Exam 3 quizzes

In terms of activation, put the following in sequential order: 1. cyclic AMP (cAMP) activates protein kinase A (PKA) 2. The a-subunit of the G protein is activated by GTP 3. An extracellular ligand binds to the GPCR 4. PKA phosphorylates its substrate

3,2,1,4

A widow's peak is a simple genetic trait controlled by one gene. It's presence is considered dominant, while its absence is recessive. If Jim (who is Ww) marries Pam (who is ww), what are the odds that their offspring will have a widows peak:

50%

Which of these proteins (or families of proteins) is important in the regulation of apoptosis?

Bcl2

Both necrosis and apoptosis involve the spewing of cell contents into the environment and the triggering of inflammation

False

Molecular switches are often associated with phosphorylation and dephosphorylation. In every case, phosphorylation via kinase leads to activation (on-switch), and dephosphorylation via a phosphatase leads to inactivation (off-switch)

False

The inner nuclear membrane is continuous with the membrane of the endoplasmic reticulum

False

Which of the following proteins results in the removal of GDP and the addition of GTP?

GEFs

Regarding Ran-GTP and Ran-GDP, which is more commonly found in the nucleus (relative to the cytoplasm)?

Ran-GTP

Which of the following statements about cell signaling is FALSE?

a given extracellular signal (e.g. acetylcholine) will cause an identical response in every cell type to which it binds

Which of the following statements is FALSE?

a mutation that arises in a mother's somatic cell often causes a disease in her daughter

You discover that the underlying cause of a disease is a protein that is now less stable than the non-disease-causing version of the protein. This change is most likely due to:

a mutation within a gene

The folding of a protein into its native shape can be best described as:

a series of repeatable events where the lowest energy structure is maintained

Which of these is NOT necessary for protein kinase C activation?

adenylyl cyclase

Which of the following is a type of stimulatory signal that a cell might receive from another cell?

all of these are stimulatory signals received by other cells

Within a cell, activation of signaling cascade can result in which of the following changes to that cells activity?

altered metabolism of the cell altered shape or motility of the cell altered gene expression in the cell

Which of the following terms best describes when an improper number of chromosomes segregate into each cell?

aneuploidy

Identify the class of protease closely associated with apoptosis.

capases

Identify the class of protease closely associated with apoptosis.

caspases

Thomas Hunt Morgan spent years breeding fruit flies for his genetics experiments. After several generations, he noticed that some flies had white eyes (as opposed to the wildtype red eyes). After this observation, he ran several experiments to find the genes responsible for eye color. This is an example of:

classical genetics

Which of these is MOST likely to be a ligand for a nuclear receptor?

cortisol (a steroid hormone)

The presence of which of these proteins in the cytoplasm is a signal that the cell should undergo apoptosis?

cytochrome c

Consider a protein in the process of folding. Which of the following is TRUE?

driven by the hydrophobic effect, hydrophobic amino acids cluster toward the center of the protein

Mitogens are:

extracellular signals that stimulate cell division

Which of these terms refers to signaling that happens WITHIN a cell?

intracellular

Which of the following statements about the unfolded protein response (UPR) is not true?

it takes place in the cytoplasm

Identify the protein that is most directly activated by phosphorylation in response to DNA damage

p53

Clotting factors are released by platelets and lead to wound repair in immediately adjacent tissues. Which type of intercellular signaling does this best describe?

paracrine signaling

Which of these is the SUBSTRATE for the enzyme phospholipase C (PLC)?

phosphatidylinositol 4,5-bisphosphate (PIP2)

Which of the following phases does NOT occur during interphase?

prometaphase

During what phase of meiosis does crossing over occur?

prophase I

Which of the following is NOT a way by which meiosis increases genetic diversity?

replicating the DNA during S phase

A protein that brings two or more other signaling proteins that they can interact more quickly and efficiently is known as a ______ protein.

scaffolding

What happens when a G-protein-coupled receptor (GPCR) activates a G protein?

the a subunit exchanges its bound GDP for GTP

In terms of the cyclin-Cdk system, which of the following remains constant during the cell cycle?

the concentration of cyclin-dependent kinases

In his now famous experiment, Anfinsen added urea and B-mercaptoethanol and caused his protein of interest to completely lose structure and function. What happened when the urea and 3-mercaptoethanol were removed?

the protein regained both structure and function

Which of these is NOT a potential outcome of a protein being released from Hsp70?

the protein returns to the ER to be degraded

Which part of the trimeric G protein is affected by the presence of the pertussis toxin?

the toxin causes the a subunit of G; is inactivated, leading to overactive adenylyl cyclase and excessive cAMP