AP Bio Unit 6

A nucleotide consists of:

-Nitrogen base -5 carbon sugar -Phosphate group

Okazaki fragments occur on the______________________ and are bonded together by_________________

-lagging strand -ligase

If a DNA molecule is found to be composed of 40% thymine, what percentage of guanine would be expected.

10%

If a parental DNA strand reads: 5' - CAATAGCA - 3' what would the complementary strand read?

3' - GTTATCGT - 5'

RNA polymerase moves in which direction along the DNA (or reads the DNA in which direction)?

3' to 5' along the template strand

Choose the option that best describes nucleotide pairing in DNA.

Cytosine will form three hydrogen bonds with guanine. Adenine will form two hydrogen bonds with thymine.

Which of the following must happen first in order for DNA replication to occur?

DNA is unwound by the enzyme helicase

Why do Okazaki fragments form?

DNA polymerase can only move in the 3' to 5' direction.

After mixing a heat-killed, phosphorescent strain of bacteria with a living non phosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait?

Descendants of the living cells are also phosphorescent.

The Trp operon is a coordinately regulated group of genes (trpA-trpE) that are required for tryptophan biosynthesis in E. coli. Based on the figure above, which of the following correctly describes the regulation of the Trp operon?

In the presence of tryptophan, the repressor is active and binds to the Trp operator, preventing RNA polymerase from transcribing the operon.

Which of the following best explains the distribution of lactase persistence in the areas shown in Figure 1 ?

Mutations conferring lactase persistence likely arose independently in different geographic areas and offered a selective advantage.

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.

The backbone of DNA is composed of...

Sugar and phosphate

Camptothecin is a five-membered ring alkaloid (nitrogenous organic compound) that targets topoismerase, thereby causing topoisomerase to lose functionality. Camptothecin belongs to a class of drugs know as topoisomerase inhibitors. Due to its ability to target topoisomerase, camptothecin is commonly used as a cancer treatment; specifically it is used to treat cancer of the lungs, colon, and ovaries. Knowing this information, which explanation below best predicts the effect that camptothecin has on cancer cells?

The DNA of the cancer cells will contain more breaks and damage as a result of camptothecin, thus resulting in the cell cycle stopping at the G2 checkpoint, triggering apoptosis.

Retroviruses have an RNA genome. HTLV-1 is a lysogenic retrovirus that establishes a latent infection in human cells. By which of the following mechanisms does infection by a retrovirus such as HTLV-1 most likely cause long-lasting genetic changes to host cells?

The RNA viral genome is reverse transcribed into DNA that integrates into the host genome.

Which of the following best explains how some cells of an individual produce and secrete a specific enzyme, but other cells of the same individual do not?

The cells transcribe and translate different combinations of genes, leading to the production of different sets of proteins.

Which of the following can best be used to justify why the GFP is expressed by E. coli cells after transformation with the plasmid?

The presence of arabinose in the nutrient agar activated the expression of the genes located downstream of the ara operon regulatory sequences.

Based on the information in Table 1, which of the following best predicts a key difference in prokaryotes and eukaryotes with regard to transcription and translation?

The two processes will occur simultaneously in prokaryotes but not eukaryotes.

Which of the following is a correct statement about mutations?

They are a source of variation for evolution.

What is a restriction digest?

Using enzymes to cut DNA at specific locations

Which of the following best describes the arrangement of the sides of the DNA molecule?

antiparalell

What is PCR technique?

cell free, automated technique where tiny pieces of DNA can be rapidly copied

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

During the infection cycle for a typical retrovirus, such as HIV, which uses RNA as genetic material, the genetic variation in the resulting population of new virus particles is very high because of

errors introduced in the DNA molecule through reverse transcription

What enzyme is responsible for breaking the hydrogen bond between the two DNA strands during replication?

helicase

The parts of a gene that do NOT code for amino acids in a protein are called

introns

That is the role of operons in prokaryote gene expression?

it accounts for the regulation of the gene activity in response to the needs of the cells

In the lac operon model, the genes within the operon will be expressed if

lactose is present in the cell

The banding patterns of the DNA fragments reveal that

the mother cannot be the biological parent of all three children

In eukaryotes, proteins that help the RNA polymerase bind to the regulatory region for transcription are called?

transcription factors