AP Biology Unit 4 Test

A group of cells is assayed for DNA content immediately following in a sample of animal cells: chlorophylls, organelle, density, picograms of DNA, cell wall components, and enzymatic activity. Which would you expect to increase significantly from M to G1? A. organelle density and enzymatic activity B. cell wall components and DNA C. chlorophyll and cell walls D. organelle density and cell walls

A

A major group of G protein-coupled receptors contains seven transmembrane alpha helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on he cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. The coupled G protein most likely interacts with this receptor A. at the loop between H5 and H6 B. along the interior margin C. at the NH3 end D. at the COO- end

A

A new mutation that arose in one copy of gene X in a somatic cell resulted in the formation of a tumor. Which of the following pieces of evidence best describes how the new mutation directly caused the tumor? A. Protein X normally stimulates cell division, and the mutation created an overactive version of protein X. B. Protein X normally activates a growth hormone receptor, and the mutation decreased the stability of protein X. C. Protein X normally prevents passage through the cell cycle, and the mutation created an overactive version of protein X. D. Protein X normally regulates gene expression, and the mutation created an underachieve version of protein X that blocked the cell cycle.

A

DNA replication occurs A. during the S phase of the cell cycle. B. as the nuclear envelope breaks down in early mitosis C. during mitosis but not during meiosis D. only in cells destined to become gametes

A

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents? A. It has half the amount of DNA as the cell that began meiosis. B. It has the same number of chromosomes but each of them has different alleles than another cell from the same meiosis. C. It has half the chromosomes but twice the DNA of the originating cell. D. It ha one-fourth the DNA and one-half the chromosomes as the originating cell.

A

If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following? A. at most, 2 alleles for that gene B. up to 18 chromosomes with that gene C. up to 18 genes for that trait D. a haploid number of 9 chromosomes

A

Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubular. Surprisingly, this stops mitosis. Specifically, Taxol must affect A. the formation of the mitotic spindle. B. anaphase C. the S phase of the cell cycle D. chromatid assembly

A

The last part of the metamorphosis of a tadpole to an adult frog results in the disappearance of the tail. this stage of development most likely occurs by A. cells of the tail dying and nutrients being absorbed and reused by the body B. shedding of the tail so energy is not spent on maintenance of an unneeded part. C. bilateral division of the tail and fusion with the developing bird limbs. D. individual cells of the tail migrating to the developing gonads.

A

Which of the following is true for the signaling system in an animal cell that lacks the ability to produce GTP? A. It would not be able to activate and inactivate the G Protein on the cytoplasmic side of the plasma membrane. B. It could activate only the epinephrine system. C. It would be able to carry out reception and transduction but would not be able to respond to a signal. D. It would us ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.

A

Which of the following most likely would be an immediate result of growth factor binding to its receptor. A. protein kinase activity B. adenylyl cyclase activity C. GTpase activity D. protein phosphotase activity

A

You have the technology necessary to measure each of the following in a sample of animal cells: chlorophylls, organelle density, picograms of DNA, cell wall components, and enzymatic activity. Which would you expect to increase significantly from M to G1? A. organelle density and enzymatic activity B. cell wall components and DNA C. chlorophyll and cell walls D. organelle density and cell walls

A

A major group of G protein-coupled receptors contains seven transmembrane alpha helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on he cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. Where would you expect to find the carboxyl end? A. at the exterior surface B. at the cytosol surface C. connected with the loop at H5 and H6 D. between the membrane layers

B

A researcher examining a root tip observes a plant cell with condensed sister chromatids, kinetochores with attached microtubules, and individual chromosomes that are aligned at the equatorial plate of the cell. Which of the following best describes what is the next process will be in the cell? A. Homologous chromosomes (each with two sister chromatids) will move toward opposite poles of the cell. B. Paired chromosomes will separate, and the new daughter chromosomes will move toward opposite poles of the cell. C. The nuclear envelope will break down, and the spindle will begin to form. D. The chromatin will decidedness, and the daughter cell will enter interphase.

B

For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable? A. It attacks cells that are density dependent. B. It interferes with rapidly dividing cells. C. It is safe enough to limit all apoptosis. D. It does not alter metabolically active cells.

B

For a newly evolving protist, what would be the advantage of using eukaryote-like cell division rather than binary fission? A. Binary fission would not allow for the formation of new organisms. B. Cell division would allow for the orderly and efficient segregation of multiple linear chromosomes C. Cell division would be faster than binary fission D. Cell division allows for lower rates of error per chromosome replication.

B

Several organisms, primarily protists, have what are called intermediate mitotic organization. What is the most probable hypothesis about these intermediate forms of cell division? A. They may be more closely related to plant forms that also have unusual mitosis B. They represent existing species that have retained from an ancestral species some of the evolutionary steps toward complete mitosis. C. They rely on totally different proteins for the processes they undergo. D. They represent a form of cell reproduction which must have evolved completely separately from those of other organisms.

B

Specis X reproduces asexually by fission and species Y reproduces sexually. Consider that all other relevant characteristics are similar between these species. When the environment gradually changes, then A. species X and Y will have an equal chance of surviving B. species Y should have a better chance of surviving than species X C. species X should have a better chance of surviving than species Y D. neither species should have an advantage in surviving since organisms often become extinct when the environment changes.

