ap central ch10-12, all of ch 10-12 of redas ap centrals combined

Directions: Each group of questions below concerns an experimental or laboratory situation or data. In each case, first study the description of the situation or data. Then choose the one best answer to each question following it. . . . . glutamine-glutamine-glutamine . . . . . . serine-serine-serine . . . Which of the following messenger RNA sequences could code for both of the two amino acid sequences above, simply by a shift in the reading frame?

. . . AGCAGCAGCAGC . . .

If 2n = 48 for a particular cell, then the chromosome number in each cell after meiosis would be

24

The following questions refer to the following DNA strand and table of codons. The mRNA transcribed from the DNA would read

5' AUC AAG UUU GGC GCA UUG UUA 3'

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. (A) Transcription(B) Translation(C) Transformation(D) Replication(E) Reverse transcription Process in which a protein is assembled at a ribosome

B

Which of the following correctly explains where DNA replication will begin on the strand oriented 5′→3′, reading from left to right?

DNA replication will be initiated immediately to the left of the RNA, since DNA polymerase requires an RNA primer.

The process depicted in the image above is best summarized by which of the following descriptions?

During meiosis, crossing over leads to recombination of alleles between homologous chromosomes.

Table 1 shows the stage and number of cells and chromosomes per cell at the end of the stage in a 2n=24 organism. Which of the following statements correctly describes the chromosomes in each daughter cell at the end of meiosis I?

Each daughter cell contains 12 chromosomes, each composed of two chromatids. Each chromosome is one of a pair of homologous chromosomes from the parent cell, with the other homologue found in the other daughter cell.

The events listed below generally take place during meiosis. I. Synapsis occurs.II. Crossing-over is completed.III. Condensation of chromosomes begins.IV. Separation of homologous chromosomes begins. Which of the following is the correct sequence of these events?

III, I, II, IV

A model that represents a process occurring in a cell of a particular organism is shown in Figure 1. Figure 1. Process occurring in a cell Which of the following correctly explains the process shown in Figure 1?

Initiation of transcription is occurring because a strand of RNA is being produced from a DNA template strand.

Figure 1. Model of crossing over between homologous chromosomes, indicating crossing over rate of selected loci. During prophase I replicated homologous chromosomes pair up and undergo synapsis. What testable question is generated regarding synapsis and genetic variability by Figure 1 ?

Is the distance between two gene loci related to crossover rate?

Scientists have found that DNA methylation suppresses crossing-over in the fungus Ascobolus immersus. Which of the following questions is most appropriately raised by this specific observation?

Is the level of genetic variation in the gametes related to the amount of DNA methylation observed?

Based on the universal genetic code, which of the following represents the correct polypeptide that will result from translation of the mRNA molecule shown, beginning with the first available start codon?

Met - Val - Thr - Lys - Phe - Gly - His

Both mitosis and meiosis begin with a parent cell that is diploid. Which of the following best describes how mitosis and meiosis result in daughter cells with different numbers of chromosomes?

Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.

A model of a process involving nucleic acids is shown in Figure 1. Which of the following best explains what process is represented in Figure 1 ?

New DNA strands are being synthesized in the 5′ to 3′ direction from their DNA templates.

Which of the following best describes an event during step 2 in the simplified model above?

Noncoding sequences are removed from a newly synthesized RNA molecule.

Which of the following best describes a characteristic of DNA that makes it useful as hereditary material?

Nucleotide bases in one strand can only be paired with specific bases in the other strand.

Erwin Chargaff investigated the nucleotide composition of DNA. He analyzed DNA from various organisms and measured the relative amounts of adenine (A), guanine (G), cytosine (C), and thymine (T) present in the DNA of each organism. Table 1 contains a selected data set of his results. Which of the following statements best explains the data set?

Since the %A and the %T are approximately the same in each sample, adenine and thymine molecules must pair up in a double-stranded DNA molecule.

Figure 1 represents part of a process essential to gene expression. Which of the following best explains what strand X represents?

The antisense strand, because it is serving as a template

Which of the following occurs during mitosis but not during meiosis I ?

The chromatids of each chromosome are separated.

Figure 1 represents part of a process that occurs in eukaryotic cells. There are untranslated regions ((UTR) in this sequence. Which of the following best explains the process represented by Figure 1 ?

The enzyme-regulated processing of pre‑mRNA into mature mRNA

Which of the following best explains why ligase is required for DNA replication?

The lagging strand cannot be replicated continuously, and ligase is needed to join the fragments.

Figure 1 shows some relevant details of a model of how a deoxynucleotide, in this case dTMP, is added to a growing strand of DNA. Figure 1. Model showing details of adding a deoxythymidine monophosphate (dTMP) nucleotide to a growing strand of DNA The features of this model provide evidence for which explanation of why all growing strands are synthesized in a 5′ to 3′ direction?

The phosphate group, attached to the 5′ carbon of the dTMP, forms a covalent bond with the oxygen atom attached to the 3′ carbon of the growing strand.

Figure 1. Protein synthesis in a prokaryotic cell Which of the following best describes a characteristic of the process shown in Figure 1 that is unique to prokaryotes?

The translation of the mRNA is occurring while the mRNA is still being transcribed.

Which of the following best describes the cells that result from the process of meiosis in mammals?

They are genetically different from the parent cell

Analysis of DNA sequences from two individuals of the same species results in a greater estimate of genetic variability than does analysis of amino acid sequences from the same individuals because

different DNA sequences can code for the same amino acid