practice
1.
Which of the following is correct about signal transduction pathways (STP)?
Answer: In STP, a single molecule can stimulate the release of thousands of molecules of
product within a cell.
2. Proteins that are involved in the regulation of the cell cycle, and that function in concentration
during the cycle.
Answer: Cyclin
2.
Which of the following is correct about protein kinase receptors?
Answer: They allow for the passage of ions such as NA+ through the plasma membrane of a
Cell.
3.
Which term describes centrioles beginning to move apart in animal cells?
Answer: Prometaphase
4.
The endocrine system incorporates feedback mechanisms that maintain homeostasis.
Which of the following demonstrates negative feedback by the endocrine system?
Answer: After a meal, blood glucose levels become elevated, stimulating beta cells of the
pancreas to release insulin into the blood.
5.
What is a phosphorylation cascade?
Answer: A series of molecules that get phosphorylated.
6.
Testosterone does not affect all cells of the body because...
Answer: Not all cells have cytoplasmic receptors for testosterone.
7.
The longest phase of the cell cycle:
Answer: Interphase
8.
Which is a protein synthesized at specific times during the cell cycle that associates with
a kinase to form a catalytically active complex?
Answer: Cyclin
9.
Since steroid receptors are located intracellularly, which of the following is true?
Answer: The steroid-receptor complex can cross the nuclear membrane.
10.
Of the following, a receptor protein in a membrane that recognizes a chemical signal is
most similar to...
Answer: The active site of an enzyme that binds to a specific substrate.
11.
ATPgammaS is a form of ATP that cannot be hydrolyzed by enzymes. If this compound
were introduced to cells so that it replaced the normal ATP present in the cell, which of the
following would you predict?
Answer: An increase in the numbers of phosphorylated proteins in the cell.
12.
Phosphorylation cascades involving a series of protein kinases are useful for cellular
signal transduction because...
Answer: They amplify the original signal many-fold.
13.
Which term describes centromeres uncoupling, sister chromatids separating, and the
two new chromosomes moving to opposite poles of the cell?
Answer: Anaphase
14.
What does a protein phosphatase do?
Answer: Removes phosphates.
loading...
Answer: They might not be able to multiply in response to growth factors from nearby cells.
31.
Ras, a small G protein located at the plasma membrane, is often mutated in different
types of cancer. Ras normally signals to a cell that it should divide. Cancer cells divide
uncontrollably. Which of the following changes to Ras would you expect to see in a cancer cell
that has mutated Ras present?
Answer: A mutation that means Ras cannot hydrolyze GTP to GDP.
32.
What is the result of mitosis?
Answer: Two genetically identical cells.
33.
Which cell cycle checkpoint would a cell fail if there were a large number of errors in the
replicated DNA?
Answer: G2
34.
The point on the chromosome where the two chromatids are held together is the...
Answer: Centromere.
35.
When a neuron responds to a particular neurotransmitter by opening gated ion channels,
the neurotransmitter is serving as which part of the signal pathway?
Answer: Signal molecule.
36.
Which needs to be present to begin M phase and activates microtubule proteins?
Answer: Mitosis Promoting factor (MPF).
37.
Which of the following can activate a protein by transferring a phosphate group to it?
Answer: Protein kinase.
38.
Which of the following molecules is necessary for progression through the G2 cell cycle
checkpoint?
Answer: CDK and Cyclin.
39.
Which is a general term for enzymes that activate or inactivate other proteins by
phosphorylating them?
Answer: Protein kinase.