Exam #4 ch. 11

Question 1

Sexual Reproduction

Answer 1

requires parent organisms to produce
two specialized cells which then fuse during fertilization to
form a single, unique cell.

Question 2

Fertilization

Answer 2

the union of two cells from two different organisms

Question 3

Haploid

Answer 3

two cells each containing one set of chromosomes

Question 4

Diploid

Answer 4

two cells each containing two sets of chromosomes

Question 5

Somatic Cells

Answer 5

body cells (contain two sets of chromosomes - diploid)

Question 6

Gametes

Answer 6

reproductive cells involved in fertilization - sex cells (sperm, egg)

Question 7

Homologue

Answer 7

a gene inherited from two species from a common ancestor

Question 8

Synaptonemal Complex

Answer 8

a protein structure that forms between homologous chromosomes during meiosis

Question 9

Crossing-Over

Answer 9

exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis

Question 10

Tetrad

Answer 10

a structure formed during meiosis consisting of two homologous chromosomes, each with two sister chromatids, resulting in a total of four chromatids

Question 11

Reduction Divison

Answer 11

the process of meiosis where the chromosome number is halved, resulting in gametes (or sex cells) with only one set of chromosomes

Question 12

Germ Cells

Answer 12

a reproductive cell responsible for transmitting genetic information to the next generation, developing into sperm in males and eggs in females

Question 13

Spores

Answer 13

a reproductive cell or structure capable of developing into a new individual

Question 14

Gametophyte

Answer 14

the haploid, multicellular reproductive stage in plants and algae that produces gametes (sperm and eggs) through mitosis

Question 15

Sporophyte

Answer 15

the diploid, spore-producing phase in the plant life cycle, which alternates with a haploid gametophyte phase

Question 16

What are the requirements for sexual reproduction to occur?

Answer 16

two parent organisms, gametes, fertilization, and the development of a zygote

Question 17

In sexual reproduction, the cells involved in the fertilization event are what ploidy level?

Answer 17

haploid (n)

Question 18

What is the main evolutionary advantage of meiosis and fertilization events?

Answer 18

variation

Question 19

What are somatic cells in humans, and what ploidy level are they?

Answer 19

sperm and eggs, diploid

Question 20

What are gamete cells in humans, and what ploidy level are they?

Answer 20

sperm and eggs, haploid

Question 21

Why are events of meiosis called reduction division?

Answer 21

because it halves the number of chromosomes in the parent cell

Question 22

When is the genetic
material replicated in the events of interphase leading up to meiotic division

Answer 22

during then S phase

Question 23

How do the sister chromatids and homologous pairs interact?

Question 24

What is the role of centrosomes and the meiotic spindle in meiosis?

Answer 24

organizing and segregating chromosomes, ensuring accurate distribution of genetic material to daughter cells

Question 25

Events in meiosis I

Answer 25

chromosome condensation, synapsis, crossing over, and the formation of tetrads

Question 26

Events in meiosis II

Answer 26

the sister chromatids separate, making haploid cells with non-duplicated chromosomes

Question 27

Events between homologous pairs during prophase I

Answer 27

homologous chromosomes pair up (synapsis) and form tetrads

Question 28

What is a synapse and what is its purpose?

Answer 28

a neuron transmits a signal to another cell, facilitate communication between cells

Question 29

What is crossing-over and where does it occur? What is the result of crossing-over?

Answer 29

Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis, specifically during prophase I. This results in new combinations of genes on each chromosome, creating genetic diversity.

Question 30

At what point are the synapsed homologues called “tetrads?”

Answer 30

during prophase I of meiosis

Question 31

In anaphase I of meiosis, the microtubules separate which structures?

Answer 31

homologous chromosomes

Question 32

Cytokinesis following meiosis I results in daughter cells that are what ploidy level?

Answer 32

haploid

Question 33

What is interkinesis?

Answer 33

Interkinesis allows cells to prepare for meiosis II without going through the entire replication process of interphase.

Question 34

How are meiosis I and II similar? How are they different?

Answer 34

both involve cell division, but they differ significantly in their primary purpose and how they separate chromosomes.

Question 35

How are mitosis and meiosis similar? How are they different?

Answer 35

both forms of cell division, but they differ in their purpose, number of divisions, and resulting cells.

Question 36

How is sexual reproduction an advantage over asexual reproduction?

Answer 36

better adapt to changing environments and resist diseases, offering a greater chance of survival and evolutionary success.

Question 37

What is “The Red Queen Hypothesis?”

Answer 37

hypothesis that species must constantly adapt, evolve, and proliferate in order to survive

Question 38

What is the ultimate source of variation between both sexual and asexual organisms?

Answer 38

mutation

Question 39

Name the events in the three types of multicellular sexual life cycles. How are they similar

Answer 39

diploid-dominant, haploid-dominant, and alternation of generations. share the common events of meiosis and fertilization

Question 40

Diploid-dominant

Answer 40

Diploid cells undergo mitosis to produce body cells. germ cells undergo meiosis to produce haploid gametes (sperm and egg). Fertilization (fusion of gametes) restores the diploid condition, forming a diploid zygote. (offspring)

Question 41

Haploid-dominant

Answer 41

Haploid cells undergo mitosis to produce body cells. Haploid cells from different individuals fuse to form a diploid zygote. The zygote immediately undergoes meiosis, producing haploid spores.

Question 42

Alternation of Generations

Answer 42

The diploid stage (sporophyte) produces haploid spores by meiosis. Haploid spores develop into the multicellular haploid stage (gametophyte). The gametophyte produces haploid gametes by mitosis. Gametes fuse to form a diploid zygote, which develops into a sporophyte.`

Question 43

What type of sexual life cycle do humans utilize?

Answer 43

diploid-dominant

Question 44

What is the most obvious multicellular life stage in each of the sexual life cycles?

Answer 44

Diploid-Dominant: multicellular diploid stage Haploid-Dominant: multicellular haploid stage Alternation of generations: both haploid and diploid stages

Question 45

How do we refer to the haploid and diploid stages in each of the sexual life cycles?

Answer 45

haplotonic (n) & diplotonic (2n)

Question 46

Name organisms that participate in each of the three types of sexual life cycles.

Answer 46

diploid, haploid, alternation of generations