lab 5

Question 1

what is a kayotype?

Answer 1

arranging adult or fetal chromosomes into pairs based on the sizes and position of centromeres. it allows for the detection of any abnormalities in chromosomes.

Question 2

how do you prepare a karyotype?

Answer 2

prepared during metaphase of mitosis because this is when chromosomes are most distinct. arranged in descending sizes (1 is longest, 22 shortest). 1- photograph of chromosomes, 2- cut out individual chromsomes, 3- arrange them in order from descending size and centromere placement (m, s, a).

Question 3

what is metacentric?

Answer 3

centromere at middle of chromosome

Question 4

what is subterminal?

Answer 4

centromere located between middle and end

Question 5

what is acrocentric?

Answer 5

centromere located very close to one end of chromosome

Question 6

why is it necessary to prepare a karyotype?

Answer 6

karyotypes allow detection of any abnormalities in the chromosomes.

Question 7

what is nondisjunction?

Answer 7

when chromosomes fail to separate properly during meiosis. gametes could have too few or too many copies of chromosomes or homologous chromosomes may have failed to separate in anaphase 1 and both members of the pair go to one pole. having extra chromosomes or missing some

Question 8

what is trisomy 21?

Answer 8

down syndrome, there is 3 copies of chromosome 21 rather than 2 due to the chromosomes failing to separate properly. this is autosomal.

Question 9

what is Patau Syndrome?

Answer 9

trisomy 13, a genetic disorder in which a person has 3 copies of genetic material from chromosome 13, instead of the usual 2 copies

Question 10

what is Edward’s syndrome?

Answer 10

Trisomy 18 is a disorder in which babies are born with 3 copies of chromosome 18 instead of 2

Question 11

what is Turner’s syndrome?

Answer 11

a condition that affects only females, results when one of the X chromosomes is missing or partially missing, resulting in short height, failure of the ovaries to develop and heart defects.

Question 12

what is Klinefelter’s syndrome?

Answer 12

affects males that have an extra X chromosome (XXY). this results in more female characteristics, small breasts, wider hips, smaller penis

Question 13

what is Cri-du-chat syndrome?

Answer 13

the loss of a half of the short arm of chromosome 5.

Question 14

what is the locus?

Answer 14

the position of a gene on a chromosome

Question 15

what is a genotype?

Answer 15

the genes present on the chromosomes of an individual (AA, Aa, aa)

Question 16

what is a phenotype?

Answer 16

the physical expression of a gene

Question 17

what are alleles?

Answer 17

alternate forms of the same gene at the same locus on homologous chromosomes that affect the same characteristic

Question 18

what is a dominant allele?

Answer 18

an allele that needs to be present on only one of the two homologous chromosomes to be expressed and masks expression of other alleles. (A)

Question 19

what is a recessive allele?

Answer 19

an allele that must be present on both homologous chromosomes in order to be expressed (aa)

Question 20

homozygous

Answer 20

the presents of identical allels on homologous chromosomes (AA, aa)

Question 21

heterozygous

Answer 21

the presents of unlike alleles on homologous chromosomes (Aa)

Question 22

what is F1 generation (first filial)?

Answer 22

offspring resulting from crossing of individuals in parental gen

Question 23

what is F2?

Answer 23

offspring resulting from crossing members of F1 gen among themselves

Question 24

what is a monohybrid cross?

Answer 24

examines the inheritance of a single trait (Aa, AA, aa)

Question 25

what is a dihybrid cross?

Answer 25

examines the inheritance of two diff traits located on two diff pairs of homologous chromosomes (AABb, aabb, ect)