes in biology

Answer 5

• male and female
• some dont fit this: such as chromosomal makeup (XXY), hormonal differences, diff. configuration/combination of genitals

Question 6

non-disjunction

Answer 6

when homologous chromosomes/sister chromatids split improperly during either anaphase

Question 7

non-disjunction terms

Answer 7

• aneuploidy: too few/too many chromosomes
• polyploidy: 3 or 4+ more sets of chromosomes (mostly in plants)
• monosomy: having one copy of a chromosome (e.g. Turner Syndrome)
• polysomy: one or more extra chromosomes
• trisomy: having 3 of one type of chromosome

Question 8

chromosomal errors

Answer 8

• deletion: sections of DNA missing
• duplication: sections are duplicated
• inversions: DNA sections attached in reverse order
• translocation: DNA sections reattached to wrong chromosome (non-homologous)

Question 9

karyotype

Answer 9

• helps find errors
• best photographed during metaphase
• 22 autosome pairs, 1 sex pair

Question 10

trisomies can be found in…

Answer 10

• chromosomes 13, 15, 18, 21 & 22
• other autosomes typically fatal