AP BIO Cell Cycle

Although cancer may originate in many regions of the body, many patients die from cancerous growth in the lungs, lymph glands, or liver. These organs are "downstream" of the original site. This is most readily explained as

2. metastasis occurring more commonly in organs that have a filter effect

The formation of a cell plate beginning across the middle of a cell and nuclei are re-forming at opposite ends of the cell. What kind of cell is this?

A plant cell undergoing cytokinesis

The retinoblastoma protein Rb is a tumor suppressor protein that is dysfunctional in several major cancers. Which of the choices best describes the image below?

All these answers are correct

The stage in which the chromatids separate and begin to move apart is

Anaphase

Using the table, Which one of the cell samples is most likely from an area near a cut?

B

What is the main difference between totipotent and pluripotent stem cells?

Both can turn into any type of body cell, but totipotent stem cells can also form the umbilical cord and placenta

Which of the following correctly indicates the order in which mitosis occurs?

C, B, A, D

During a fight-or-flight response, epinephrine is released into the body's circulatory system and transported throughout the body. Some cells exhibit a response to the epinephrine while other cells do not. Which of the following justifies the claim that differences in components of cell signaling pathways explain the different responses to epinephrine?

Cell signaling depends on the ability to detect a signal molecule. Not all cells have receptors for epinephrine. Only cells with such receptors are capable of responding

Which protein is a positive regulator that phosphorylates other proteins when activated?

Cyclin-dependent kinase (Cdk)

A motor neuron was once part of the__________________________ layer, which is also part of the embryonic stem cell.

Endoderm

Which checkpoint is correctly associated with its activity?

G1 checkpoint: p53 stops cell growth until DNA is checked for mutations

The critical checkpoints that control the cell cycle are at the

G1 to S stage and G2 to M stage.

The overall process of mitosis functions to ensure

Growth and tissue repair

The epidermal growth factor receptor EGFR is a cell surface receptor. When a growth factor binds to EGFR , the receptor is activated. The activated EGFR triggers a signal transduction pathway, which leads to increased frequency of cell division. Which of the following best predicts the effect of a mutation that causes EGFR to be active in the absence of a growth factor?

Increased cell division will lead to the formation of a tumor

What are the differences between internal receptors and cell-surface receptors?

Internal receptors bind to ligands that are hydrophobic;. Cell surface receptors bind to hydrophilic ligands

Aldosterone is a steroid hormone that regulates reabsorption of sodium ions in the kidney tubular cells. What is the probable mechanism of action of aldosterone?

It binds gated ion channels and causes a flow of ions in the cell.

Metformin is a drug used to treat type 2 diabetes by decreasing glucose production in the liver. AMP -activated protein kinase (AMPK) is a major cellular regulator of glucose metabolism. Metformin activates AMPK in liver cells but cannot cross the plasma membrane. By blocking AMPK with an inhibitor, researchers found that AMPK activation is required for metformin to produce an inhibitory effect on glucose production by liver cells.Which of the following best describes the component that metformin represents in a signal transduction pathway that regulates glucose production in the liver?

It is a ligand that activates the signal transduction pathway of the activation of AMPK

Which letter shows metaphase?

Multipotent

Explain the roles of the positive cell cycle regulators compared to the negative regulators.

Positive regulators promote the cell cycle but negative regulators arrest the cell cycle until certain events have occurred

The stage in which the DNA coils and becomes visible chromosomes is

Prophase

One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding phosphate groups, and then activating relay proteins. Which type does this?

Receptor tyrosine kinases

In a study on cell division, researchers culture synchronously dividing human cells with thymidine. This causes the cells to arrest at the G_1 boundary. The cells are then placed in medium lacking thymidine, which releases the block, and the cells begin to divide again. Starting with Sample A and ending with Sample D, the DNA content of the cells is measured at different times after thymidine is removed. Results for four samples (A-D) are shown in the graph. Which sample presents the expected results for cells in S-phase? *

Sample B

In a study on cell division, researchers culture synchronously dividing human cells with thymidine. This causes the cells to arrest at the G_1 boundary. The cells are then placed in medium lacking thymidine, which releases the block, and the cells begin to divide again. Starting with Sample A and ending with Sample D, the DNA content of the cells is measured at different times after thymidine is removed. Results for four samples (A-D) are shown in the graph. Explain what is happening in terms of the cell cycle and DNA content in sample B. *

The DNA content of the cell has doubled.

