Bmb 555 Exam 2

What is the order of the intrinsic pathway of apoptosis

1. Apoptotic stimuli (virus, infection, radiation, etc) 2. Oligomerization of Bax/Bak on mitochondria 3. Mitochondrial membrane permeability increases 4. Release of cytochrome C 5. Assembly of Apoptosome complex 6. Recruitment and activation of caspases 7. Caspase cascade

A diploid cell containing 32 chromosomes will make a haploid cell containing __________ chromosomes

16

what do condensins do

Assemble into compleces on the DNA when phosphorylated by M-Cdk

Kinetochores

Assemble onto chromosomes during late prophase

Which of the following percede the reformation of the nuclear envelope during M phase in animal cells?

Assembly of the contractile ring

in which phase of the cell cycle do cells check to determine whether the DNA is fully and correctly replicated

At the end of G2

You create cells with a version of the origin recognition complex, ORC, that cannot be phosphoryated by S-Cdk and thus cannot be inactivated. Which of the following statements describes the likely consequence of this change on ORC?

Cells will replicate some regions of the genome more than once in a cell cycle

The principal microtubule-organizing center in animal cells is the _________

Centrosome

at the end of DNA replication the sister chromatids are held together by the _________

Cohesins

How does S-Cdk help guarantee that replication occurs only once during each cell cycle?

It phosphorylates and inactivates Cdc6 and the ORC

Levels of Cdk activity change during the cell cycle, in part because (3 reasons)

Cyclin concentrations change during the cycle b/c of gene expression or cyclin degradation; Cdk can be phosphorylated or dephosphorylated ; the levels of Cdk inhibitors change

A cell with nuclear lamins that cannot be phosphorylated in M phase will be unable to

Disassemble its nuclear lamina at pro-metaphase

During sexual reproduction, novel mixtures of alleles are generated. This is because

During meiosis, the segregation of homologs is random such that different gametes end up with different alleles of each gene

All traits that Mendel Studied were dominant. True or False

False

An apoptotic animal cell is chemotactic and this leading to massive cell and tissue death. True or false

False

Cdc 25 dephosphorylation of Wee1 activates the kinase, promoting the G3/M transition. True or False

False

G2 phase is a period of rapid cell growth and protein synthesis during which the cell prepares itself for mitosis. It ends when a threshold level of active cyclin B/Cdk1 complex has been reached. True or False

False

Mutations in somatic cells are passed on to individuals of the next generation. True or false

False

Once a cell decides to enter the cell cycle, the time from start to finish is the same in all eukaryotic cells. True or false

False

The anaphase promoting complex (APC) is continuously active throughout the cell cycle. True or False

False

The cleavage furrow always forms in the middle of the cell. True or False?

False

The loading of the origin recognition complexes (ORCs) is triggered by S-Cdk. True or False

False

The phenotype of an organism reflects all of the alleles carried by that individual. True or False

False

Which of the following does not occur during M phase in animal cells?

Growth of the cell

Using the diagram, which of the following statements about the experiment diagrammed in the figure is true?

If you crossed all the round seeded pea plants from the F2 generation with true breeding wrinkle-seeded pea plants, you would get more rounded seeded pea plants in the next generation than if you crossed all the round seeded pea plants from the F1 generation with true breeding wrinkle seeded pea plants

Disassembly of the nuclear envelope:

Must occur for kinetochore microtubules to form in animal cells

Using the diagram, If you crossed the rounded seeded plants obtained in the F1 generations with a true breeding strain of round seeded plants (figure), how many wrinkle seeded plants would you expect to obtain in the next generation

None

loss of function mutations...

are usually recessive

mitogens are

extracellular signals that stimulate cell division

Cytokinesis in animal cells:

Requires ATP

Sister chromatid seperation occurs because ______________ are destroyed by the APC/C

Securins

Conditional alleles are mutant gene versions encoding proteins that can function normally at the permissive condition but are defective at the restrictive condition. One commonly used condition is temperature. Conditional alleles are especially useful to geneticists because they permit the study of essential genes. At the permissive temperature, the organism lives normally. When the organism is shifted to the non permissive temperature, the effect of inactivating the gene can be studied. Which of the three types of mutation shown in the following figure is most likely to lead to a conditional allele?

