Genetic Variation

Question 1

Stages of meiosis 1

Answer 1

interphase, prophase 1, metapahse 1, and anashase 1

Question 2

what happens in interphase

Answer 2

chromosomes duplicate

Question 3

what happens in prophase 1

Answer 3

Homologous chromosomes pair and exchange segments

Question 4

what happens in metaphase 1

Answer 4

tetrads line up

Question 5

what happens in anaphase 1

Answer 5

pairs of homologous chromosomes split up

Question 6

what is the Independent assortment of chromosomes

Answer 6

-The orientation of the chromosomes is random like a flip of coin: Heads or Tail
-Each gamete has 50:50 chance of having paternal or
maternal chromosomes or of having both
-Each gamete represents one of many possible
combination of maternal and paternal chromosomes

Question 7

What is the number of possible combinations for the gametes

Answer 7

2^n= where n is the number of chromosomes in the genome

Question 8

What is the independent assortment of chromosomes for humans

Answer 8

A human gamete contains 1 or 8 million possible assortments of the chromosomes inherited from the mother and father

Question 9

What is random fertilization

Answer 9

the random chance of any one sperm and egg coming together is a product of these two probabilities
Egg->1/8million x 1/8 million

Question 10

What are contributors to genetic variation

Answer 10

Each gamete has a unique genetic identity therefore the zygote will have a unique genetic identity therefore each human being is genetically unique (exemption- identical twins)

Question 11

What are human Karyotypes

Answer 11

contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes

The display of the chromosome paid off a cell arranged by size, shape and staining patterns

Question 12

What is the methodology to obtain a karyotype

Answer 12

Obtain sample from the individual being studied

• culture the cells in synchrony and when they are dividing vigorously, stop the cell division in metaphase by treatment with colchicine
• chromosomes are stained with special staining
• chromosomes are then examined with the microscope for their length, size shape and position of the centromere and pattern of staining

Question 13

How do scientists identify the sec of a baby or abnormalities that indicate genetic diseases or tumor cells

Answer 13

Using combination of dyes, shapes and number

Question 14

what is the condition Polyploidy

Answer 14

A chromosomal alteration in which the organism has more than two complete sets of chromosomes

Question 15

What’s an aneuploidy

Answer 15

A chromosomal alteration in which certain chromosomes are present in extra copies or are deficient in number

Question 16

What is Down syndrome

Answer 16

An aneuploid condition that results from three copies of chromosome 21
- trisomy 21

Question 17

How do aberrations form

Answer 17

Non- disjunction

Question 18

What is non - disjunction

Answer 18

An error in meiosis 1 in which members of a pair of homologous chromosomes fail to separate properly from each other or an error in meiosis 2 in which a pair of sister chromatids fail to separate properly from each other

Question 19

2n-1

Answer 19

Mono sonic turners syndrome

Short sterile, do not develop secondary sex characteristics normal intellectually

Question 20

Breakage if a chromosome can lead to how many types of changes in chromosome structure

Answer 20

Deletion- removed a chromosomal segment
Duplication- repeats a segment
Inversion- reverses a segment within a chromosome
Translocation- moves a segment from a non homologous chromosome to another