Chapter 14-16

The synthesis of RNA in a prokaryotic cell specifically begins at the

+1 DNA site.

Place the following steps of prokaryotic transcription in order, from first (1) to last (7)?

1. Holoenzyme binds to the -35 consensus sequence 2. Sigma dissociates (comes apart) from the core RNA polymerase complex. 3. Hydrogen bonds between the DNA strands break around the -10 site. 4. Core RNA polymerase reads the DNA template and incorporates ribonucleotides into a complementary RNA strand. 5. Core RNA polymerase dissociates (comes apart) from the DNA. 6. Core RNA polymerase reaches the termination signal. 7. Transcription bubble closes.

15; A particular protein is 450 amino acids in length. Therefore, the instructions to make this protein consists of __________ DNA bases.

1350

How many potential reading frames are present in an mRNA molecule? Enter only a number/numeral in the provided box

3

14; Which of the following nucleotide sequences represents the complement to the DNA strand 5' TTA CTG AGT 3' ?

3' AAT GAC TCA 5'

15; What would be a possible anticodon that would be found on a tRNA bound to alanine (ALA)?

3' CGG 5'

Which of the following sequences could represent the anticodon of a tRNA molecule that is attached to arginine (ARG)?

3' GCC 5'

14; How many hydrogen bonds would be found between a double-stranded DNA molecule if one strand contained 5' ACC GAT TAC CCG 3' ?

31

14; Which RNA primer contains only pyrimidines?

5' CCU UUC UCU 3'

Consider the following DNA molecule: 5' GTA ACC GGA 3' 3' CAT TGG CCT 5' If this molecule were transcribed, what would be the resulting RNA molecule?

5' GUA ACC GGA 3'

15; If you have a 3-letter alphabet and make words which are 4 letters long, how many unique words can you make?

81

14; How many hydrogen bonds would form between the DNA sequence ATTG and its complement on the other strand in a double helix?

9

14; In an analysis of the nucleotide composition of DNA, which of the following will be found?

A + C = G + T

15; What is the relationship among DNA, a gene, and a chromosome?

A chromosome contains hundreds of genes which are composed of DNA.

Which statement applies to both DNA replication and transcription?

A phosphodiester bond is formed between a 5' phosphate group and a 3' hydroxyl group.

15; B is an intron between two exons A and C. Which representation best describes how this region of mRNA will appear after it is transcribed and processed by splicing?

A-C

14; If a certain species is found to have DNA composed of 31% cytosine, what would be the percentages of the other three bases?

Adenine = 19% Thymine = 19% Guanine = 31% A=T G=C

What mechanism plays a role in generating protein diversity?

Alternative splicing.

14; In the image below, each letter indicates a single end of the newly synthesized strand. Which letters indicate ends that would have RNA primers on them? Select all that apply.

B

14; Why is an RNA primer needed for DNA replication?

Because DNA polymerse can add nucleotides to a growing strand of DNA, but cannot begin a strand

14; Which of the following single-stranded DNA sequences contains ONLY pyrimidines?

CTCCTCT

14; What is the function of DNA ligase?

Connect Okazaki fragments to form a continuous strand of DNA.

14; Nicked segments of single-stranded DNA are linked by

DNA ligase.

Select all of the events that occur within the nucleus

Eukaryotic transcription Splicing Modification of the RNA ends

Eukaryotic DNA is closely associated with many proteins. What is responsible for shuffling the proteins out of the way of the transcription machinery?

Facilitates chromatin transcription

Which of the following statements describes one mechanism of transcription termination?

Formation of stem-loop/hairpin structures in the RNA sequence.

14; If the GC content of a DNA molecule is 60%, what are the percentages of the four bases (G, C, T, A)?

G = 30%, C = 30%, A = 20%, T = 20%

14; What kind of chemical bonds are found between paired bases of the DNA?

Hydrogen

14; During the transcription of a certain protein, an extra cytosine was placed into a gene region, throwing off the correct amino acid sequence. What type of mutation occurred?

