Section 4 Cell Bio

Which of the following statements is FALSE? -Somatic cells only divide a limited number of cycles, likely due to the shorten of telomeres. -A loss-of-function mutation of telomerase will convert a normal cell to a cancer cell. -Cancer cells proliferate indefinitely, presumably related with the stabilization of telomeres. -Telomerase carries a RNA template, synthesizes and extends template DNA strand at telomere.

-A loss-of-function mutation of telomerase will convert a normal cell to a cancer cell.

Which of the following statements about cancer is FALSE? -Many cancer cells have abnormal chromosomes representing genetic instability. -A mutation in a single cancer-critical gene is sufficient to convert a normal cell into a cancer cell. -Cancers are caused by the accumulation of a series mutations on oncogenes and tumor suppressor genes. -Carcinogens cause cancer by changing the nucleotide sequence of DNA.

-A mutation in a single cancer-critical gene is sufficient to convert a normal cell into a cancer cell.

Which of the following statements about apoptosis is TRUE? -Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria. -Bax and Bak promote apoptosis by binding to procaspases in the apoptosome -The Fas ligand and Fas receptor work to inhibit apoptosis -Cells that constitutively express Bcl2 will be more prone to undergo apoptosis -

-Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria.

In DNA replication the lagging strand is synthesized discontinuously at the replication fork because -DNA polymerase removes the last few nucleotides synthesized whenever it stops. -DNA polymerase always falls off the template DNA every ten nucleotides or so. -DNA polymerase can polymerize nucleotides only in the 5'-to-3' direction. -DNA polymerase needs RNA primer to start DNA synthesis.

-DNA polymerase can polymerize nucleotides only in the 5'-to-3' direction.

Which of the following statements is TRUE? -In anaphase A, chromosome movement is driven by shorten of aster microtubules. -Anaphase A is driven by motor proteins kinesis and dyenin -In anaphase A, both kinetochore microtubules and interpolar microtubules shorten. -In anaphase B, microtubules associated with the cell membrane shorten.

-In anaphase B, microtubules associated with the cell membrane shorten.

A multipotent cell _________. -can produce only white blood cells -can only give rise to stem cells -is considered to be terminally differentiated -can give rise to some cell types in the body

-can give rise to some cell types in the body

When a terminally differentiated cell in an adult body dies, it can typically be replaced in the body by a stock of ________. -proliferating precursor cells that are derived from adult stem cells -embryonic stem cells -induced pluripotent cells -cells more apically located than the terminally differentiated cells

-proliferating precursor cells that are derived from adult stem cells

Place the following events of M phase into the correct order. 1. Alignment of the chromosomes at the spindle equator 2. Attachment of microtubules to chromosomes 3. Breakdown of nuclear envelope 4. Reformation of the nuclear envelope 5. Condensation of the chromosomes 6. Separation of sister chromatids

5,3,2,1,6,4

Suppress of apoptosis can promote cancer cell survival. Which of the following compound could be an anti-cancer drug? A. A compound that inhibits Bax B. A compound that inhibits Bad C. A compound that inhibits Bcl2 D. A compound that inhibits Fas-receptor

A compound that inhibits Bcl2. (will prevent Bax complex and promote cell survival)

Which of the following statements is CORRECT? -Loss-of-function mutation in one allele of tumor suppressor gene may be sufficient to stimulate cell division. -A gain-of-function mutation in only one allele of oncogene can stimulate cell survival or division -Loss-of-function mutations in a tumor suppressor gene make the coding protein hyperactive -Loss-of-function mutation in an oncogene makes the coding protein hyperactive

A gain-of-function mutation in only one allele of oncogene can stimulate cell survival or division

Which of the following transcription factors is needed to convert an adult cell into an induced pluripotent stem (iPS) cell? -KIf4 -Oct4 -Sox2 -all of them

All of them

The following genes could become oncogene except_____ A. E2F B. Bcl2 C. BAD D. mTOR

BAD (inhibits cell survival and promotes death)

If the anaphase promoting complex (APC/C) is temperature sensitive (active at 30 degree, but inactive at 40 degree), shifting to the higher temperature (40 degree) at the start of M phase would prevent which of the following? -Degradation of M-Cdk -DNA replication -Degradation of securin and separation of sister chromatids. -Entrecnce into M phase

Degradation of securin and separation of sister chromatids.

Which of the following compounds can be a potential anti-cancer drug? A compound that inhibit A. p53 B. Rb C. E2F D. p21 E. S-Cdk F. A and B G. C and E

G) C and E

Irradiated mammalian cells usually stop dividing and arrest at a G1 checkpoint. Place the following events in the order in which they occur. I. production of p21 II. DNA damage III. inhibition of cyclin-Cdk complexes IV. activation of p53

II-IV-I-III

A particular strain of yeast produces strains with a mutant cdc2 (M-Cdk) gene, resulting in little to no production of the M-Cdk protein kinase. As a result, what would be expected? -These cells will have chromosome condensation. -These cells will enter M phase -These cells will have the nuclear envelope disperse. -None of these.

None of these

In a PCR experiment, you added DNA template, dNTPs, and Taq DNA polymerase into the buffer, but didn't get any product. What is missed in your system?

Primer

In the cell containing a loss-of-function mutation of the separase gene, which of the following phenotypes can be predicted? -The condensing complex will not be assembled. -The cohesion complex will not be assembled -Mitotic spindles will not be aligned correctly in Metaphase -Sister chromatids will not be segregated after metaphase

Sister chromatids will not be segregated after metaphase

An adult hematopoietic stem cell found in the bone marrow ______________________. -can produce only white blood cells -will occasionally produce epidermal cells when necessary -can undergo self-renewing divisions for the lifetime -can produce only red blood cells

can undergo self-renewing divisions for the lifetime

What would be the consequence of inactivation of E2F? -The Rb protein would become activated. -Cells would develop cancer -Cells would enter S phase. -Cells would be unable to enter the S phase

cells would be unable to enter the S phase

A cell with mutated lamins that cannot be phosphorylated in M phase will be unable to____. -disassemble its nuclear lamina at prometaphase. -reassemble its nuclear envelope at telophase. -begin to grow microtubules for spindle assembly. -condense its chromosomes at prophase.

disassemble its nuclear lamina at prometaphase.

A malignant tumor is more dangerous than a benign tumor because its cells ________________. -attack and phagocytose neighboring cells -cause neighboring normal cells to mutate -invade other tissues -proliferate faster

invade other tissues

Embryonic stem cells are such a powerful possible treatment for disease because they are______. -multipotent -derived from fetuses -well understood -pluripotent

pluripotent

an animal cell that has 8 chromosomes in G1 phase. How many of each of the following structures will the cell have during mitosis? sister chromatids / centromeres / kinetochores / centrosomes

sister chromatids:16 centromeres:16 (each sister chromatid has 1) kinetochores: 16 centrosomes: 2 (always 2 centrosomes)

Progression through the cell cycle requires a cyclin to bind to a Cdk because _________. -the binding of a cyclin to Cdk is required for Cdk enzymatic activity -cyclin binding inhibits Cdk activity until the appropriate time in the cell cycle -without cyclin binding, a cell cycle checkpoint will be activated -the cyclins are the molecules with the enzymatic activity in the complex

the binding of a cyclin to Cdk is required for Cdk enzymatic activity