Honors Biology Ch. 10 Test

S Phase

("Synthesis Phase, means to build more DNA) DNA that makes up the chromatin replicates.

Telophase

(Final phase) -Centrioles and spindle fibers disappear. -Chromatids unwind & elongate into threadlike structures of DNA now called chromatin. -A nuclear membrane forms around each mass of chromatin.

G1 Phase

(Gap 1) The cell doubles in size, enzymes and organelles double in number; cytoplasm increases in volume.

G2 Phase

(Gap 2) The cell undergoes rapid growth and prepares to divide. Scientists do not know what exactly happens here.

Prophase

-Chromatin coils & forms chromosomes -nuclear membrane disappears -Chromosomes are visible for the first time. -Centrioles appear & begin to move away from each other to opposite poles of the cell. -Spindle fibers develop proteins that aid in the movement of chromosomes.

Metaphase

-Kinetechore fibers move the chromosome to the center of the cell. -Once in place, the chromosome is held in place by the kinetechore fibers. -made of microtubules.

Cytokinesis

-Occurs when cytoplasm from the original cell splits and forms 2 new cells.

What are the similarities and differences between internal and external cell cycle regulators?

-Similarities: both regulate speed of cell division. -Differences: one regulates inside, one regulates outside.

Anaphase

-The centromere of each pair of chromatids divide, so chromatids separate and move towards opposite poles of the cell.

What feature(s) of a chromosome is a cytogeneticist looking for in a karyotype (CASE STUDY)?

-length of the chromosomes (is one shorter?)

What are the 2 main reasons why cells divide rather than continuing to grow indefinitely?

1) DNA "overload." 2) Exchange of materials.

Events of the Cell Cycle

1) Interphase 2) G1 3) S 4) G2 5) M Phase- Prophase, Metaphase, Anaphase, Telophase 6) Cytokinesis 7) G0

What do 2 jobs of internal regulators?

1) proof reads all chromosomes and ensures that every single one is copied before mitosis occurs. 2) ensures all chromosomes are attached to a spindle before anaphase occurs.

When a cell divides, it results in the formation of what?

2 daughter cells.

What are the 46 chromosomes?

23 homologues #1-22 autosomes *rest are sex traits.

How many chromosomes do humans have? Goldfish?

46; 94

How much do devils eat?

5-10% of their body weight a day; feast on dead animals; growl and bite each other on their faces.

Define diploid.

A cell that contains both chromosomes of a homologus pair. = 2N (46). 46 is the number of diploids, half of this number is a haploid.

Define haploid.

A cell that only has 1 chromosome of a homologous pair. 1N (human sex cell 23).

Agar

A nutrient broth that loves cell division; triptaphan soy agar is used to build cells from school.

Enzymes

A protein that runs everything in a cell; the cell gets proteins from DNA because it has all the instructions to make all needed proteins; even the ones that unravel DNA.

Name a place in your body that mitosis might be going on. (LAB)

A scab; intestinal tract.

How does an animal cell differ from a plant cell during cell division?

An animal cell goes through the cell cycle whereas plant cells construct a cell plate and then divides.

What is the easiest phase to spot?

Anaphase.

What is the taxonomy of a Tazmanian devil?

Animalia Chordata Mammalia Marsupialia Polyprotondta Dasyuromorphia Dasyuridae Sacrophilus harrisii.

What causes the abnormal growth of cancer cells?

Cancer cells do not respond to the signals that regulate the growth of most cells. As a result, they form masses of cells called tumors that damage surrounding tissue.

Explain why the terms cell division and mitosis should not be used interchangeably.

Cell division- entire process Mitosis- a phase in cell division, specifically the division of the nucleus.

What do chromatin form?

Chromatin coil tightly to form a chromosome.

What state is DNA in a non-dividing cell during interphase?

Chromatin.

What are chromosomes made of?

DNA and proteins.

What is DFTD? What has happened to the devil population since this disease was first observed?

Devil Facial Tumor Disease; it has expected to reduce the devil population by 50%.

What are chromatids?

Each replicated chromosome consists of 2 identical parts, called chromatids. AKA "sister chromatids".