B

The mechanism of action of many common medications involves interfering with the normal pathways that cells use to respond to hormone signals. Which of the following best describes a drug interaction that directly interferes with a signal transduction pathway? A. A medication causes the cell to absorb more of a particular mineral, eventually poisoning the cell. B. A medication enters the target cell and inhibits an enzyme that normally synthesizes a second messenger. C. A medication enters the target cell's nucleus and acts as a mutagen. D. A medication interrupts the transcription of ribosomal RNA genes.

B

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A. It must be human. B. It must be a primate. C. Its gametes must have 23 chromosomes. D. It must be sexually reproducing.

C

Apoptosis refers to cell death and A. is always biologically detrimental to an organism B. is merely the accumulation of genetic errors. C. can be programmed and is essential to normal development D. is a failure in the translation of transcription mechanism

C

Besides the ability of some cancer cells to over-proliferate, what else could logically result in a tumor? A. enhanced anchorage dependence B. changes in the order of cell cycle stages C. lack of appropriate cell death D. inability to form spindles

C

Cell communication is critical for the function of both unicellular and multicellular eukaryotes. Which of the following is likely true of cell signaling? A. Cell signaling uses the highest molecular weight molecules found in living cells. B. Cell signaling has largely been replaced by other cell functions in higher mammals. C. Similar cell signaling pathways in diverse eukaryotes are evidence of conserved evolutionary processes. D. Cell signaling functions mainly during early developmental stages.

C

If chemical signals in the cytoplasm control the progression of the cell to the M phase of the cell cycle, then fusion of cell in G1 with a cell in early M phase would most likely result in the A. replication of chromosomes only in the G1 cell. B. exciting of both cells from the cell cycle and into the G0 phase. C. condensation of chromatin in preparation of nuclear division in both cells. D. transfer of organelles from the G1 cell to the cell in the M phase.

C

In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common? A. Length and position of the centromere only B. Length, centromere position, and staining pattern only C. Length, centromere position, staining pattern, and traits coded for by their genes D. Length, centromere position, staining pattern, and DNA sequences

C

Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. Such molecules must have which of the following properties? A. They must persist throughout the cell cycle. B. They must be removed before meiosis can begin. C. They must be removed before sister chromatids or homologous chromosomes can separate. D. They must reattach to chromosomes during G1.

C

Which of the following is the best explanation for the fact that most transduction pathways have multiple steps? A. Most of the steps were already in place because they are steps in other pathways. B. Multiple steps in a pathway require the least amount of ATP. C. Multiple steps provide for greater possible amplification of a signal. D. Each individual step can remove excess phosphate groups from the cytoplasm.

C

Which of the following is true of a species that has a chromosome number of 2n = 16? A. The species is diploid with 32 chromosomes. B. The species has 16 sets of chromosomes per cell. C. Each cell has eight homologous pairs. D. During S phase of the cell cycle there will be 32 separate chromosomes.

C

Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins? A. Phosphatase activity B. G protein-coupled receptor binding C. Receptor tyrosine kinase activity D. Adenylyl cyclase activity

C

Why do bacteria undergo binary fission instead of mitosis? A. Mitosis does not produce identical new cells. B. Binary fission is a type of sexual reproduction that is used for new organisms. C. Mitosis is not needed to break down the nuclear envelope and organize the chromosomes. D. Mitosis requires more energy to complete.

C

A major group of G protein-coupled receptors contains seven transmembrane alpha helices. The amino end of the protein lies at the exterior of the plasma membrane. Loops of amino acids connect the helices either at the exterior face or on he cytosol face of the membrane. The loop on the cytosol side between helices 5 and 6 is usually substantially longer than the others. If you wish to design an experiment to block the G protein-coupled receptor interaction, the clock would preferentially affect which of the following? A. the exterior (cytoplasmic) end of the receptor B. the cytosolic end of the receptor C. the phospholipid's transmembrane domain D. the amino acid sequence in the binding site for the G protein

D

A research team began a study of a cultured cell line. Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away? A. The cells originated in the nervous system. B. The cells are unable to form spindle microtubules C. They have altered series of cell cycle phases D. The cells show characteristics of tumors.

D

An accident has injured your Achille's tendon (muscle). Would you expect this tendon to regrow? Why or why not? A. Yes, the tendon will regrow, p53 signals will activate the G1 stage. B. Yes, the tendon will regrow. It has been in an inactive (G0) to conserve nutrients and energy. C. Yes, the tendon will regrow because it is a living tissue. D. Yes, the tendon will regrow provided proper signals are received by the cells.

D

How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? A. They have twice the amount of cytoplasm and half the amount of DNA. B. They have half the number of chromosomes and half the amount of DNA. C. They have the same number of chromosomes and half the amount of DNA. D. They have half the number of chromosomes and one-fourth the amount of DNA.

D

How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid number of 8 (2n = 8)? A. 2 B. 4 C. 8 D. 16

D

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels range from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA? A. G0 B. G1 C. S D. G2

D

When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? A. receptor B. relay molecule C. transducer D. signal molecule

D

Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells? A. 4 B. 8 C. 16 D. 32

D (2^5)