Single nucleotide substitution

Which of the following statements about genome wide association studies (GWAS) is false?

Studies using GWAS only examine SNPs that occur very rarely in the population, as those SNPs are most likely to cause disease

What would happen if a cell lacked a protein required for a checkpoint mechanism that operated G2

The cell would enter M phase under conditions when normal cells would not

Imagine meiosis in a diploid organism that only has a single chromosome, it received one copy of this chromosome from each of its parents and the two homologs are genetically distinct. If only a single homologous recombination even occurs during meiosis, which of the following choices below correctly describes the four gametes formed?

Two of the gametes will have chromosomes identical to the chromosomes found in the original diploid cell, while two of the gametes will have chromosomes that are different

Organisms that reproduce sexually

Undergo a sexual reproductive cycle that involves an alternation of haploid cells with the generation of diploid cells

Using the diagram, which of the following statements about the round seeded pea plants obtained in the F2 generation is false (figure)?

We expect 25% of these plants to be homozygous for the seed shape allele

Mitochondria actively participates in animal apoptosis. True or false

True

Programmed cell death occurs by means of an intracellular suicide program. True or false

True

Somatic cells leave no progeny. True or False

True

another bane for the fertilized egg cell is the zygote. True or False

True

A cell that is terminally differentiated will

dismantle the cell-cycle control system.

Progression through the cell cycle requires a cyclin to bind to a Cdk because

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

In the absence of recombination, how many genetically different types of gametes can an organism with six homologous chromosome pairs produce?

64

If you crossed the round seeded plants obtained in the F1 generation with a true breeding strain of wrinkle seeded plants (figure), how any round seeded plants would you expect to obtain in the next generation

50%

Finding co-inheritance of an SNP variant and a disease tells scientists that:

A gene important for causing the disease is linked to the SNP

The formation of a bivalent during meiosis ensures that

All 4 sister chromatids remain together until the cell is ready to divide

Using the diagram, Which plants could be considered as a true breeding strain for the seed shape phenotype?

All of the wrinkle seeded plants

Which of the following reasons was essential for mendel's law of independent assortment?

All the traits that mendel examined involved genes that did not display linkage

Which event does not usually occur during interphase?

The nuclear envelope breaks down; duplicated chromosomes pull apart

Which of the following reasons was essential for Mendel to disprove the theory of blended inheritance

The traits that mendel examined involved an allele that was dominant and an allele that was recessive

Meiosis involves a single round of DNA replication followed by two successive cell divisions. True or False

True

There are organisms that go through meiosis but do not undergo recombination when forming haploid gametes. Which of the following statements correctly describes the gametes produced by such an organism? (assume that these organisms are diploid, chromosomes are genetically distinct as typically found in the wild, and that these organisms have more than one chromosome)

This organism could potentially produce 2^n genetically distinct gametes where n is the haploid number of chromosomes

A single nondisjunction event during meiosis will result in the production of two normal gametes if it occurs during meiosis 2. True or false

True

After the first meiotic cell division, cells are produced that contain same number of chromosomes as somatic cells. True or false

True

Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria. True or false

True

Apoptosis differs from necrosis in that necrosis causes cells to swell and burst, whereas apoptotic cells shrink and condense. True or false

True

During meiosis, the paternal chromosomes pair with the maternal chromosomes before lining up at the metaphase plate. True or False

True

Cells in the G0 state

have entered this arrest state from G1 and do not divide, but they can reenter the cell cycle

The retinoblastoma protein blocks cells from entering the cell cycle by

inhibiting the trancription of genes (eg. cyclins) required for entry into S phase

The G1 DNA damage checkpoint:

involves the stabilization of p53 and the inhibition of cyclin-Cdk complexes by p21

The phosphorylated retinoblastoma protein allows cells to enter the cell cycle by

releasing the transcription regulators needed to the transcription of genes required for entry into S phase

The concentration of mitotic cyclin (M cyclin):

rises gradually during G2 and falls toward the end of M phase as a result of ubiquitylation and degradation