AP Biology Final

Control of gene expression in eukaryotic cells occurs at which level(s)

D. Epigenetic and transcriptional, transtional, and post-translational levels

If glucose is absent but lactose is present, the lac operon will be:

A. activated

What would happen if the operator sequence of the lac operon contained a mutation that prevented the repressor protein from binding the operator?

B. in the absence of lactose, the lac operon will be transcribed

What would happen if the operator sequence of the trp operon contained a mutation that prevented the repressor protein from binding to the operator?

In the presence of tryptophan, the genes trpA-E will be transcribed

What are epigenetic modifications?

the addition of reversible changes to histone proteins and DNA

Which of the following is true of epigentic changes

B. they allow movement of histones

The binding of what is required for transcription start?

RNA polymerase

What would be the outcome of a mutation that prevented DNA binding protein from being produced?

B. decreased transcription because enhancers would not be able to bind to transcription factors

What will result from the binding of a transcription factor to an enhancer region?

B. increased transcription of a distant gene

At metaphase I, homologous chromosomes are connected only at what structures?

A. Chiasmata

The sequence that signals the end of transcription is called the :

D. terminator

Which feature promoters can be found in both prokaryotes and eukaryotes?

TATA Box

Which of the following features distinguishes eukaryotic transcription from bacterial transcription?

C. Eukaryotic transcription and translation do not take place at the same time

What processing step enhances the stability of pre-tRNAs and pre-rRNAs?

B. Methylation

What are introns?

D. untranslated DNA sequences in a gene

What is often the first amino acid added to a polypeptide chain?

C. methionine

In prokaryotic cells, ribosomes are found in/on the:

A. cytoplasm

What would happen if the 5' methyl guanosine was not added to an mRNA?

A. the transcript would degrade when the mRNA moves out of the nucleus to the cytoplasm.

The RNA world hypothesis proposes that the first complex molecule was RNA and it preceded protein formation. Which major function of the ribosomal RNA supports the hypothesis?

A. rRNA has catalytic properties in the large subunit and it assembles proteins

Consider a cross to investigate the pea pod texture trait, involving constricted or inflated pods. Mendel found that the traits behave according to a dominant/recessive pattern in which inflated pods were dominant. If you performed this cross and obtained 650 inflated pod plants in the F_2 generation bred from true-breeding stock, approximately how many constricted pod plants would you expect to have?

C. 217

The ABO blood groups in humans are controlled by the IA, IB, and i alleles. The IA allele encodes the A blood group antigen, IB encodes B, and i encodes O. Both A and B are dominant to O. if a heterozygous blood type A parent (iAi) and a heterozygous blood type B parent (iBi) mate, one quarter of their offspring will have AB blood type (iAiB_ in which both antigens, are expressed equally. Therefore, the ABO blood groups are an example of ________.

D. multiple alleles and co dominance

In pea plants smooth seeds (S) are dominant to wrinkled seeds (s). In a genetic cross of two plants that are heterozygous for the seed shape trait, the Punnett square is shown. What is the missing genotype?

D. ss

Four o clock flowers may be red, pink or white. In the crossing of a true breeding red and true breeding white plants, all the offspring are pink. Use a Punnett square to determine the correct genotype of the offspring if the red parent has genotype RR and the white parent has genotype rr.

C. Rr only

Which cellular process underlies Mendel's law of independent assortment?

A. chromosomes align randomly during meiosis.

While studying meiosis, you observe that gametes receive one copy of each pair of homologous chromosomes and one copy of the sex chromosomes. This observation is the physical explanation of Mendel's law of _____________.

D. segregation

When the expression of the one gene pair masks or modifies the expression of another, the genes show _______________.

B. epistasis

During which phase does the second round of genetic variation occur during meiosis?

B. metaphase I

What is a disadvantage of sexual reproduction over asexual forms of reproduction?

A. Half the population is capable of carrying offspring.

Explain how the orientation of homologous chromosomes during metaphase I of meiosis contributes to greater variation of gametes.

A. The random alignment of homologous chromosomes at the metaphase plate ensures the random destination of the chromosomes in the daughter cells.

Compare the three main types of life cycles in multicellular organisms and give an example of an organism that employs each.

