BIOCHEM 2EE3 Study Guide - Final Guide: Thymine, Methyl Group, Aminoacyl-Trna
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What step in DNA replication precedes the pairing of complementary bases?
A. | polymerization of DNA. | |
B. | formation of the histone core. | |
C. | mitotic division. | |
D. | separation of the two strands. | |
E. | joining of the two strands. |
In eukaryotes, transcription occurs in the
A. | ribosome. | |
B. | mitochondria. | |
C. | cell membrane. | |
D. | cytoplasm. | |
E. | nucleus. |
Normal human body cells contain how many chromosomes?
A. | 46 | |
B. | 22 | |
C. | 23 | |
D. | 44 | |
E. | 42 |
Hershey and Chase performed an experiment in which they used radioactive isotopes to phosphorus and sulfur to label different components of bacterial viruses. Their results clearly showed that
A. | the viruses did not contain protein. | |
B. | genetic material normally contains radioactive isotopes. | |
C. | the viruses did not contain DNA. | |
D. | protein was entering into the infected bacteria. | |
E. | DNA was entering into the infected bacteria. |
A package of histones with DNA wrapped around them forms spherical structures called
A. | nucleosomes. | |
B. | lysosomes. | |
C. | ribosomes. | |
D. | nucleoli. | |
E. | chromatin. |
DNA replication
A. | does not require proteins. | |
B. | is constantly happening in a cell. | |
C. | occurs in G1 of interphase. | |
D. | takes place in the nucleus of the cell. | |
E. | occurs in the cytoplasm of the cell. |
The two subunits of the ribosome join during
A. | promotion of transcription. | |
B. | initiation of translation. | |
C. | termination of transcription. | |
D. | termination of translation. | |
E. | elongation. |
DNA replication of a single DNA molecule is referred to as semiconservative because
A. | each of the two DNA molecules will consist of one parental strand and one newly synthesized strand. | |
B. | all the DNA strands in the two DNA molecules will have both parental and newly synthesized DNA. | |
C. | it results in two nonidentical DNA molecules. | |
D. | of the two DNA molecules, one is made up totally of parental DNA, while the other is entirely newly synthesized DNA. | |
E. | one DNA strand is replicated continuously, while the other must be replicated discontinuously. |
The bases are bonded to what part of the backbone of the DNA molecule?
A. | the 4â carbon atom of the sugar molecule. | |
B. | the 3â carbon atom of the sugar molecule. | |
C. | the 5â carbon atom of the sugar molecule. | |
D. | the 1â carbon atom of the sugar molecule. | |
E. | the 2â carbon atom of the sugar molecule. |
13. The arms of a human and the wing of a bat are _________________ structures, composed of the same bones that have been modified for different functions.
a. | analogous |
b. | vestigial |
c. | homologous |
d. | convergent |
14. Xeroderma pigmentosum is an autosomal recessive genetic disorder. People who are homozygous for the disease-causing allele have skin that is damaged by exposure to ultraviolet radiation; this can lead to skin cancer at an early age. The mutation that causes this disorder is in a gene that functions:
a. | to repair DNA by excising (removing) nucleotides damaged by UV light. |
b. | in lysosomes, to break down lipids that otherwise accumulate in the nervous system. |
c. | to produce the UV blocking pigment melanin in the skin cells |
d. | in red blood cells to carry oxygen to the skin. |
15. The Amish are a religious sect descended from a small group of colonists who came to the United States over 200 years ago. Their religious beliefs have kept them isolated from society. The Amish have a much higher than average incidence of both polydactyly (extra fingers and toes) and dwarfism in their communities. This is most likely explained by:
a. | inheritance of acquired characters. |
b. | the founder effect. |
c. | disruptive selection. |
d. | natural selection. |
16. In the structure of DNA that Watson and Crick proposed, the sides of the "ladder" of the DNA molecule are always the same distance apart, making the molecule a constant width. This occurs because when the bases hydrogen bond to form the rungs of the "ladder", a:
a. | purine always pairs with a pyrimidine. |
b. | purine always pairs with a purine. |
c. | pyrimidine always pairs with a pyrmidine. |
d. | The structure of the double helix is not determined by how the bases pair. |
17. The RNA transcript of DNA that travels to the cytoplasm, carrying the instructions to make a protein, is called:
a. | rRNA. |
b. | tRNA. |
c. | mRNA. |
d. | RNA polymerase. |
18. When DNA is replicated, the error rate is approximately one error for every 10,000 nucleotides copied. However, that error rate is reduced to only 1 error for every 1 billion nucleotides. The DNA sequence is "corrected" by:
a. | repeating S phase to see if the error rate is lower the second time around. |
b. | enzymes that proofread the DNA and repair errors. |
c. | messenger RNA during the process of transcription. |
d. | Any errors made during DNA replication cannot be corrected. If errors are detected after S phase, the cell is destroyed. |
19. Mendel's principle of segregation says that:
a. | when gametes are formed, each gamete receives only one allele for a particular gene. |
b. | some genes are dominant to others. |
c. | a testcross must be used to determine the genotype of an organism with a dominant phenotype. |
d. | all of the above |
20. Tay-Sachs disease is lethal before reproductive age, but the allele persists in Louisiana French Canadians because:
a. | it is a dominant allele. |
b. | new mutations causing this disease are common in that population. |
c. | it is not expressed in the phenotype of heterozygous individuals. |
d. | the disease is contagious and can be transmitted by nonheritable means. |
21. Physical features that are similar in organisms which are not closely related to each other are most likely a result of ____________. A good example of this is the similarities seen between some marsupial and placental mammals.
a. | natural selection. |
b. | adaptation to similar environments |
c. | convergent evolution |
d. | All of the above phrases can be used to correctly fill this blank. |
22. In humans, which of the following sex chromosome compliments could be found in males?
a. | XY |
b. | XX |
c. | Y |
23. The proteins that are associated with eukaryotic chromosomes:
a. | help to package the DNA within the nucleus. |
b. | are involved in gene expression, through binding with the DNA. |
c. | may be replicating or transcribing the DNA. |
d. | All of these are true of proteins that are associated with eukaryotic chromosomes. |
24. A sequence of DNA nucleotides that contains the information to produce a single protein is a(n):
a. | codon. |
b. | gene. |
c. | polypeptide. |
d. | anticodon. |