Biology Ch. 8 How Cells Reproduce

allele vs gene

A gene is a stretch of DNA or RNA that determines a certain trait; an allele is one of these forms of a gene. e.g. gene for eye color has several alleles (variations) such as an allele for blue eye color or an allele for brown eyes.

recombinant chromosomes

A chromosome created when crossing over combines the DNA from two parents into a single chromosome.

In which phase of mitosis do sister chromatids move to opposite ends of the cell? a. prophase b. metaphase c. anaphase d. telophase

C

In which phase of the cell cycle does cytokinesis occur? a. G1 b. G2 c. M d. S

C

In which stage of meiosis are the homologous chromosomes separated? a. Anaphase b. Telophase I c. Anaphase I d. Homologous chromosomes are only separated in mitosis, not in meiosis.

C

Interphase is the part of the cell cycle when ___________. a. a cell ceases to function b. the spindle forms prior to nuclear division c. DNA replication occurs d. mitosis proceeds

C

What sex chromosomes belong to a normal human female? a. XO b. XY c. XX d. OY

C

cell plate formation

Cytokinesis in plant cells where vesicles from the Golgi supply cellulose and other material to make a new cell wall in the middle of the cell to separate it and form two daughter cells.

In which phase of meiosis do all of the homologous chromosomes separate and being heading toward the spindle poles? a. Anaphase II b. Telophase I c. Telophase II d. Anaphase I

D

In which phase of meiosis do homologous chromosome pairs align between spindle poles. Spindle microtubules attach the two chromosomes of each pair to opposite spindle poles? a. Metaphase II b. Anaphase II c. Telophase I d. Metaphase I

D

In which phase of meiosis does the nuclear envelope break up? a. Metaphase II b. Prophase II c. Prophase I d. Both b and c

D

In which phase of mitosis does the nuclear envelope re-form? a. prophase b. metaphase c. anaphase d. telophase

D

In which phase of the cell cycle do normal metabolic activities occur? a. anaphase b. prophase c. S phase d. G1

D

In which phase of the cell cycle does a cell spend most its life? a. G1 b. S c. G2 d. all of the above

D

Mitosis and cytoplasmic division function in ___________. a. asexual reproduction of single-celled eukaryotes b. growth and tissue repair in multicelled species c. asexual reproduction in prokaryotes d. both a and b

D

Sexual reproduction in animals requires _______. a. meiosis b. fertilization c. gametes d. all of the above

D

Which of the following increases genetic diversity in sexual reproduction? a. crossing over b. mutations c. independent assortment of chromosomes into gamete cells d. All of the above

D

Which of the following is a function of meiosis? a. Organismal growth b. Replacement of damaged cells c. Chromosome replication d. Gamete production

D

Which process is accomplished via a cleavage furrow? a. telophase b. cytokinesis of a plant cell c. mitosis d. cytokinesis of an animal cell

D

mitosis vs meiosis similarities

-Both are cell divisions that occur in humans -Both duplicate chromosome only once -Both are preceded by the DNA replication during interphase

Mitosis stages

1. Prophase 2. Metaphase 3. Anaphase 4. Telophase

Homologous chromosomes _____________. a. originate with two parents b. are sister chromatids

A

How many chromosomes does a normal human sperm cell contain? a. 23 b. 22 c. 46 d. 1

A

In which phase of meiosis do homologous chromosomes condense, pair up, and swap segments? a. Prophase I b. Metaphase I c. Prophase II d. Telophase I

A

In which phase of meiosis do the chromosomes align midway between spindle poles? a. Metaphase II b. Anaphase II c. Telophase I d. Metaphase I

A

In which phase of mitosis do chromatin fibers condense within the nucleus to form the visible chromosomes observable under a microscope? a. prophase b. metaphase c. anaphase d. telophase

A

In which phase of meiosis does the chromosomes condense. Spindle microtubules attach to each sister chromatid as the nuclear envelope breaks up? a. Metaphase II b. Prophase II c. Prophase I d. Both b and c

B

In which phase of mitosis do chromosomes line up in the middle of the cell? a. prophase b. metaphase c. anaphase d. telophase

B

In which phase of the cell cycle does DNA replication occur? a. G1 b. S c. G2 d. M

B

In which phase of the cell cycle does a cell synthesize proteins to be used in cell division? a. M b. G2 c. S d. G1

B

Meiosis is a necessary part of sexual reproduction because it __________. a. divides two nuclei into four new nuclei b. reduces the chromosome number for gametes c. produces clones that can cross over

B

Mitosis and meiosis are similar because a. both contain the same number of stages. b. both are preceded by DNA replication in S phase. c. both processes divide the cytoplasm. d. both processes occur to form new somatic cells.