Scientists were studying a group of cells that underwent mitosis but not cytokinesis. How did the scientists determine this fact?

The cells were multinuclated

Cancer cells behave differently than normal body cells. For example, they ignore signals that tell them to stop dividing. Which of the following conditions will most likely cause a normal body cell to become a cancer cell?

The environment contains mutagens that induce mutations that affect cell-cycle regulator proteins

A hydrophilic peptide hormone is produced in the anterior pituitary gland located at the base of the brain. The hormone targets specific cells in many parts of the body. Which of the following best explains a possible mechanism that would enable the hormone to efficiently reach all of the target cells in the body?

The hormone is released into the bloodstream where it can be transported to all cells with the correct receptors.

Based on the diagram below, which of the following is true?

The normal functioning of p53 would be a negative feedback loop in that it ends the proliferation of abnormal cells and the mutated p53 would represent a positive feedback loop

Vertebrate immune responses involve communication over short and long distances. Which of the following statements best helps explain how cell surface proteins, such as MHC proteins and T cell receptors, mediate cell communication over short distances?

The proteins interact directly with proteins on the surfaces of other cells.

Which of the following is FALSE regarding the image below?

The purple and green are sister chromatids

The hormone insulin binds to a receptor tyrosine kinase on the surface of target cells. Which of the following steps takes place before phosphorylation of tyrosine residues?

The receptor forms a dimer.

Which of the following statements about structure 1 on the karyotype is NOT true?

The two parts of structure 1 will have genes in different loci (different locations)

Researchers studying cell cycle regulation in budding yeast have observed that a mutation in the CDC15 gene causes cell cycle arrest in telophase when the yeast cells are incubated at an elevated temperature. Which of the following statements best predicts the effect of the cell cycle arrest on proliferating yeast cells?

The yeast cells will replicate their chromosomes but will fail to complete cytokinesis

Which statement best predicts why a cell's progression through the cell cycle might be halted at the G1 / S checkpoint?

There are not enough nucleotides available to construct new DNA

Adjacent plant cells have narrow channels called plasmodesmata that pass through the cell walls of the connected cells and allow a cytoplasmic connection between the cells. This helps the cell because plasmodesmata...

They allow the movement of molecules from one cell to another, enabling communication between cells

The tumor suppressor protein p53 binds to DNA and activates target genes, which results in the synthesis of p21 , CD95 , and other proteins. The p21 protein promotes cell-cycle arrest, whereas the CD95 protein promotes apoptosis. Which of the following will most likely result from a loss of p53 function?

Uncontrolled cell proliferation

Which of the following steps in a signaling pathway typically occurs first once a chemical messenger reaches a target cell?

a ligand binds to a receptor

Which of the following would be observed in healthy cells, but not in cancerous cells?

apoptosis of cells without appropriate cyclins

Dopamine is a neurotransmitter in the brain that causes long-term responses in neurons and binds to a G-protein-linked receptor. Which of the following chemicals would you expect to increase in concentration after dopamine binds its receptor?

cAMP

G proteins are a family of receptor proteins that are involved in transmitting signals from outside a cell to inside a cell. When a signaling molecule binds to a G protein, the G protein is activated. The G protein then activates an enzyme that produces a second messenger called cAMP. Which of the following describes a critical role of cAMP during the transduction stage of a G protein signal transduction pathway?

cAMP results in the activation of an enzyme that amplifies the signal by acting on many substrate molecules.

Apoptosis refers to cell death and

can be programmed and is essential to normal development

True or False? Based on this model, a motor neuron can become a neural stem cell.

false

The class of enzymes that are involved in triggering events in the cell cycle are called:

kinases

Which of the following events does not occur during some stages of interphase?

separation of sister chromatids

An accident has injured your Achilles's tendon (made of connective tissue). However, over the course of several weeks, your body repairs and regrows the damaged tissue. What allows this regrowth to take place?

the inactive stage (G0) which allows it to conserve nutrients and energy