Chapter 11

Question 1

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

Answer 1

Sexual reproduction

Question 2

Union of two haploid cells from two individual organisms

Answer 2

fertilization

Question 3

Cells that contain one set of chromosomes

Answer 3

haploid

Question 4

Cells resulting from fertilization that has two sets of chromosomes

Answer 4

diploid

Question 5

All the cells of a multicellular organism except the gametes or reproductive cells

Answer 5

somatic cells

Question 6

Cells in a multicellular organism that are haploid; also known as reproductive cells

Answer 6

gametes

Question 7

Chromosomes that have the same genes in the same location

Answer 7

homologue

Question 8

Protein lattice that forms between homologous chromosomes during prophase I, supporting crossover

Answer 8

synaptonemal complex

Question 9

The exchange of chromosomal segments between non-sister chromatid homologous pairs that incorporate genes from both parents of the organisms

Answer 9

crossing-over

Question 10

Two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase I

Answer 10

tetrad

Question 11

nuclear division that produces daughter nuclei each having one-half as many chromosome sets as the parental nucleus; meiosis I

Answer 11

reduction division

Question 12

Specialized cell line that produces gametes, such as eggs or sperm

Answer 12

germ cells

Question 13

Haploid cell that can produce a haploid multicellular organism or can fuse with another spore to form a diploid cell

Answer 13

spores

Question 14

A multicellular haploid life-cycle stage that produces gametes

Answer 14

gametophyte

Question 15

A multicellular diploid life-cycle stage that produces haploid spores by meiosis

Answer 15

sporophyte

Question 16

What are the requirements for “sexual reproduction” to occur?

Answer 16

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

Question 17

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

Answer 17

The cells are half of the normal ploidy level; in humans, the cells are haploid

Question 18

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

Answer 18

Meiosis provides genetic variation and has the ability to pass on the better evolved traits to offspring

Question 19

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

Answer 19

The body cells which are diploid

Question 20

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

Answer 20

The sex cells (egg and sperm) which are haploid

Question 21

Be able to describe why events of meiosis are called “reduction division.”

Answer 21

There are two cycles of meiosis, the first splits the chromosomes in half and then the second duplicates the new cells

Question 22

Recall the events of Interphase leading up to meiotic division. When is the genetic material replicated?

Answer 22

Interphase has G1, S, and G2 phases. The DNA is duplicated during the S phase prior to meiosis

Question 23

Be able to use terms such as centromere, cohesion proteins, synapse, and kinetochores to describe how the sister chromatids and homologous pairs interact.

Answer 23

The centromere holds the two sister chromatids together. The cohesion proteins what is at the centromere to actually hold the sister chromatids together. The synapse is the tight pairing of homologues. Kinetochores are proteins found at the centromeres

Question 24

Understand the role of centrosomes and the meiotic spindle in meiosis.

Answer 24

Centrosomes are able to organize the microtubules and attach to the microtubules which connect to the tetrads

Question 25

Understand and be able to recall events that happen in each Prophase I

Answer 25

Nuclear envelope breaks down, synaptonemal complex forms, synaptonemal complex begins to break down and chromosomes condense, tetrads are formed

Question 26

Understand and be able to recall events that happen in each Prometaphase I

Answer 26

Spindle fibers microtubules attach to the kinetochore proteins at the centromeres and nuclear membrane has completely broken down

Question 27

Understand and be able to recall events that happen in each Metaphase I

Answer 27

Tetrads line up at the metaphase plate, chromosomes reach the poles and the meiotic spindle is formed fully

Question 28

Understand and be able to recall events that happen in each Anaphase I

Answer 28

Tetrads are pulled apart, the homologous pairs separate to opposite ends of the cell; and the sister chromatids remain tightly bound together at the centromere

Question 29

Understand and be able to recall events that happen in each Telophase I

Answer 29

Separated chromosomes arrive at opposite poles

Question 30

Understand and be able to recall events that happen in each Prophase II

Answer 30

Centrosomes that were duplicated move to opposite poles of the cell and new meiotic spindles are assembled

Question 31

What happens in Prometaphase II

Answer 31

Nuclear envelopes are completely broken down, each sister chromatid forms an individual kinetochore that attaches to microtubules from opposite poles

Question 32

Understand and be able to recall events that happen in each Metaphase II

Answer 32

The meiotic spindle is completely reformed, the sister chromatids are maximally condensed and align at the metaphase plate of the cell

Question 33

Understand and be able to recall events that happen in each Anaphase II

Answer 33

The sister chromatids are pulled apart by the kinetochore microtubules and move toward opposite poles

Question 34

Understand and be able to recall events that happen in each Telophase II

Answer 34

The chromosomes arrive at opposite poles and begin to de-condense, nuclear envelopes form around the cells

Question 35

Describe events between homologous pairs during prophase I. What is a synapse and what is its purpose?

Answer 35

Homologous pairs find each other and form a synaptonemal complex. A synapse is the chromatids that align with each other so there is precise overlap in genes

Question 36

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

Answer 36

Crossing-over occurs in Prophase I, when there is a reciprocal exchange of equivalent DNA between a maternal and paternal chromosome, this is the first source of genetic variation in meiosis; the result is a unique combination of genes from the mother and father

Question 37

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

Answer 37

They become tetrads after the chromosomes condense and become a visible structure

Question 38

What is Independent Assortment? When does it happen? What is the significance of it?

Answer 38

The tetrads line up at the metaphase plate in a completely random order, this happens during Metaphase I, this is the second source of genetic variation produced my meiosis

Question 39

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

Answer 39

They pull the tetrads apart

Question 40

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

Answer 40

haploid

Question 41

What is interkinesis?

Answer 41

Brief interphase before entering meiosis II, if this happens, there is no S phase as the chromosomes do not replicate before Meiosis II

Question 42

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

Answer 42

Sister chromatids

Question 43

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

Answer 43

Both are a form of cellular division; mitosis is a single nuclear division event resulting in genetically identical daughter cells; Meiosis consists of 2 nuclear divisions resulting in 4 genetically unique daughter cells with a ploidy level that has been reduced

Question 44

How is sexual reproduction an advantage over asexual reproduction?

Answer 44

This allows for genetic variation which is important to the survival and reproduction of the population

Question 45

What is “The Red Queen Hypothesis?”

Answer 45

The variation in offspring created by sexual reproduction is very important to the survival and reproduction of the population

Question 46

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

Answer 46

mutation

Question 47

Name and describe the events in the three types of multicellular sexual life cycles. How are they similar? How do they differ?

Answer 47

Diploid-dominant is where the multicellular diploid stage is the most obvious stage of life where the haploid cells are the gametes Haploid-dominant is where the multicellular is haploid and they grow and divide using mitosis Alternation of generations is where both the haploid-dominant and diploid-dominant are apparent to different degrees: Haploid plants are gametophytes and diploid plants are sporophytes

Question 48

What type of sexual life cycle do humans utilize?

Answer 48

Diploid-dominant

Question 49

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

Answer 49

Diploid-dominant=most animals including humans; Haploid-dominant=all fungi and some algae; Alternation of generations=plants