L9 MEIOSIS

Question 1

What is the genetic makeup of asexual offspring?

Answer 1

They are identical copies of parents, have identical DNA copies.

Question 2

What is the genetic makeup of sexual offspring?

Answer 2

Their genes are a unique combination of maternal and paternal genes.

Question 3

What is a somatic cell?

Answer 3

A non-sex cell

Question 4

How many chromosomes do somatic cells have?

Answer 4

46 chromosomes, or 23 pairs of chromosomes.

Question 5

How may chromosomes do gametes have?

Answer 5

23 chromosomes, no pairs.

Question 6

TRUE OR FALSE: the daughter cells produced in meiosis are exact copies of parental cells.

Answer 6

FALSE: in mitosis, daghter cells are copies. In meiosis, daughter cells have unique genes.

Question 7

What is an autosome?

Answer 7

A non-sex chromosome.

Question 8

Fill in the blanks.

Answer 8

CHROMOSOME consisting of one CHROMATID.
Both chromosomes are SISTER CHROMATIDS.
On the right is a DUPLICATED CHROMOSOME
The middle of the chromosome is the CENTROMERE.

Question 9

Fill in the blanks.

Answer 9

PROPHASE I:
The REPLICATED chromosomes condense. Homologous chromosomes come together in SYNAPSIS and CROSSING-OVER occurs. Chromosomes attach to the SPINDLE.

Duplicated/replicated chromosomes are NOT the same as homologous chromo.

The replication of the chromosome happened in interphase.

Question 10

Fill in the blank.

Answer 10

METAPHASE I:
TETRADS like up at the METAPHASE plate.

Spindles also attach to kinetochores.

Question 11

Fill in the blanks.

Answer 11

ANAPHASE I:
Each CHROMOSOME separates from its TETRAD. They move to OPPOSITE POLES OF THE CELL.

goes from 2N > N

Question 12

Fill in the blanks.

Answer 12

TELOPHASE I:
The nucleus completes division. The CHROMOSOMES are still composed of SISTER CHROMATIDS.

These sister chromatids are no longer identical due to crossover.

Question 13

Fill in the blanks.

Answer 13

PROPHASE II:
The CENTRIOLES in the two new cells move to opposite poles and new SPINDLE FIBRES form. The CHROMOSOMES become attached to the SPINDLE.

Question 14

Fill in blanks.

Answer 14

METAPHASE II:
CHROMOSOMES line up at the METAPHASE plate.

Question 15

Fill in the blanks.

Answer 15

ANAPHASE II:
RECOMBINED/SISTER CHROMATIDS of each chromosome separate and move to OPPOSITE POLLS.

Question 16

Fill in the blanks.

Answer 16

TELOPHASE II:
The cytoplasm separates, leaving FOUR HAPLOID DAUGHTER cells. The CHROMOSOME number has been reduced by half.

Question 17

When does chromosome replication occur?

Answer 17

During Interphase before the meiosis.

Question 18

Whay is synapsis?

Answer 18

Synapsis is the process where homologous chromosomes come together to form tetrad and are held together by proteins.

Question 19

What is Chiasma?

Answer 19

Chiasma is the physical manifestation of crossing over.

Question 20

What is the main goal of Meiosis II?

Answer 20

To separate the sister chromatids, and distribute each copy of each chromosome into a new cell.

Question 21

What three mechanisms contribute to genetic variation in meiosis?

Answer 21

1. Independent assortment of chromosomes.
2. Crossing over.
3. Random fertilization.

Question 22

What are the names for the processed of male and female gamete cells going through meiosis?

Answer 22

Spermatogenesis and Oogenesis.

Question 23

Why is independent assortment of chromosomes important?

Answer 23

The randion orientation of chromosomes at metaphase I allow for millions of possible chromosome combination = extreme diversity.

Question 24

What is a recombinant chromosome?

Answer 24

The result of crossing over, where a chromosome has been recombined with new genes. # of genes stays the same, but alleles may differ.

Question 25

What is meant by random fertilization?

Answer 25

Any sperm can fuse with any ovum during reproduction.

Question 26

What is a polar body?

Answer 26

Non-functional gamete cell produced in Oogenesis.