Propose some possible methods of containing or eliminating Devil Facial Tumor Disease (DFTD) from the Tasmanian devil population. (CASE STUDY)

Eliminate the cancer cells from a male and female Devil, creating a smaller gene bottleneck free of cancer.

Mating patterns in devils?

Females typically bite the male after mating.

Genetic bottle neck

Fraction of a gene pool left, so inbreeding occurs.

Why did the Taz. Devil population decrease?

Human extermination.

Define homologous (homologue).

In all sexually reproducing organisms, chromosomes occur in pairs.

What are four phases of the cell cycle?

Interphase, mitosis phase, cytokinesis, and Go.

Which phase were the most cells currently in when the slide was made? (LAB)

Interphase.

What is a "chromatin"

It exists as thin uncoiled strands of DNA when the cell is not dividing. It is found in the nucleus. It is composed of DNA and proteins.

What are the 2 types of spindle fibers?

Kinetechore & polar.

Explain what "exchange of materials" means?

Most materials necessary for proper cell function are transported across the membrane. The rate at which this occurs depends on the surface area of the cell. The smaller the cell is, the surface area to volume ratio increases. A cell is more efficient with a greater ratio.

Do all cells in the body have the same growth rate?

No; intestinal tract cells go through mitosis in 4-5 days.

In the case of Errol's karyotype of normal cells, explain why one chromosome showed a different structure than the homologous chromosome (CASE STUDY) ?

One chromosome was genetically altered/mutated.

Many plant cells have more than two complete sets of chromosomes in each cell. What are they called and why?

Polyploytide; the cell plate did not split properly.

Apoptosis

Programmed cell death; genetically directed process of cell self-destruction that is marked by the breaking apart of DNA (activated by stimulus or removal of a suppressing agent/stimulus & is a normal physiological process).

What are cell cycle regulators?

Proteins (called cyclins) that regulate the timing of the cell cycle in eukaryotic cells.

What are nucleosomes?

Proteins that make up chromatin.

Asters

Proteins that radiate from the centriole.

Internal Regulators

Proteins that respond to events inside the cell.

External Regulators

Proteins that respond to events outside the cell.

Centrioles

Small, dark, cylindrical bodies; anchor for spindles.

What does human growth factor do?

Stimulate cell division.

Where are Taz. devils found?

Tasmania.

What happens when a cell begins to divide?

The DNA is replicated.

What about the cancerous cell karyotype appears different from the normal karyotype? (CASE STUDY).

The cancerous karyotype appears shorter than the normal karyotype.

Explain the phenomenon of identical cancers among devils in terms of transmission (CASE STUDY).

The cancers are identical because of the dramatically shrunken gene pool from years ago, so the disease is hereditary as well as transmissible.

Interphase

The cell prepares to divide; a random sample will most likely show cells primarily in interphase because it is the longest phase. (DNA is in Chromatin)

Define mitosis.

The division of the cell nucleus in which the chromosomes in the parent cell divide into 2 identical sets; reasons: growth, repair, maintenance.

Telomere

The end of chromosomes; cellular aging bc with every division, the end of our chromosomes are shortened; causes us to age. If we preserved the telomeres, we would no longer age.

If cells are actively in mitosis, what does this tell you about this region of the onion plant? (LAB)

The onion's root is growing.

What is the centromere?

The point at which the chromatids attach.

Cleavage Furrow

The section that dips between cells during telophase.

What happens when the cell copies its chromosomes?

The synthesis of DNA occurs, during the S phase.

Explain what DNA "overload" means.

There are too many organelles for the DNA to manage, like a city too big for the government.

How are male devils identified?

They are larger.

What do molecules on the surface of neighboring cells do?

They inhibit cell division.

Cancer

Uncontrolled cell growth.

What is a chromosome?

When replicated strands of DNA coil up (chromatin), they become thick and visible (chromosome).

Do the daughter cells have the same traits as the parent?

Yes.

In dividing the cytoplasm, cytokinesis also separates what?

organelles.

What are histones?

proteins in DNA, which coil into nucleosomes.

Why do cells maximize surface area?

so the cells can exchange materials better.

What is the function of cyclin in eukaryotic cells?

to regulate the timing of the cell cycle.