Molecular Cell Biology

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Questions and Answers

Which of the following triggers apoptosis?

NGF

TNFα

Fas ligand

Fas ligand and TNFα (correct)

What role does cytochrome c play in apoptosis?

Promotes cell division

Binds to and activates Apaf-1 (correct)

Releases harmful toxins

Activates ATP production

Mitochondrial permeabilization results in increased ATP synthesis.

False

What is released from mitochondria to trigger apoptosis?

cytochrome c Signup and view all the answers

Apoptosis can be induced by the release of ________ into the cytosol, which activates Apaf-1.

cytochrome c Signup and view all the answers

Which event has likely NOT occurred if a cell exhibits condensed chromatin and a shrunken cytoplasm?

Activation of caspases Signup and view all the answers

Match the protein with its function in apoptosis:

XIAP = Inhibits initiator and effector caspases SMAC/DIABLO = Promotes caspase activation Bax = Forms channels in the mitochondrial membrane Bad = Promotes apoptosis by inhibiting Bcl-2 Signup and view all the answers

Which mitochondrial protein binds to Apaf-1 to activate the caspases?

Cytochrome c Signup and view all the answers

What role does the niche play in stem cell division?

It orients the mitotic spindle. Signup and view all the answers

Tight junctions in epithelial cells recruit apical PAR complexes.

True Signup and view all the answers

What is the function of PAR proteins during asymmetric cell division?

They facilitate the orientation of the spindle. Signup and view all the answers

In C. elegans, the gene ______ encodes a caspase.

ced-3 Signup and view all the answers

Which of the following best describes necrosis?

None of the above. Signup and view all the answers

Match the apoptotic proteins with their descriptions:

CED-3 = Caspase involved in apoptosis CED-4 = Activator of caspases CED-9 = Homologous to human Bcl-2 EGL-1 = Displaces CED-9 from mitochondria Signup and view all the answers

What happens to the daughter cells after asymmetric cell division?

They inherit different fate determinants. Signup and view all the answers

CED-9 is a pro-apoptotic protein in C. elegans.

False Signup and view all the answers

Which statement is FALSE regarding the stem cells in the epithelial lining of the small intestine?

Lgr5 encodes an R-spondin receptor. Signup and view all the answers

Which of the following is part of the cell lineage that gives rise to T cells?

Pluripotent hematopoietic stem cell Signup and view all the answers

Floral meristems only give rise to leaves.

False Signup and view all the answers

What proteins do cap cells in the Drosophila ovary secrete that aid in maintaining germ-line stem cells?

Dpp and Gbb Signup and view all the answers

When a germ-line stem cell divides, the daughter cell maintaining the _______ association becomes a stem cell.

E-cadherin Signup and view all the answers

Match the following terms with their descriptions:

Apoptosis = Programmed cell death Mitochondria = Powerhouse of the cell, involved in energy production Tight junctions = Barrier that controls passage of molecules between cells Stem cell niche = Microenvironment regulating stem cell behavior Signup and view all the answers

What is the primary role of mitochondria in the process of apoptosis?

Release cytochrome c into the cytoplasm. Signup and view all the answers

Homotypic E-cadherin interactions are essential for maintaining the stem cell niche in Drosophila.

True Signup and view all the answers

Study Notes

Molecular Cell Biology - Test Bank

Cell Birth, Lineage, and Death: Mammals follow a specific chronological order in development: zygote, four-cell stage, compacted morula, blastocyst.
Gamete Fusion (Fertilization): Mouse sperm must penetrate cumulus cells and the zona pellucida (ZP) layer. ZP3 glycoprotein binding on the sperm triggers the acrosomal reaction, releasing enzymes to degrade the ZP. This allows sperm-egg membrane interaction. Calcium release in the egg triggers cortical granule exocytosis, preventing polyspermy (multiple sperm entry).
Somatic Cell Nuclear Transfer (Cloning): Involves transferring the nucleus of a differentiated cell into an enucleated egg. This technique can efficiently be used in cloning mice.
Differentiation: The first differentiation event occurs when the trophoectoderm separates from the inner cell mass in the mouse embryo. These pluripotent stem cells are found in the inner cell mass.
Stem Cells: Daughter cells generated through asymmetric cell division can have different sizes, shapes, and protein compositions. Genes specifically expressed in pluripotent embryonic stem cells, such as Nanog, Sox2, and Oct4, are key indicators. Retroviral vectors expressing KLF4, c-MYC, and SOX2 proteins can reprogram differentiated cells into pluripotent stem cells.
Dolly the Sheep: Cloning Dolly involved somatic cell nuclear transfer.
Yamanaka's Studies: Researchers successfully reprogrammed differentiated cells back to stem cells through retroviral infection with transcription factors.

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Description

This quiz covers key concepts in Molecular Cell Biology, focusing on development stages, gamete fusion, and cloning techniques. It includes questions about mammalian development, fertilization processes, and stem cell differentiation. Perfect for students seeking to test their understanding of current biological principles.