BIOCHM 1090 Lecture Notes - Lecture 29: Guanine, Cell Nucleus, Adenine
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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. |
1.
__________ are fairly small organelles that provide a safe place within the cell to carry out certain biochemical reactions that generate harmful, highly reactive oxygen species. These chemicals are both generated and broken down in the same location.
Lysosomes |
Endosomes |
Peroxisomes |
Nucleosomes 2. Biologists cannot possibly study all living species. Instead, they try to understand cell behavior by studying a select subset of them. Which of the following characteristics are useful in an organism chosen for use as a model in laboratory studies?
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