Unit 4 AP Biology (Cell Communication & Cell Cycle)

Blood glucose level is high, pancreas releases insulin. The insulin causes the cells to take up blood sugar so the sugar level decreases. Which type of feedback is described above?

• Positive

• Negative

Answer explanation

The release of insulin is due to a high blood glucose level. The release of the insulin will stimulate cells to take up the glucose which will reduce the blood glucose level.

Tags

NGSS.HS-LS1-3

Which extracellular component aids in direct cell-cell communication?

• Cell Wall

• Cytoskeleton

• Glycolipid

• Secretory Vesicle

Answer explanation

Glycolipids are short carbohydrates attached to lipid molecules. These are used for cell to cell communication. The sugar component will bind to an active site on a receptor protein of another cell to communicate.

Predict what would happen if overactive pituitary with TSH release.

• TRH levels decrease

• TRH levels increase

• TRH levels stay the same

Answer explanation

The pituitary will release TSH which will cause the Thyroid Gland to release the thyroid hormone. The thyroid hormone has a negative feedback with the hypothalamus. The hypothalamus releases the TRH. If there is an increase in TSH and thyroid hormone, there is a decrease in TRH levels.

Tags

NGSS.HS-LS1-3

Signaling where a ligand binds to a nearby cell is known as...?

• Autocrine

• Hormonal

• Paracrine

• Synaptic

Answer explanation

Paracrine signaling refers to a local signaling where the signaling molecule is released from a nearby cell then binds to a receptor on the target cell.

Crossing Over?

• Does NOT occur

• Does occur

Answer explanation

Crossing over involves nonsister chromatids exchanging genetic information. Mitosis involves sister chromatids so crossing over does not occur.

Tags

NGSS.HS-LS3-2

An inhibitor that binds to the active site, inhibiting the substrate.

• Allosteric Inhibitor

• Competitive Inhibitor

• Noncompetitive Inhibitor

• Repressor Inhibitor

Answer explanation

If the inhibitor is binding to the same site, it is competing for the active site. Due to this competition, this is called a competitive inhibitor.

Muscle contraction occurs when calcium binds in the muscle cells. Where is the calcium stored in the muscle cells?

• Lysosome

• Nucleus

• Smooth ER

• Vacuole

Answer explanation

The smooth ER has a couple different functions including:

› Detoxification

› Synthesis of Lipids

› Storage of Ca2+ ions

Which of the following act as secondary messengers?

• ATP and Ca²⁺

• Ca²⁺ and cAMP

• cAMP and ligand

• Ligand and ATP

Answer explanation

Secondary messengers are small molecules that will move within the cell to transfer a signal. Traditionally, we discuss cAMP and Ca2+. These molecules will bind to another receptor as part of the transduction pathway,

Which phase involves single chromatids moving to poles?

• Anaphase

• Metaphase

• Prophase

• Telophase

Answer explanation

Anaphase involves the sister chromatids moving apart to opposite poles. The microtubules are attached to each centromere and shorten which "reels" the chromosomes to the poles.

Tags

NGSS.HS-LS1-4

Cancer treatment involves chemotherapy with drugs that inhibit microtubules from depolymerizing. Which phase would the cell be stopped in?

• Anaphase

• Metaphase

• Prophase

• Telophase

Answer explanation

Metaphase is the phase where the sister chromatids are bound to microtubules on the metaphase plate while anaphase is the depolymerizing of the microtubules to pull them to the opposite poles.

Tags

NGSS.HS-LS1-4