Meiosis & Sexual Life Cycles

Question 1

Asexual Reproduction

Answer 1

A single individual passes all of its genes to its offspring without fusion of gametes

Question 2

Clone

Answer 2

An individual that reproduces asexually gives rise to individuals that are genetically identical to the parent

Question 3

Sexual Reproduction

Answer 3

2 parents give rise to offspring
that have unique combinations
of genes inherited from 2
parents

Offspring vary genetically from their siblings and both parents

Question 4

Homologous Chromosomes (Homologs)

Answer 4

a set of one maternal and one paternal chromosome that pair up with each other inside a cell during fertilization.

Question 5

Somatic Cells

Answer 5

cells in the body other than sperm and egg cells

Question 6

Diploid

Answer 6

2 sets of chromosomes (2n)

For humans, diploid number is 46 (2n = 46)

Question 7

Haploid

Answer 7

1 set of chromosomes (n)

For humans, haploid number is 23 (n = 23)

Question 8

Sister Chromatids

Answer 8

the identical copies (chromatids) formed by the DNA replication of a chromosome, with both copies joined together by a common centromere

Each replicated chromosome consists of 2 identical sister chromatids

Question 9

Centromere

Answer 9

links a pair of sister chromatids together during cell division

Question 10

Meiosis I

Answer 10

Homologous chromosomes pair up and separate, resulting in 2 haploid daughter cells with replicated chromosomes

Question 11

Meiosis II

Answer 11

Sister chromatids separate

Question 12

Meiosis (Result)

Answer 12

2 cell divisions result in 4 daughter cells, rather than the 2 daughter cells in mitosis

Each daughter cell has only half as many chromosomes as the parent cell

Question 13

Prophase I

Synapsis

Answer 13

DNA breaks are repaired, so each broken end is joined to corresponding segment of nonsister chromatid

Question 14

Prophase I

Crosssing Over

Answer 14

Nonsister chromatids exchange DNA segments

Question 15

Prophase I

Chiasma

Answer 15

X-shaped regions where crossing over
occurred

Question 16

Prophase I

Each pair of chromosomes forms a tetrad

Answer 16

a group of 4 chromatids

Question 17

Mitosis vs. Meiosis

Meiosis reduces the number of chromosome sets from 2 (diploid) to 1 (haploid)

Answer 17

During meiosis II, sister chromatids separate producing 4 haploid cells that differ genetically from each other and from the parent cell

Question 17

Mitosis vs. Meiosis

Mitosis conserves the number of chromosome
sets

Answer 17

Producing 2 diploid cells that are genetically identical
to the parent cell

Question 18

Mitosis vs. Meiosis

Synapsis and crossing over in prophase I:

Answer 18

Homologous duplicated chromosomes pair up and exchange genetic information (crossing over)

Question 19

Mitosis vs. Meiosis

Separation of homologous chromosomes during anaphase I

Answer 19

In mitosis sister chromatids separate

Question 20

3 mechanisms contribute to genetic variation:

Answer 20

• Independent assortment of chromosomes
• Crossing Over
• Random Fertilization

Question 21

Law Independent Assortment

Answer 21

each pair of alleles segregates independently of any other pair of alleles during gamete formation

alleles of two or more genes get sorted into gametes independently

Question 22

Random fertilization

Answer 22

during sexual reproduction, the male gamete and female gamete that fuse to produce an offspring are selected randomly from the pool of male and female gametes