A. In a diploid dominant cycle, the diploid multicellular stage is present, as in humans. Haploid dominant life cycle have a multicellular haploid stage, as in fungi. In alternation of generations, both haploid dominant and diploid dominant stages are multicellular and alternate, as in plants.

One of the ways that sexual reproduction enhances the diversity of offspring from the same parents is through a process called crossing over. What entities does this occur between during prophase I ?

D. non sister chromatids of homologous chromosomes

There are three sources of genetic variation in sexual reproduction. Which is not considered random?

A. All are random

Which one of three types of life of sexually reproducing organisms does not have a multicellular haploid stage?

B. Diploid dominant

What are identical copies of chromatin held together by cohesion at the centromere called?

D. sister chromatids

Which of the following events does not occur during some stages of interphase?

D. separation of sister chromatids

What would be the outcome of blocking S-phase of interphase?

B. DNA replication would not occur

What do you call changes to the order of nucleotides in a segment of DNA that codes for a protein?

C. gene mutations

Human papillomavirus can cause cervical cancer. The virus encodes E6, a protein that binds p53. Based on this fact and what you know about p53, what effect do you think E6 binding has on p53 activity?

D. E6 binding marks p53 for degradation

What is a gene that codes for a positive cell cycle regulator called?

C. proto-oncogenes

Which eukaryotic cell cycle events are missing in binary fission?

C. karyokinesis

Which of the following components is not used by both plants and cyanobacteria to carry out photosynthesis?

B. Chloroplasts

Dopamine is a neurotransmitter in the brain that causes long term responses in neurons and binds to a G-protein linked receptor. Which of the following chemicals would you expect to increase in concentration after dopamine binds its receptor?

B. cAMP

The hormone insulin binds to a receptor tyrosine kinase on the surface of target cells. which of the following steps takes place before phosphorylation of tyrosine residues?

C. the receptor forms a dimer

How does NF-kB induce gene expression?

D. Phosphorylation of the inhibitor IkB dissociates the complex between it and NF-kB allowing NF-kB to enter the nucleus and stimulate transcription.

Apoptosis can occur in a cell under what conditions?

A. when a cell is infected by a virus

B. When a cell is damaged

C. when a cell is no longer needed

D. All of the above

Answer: D

Cancer cells that continue to divide when defective often show changes in what cellular function?

A. Apoptosis

Epinephrine mediates the fight- or flight response of the body one of the effects is to increase the amount of glucose available to muscles. What does the signaling pathway triggered by epinephrine cause to occur in liver cells?

A. activation of metabolism

Yeast releasing mating factor can be classified as which type of signal?

C. paracrine

What is a part of grana ?

D. thylakoids

What is the function of carotenoids in photosynthesis?

D. they limit chlorophyll absorption

What can be calculated from wavelength measurement of light?

C. the amount of energy of a wave of light

Which molecule must enter the Calvin cycle continually for the light independent reactions to take place?

A. CO_2

Which statement correctly describes carbon fixation?

A. the conversion of CO_2 into an organic compound

Carbon in the form of CO_2, must be taken from the atmosphere and attached to an existing organic molecule in the Calvin cycle. Therefore, the carbon is bound to the molecule. The products of the cycle only occur because of the added carbon. What are the products of the Calvin cycle and what is regenerated?

A. the product of the Calvin cycle is glyceraldehyde-3 phosphate and RuBP is regenerated.

How do desert plants prevent water loss from the heat, which would compromise photosynthesis?

B. By using CAM photosynthesis and by opening of stromal pores during the night

When comparing humans (or in Drosophila) are X linked recessive traits observed more frequently in males, in similar numbers between males and females, more frequently in females, or is the frequency different depending on the trait? Why?

A in more males than females

Which recombination frequency corresponds to perfect linkage and violates the law of independent assortment?

A. 0

Which recombination frequency corresponds to independent assortment in and the absence of linkage?

C. 0.5

Based on the diagram, which of the following statements is true?

A. recombination of the body color and red/cinnabar eye alleles will occur more frequently than recombination of the alleles for wing length and aristae length.

Which of the following codes describes position 12 on the long are of chromosome 13?

B. 13q12

Assume a pericentric inversion occurred in one of two homologs prior to meiosis. The other homolog remains normal. During Meiosis, what structure, if any, would these homologs assume in order to pair accurately along their lengths?

C. a loop