AP Bio study set for unit 2 test

a developing worm embryo at four stages. when cell 3 divides the anterior daughter makes gonads and muscles and the posterior daughter cell gives rise to the intestine. if the cells in the embryo are separated, no intestine will form. if cells 3 and 4 are recombined after the separation the daughter cell 3 posterior will give rise to the intestine again. which of the following explains why this happens

A cell surface protein on cell 4 signals cell 3 to induce formation of the worms intestine.

the illustration depicts a neuromusclar junction of a paitent with an autoimmune disorder. Acetylcholine is a stimulatory neurotransmitter. which of the following would be the most likely result of the continued presence of the antibody

A decrease in action potentials in the muscles , causing muscle weakness and fatigue

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 tumer?

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

A medicine is being developed to interfere with signal reception of a cell. which of the following describes a drug interaction that directly interferes with reception of a signal.

A medicine binds with a protein on the cell membrane that typically binds the ligand

the figure is a model of a ligand precursor being cut to produce and active ligand that bonds to a specific receptor. which would reduce the binding of the active ligand to its receptor??

A mutation in the receptor gene that causes a substitution of a charged amino acid for a nonpolar amino acid in the ligand site of the receptor

Damaged tissue releases chemicals that activate platelets and stimulate the formation of blood clots. Which of the following predictions about the activity of platelets best describes a positive feedback mechanism.

Activated platelets release chemicals that activate more platelets.

Based on the model presented, which of the following statements express the proper relationship between ADH release and urine production

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

Glycogen synthetase kinase 3 beta is a protein kinase that has been implicated in many types of cancer. depending on cell type, the gene for glycogen synthetase kinase 3 beta (GSK3b)can act either as an oncogene or as a tumor suppressor. which of the following best predicts how GSK3b mutations can lead to the development of cancer?

Cells with inactive GSK3b fail to trigger apoptosis

which of the following is a valid interpretation of the experimental results that explains how individuals with type 2 diabetes differ from individuals.

The relatively low levels of glucose uptake in individuals with type 2 diabetes

Based on the model presented, which of the following best explains how regulation of neurotransmitters release might increase the range of responses to a stimulus in the nervous system

Different neurons in the same neural network can release neurotransmitters.

Epinephrine is a protein hormone found in many animals. Epinephrine stimulates a signaling pathway that results in the breakdown of glycogen to glucose in the liver cells. Which of the following describes the initial step in the process whereby epinephrine stimulates glycogen breakdown

Epinephrine binds to a cell - surface receptor, the activated receptor stimulates production of the second messenger cAMP

Which of the following patterns is shown by the data( data: percent of mitotic cells on side and on bottom prophase mataphase anahase and telophase. wild type: prophase at 52 metaphase at 18 anaphase at 15 and telophase at 15. Mutant 1 : prophase at 54, metaphase at 16, anaphase at 14 and telophase at 1. mutant 2 at at prophase 72, metaphase at 12, anaphase at 6 and telophase at 5. mutant 3 : prophase at 78, metaphase at 15, anaphase at 4, and telophase 3.

In mutant 3 cells, more time is spent in prophase/prometaphase than in the later stages of mitosis

Scientists have found that DNA methylation suppresses crossing - over in the fungus Asobolus immersus. which of the following questions is most appropriately raised by this specific observation.

Is the level of genetic variation in the fametes related to the amount of DNA methylation observation

Ethylene causes fruits to ripen. In a signaling pathway, receptors activate transcription factors, which ultimately leads to ripening

Loss - of - function mutations in ethylene receptors result in changes to the ripening process

these cells are the result of nondisjunction during which of the following phases.(sperm with n+2, sperm with n+2, sperm with n-1, and last sperm with n-1)

Meiosis 1

on the tip of a plant cell there are sister chromotids, kinetochores with 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 chromosome will move towards opposite poles of the cell.

Cell communication is critical for the function of both unicellular and multicellular eukaryotes. Which of the following is likely true of cell signaling.

Similar cell signaling pathways in diverse eukaryotes are evidence of conserved evolutionary processes ( we are all similar)

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

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

Cyclic AMP phosphodiesterase is an enzyme that catalyzes the conversion of cyclic AMP to a different molecule. Which of the following best predicts the effects of inhibiting cyclic AMP phosphodiesterase in a muscle dell stimulated by epinephrine

The concentration of cyclic AMP will decrease because adenylyl cyclase will no longer be activated

Glucocorticoids are steroid hormones that control cellular responses through several different signaling pathways. one of the signaling pathways involves the glucocorticoid receptor, an intracellular protein that is activated by binding to a glucocorticoid molecule. Which of the following statements best predicts the effect of a mutation that results in a loss of the glucocorticoid receptor's ligand binding function?

The glucocorticoid receptor will remain associated with the accessory proteins.

The epinephrine signaling pathway plays a role in regulating glucose homeostasis in muscle cells. The signaling pathway is activated by the binding of epinephrine to the beta - 2 - adrenergic receptor. Based on the pathway, which of the following statements best describes the epinephrine signaling pathway?

it involves enzymes activating other enzymes.

the process illustrated in the models depicted above all the results in which of the following

more genetic variation

Which of the following statements best describes the action of this hormone on the cells of the human gonads.

the hormone readily passes through the cell membrane and binds to a receptor in the cytoplasm. The hormone and receptor then enter the nucleus and act as a transcription factor that turns on one or more genes.

based on the experimental results, which of the following describes the most likely defect in muscle cells of patients with type 2 diabetes

when IRS-1 activation is reduced at high insulin concentration.

within a forest ecosystem, where is a large amount of diversity among the members of a warbler species. of the following stages of meiosis illustrated for a typical cell, which contributes most to diversity amoung the warbers

when crossing over happens and the homologus pairs are in the middle of the cell