Bio Chapter 5:

Mitosis (Telophase)

(New chromosomes reach poles. Nuclear envelopes re-form and chromatin decondenses)

Interphase

- Gap 1: First phase in newly divided cell - Prepares DNA - S phase: DNA is replicated centromere forms - Gap 2: After s phase

Why cells divide

1. To reproduce the organism 2. Grow and repair multi cellular organism

An actively dividing cell has six chromosomes. How many sister chromatids are present within this cell at the end of G2 phase? Select one: a. 12 b. 3 c. 6 d. 0

A

When examining the rapidly dividing cells of a fish embryo, you notice a cell that seems to contain two nuclei. The middle of the cell is pinched inward. This cell must be in ________ of mitosis. Select one: a. telophase b. metaphase c. anaphase d. prophase

A

Which of the following is true of the chromosomes in a homologous pair? Select one: a. They carry the same genes. b. They both came from the organism's mother. c. They both came from the organism's father. d. They do not join together during meiosis.

A

Cytokinesis

After DNA is copied and divided to both daughter cells, the cytoplasm and cell organelles are divided.

All of the following contribute to genetic uniqueness EXCEPT Select one: a. independent assortment. b. binary fission. c. crossing over. d. random fertilization.

B

What are the stages of interphase? Select one: a. G0, G1, and S b. S, G1, and G2 c. G0, G1, and G2 d. S1, S2, and G0

B

Which of the following cell types is produced by meiosis? Select one: a. muscle cells b. sperm cells Correct c. pancreatic cells d. skin cells

B

A scientist wishing to generate cancerous cells in vitro could subject the cells to which of the following procedures? Select one: a. starve the cells of nutrients b. overfeed the cells by frequently feeding them c. expose cells to chemicals that disrupt mitosis d. immerse the cells in water for extended periods of time

C

Cancers are groups of cells that divide rapidly and uncontrollably. Thus, cancer cells Select one: a. are always in the G0 phase. b. never enter the cell cycle. c. have a relatively short G1 phase. d. are stuck at the metaphase plate.

C

Which of the following differentiates meiosis from mitosis? Select one: a. Mitosis occurs in prokaryotic cells, whereas meiosis occurs in eukaryotic cells. b. Meiosis is a form of asexual division, whereas mitosis is a form of sexual division. c. Mitosis is used for the repair of cells, whereas meiosis creates cells for sexual reproduction. d. In mitosis four identical daughter cells are produced, whereas two genetically different cells are produced in meiosis.

C

If a plant has a total of 18 chromosomes, how many chromosomes would be present in each of its gametes? Select one: a. 36 b. 18 c. 6 d. 9

D

In genetic engineering, molecular biologists often combine segments of DNA from two separate organisms. This is an example of genetic recombination that occurs in a laboratory setting. Which of the following is a form of genetic recombination that occurs naturally within cells? Select one: a. asexual reproduction b. mitosis c. independent assortment d. crossing over

D

Regulatory proteins

During G1 regulatory proteins advance cells to the S phase to begin replication. These can be influenced by internal (within the cell) or external signals, nutrient supply, or DNA damage

Meiosis

Produces sperm and eggs that have half as much DNA as the mother cell. Occurs in gametes cells

Mitosis(Prophase)

Replicated chromosomes condense and attach to mitotic spindles made of cytoskeletal proteins. Nuclear envelope breaks down.

Mitosis (Anaphase)

Sister chromatids are separated and become individual chromosomes. Spindles are shortened and new chromosomes are moved towards the poles of the cell.

Cancer

Uncontrolled cell division

Another name for prokaryote cell division

binary fission

Benign tumors

cancer cells that remain to a single site

Anchorage independence

cell maintains its capacity to spread, divide and function despite of the absence of a stable or inert surface to anchor with.

Anchorage dependence

cells are firmly anchored in one place and will stop dividing if they are detached from their surroundings

Chromatids

chromosomes with proteins

Somatic cells

diploid cells identical and having as much DNA as parent cells

Chromosomes

formed when the DNA wraps around proteins

Fertilization

fusion of two gametes

Gametes

haploid sex cells (sperm or eggs) having half as much DNA as parent cell

Mitosis(Metaphase)

mitotic spindle aligns and replicated chromosomes at the center of the cell

Mitosis

produces two identical daughter cells, assexual

Independent assortment

random distribution of homologous chromosomes into daughter cells during meiosis I

Zygotes

single cells that have all of the DNA required to begin

Metastisis

the spread of a disease from one organ to another

Crossing-over

—physical exchange of chromosome segments between nonsister chromatids when they are paired with homologous chromosomes

genetic recombination—

—the DNA is switched between chromosomes, which separate into new daughter cells