Chapter 9: Sexual Reproduction And Meiosis

Question 0

Why do so many organisms use sexual reproduction?

Answer 0

Sexually reproduction generates genetic variability, which increases the chance that at least some members of the population will survive.

Question 1

Define karyotype?

Answer 1

A size ordered chart of all the chromosomes in a cell.

Question 2

Compare sexual and asexual reproduction?

Answer 2

Asexual reproduction is when an organism simply copies it’s DNA and splits the contents of one cell into two.

Sexual reproduction, in contrast, requires two parents the male parent contributes sperm cells, one of which fertilizes a female’s egg cell to begin the next generation.

Question 3

Define conjugation?

Answer 3

One bacterial cell uses an outgrowth called a sex pilus to transfer genetic material to another bacterium.

Question 4

Define chromosome.

Answer 4

Is a single molecule of DNA and it’s associated proteins.

Question 5

Define Diploid.

Answer 5

Contain two sets of chromosomes; one set is inherited from each parent.

Question 6

Define homologous pairs.

Answer 6

Matching pair of chromosomes that look alike and have the same sequence of genes.

Question 7

Define allele

Answer 7

One of two or more alternative genes.

Question 8

Compare autosomal and sex chromosomes.

Answer 8

Autosomes are chromosomes that are the same for both sexes.

Sex chromosomes determine whether an individual is female or male.

Question 9

How are the members of homologous pair of chromosomes similar?

Answer 9

They share the same size, centrosome position. They have the same basic structure. They carry the same sequence of genes.

Question 10

How are they different?

Answer 10

They differ in combinations of alleles. Each allele of a gene encodes a different version of the same protein.

Question 11

Compare sister chromatid, replicated chromosomes, and homologous pair of chromosomes.

Answer 11

An homologous pair is a pair of chromosomes that look a like and have the same gene sequence. Each of those chromosomes have a sister chromatid.

Question 12

Define gamete?

Answer 12

Sex cells that combine to form a new offspring.

Question 13

Define zygote.

Answer 13

Is the first cell of the new organism.

Question 14

Define fertilization.

Answer 14

Merges the gametes from two parents, creating a new cell.

Question 15

How is meiosis essential for sexual reproduction?

Answer 15

All sexual life cycles include meiosis and fertilization; mitotic cell division enables a cell to grow.

Question 16

Compare diploid and haploid cells.

Answer 16

Haploid cells contain one full set of genetic information instead of two.

Diploid cells contain two full set of genetic information.

Question 17

Compare mitosis and meiosis.

Answer 17

Mitosis produces the cells needed for growth, development, and tissue repair.

Meiosis forms genetically variable gametes that each contain half the number of chromosomes as the organisms diploid cells.

Question 18

Compare somatic and germ cells?

Answer 18

Germ cells occur only in the ovaries and testes.

Somatic cells do not participate directly in reproduction.

Question 19

Why does DNA replicate jus once in meiosis?

Answer 19

DNA replicates to produce the proteins needed for cell division.

Question 20

Define crossing over.

Answer 20

It is a process in which two homologous chromosomes exchange genetic material.

Question 21

What are homologous pairs of chromosomes?

Answer 21

Two chromosomes that look a like and have the same sequence of genes.

Question 22

What happens to homologous pairs of chromosomes during meiosis 1?

Answer 22

Homologous chromosomes pair up and separate.

Question 23

What is happening to haploid a in meiosis 2?

Answer 23

It is dividing into four cells.

Question 24

In general terms what occurs during meiosis?

Answer 24

Meiosis halves the chromosomes and scrambles the allele.

Question 25

How does meiosis generate variability?

Answer 25

It generate variability through three mechanisms crossing over, independent assortment, and random fertilization.

Question 26

How can more than 8 million possible chromosomes combinations be produced in the gametes by an individual?

Answer 26

By random fertilization.

Question 27

Compare monozygotic and dizygotic?

Answer 27

Monozygotic are genetically identical because they come from the same zygote. Dizygotic are more alike than non twin siblings because they start as two different zygotes.

Question 28

Compare the errors which can occur during meiosis?

Answer 28

Failure for the spindle to form properly, can produce a polyploid cell with one or more complete sets of extra chromosomes. Some gametes have just one extra or missing chromosomes. The cause of the abnormality is an error called nondisjunction.

Question 29

Define nondisjunction

Answer 29

Occurs when chromosomes fail to separate at either the first or second meiotic division.

Question 30

Define trisomy

Answer 30

An extra chromosome rather than a missing one.

Question 31

Define alteration of generations.

Answer 31

The sexual life cycle of plants and many green algae, which alternates between a diploid sporophyte stage and a haploid gametophyte stage.

Question 32

Which process produces gametes in plants?

Answer 32

Mitosis

Question 33

Compare spermatogenesis and oogenesis?

Answer 33

Spermatogenesis, sperm formation, diploid primary spermatocytes undergo meiosis, yielding four equal sized haploid sperm. Of the normal 23 pair of chromosomes only one pair of autosomes and one pair of sex chromosomes are shown. Oogenesis, ovum formation, diploid primary oocytes undergo meiosis. Meiotic division in females allocates most of the cytoplasm to one large egg cell. The body discards the other products of meiosis, called polar bodies, which contain the other sets of chromosomes. Of the normal 23 pair of chromosomes, only one pair of autosomes and one pair of sex chromosomes are shown.

Question 34

During meiosis the chromosomes

Answer 34

Segregate

Question 35

The daughter cells are haploid after ______ of meiosis.

Answer 35

Telophase

Question 36

During meiosis, the different homologous pairs

Answer 36

Assort independently

Question 37

Which following processes results in only one of the haploid cells being viable?

Answer 37

Oogenesis