Exam 4

Which of these human cell undergoes the most rapid turnover?

Intestinal epithelial cells

The five stages of mitosis occur in which order?

prophase, prometaphase, metaphase, anaphase, telophase

How many kinetochores are present in a human cell during mitosis?

92

Keratins are NOT found in:

Bones

Which type of mutation would NOT typically convert a proto-oncogene into an oncogene?

Chromosomal deletion of the region containing the proto-oncogene

If the cell is deprived of mitogens for a prolonged period of times, it will enter a nonproliferating state: a) days b) weeks c) months d) Any of the above

D

Many of the genes mutated in individual tumors are involves with which of the following regulatory pathways? a) Pathway controlling cell growth b) Pathways governing the initiation of cell division c) Pathways regulating the cell's response to DNA damage or stress d) All of the above

D

The cell-cycle control system uses which of the following methods to delay progress through the cycle? a) It inhibits the activation of APC to prevent the degradation of cyclins b) It inhibits the phosphatases required to activate a Cdk c) It uses Cdk inhibitors d) All of the above

D

Which type of mutation would NOT be involved in the inactivation of a tumor suppressor gene?

Duplication of the gene

The inactivation of M-Cdk leads to which of the following?

Exit from mitosis

Supportive tissues, such as bone or wood, derive their strength from:

Extracellular matrix

Therapeutic cloning is used to:

Generate personalized embryonic stem (ES) cells

Epithelial cells are attached to the basal lamina by:

Hemidesmosomes

Which is the toughest and most durable of the different types of cytoskeletal filaments?

Intermediate filaments

Abnormally stretchy skin is part of a genetic syndrome that could result from which of the following?

Loss of proteinase that cleave procollagen

Cells export collagen to the extracellular matrix as:

Procollagen (a precursor with additional peptide extensions at each end)

Which of the following statements is false?

The depth-promoting members of Bcl2 family include Bcl2 itself

If GTP hydrolysis occurs on a tubulin molecule at the plus end of a microtubule protofilament before another tubulin molecule is added, what typically happens?

The microtubule depolymerizes

Which feature of glycosaminoglycans (GAGs) allows the extracellular matrix in cartilage to resist compression?

The negative charges on GAGs attract sodium ions, which draw water into the extracellular matrix to form a water-filled gel

Which of the following determines the direction in which cellulose microfibrils are laid down in the extracellular space of a plant cell?

The orientation of microtubules on the cytoplasmic side of the plasma membrane

The nuclear envelope breaks down at the start of prometaphase because:

The replicated chromosomes decondense

Different cyclin-dependent protein kinases (Cdks) trigger different stages of the cell cycle in part because:

Their activities increase at different stages of the cycle

Which of the following is FLASE about cells that are in G0?

Their cell-cycle control system is dismantled irreversibly

Which of the following is NOT true of gap junctions?

They allow ATP-driven pumps to move substances between attached cell

Which is true of induced pluripotent stem (iPS) cells?

They behave live embryonic stem cells

Which is true about stem cells?

They can divide for the lifetime of the organism

Which of the following statements describes how growth factors stimulate animal cell enlargement?

They simulate intracellular protein synthesis

Which epithelial cell junctions serve to seal neighboring cells together so that water-soluble molecules cannot easily leak between them?

Tight junctions

Some types of cancer run in families: individuals in such predisposed families are prone to develop these cancers early in adult life. Mutations in which type of cancer-critical gene would most likely be responsible for "hereditary" cancers?

Tumor suppressor gene

In a centrosome, which structures serve as nucleation sites for the formation of microtubules?

y-tubulin rings

What is the difference between a malignant and benign tumor?

A malignant tumor invades and colonizes other tissues, while a benign tumor does not

During vertebrate development, a sheet of epithelial tissue invaginates to form the neural tube, a structure that eventually forms the spinal cord and brain. Mutations that interfere with the function of which proteins would be most likely to disrupt the epithelial sheet movement that drives this developmental process?

Cadherins