AP Bio Final Review From DNA to Protein

B

*5' - E1 I1 E2 I2 E3 I3 E4 = 3'* Which components of the eukaryotic pre-mRNA given above will also be found in mRNA in the cytosol? a) 5' - I1 I2 I3 - 3' b) 5' - E1 E2 E3 E4 - 3' c) 3' - E1 E2 E3 E4 - 5' d) 3' - I1 I2 I3 - 5' e) 5' - E1 I1 E2 I2 E3 I3 E4 - 3'

E

A culture of E. Coli bacteria are actively replicating. You decide to replace the thymine nucleotides in the culture with radioactive thymine that will act as a tag for you to trace the DNA replication pattern. Knowing that replication is semiconservative, what would you expect from the DNA after one round of replication? a) one of the daughter molecules, but not the others, would have radioactive DNA b) neither of the two daughter molecules would be radioactive c) all four bases of the DNA would be radioactive d) radioactive thymine would pair with nonradioactive guanine e) one strand of DNA in both daughter molecules would be radioactive

B

A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that A) none of the proteins in the cell will contain phenylalanine. B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. C) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons. D) the ribosome will skip a codon every time a UUU is encountered. E) none of the options will occur; the cell will recognize the error and destroy the tRNA.

A

A particular triplet of bases in the template strand of DNA is 5' - AGA - 3'. The corresponding codon for the mRNA transcribed is a) 3' - UCU - 5' b) 3' - AGA - 5' c) 5' - TCT - 3' d) 5' - UCU - 3' e) either UGA or TCA, depending on wobble in the first base

C

A transfer RNA (#1) attached to the amino acid lysine enters the ribosome. The lysine binds to the growing polypeptide on the other tRNA (#2) in the ribosome already. *Where does tRNA #2 move to after this bonding of lysine to the polypeptide?* a) A site b) P site c) E site d) directly to the cytosol

A

Adenine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be guanine? a) 12% b) 24% c) 38% d) 76% e) it cannot be determined from the information provided

leading strand

During DNA replication, the daughter strand that is replicated continuously (following the DNA helicase) is known as the ______________

Composed of a sugar, phosphate, and nitrogenous base. In a double helix shape with two antiparrallel sugar phosphate backbones twisting around each other. The sugar binds the phosphate to the nitrogenous bases which make up the rungs of the ladder. Each rung is composed of a complementary base pair between a single purine (G or A) and a single pyrimidine (T or C), binded by hydrogen bonds

Explain the structure of the DNA molecule

B

If a cell were unable to produce histone proteins, which of the following would be a likely effect? a) there would be an increase in the amount of "satellite" DNA produced during centrifugation b) the cell's DNA couldn't be packed into its nucleus c) spindle fibers would not form during prophase d) amplification of other genes would compensate for the lack of histones e) pseudogenes would be transcribed to compensate for the decreased protein in the cell

C

If a polypeptide is made of 60 amino acids, how many nucleotides would be present in the mRNA strand that codes for its production? a) 60 b) 20 c) 180 d) 120 e) 100

E

In comparing DNA replication with RNA transcription, which of the following is true only of replication? a) it uses RNA polymerase b) it makes a new molecule form its 5' end to its 3' end c) the process is extremely slow d) the process occurs in the nucleus of a eukaryotic cell e) the entire template molecule is represented in the product

transcription; translation

In eukaryotic cells, _____________ occurs in the nucleus, resulting in the production of mRNA. The mRNA then travels to the cytoplasm and is decoded to form a polypeptide in a process known as ___________

B

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts? a) DNA contains sulfur, whereas protein does not b) DNA contains phosphorus, whereas protein does not c) DNA contains nitrogen, whereas protein does not d) DNA contains purines, whereas protein includes pyrimidines e) RNA includes deoxyribose, whereas DNA includes ribose sugars

E

Of the following, which is the most current description of a gene? a) a unit of heredity that causes formation of a phenotypic characteristic b) a DNA subunit that codes for a single complete protein c) a discrete unit of hereditary information that consists of a sequence of amino acids d) a DNA-RNA sequence combination that results in an enzymatic product e) a DNA sequence that is expressed to form a functional product: either RNA or polypeptide

missense mutation- a single nucleotide is wrongly inserted, altering a single protein in the sequence. If that protein's characteristics aren't similar to the original's, changes in the function can be evident nonsense mutation- a dingle nucleotide is changed resulting in a premature stop codon, ending the sequence early

Sometimes there are errors that occur during DNA replication. If these errors are not repaired they can alter the DNA sequence. *List two examples of point mutations and describe howthey can affect the protein product of that gene*

A frameshift mutation is when an extra nucleotide is inserted or one is taken out, shifting which codons are paired from that point on and altering which proteins are produced

Sometimes there are errors that occur during DNA replication. If these errors are not repaired they can alter the DNA sequence. *What is a frameshift mutation and how does it affect the protein product of a gene?*

B

There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that a) competitive exclusion forces some tRNAs to be destroyed by nucleases b) the rules for base pairing between the third base of a codon and tRNA are flexible and create a phenomenon called wobble c) many codons are never used, so the tRNAs that recognize them are dispensable d) the DNA codes for all 61 tRNAs but some are then destroyed

True

True or false: A DNA template strand is always read in the 3' to 5' direction because the synthesis of a new strand of DNA or RNA must occur in the 5' to 3' direction

False

True or false: Chargaff found that the amounts of the four bases vary from species to species, but the amount of adenine always equals the amount of guanine and the amount of thymine always equals the amount of cytosine

True

True or false: DNA helicase breaks the hydrogen bonds between complementary base pairs during DNA replication, therefore creating a replication fork

False

True or false: Every mRNA codon codes for an amino acid

False

True or false: tRNA is necessary for transcription to occur

A

What is the function of topoisomerase? a) relieving strain in the DNA ahead of the replication fork b) elongating new DNA at a replication fork by adding nucleotides to the existing chain c) adding methyl groups to bases of DNA d) unwinding of the double helix e) stabilizing singe-stranded DNA at the replication fork

C

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? a) it synthesizes RNA nucleotides to make a primer b) it catalyzes the lengthening of telomeres c) it joins Okazaki fragments together d) it unwinds the parental double helix e) it stabilizes the unwound parental DNA

B

Which component is not directly involved in translation? a) mRNA b) DNA c) tRNA d) ribosomes e) GTP

C

Which of the following does not occur in prokaryotic gene expression, but does in eukaryotic gene expression? a) mRNA, trNA, and rRNA are transcribed b) RNA polymerase binds to the promoter c) A poly-A tail is added to the 3' end of an mRNA and a cap is added to the 5' end d) transcription can begin as soon as translation has begun even a little e) RNA polymerase requires a primer to elongate the molecule

B

Which of the following statements is true about protein synthesis in prokaryotes? a) extensive RNA processing is required before prokaryotic transcripts can be translated b) translation can begin while transcription is still in progress c) prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate cellular organelles d) unlike eukaryotes, prokaryotes require no initiation or elongation factors

E

While attempting to develop a pneumonia vaccine, Frederick Griffith accidentally discovered the ability for bacteria to undergo transformation. What does the term transformation refer to? a) the creation of a strand of DNA from an RNA molecule b) the creation of a strand of RNA from a DNA molecule c) the infection of cells by a phage DNA molecule d) the type of semiconservative replication shown by DNA e) uptake of external DNA into a cell