Biol 302 Exam 2

Which of the following statements concerning splicing is NOT TRUE? a. introns are the regions of eukaryotic genes that code for protein; exons are excised by splicing b. special proteins called snRNPs are involved in splicing c. the spliceosome is a molecular machine that controls splicing d. alternative splicing can result in multiple distinct proteins expressed from a single gene e. all of the above are true

a. introns are the regions of eukaryotic genes that code for protein; exons are excised by splicing

Mediator is a complex of proteins that: a. links distant transcription regulators with basal transcription machinery b. links TFIID to RNA polymerase II c. links RNA polymerase II to the ribosome d. links the new RNA strand to the DNA template e. links the mRNA to the ribosome

a. links distant transcription regulators with basal transcription machinery

Which of the following DNA molecules is self-complementary? a. 5'- ACGACTAG -3' b. 5'- AGCTAGCT -3' c. 5'- ATGCGGAT -3' d. 5'- AGCTGATC -3' e. 5'- ACCTGATC -3'

b. 5'- AGCTAGCT -3'

In the picture below, ______ corresponds to the leading strand in the right hand replication fork and _____ correspons to the first synthesized okazaki fragment of the lagging strand in the left-hand replication fork. a. B,H b. B,C c. A,H d. A,C e. B,E

b. B, C

An enucleated egg from an adult cow, when injected with the nucleus from a differentiated cell from another adult cow then implanted into a foster mother will be a clone of: a. The cow that donated the egg b. The cow that donated the nucleus c. the cow that served as the foster mother d. all of the above e. none of the above

b. The cow that donated the nucleus

Which of the following statements is likely true for transcription factors that coordinately regulate many genes? a. They can active but not repress any of the target genes b. They typically bind to upstream regulatory regions in the target genes c. All of the target genes must be on the same chromosome d. No other transcription factors will bind to the target genes e. They always bind to exons in the target genes

b. They typically bind to upstream regulatory regions in the target genes

Operons: a. are commonly found in mammalian cells b. contain an operator site for binding of regulatory proteins c. contain only 1 gene d. can only be regulated by repressor proteins e. all of the above are true

b. contain an operator site for binding of regulatory proteins

Which of the following statements about transcription factors is true? (used on bonus questions) a. they usually interact with the minor groove of DNA b. they form non-covalent bonds with DNA c. they can only stimulate transcription d. they can only repress transcription e. they disrupt the hydrogen bonds that hold the double helix together

b. they form non-covalent bonds with DNA

The distinct characteristics of different cell types in a multicellular organism result mainly from the differential regulation of the _______. a. replication of specific genes in S-phase b. transcription of genes by RNA polymerase II c. transcription of genes by RNA polymerase I d. DNA repair machinery e none of the above

b. transcription of genes by RNA polymerase II

DNA polymerase: a. Uses RNA as a template b. Adds nucleotides to the 5' end of a new strand c. Has exonuclease activity to fix mistakes d. Does not function on the lagging strand e. All of the above

c. Has exonuclease activity to fix mistakes

Multidrug resistant bacterial strains arise because of: (used on bonus questions) a. Homologous recombination b. miRNA transfer between bacteria c. New plasmid acquisition via conjugation d. Loss of resistance genes e. All of the above

c. New plasmid acquistion via conjugation

mRNA is synthesized by: a. RNA polymerase I b. DNA polymerase c. RNA polymerase II d. primase e. none of the above

c. RNA polymerase II

Prokaryotic RNA polymerase has a special subunit that is important for transcription initiation. This subunit is called: a. TFIIH b. TATA Box c. Sigma factor d. operon e. spliceosome

c. Sigma factor

Which of the following statements regarding DNA and RNA is true? a. both DNA and RNA are always double stranded b. both DNA and RNA contain the sugar ribose c. both DNA and RNA contain adenine, cytosine and guanine d. the synthesis of both DNA and RNA is said to be semi-conservative e. none of the above

c. both DNA and RNA contain adenine, cytosine and guanine

DNA replication occurs only: a. During G2 b. Outside the nucleus c. during S-phase d. during M phase e. None of the above

c. during S-phase

Repair by homologous recombination occurs most often: (used on bonus questions) a. During G2 b. Outside the nucleus c. during S-phase d. during M phase e. None of the above

c. during S-phase

Under which conditions would the trp operon be transcribed? a. high glucose, low lactose b. high tryptophan c. low tryptophan d. high lactose, low glucose e. none of the above