B

One evolutionary advantage of sexual over asexual reproduction may be that it produces a. more offspring per individual b. more variation among offspring c. healthier offspring

B

Which of the following can result from uncontrolled, unregulated cell division by mitosis? a. Down's syndrome b. A neoplasm c. A zygote d. A proto-oncogene

B

Which of the following is an advantage of sexual reproduction over asexual reproduction? a. Sexual reproduction produces organisms that have more chromosomes. b. Sexual reproduction results in more genetic variation which can increase the odds of aspecies' survival in changing environments. c. Sexual reproduction produces chromosomes with longer telomeres, which leads to longer life spans for organisms. d. Sexual reproduction results in less genetic variation which can increase the odds of a species' survival in changing environments.

B

Which of the following is one of the very important differences between mitosis and meiosis? a. Chromosomes align in the middle of the cell only in meiosis b. Homologous chromosomes swap segments only in meiosis c. Sister chromatids separate only in meiosis

B

Which stage of meiosis does crossing over occur in, and what is the result of the crossing over process? a. Prophase; recombinant chromosomes will be present in some gametes b. Prophase I; recombinant chromosomes will be present in some gametes c. Prophase II; cloned cells d. Crossing over only occurs in mitosis, not in meiosis.

B

In which phase of mitosis does the mitotic spindle disappear? a. prophase b. metaphase c. anaphase d. telophase

D

gamete

Mature, haploid reproductive cell; e.g., an egg or a sperm.

mitosis vs meiosis differences

Mitosis: one division forming 2 identical cells (clones); Produces somatic cells; single division of the nucleus followed by cytokinesis Meiosis: two divisions forming 4 genetically different cells; Produces sex cells; two divisions of the nucleus each one followed by cytokinesis.

Meiosis 2: Prophase 2

The nuclear envelope breaks down. Spindle microtubules from each pole of the cell attach to the centromere of each connected sister chromatid pair.

benign tumor

a mass of abnormal cells that remains at the site of origin

tumor

a neoplasm that forms a lump

neoplasm

an accumulation of abnormally dividing cells

homologous chromosomes

chomosomes with the same length, shape, and set of genes

Zygote

diploid cell that forms when two haploid gametes unite during fertilization

alleles

forms of a gene with slightly different DNA sequences; may encode slightly different versions of the gene's product

cleavage furrow

in a dividing animal cell, the indentation where cytoplasmic division will occur

asexual reproduction

process of reproduction involving a single parent that results in offspring that are genetically identical to the parent

Gametogenesis

production of gametes

seuxal reproduction

reproductive mode by which offspring arise from two parents and inherit genes from both

chaisma

site of crossing over

A cell with two of each type of chromosome has a chromosome number that is ____________. a. diploid b. haploid c. tetraploid d. abnormal

A

A tumor that remains only at its site of origin is called______; while a tumor that can spread cells to other locations is called_______. a. benign; malignant b. an oncogene;malignant c. malignant; benign d. a neoplasm; benign

A

After mitosis, the chromosome number of a descendant cell is the _________parent cell's. a. the same as b. one-half of c. rearranged compared to d. doubled compared to

A

In which phase of mitosis is the mitotic spindle formed? a. prophase b. metaphase c. anaphase d. telophase

A

_________produces offspring that are genetically identical to their parent. a. asexual reproduction b. meiosis c. the cell cycle d. sexual reproduction

A

malignant tumor

A cancerous tumor that is invasive enough to impair the functions of one or more organs.

haploid cell

A cell containing only one set of chromosomes (n).

Alternative forms of the same gene are __________. a. gametes b. homologous c. alleles d. oncogenes

C

In which phase of meiosis are two haploid cells formed? a. Prophase II b. Telophase II c. Telophase I d. Anaphase II

C

A duplicated chromosome has how many chromatids? a. one b. two c. three d. four

B

Crossing over mixes up ________. a. chromosomes b. alleles c. zygotes d. gametes

B

In a cell containing 10 chromosomes, mitosis results in the formation of ____daughter cells, each containing ______ chromosomes. a. 4; 5 b. 2; 10 c. 4; 10 d. 2; 5

B

In which of the following processes does a cell plate form? a. telophase b. plant cell cytokinesis c. mitosis d. animal cell cytokinesis

B

In which phase of meiosis are four haploid cells formed? a. Prophase II b. Telophase II c. Telophase I d. Anaphase II

B

In which phase of meiosis do the sister chromatids separate? a. Metaphase II b. Anaphase II c. Telophase I d. Metaphase I

B

A mutation that produces an oncogene can cause_____. a. extra proteins to be synthesized. b. a proto-oncogene to develop. c. the growth of a cancerous tumor. d. nondisjunction.

C

Which of the following correctly describes the relationship between meiosis and sexual reproduction? a. The stages of meiosis accomplish sexual reproduction. b. Crossing over in meiosis combines the male's chromosomes with the female's chromosomes to accomplish sexual reproduction. c. Meiosis produces haploid gametes which are necessary for sexual reproduction to occur. d. Meiosis produces diploid gametes which are necessary for sexual reproduction to occur.

