Cell Exam 3 - Practice Problems

Which part of the mitochondrion contains cardiolipin making it impermeable?

c. Inner mitochondrial membrane

Which of the following is NOT a product of the Krebs cycle?

d. Acetyl CoA

In eukaryotes, pyruvate is converted to acetyl CoA:

c. In the mitochondrial matrix

If one glucose is fully oxidized in eukaryotes, how many NADH and ATP are produced?

d. 10, 36

Which statement is NOT evidence for the chemiosmotic model?

e. Uncouplers stop ATP synthesis

Which ETC complex is INCORRECTLY paired?

d. Complex IV: cytochrome c reductase

Correct electron flow from NADH?

a. Complex I → CoQ → III → cytochrome c → IV → O₂

ATP synthase structure:

d. Proton channel, catalytic subunit

Glycerol enters metabolism where and as what?

d. Glycolysis, dihydroxyacetone phosphate

 The TCA cycle is considered:

b. Amphibolic

Peroxisomal enzymes:

1. Produce H₂O₂

2. Break down H₂O₂

Include catalase:

d. 1, 2, and 3

Oxygen released in photosynthesis comes from:

a. Water

Mitochondria vs chloroplast energy conversion:

a. Chemical from food → ATP ….. light → ATP

Chloroplasts contain:

b. Circular DNA, 70S ribosomes

Accessory pigments:

d. Transfer energy to chlorophyll a

Photophosphorylation uses energy to move:

c. H+, stroma, ATP

In the Calvin cycle:

b. NADPH is oxidized

 Which did NOT arise from endosymbiosis?

c. III and IV

Nuclear envelope is continuous with:

b. Rough ER

RNA export occurs by:

c. Selective transport

 Highly condensed inactive chromatin:

b. Heterochromatin

Which is NOT part of histone core?

a. H1

Chromosomes are arranged:

d. In distinct territories

 rRNA coding region is:

b. Nucleolar organizing region

Ribosomes making different proteins:

c. No difference

Transport into ER vs nucleus:

c. Translocon; importin

Vesicle coat proteins: 2 layers + ___ + …..

d. All correct

Dynein vs kinesin direction:

b. Center to periphery

Rough ER RNAs encode:

d. All

 NOT in ER lumen:

b. O-linked glycosylation

NOT uptake into cell:

d. Exocytosis

Lysosome protection:

c. Carbohydrate chains on membrane proteins

_-_ experiment is:

c. Pulse-chase

In endocrine signaling,___

c. Travels via bloodstream - the messenger molecules reach their target cells via passage through bloodstream

Receptor tyrosine kinases (RTKs) are activated by:

b. Ligand-induced dimerization

The primary activity of receptor tyrosine kinases after activation is:

c. Autophosphorylating tyrosine residues

Adaptor proteins in RTK pathways function to:

b. Bind phosphorylated receptors and recruit signaling proteins

The Ras protein is best described as a:

c. Small GTP-binding protein

Ras is activated when:

c. GDP is exchanged for GTP

What happens when Ras is mutated so it cannot hydrolyze GTP?

c. It remains constitutively active

MAP kinase cascade function:

b. Amplifies the signal through phosphorylation cascades

The final effect of many RTK pathways is:

c. Changes in gene expression

Signal amplification refers to:

c. A single activated receptor triggering many downstream molecules

Protein kinases function to:

b. Add phosphate groups to proteins

Protein phosphatases function to:

b. Remove phosphate groups

Why are signaling pathways tightly regulated?

b. To ensure signals are brief and appropriate

In the epinephrine signaling pathway: what is the primary messenger?

a. epinephrine

In the epinephrine signaling pathway: what is the secondary messenger?

d. cAMP

What is the response of a receptor to the binding of a ligand to it at the cell's extracellular surface?

b. the receptor relays a signal across the membrane to the receptor's cytoplasmic domain at the inner membrane surface

What role do the 3 of the loops on the GPCR at the outside of the cell play in the signaling process?

a. together they serve as a ligand-binding site for extracellular signaling molecules

What enzyme below does diacylglycerol (DAG) recruit and activate?

c.  protein kinase C

Which of the following statements is TRUE?

b. GCPRs bind G proteins internally, causing them to become active and separate into subunits

The Ras G protein is a key component of a cascade that plays a key role in regulating vital activities like cell proliferation and differentiation. What is the name of the cascade?

c. the Ras-mitogen activated protein kinase cascade

While animals have many signaling pathways that use tyrosine kinases whereas plants more often use:

b. histidine kinases

Which of the following statements is TRUE?

a. extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor to signal a target cell to change its behavior