c. low tryptophan

Which is true of mutations? a. Can drive evolution if they occur in somatic cells b. are transient changes in DNA sequence c. often occur because of failure of the replication or repair machinery d. Are always detrimental to the cell or organism e. Are always associated with the change in gene expression

c. often occur because of failure of the replication or repair machinery

Which type of RNA forms the core of the ribosome? a. mRNA b. tRNA c. rRNA d. small RNAs e. none of the above

c. rRNA

Given the following template strand of DNA, what is the sequence of the RNA molecule that would be made from it? 5'-GGTCCATTGGAG-3' a. 5'- CTCCAATGGACC-3' b. 5'- CCAGGTAACCTC-3' c. 5'- CCAGGUAACCUC-3' d. 5'- CUCCAAUGGACC-3' e. None of the above

d. 5'- CUCCAAUGGACC-3'

Repressors can reduce transcription initiation by _______. a. Sequestering activators in the cytoplasm b. Binding to enhancers and preventing activators from binding c. altering chromatin structure d. All of the above e. none of the above

d. All of the above

Which of the following is not required for transcription? (also asked on extra credit questions) a. Double stranded DNA molecule b. RNA polymerase c. Ribonucleotides d. Primase e. none of the above

d. Primase

Ribosomes are large molecular machines composed of: a. RNA and lipid b. RNA and DNA c. Protein and DNA d. Protein and RNA e. DNA and lipid

d. Protein and RNA

Nucleosomes are important because? a. They provide a means of compacting the DNA in the nucleus b. They provide a regulatory node for gene expression c. They prevent DNA falling apart d. a and b are correct e. a and c are correct

d. a and b are correct

Reverse transcriptase: a. is often used in the lab to generate "cDNA" from mRNA b. converts RNA to DNA c. Is an enzyme carried by viruses d. all of the above e. none of the above

d. all of the above

Under which of the following conditions would the lac operon be transcribed? a. high glucose, low lactose b. high lactose, high glucose c. low tryptophan d. high lactose, low glucose e. none of the above

d. high lactose, low glucose

Aminoacyl tRNA synthetases a. remove amino acids from tRNA after translation b. add amino acids to the growing peptide chain during translation c. convert mRNA to tRNA d. link amino acids to tRNA before translation e. function during transcription

d. link amino acids to tRNA before translation

In order for a change in DNA sequence to result in a heritable change in the reproductive success of a population the change must: a. occur in an exon of a protein coding gene b. be large enough to significantly alter the chromosome c. occur in a somatic cell d. occur in a germ-line cell e. none of the above

d. occur in a germ-line cell

_______ refers to the copying of one strand of DNA to make a complementary RNA molecule while _______ refers to the process in which the information encoded in RNA is used to synthesize a protein. a. translation, transcription b. replication, translation c. replication, transcription d. transcription, translation e. none of the above

d. transcription, translation

Which of the following proteins change the spacing of the nucleosome? a. RISC complexes b. sliding clamp c. DNA polymerases d. Primases e. Chromatin remoldeling complexes

e. Chromatin remodeling complexes

Distal binding sites for eukaryotic transcription factors are called: (Used again for bonus questions) a. promoters b. activators c. repressors d. domains e. enhancers

e. enhancers

All chromosome rearrangements are detrimental to the organism. true/false

false

An RNA polymerase muse wait until a gene has been fully transcribed by the polymerase before it can bind to the promoter and initiate transcription. true/false

false

Epigenetic inheritance is typically influenced by changes in the base pair sequence of DNA in chromosomes. true/false

false

In eukaryotes mutations are most likely to occur in exons. true/false

false

NHEJ is more precise than HR. true/false

false

A gene that resides close to a region of heterochromatin may be expressed to a lesser extent than if the same gene were located farther away from the region of heterochromatin. true/false

true

A major difference between transcription in eukaryotic cells and prokaryotic cells is that in prokaryotic cells, several genes may be transcribed as a single RNA molecule. true/false

true

Alternative splicing increases the protein coding potential of the genome. true/false

true

Mismatch repair machinery recognizes a distortion in the double helix. true/false

true

Mutations that alter the third base pair in triplet codons are less likely to be harmful. true/false

true

Primase is needed to initiate DNA replication on both the leading strand and the lagging strand. true/false

true

Some amino acids are coded for y more than one triplet codon. true/false

true

The RISC complex regulates mRNA levels in response to miRNA expression. true/false

true