Unit 4- ap bio

What is the expected percent change in the DNA content of a typical eukaryotic cell as it progresses through the cell cycle from the start of the G1 phase to the end of the G2 phase

+100%

Following surgical removal of the thyroid gland, the level of TSH in the blood will increase. Which of the following best explains this increase?

A decrease in thyroxine levels means a loss of inhibition to the hypothalamus and anterior pituitary, leading to increased TSH secretion

Cancer can result from a variety of different mutational events. Which of the following is LEAST likely to result in the initiation of a cancerous tumor?

A defect in a cell-cycle checkpoint prevents a cell from entering the S phase

The endocrine system incorporates feedback mechanisms that maintain homeostasis which of the following demonstrates negative feedback by the endocrine system?

After a meal, blood glucose levels become elevated, stimulating beta cells of the pancreas to release insulin into the blood. Excess glucose is then converted to glycogen in the liver, reducing blood glucose levels.

Which of the following statements expresses the proper relationship between osmolarity, ADH release, and urine production

As tissue osmolarity rises, more ADH is released, causing less water to be excreted as urine

A dog is following the scent of a jack rabbit. Which of the following accurately describes how the dogs brain integrates information for smell?

Chemo receptor cells in the nasal cavity send impulses to the appropriate area of the brain

If chemical signals in the cytoplasm control the progression of a cell to the M phase of the cell cycle the fusion of a cell in G1 with a cell in early and phase would most likely result in the

Condensation of chromatin in preparation of nuclear division in both cells

Which of the following best describes the role of mitosis in the cell cycle?

Distribution replicated chromosomes to daughter nuclei

During the contraction of a vertebrae skeletal muscle fiber, calcium ions

Find with troponin, changing its shape so that the myosin binding sites on actin are exposed

Which of the following statements accurately uses the information presented to support the hypothesis that interruption of M function in a single body cell can result in cancer?

Growth factor signaling can sugar mitosis in cells that are in direct contact with other cells

A researcher examining a root tip observes a plant cell with condensed sister chromatids, kinetic Kors and attached microtubules and individual chromosomes that are aligned at the equatorial plate of the cell. Which of the following best describes what the next process will be in the cell?

Paired chromatids will separate and the new daughter chromosomes move toward opposite poles of the cell

During mitosis which of the following normally occurs

Replicated chromosomes line up on the equatorial plate

A stimulus has opened the voltage gated sodium channels in an area of a neuron's plasma membrane as a result, __________ rushes into the neuron and diffuses to adjacent areas; this intern results in the_________ In the adjacent areas

Sodium; opening of voltage gated sodium channels

Which of the following best describes what occurs when the action reaches a chemical synapse at the end of an axon

The action potential causes the release of neurotransmitters that travel across the synapse

Which of the following best describes how the amount of DNA in the cell changes during M phase

The amount of DNA is halved as the cell divides into two daughter cells

Based on the model of eukaryotic cells cycle shown in the figure, which is the following best describes the effect of a drug that blocks the production of the mitotic cyclin?

The cell would be prevented from entering mitosis, and the cell would stop dividing

Most cells that have become transformed into cancer cells have which of the following characteristics when compared to normal, healthy cells?

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

If ADH secretion is inhibited which of the following would initially result?

The person would produce greater amounts of dilute urine

If axon two was damaged before the pin prick, which of the following is most likely?

The persons finger will not withdraw reflexively

Which of these causes the release of neurotransmitter molecules

an action potential reaching the end of the axon

Where are neurotransmitter receptors located?

postsynaptic membrane