Chapter 8 Biology LECTURE

Which of the following does NOT describe a cancer cell?

a cell regulated by contact inhibition

Cytokinesis usually, but not always, follows mitosis. If a cell undergoes mitosis and not cytokinesis, this would result in

a cell with two nuclei.

Losing weight can reduce an obese person's risk for cancer by up to

40%.

If a cell has 46 chromosomes at the beginning of mitosis, then at the end of anaphase there would be a total of

92 chromosomes.

Which cancer therapy can lead to side effects such as nausea and hair loss?

chemotherapy

In an experiment, cells grown in a petri dish divided until they formed a thin single layer. When cells were removed from the middle of the dish, the cells bordering the open space began dividing until they had filled the empty space. This type of regulation is called

contact inhibition.

What structure is formed by two sister chromatids being held together by a centromere?

duplicated chromosome

When during the cell cycle are chromosomes visible under a microscope?

during M phase

If tumor cells have a faulty, non-functional proteinase, they will be unable to undergo which of the following processes?

metastasis

The mitotic spindle is composed of________, which originate from the________.

microtubules; centrosome

Cells that do not receive the correct signals to move from G1 into S phase will enter G0 and therefore will

not undergo mitotic division unless it later receives the go-ahead signal.

Chromatin wrapped around histones form a bead-like structure known as a

nucleosome.

Anushka was examining a cell under the microscope and she noticed the formation of a cell plate in the midline of the cell and the formation of nuclei at opposite poles of the cell. The cell under examination was most likely a(n)

plant cell undergoing cytokinesis.

Plant cells and animal cells differ in cytokinesis because

plant cells need to build a cell wall, while animal cells do not.

Some of the drugs used in chemotherapy work by

preventing spindle formation.

Unicellular organisms undergo mitotic division to

produce new organisms.

Telomeres function to

promote chromosomal stability.

Which of the following represents the phases of mitosis in their proper sequence?

prophase, metaphase, anaphase, telophase

Cancer is a disorder in which some cells have lost the ability to control their

rate of cell division.

Which of the following occurs prior to prophase?

synthesis of DNA

During which stage of the cell cycle does the spindle disappear?

telophase

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 10 picograms of DNA in the nucleus during G1. Those cells would have________ picograms at the end of the S phase and________ picograms at the end of G2.

20; 20

If there are 20 centromeres in a cell, how many sister chromatids are there?

40

Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. Which of the following statements explains why this occurs?

Cell division can be inhibited by the proximity of other cells.

If a cell is inhibited during the S phase of its cycle, it will not reproduce due to lack of

DNA synthesis.

Differentiated cells, such as nerve cells, would be in which of the following stages of the cell cycle?

G0

Which of the following is mismatched?

G2 stage - mitosis begins

Which of the following organelles would be abundant and in close proximity to the cell plate in a plant cell undergoing cytokinesis?

Golgi apparatus

Which of the following statements is correct regarding the events of the cell cycle?

Interphase consists of G1, S, and G2.

Pevita has a tumor in her ovaries. She recently underwent a series of tests and is returning to the doctor to find out the results. Which of the following would be the best news that Pevitacould receive from her doctor?

It is a benign tumor.

The drug chloral hydrate prevents elongation of microtubules. During which stage of the cell cycle would chloral hydrate be most harmful?

M phase

Nuclear division occurs during

M phase.

Inheritance of mutant forms of some genes may lead to a predisposition to develop cancer. Which of the genes listed below takes its name from its association with an eye tumor?

RB

Which of the following pairs is correctly matched?

S phase - DNA replication

A tumor suppressor gene undergoes a mutation that causes it to lose its normal function. What would be the most likely result of this mutation?

The cell no longer responds to signals that cause it to stop dividing or undergo apoptosis.

Which of the following is an inaccurate statement about mitosis?

The cells arising from mitosis contain only half of the necessary genetic material.

How do the daughter cells at the end of mitosis and cytokinesis compare to their parent cell when it was in G1 of the cell cycle?

The daughter cells have the same number of chromosomes and the same amount of DNA.

Why might a cell be prevented from proceeding through the G1 checkpoint?

There is DNA damage.

An oncogene is more likely to lead to cancer than a proto-oncogene because

an oncogene is more likely to accelerate the cell cycle.

During which phase of mitosis are the sister chromatids separated and consequently become daughter chromosomes?

anaphase

Which of the following would increase your risk of cancer?

avoiding a high-fiber, low-sodium diet

Telomerase normally functions in

both embryonic and adult stem cells.

Denzel was looking at onion root tip cells under the microscope in biology class. He saw one cell that had two nuclei within it. What stage of the cell cycle was this cell in?

telophase/cytokinesis

Apoptosis

can be used to remove damaged or malfunctioning cells.

Translocations

can lead to cancer if they disrupt the genes that regulate the cell cycle.

An enzyme that promotes apoptosis is generally known as a(n)

caspase.

What is the structure that holds together the two sister chromatids that form a chromosome?

centromere

What structure holds two sister chromatids together?

centromere

A translocation may lead to cancer if it

disrupts control of expression of genes that regulate the cell cycle.

A mutation that causes an increase in function in a tumor suppressor gene would not likely cause cancer because a tumor suppressor protein

does not promote cell division.

The presence of which protein is required in order for chromatin to compact correctly within the nucleus?

histone

Multicellular organisms undergo mitotic cell division to

increase the size of the organism.

If you were looking under the compound light microscope at an onion root tip, in what stage of the cell cycle would the majority of the cells be?

interphase

A centromere holds together two

sister chromatids.

Which lifestyle choice is responsible for 90% of the cases of lung cancer among men?

smoking

The term metastasis refers to the fact that cancer cells tend to

spread

A proto-oncogene differs from a tumor suppressor gene because a proto-oncogene

stimulates cell division in a normal cell, whereas a tumor suppressor gene inhibits cell division.

Proto-oncogenes function by

stimulating the cell cycle when appropriate signals and growth factors are present.

If a solid tumor is discovered at an early stage, which treatment method is most often used?

surgery

The G2 checkpoint prevents the cell cycle from continuing until

the DNA has finished replicating.

Cytokinesis in plants occurs as________ and in animals as________.

the Golgi apparatus produces membrane-bound vesicles filled with materials to make the cell wall; actin fibers pull the membrane inward until the two sides touch

A positive genetic test for telomerase in an adult somatic body cell, such as a fibroblast, may indicate that

the cell is cancerous.

A mutation results in a cell that no longer produces a normal protein needed for the M-phase checkpoint. Which of the following would likely be the immediate result of this mutation?

the cell would never leave metaphase

If the production of cyclins halted during the cell cycle

the cell would not proceed to the next phase of the cell cycle.

Which of the following is a characteristic of cancer cells?

the nucleus is abnormally shaped.

Cancer occurs when

the regulation of the cell cycle is lost and uncontrolled cell division occurs.

When a portion of a chromosome breaks off and attaches to a different chromosome, this is called a(n)

translocation