3.3

Question 1

Nondisjunction

Answer 1

The inability of homologous chromosomes to separate during anaphase.

Question 2

Diseases caused by nondisjunction.

Answer 2

Down syndrome - trisomy 21
Klinefelter’s - XXY
Turner’s - X-

Question 3

Karotype

Answer 3

The number and appearance of chromosomes in an organism.

Question 4

Stages of meiosis

Answer 4

Prophase I
Metaphase I
Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase II

Question 5

Meiosis

Answer 5

One diploid cell divides to produce haploid cells (gametes)

Allows sexual life cycle with fusion of gametes.

Question 6

Telophase II

Answer 6

Telophase in mitosis

Question 7

Genetic diversity

Answer 7

Crossing over of chromosomes.
Random orientation of Homologous chromosomes.
Fusion of gametes from separate parents.

Question 8

Karotyping

Answer 8

A procedure to determine the appearance and number of chromosomes in an organism.

Question 9

Metaphase I

Answer 9

Homologous pairs (bivalents) line up at the equator in a random order.
Metaphase in mitosis.

Question 11

Prophase I

Answer 11

(Before) DNA synthesis produces sister chromatids.
Homologous chromosomes pair.
Crossing over of chromosomes (chiasmata)
Prophase in mitosis

Question 12

Prophase II

Answer 12

No DNA synthesis.

Prophase in mitosis

Question 13

Telophase I

Answer 13

Telophase in mitosis

Question 14

Chronic villus sampling

Answer 14

Chronic Vill develops from Outer cells of zygote/ will become placenta.
After 11-12 weeks of pregnancy
1% risk of miscarriage

Question 15

Anaphase II

Answer 15

Sister chromatids separate and chromosomes move to poles.

Question 16

Anaphase I

Answer 16

Homologous pairs separate.

Halves The chromosome number.

Question 16

Metaphase II

Answer 16

Chromosomes line up across the equator, and attach to spindle fibers

Question 17

Amniocentesis

Answer 17

Sample of amniotic fluid
After 16 weeks of pregnancy.
.5% risk of miscarriage