Insertion

14; What enzyme catalyzes the formation of a covalent bond between an adjacent 5' phosphate of one DNA fragment and a 3' OH of another DNA fragment?

Ligase is responsible for forming the phosphodiester bond between adjacent DNA fragments.

14; If a prokaryotic cell experienced a mutation that eliminated DNA polymerase's 3' to 5' exonuclease activity, what part of DNA synthesis would be affected?

Proofreading would not occur.

16; The binding of ________ is required for transcription to start.

RNA polymerase

14; Which statement correctly describes the role of RNA during DNA replication?

RNA provides a 3' OH for DNA polymerase to add nucleotides to.

14; Which statement correctly explains the chemical basis of Chargaff's rules?

Specific purines and specific pyrimidines will always be found opposite each other in the two opposing DNA strands.

15; During translation, chain elongation continues until what happens?

Stop codons occur.

14; Which aspect of eukaryotic DNA structure makes telomerase activity necessary?

The double-stranded DNA molecule is linear.

14; During semi-conservative replication, which step must occur first?

The hydrogen bonds found between the nitrogenous bases must be broken.

14; In the image below, which letter represents the position where DNA polymerase would attach the next nucleotide?

The next nucleotide would be added at "D". DNA polymerase attaches nucleotides to the free 3' OH of the nucleotide chain.

15; Which of the following basis is never found in RNA?

Thymine

Provide one sequence that would be specifically recognized by a release factor: Enter only 3 letters in the provided box.

UAA

14; In a double stranded molecule of DNA, the ratio of purines : pyrimidines is:

always 1:1

14; Which of the following molecules does not form part of DNA?

amino acid

15; "Recognition" of the codons on the mRNA involves their binding to:

anticodons on the tRNA's

16; Nucleosomes inhibit

assembly of transcription factor complexes

14; The fact that that adenine and thymine are always present in equal amounts in DNA is explained by:

complementary base-pairing

16; Which of the following are involved in posttranscriptional control?

control of RNA splicing control of RNA transport control of RNA stability

14; Which of the following is a nucleotide found in DNA?

deoxyribose + phosphate group + cytosine

15; Your muscle and bone cells are different because

different genes are switched on and off in each type of cell.

16; Enhancers are

distant sites where regulatory proteins bind

Which the following is not involved in enhancing RNA stability?

histones

14; What type of bonds are located between the nucleotides found in opposing DNA strands (i.e. the strands that are across from each other)?

hydrogen

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

increased transcription of a distant gene

14; The genetic information in cells consists of the sequential arrangement of:

nucleotides in nucleic acids.

16; Cancer causing genes are called ________.

oncogenes

15; What type of chemical bonds are constructed by the ribosomes?

peptide bonds

14; What type of bonds are located between the nucleotides found in the same DNA strand ?

phosphodiester

16; In order for a gene to be transcribed, RNA polymerase must have access to the DNA helix and be able to bind to the genes

promoter

16; Post-translational modifications of proteins can affect which of the following?

protein function

16; Post-translational control refers to:

regulation of gene expression after translation

15; In protein synthesis, the actual linking of amino acids to make protein occurs in the ___________ of cells.

ribosomes

14; After the DNA strands have been separated from each other, what enzyme/protein prevents the strands from reforming the double helix?

single-stranded binding proteins

15; What is an anticodon part of?

tRNA

16; What are epigenetic modifications?

the addition of reversible changes to histone proteins and DNA

What gene region is responsible for helping the RNA polymerase determine where to begin transcribing DNA into RNA?

the promoter

16; Prokaryotic cells lack a nucleus. Therefore, the genes in prokaryotic cells are:

transcribed and translated almost simultaneously transcriptionally controlled because translation begins before transcription ends

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

transcriptional posttranscriptional translational posttranslational epigenetic

14; Following the immediate completion of DNA synthesis, the two identical DNA strands represent

two sister chromatids.