C

Which of the following is not a stage of mitosis? a. metaphase b. telophase c. interphase d. prophase

C

Which of the following occurs in metaphase II of meiosis? a. Spindle fibers separate the sister chromatids, pulling them in opposite directions. b. Homologous pairs align on the midline of the cell. c. Sister chromatids align on the midline of the cell. d. Spindle fibers pull apart homologous pairs, pulling them in opposite directions.

C

Which of the following occurs in prophase of mitosis? a. Chromosomes condense into chromatin. b. Sister chromatids are separated and pulled to opposite ends of the cell. c. Chromatin condenses into chromosomes. d. Homologous chromosomes are separated and pulled to opposite ends of the cell.

C

Interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

Meiosis 1: Prophase 1

Chromatin condenses into chromosomes. Each sister chromatid bundle pairs up with its homologous sister chromatids bundle, resulting in a structure with four chromatids (2 pairs of sister chromatids that are homologous to one another). Spindle fibers attach to each sister chromatid pair. During this phase, some chromosomes may randomly engage in crossing over where two homologous chromosomes exchange the same sections of genetic information with another which creates recombinant chromosomes. Crossing over is explained in more depth below and within the text reading assignment.

Prophase (Mitosis Phase 1)

Chromatin fibers condense within the nucleus to form the visible chromosomes observable under a microscope. The nuclear envelope (which separates the contents of nucleus from the cytoplasm) breaks up. A key feature of this stage is the formation of the mitotic spindle which plays a role in the separation of daughter chromosomes. The spindle fiber microtubules are formed from the centrioles of the cell and attach to the centromeres of the sister chromatids.

Telophase and Cytokinesis (Mitosis Phase 4)

Chromosomes reach the two opposite poles of the cell, the nuclear envelope re-forms around the chromosomes gathered at each pole, and chromosomes begin to uncoil. The mitotic spindle disappears. By the end of telophase, cytoplasmic division by the process of cytokinesis is complete.

Cytokinesis

Division of the cytoplasm during cell division

Anaphase (Mitosis Phase 3)

During anaphase, microtubules begin retracting towards each pole, pulling the sister chromatids apart, into individual chromosomes which move toward opposite poles of the cell.

Meiosis 1: Telophase 1

During telophase, the (still connected) sister chromatids arrive at each pole of the cell (opposite from their homologous sister chromatid pair). A nuclear envelope forms around each chromatid bunch, forming 2 new daughter nuclei. Cytokinesis occurs producing two daughter cells that each contain nuclei holding connected sister chromatids for each chromosome number. Each of the two daughter cells contains a sister chromatid pair of each chromosome. But since sister chromatids are technically exact copies of one another (excepting any random recombinants), these daughter cells can be considered haploid (having one set of chromosomes). But they technically still contain 2 exact copies of each chromosome (again ignoring any recombinants), as the chromosomes are each in the form of connected sister chromatids.

Nondisjunction

Error in meiosis in which homologous chromosomes fail to separate. Occurs in (Anaphase 1 or Anaphase 2)

Meiosis 1: Metaphase 1

Homologous chromosome bundles align on the metaphase plate, in an arrangement where each member of a homologous pair of chromosomes (in the form of a paired sister chromatid) is attached to a spindle microtubule from opposite poles of the cell.

Meiosis 2: Telophase 2

Individual chromatids arrive at the 2 poles of the cell. The nuclear envelope forms around each bundle of chromosomes, and cytokinesis occurs.

Eukaryotic Cell Cycle

Interphase (g1, s phase, g2 phase) and then Mitotic phase (mitosis, cytokinesis)

Meiosis 2: Anaphase 2

Microtubules retract, breaking apart the sister chromatid pairs at the centromere, and separated sister chromatids move toward opposite poles of the cell.

mitosis

Nuclear division mechanism that maintains the chromosome number

Meiosis

Nuclear division process that halves the chromosome number. Basis of sexual reproduction.

Meiosis 1: Anaphase 1

Pairs of homologous chromosomes are separated and pulled to opposite ends of the cell. (This stage differs from anaphase in mitosis because only the homologous chromosomes are separated from one another. Connected sister chromatids have traveled together and have not been split, yet.)

crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Meiosis 2: Metaphase 2

Sister chromatids line up on the metaphase plate. Microtubules are attached to sister chromatids along each side.

spindle

Temporary structure that moves chromosomes during nuclear division; consists of microtubules.

metastasis

The spread of cancer cells beyond their original site

Metaphase (Mitosis Phase 2)

This stage is easily identifiable because the chromosomes (in the form of connected sister chromatids) line up on the metaphase plate, with the spindle microtubules from the opposite poles of the cell attached to the centromeres of the sister chromatids.

cell cycle

the collective series of intervals and events of a cell's life, from the time it forms until it divides