Biology Practice Exam 3
14) What unwinds the DNA double helix?
Helicase
5) Cytosine makes up 32% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
18
11) A particular triplet of based in the template strand of DNA is 5'ACG3'. The corresponding codon for the mRNA transcribed is ______________.
3'UGC5'
10) During RNA processing, which of the following are added to help(s) to stabilize mRNA by inhibiting its degeneration?
5' cap and poly (A) tail
8) A DNA template strand reads 3'TTACGGAC5'. During DNA Replication, what specific complementary DNA sequence will be added to the growing new strand?
5'AATGCCTG3'
12) Which one of the following point mutations is most likely to have no effect on the final protein product?
A silent mutation
17) For the following mRNA strand, indicate the correct polypeptide sequence that will be produced:
ALA-SER-ALA-ARG
6) Suppose you are provided with an actively dividing culture is E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
DNA in both daughter cells would be radioactive.
16) What adds DNA nucleotides at the 3' end using a DNA template strand to pair complementary bases?
DNA polymerase
4) A new DNA strand elongates only in the 5' to 3' direction because...
DNA polymerase begins adding nucleotides at the 5' end of the template.
2) What kind of chemical bond is found between paired bases of the DNA double helix?
Hydrogen
25) Natural selection is not based on...
Individuals adapt to their environments and, thereby, evolve.
13) In translation, what is the function of the release factor (RF)?
It binds to the stop codon in the A site in place of a tRNA.
20) What effect will the mutation described in question 19 have on the polypeptide strand that is synthesized from it?
It will change an amino acid. The amino acid "Asp" will be changed to "Glu."
24) Characteristics that an organism acquires during their lifetime are NOT normally inherited by offspring. Which of the following scientists came up with the idea of "inheritance of acquired characteristics?"
Jean-Baptiste de Lamarck
15) What repairs any breaks in the sugar-phosphate backbone; joint Okazaki fragments?
Ligase
19) A point mutation occurs, changing the DNA template strand from 3'CTG5' to 3'CTC5'. What type of mutation is this?
Missense
26) A group of individuals of the same species that live in the same local area and can interbreed to produce fertile offspring is a _________________________.
Population
18) Complete the sentence with the most correct answer. One gene codes for ____________.
Protein
21) Which of the following describe best describes Chargaff's base-pair bonding rules?
Pyrimidines always bind to purines.
28) A large population of field mice is decimated by the flooding of their habitat. Over 90% of the mice die in the flood. Now, only a few mice are left. By chance, only brown-furred mice survived, and all of the black-
The bottleneck effect
7) During DNA replication, the DNA strand that is synthesized as short Okazaki fragment is called the _________________________.
The lagging strand
1) What determines the nucleotide sequence of the newly synthesized strand of DNA replication?
The nucleotide sequence of the template strand.
3) DNA replication is called semi conservative because...
The two resulting DNA molecules each have one new DNA strand and one old strand from the origional DNA molecule.
22) An RNA copy of the DNA template strand is made. This describes the process of ________________________, Which takes place in the ________________________.
Transcription; nucleus.
23) The type of RNA that brings the correct amino acid to the ribosome so it can be added to the growing polypeptide chain is __________________ RNA.
Transfer
9) Which of the following processes does not occur within the nucleus?
translation
