Exam 3 Old Tests Flashcards
If the GC content of a DNA molecule is 60%, what are the percentages of the four bases (G, C, T, A)?
G = 30%, C = 30%, A = 20%, T = 20%
Which of the following represents the lowest level (least compact) of eukaryotic chromosome condensation?
DNA wrapping to form nucleosomes
Okazaki fragments do which of the following?
Are formed during the synthesis of the lagging strand
Small molecules, such as cAMP, that relay signals within the cell are called
Second messengers
T/F: Mutation of the tumor suppressor protein, p53, is a common cause of cancer.
True
T/F: During signal transduction, the original signal is converted to a new signal inside the cell.
True
T/F: Bacterial chromosomes are circular and eukaryotic chromosomes are linear.
True
T/F: Beadle and Tatum provided scientific evidence for the “one gene, one polypeptide”
True
T/F: The sequence of amino acids that results from gene transcription and mRNA translation represents the primary structure of the protein.
True
T/F: Cancer cells have extremely high levels of telomerase enzyme activity.
True
T/F: Receptors for steroid hormones are transmembrane proteins located on target cells.
True
Which of the following is NOT correct concerning telomeres?
Telomeres are areas of the chromosomes which contain many protein-coding genes.
The compartmentalization of areas within eukaryotic cells ____.
- Allows for a smaller overall cell size relative to prokaryotic cells
- Allows them to perform several biochemical functions simultaneously
- Decreases their overall biochemical efficiency compared to prokaryotic cells
- Makes them more susceptible to sudden environmental changes
- Is more complex in animal cells than in plant cells
Allows them to perform several biochemical functions simultaneously
Which of the following represents the lowest level (least compact) of eukaryotic chromosome condensation?
DNA wrapping to form nucleosomes
On the ribosome, during the process of translation, ______.
The charged tRNA enters in the A site.
Point mutations that do not alter the amino acid sequence of the resulting gene product are called ______ mutations.
Silent
A mutation in which of the following regions is least likely to affect gene function?
Intergenic region
If an organism’s diploid number is 12, its haploid number is
6
Consider an organism whose karyotype shows it to have a total of 60 chromosomes. How many chromosomes would be contained in the sperm of this organism?
30
T/F: Glycolysis requires oxygen to produce energy.
False
T/F: Transmembrane proteins are important for allowing large, charged molecules through cell membranes
True
T/F: In the genetic code, each amino acid is specified by only one codon.
False
T/F: DNA replication is semi-conservative.
True
T/F: Proto-oncogenes prevent cancer growth
False
T/F: Check-point proteins are an example of proteins produced by tumor suppressor genes
True
T/F: Individuals with non-functional Nucleotide Excision Repair systems must avoid prolonged sun exposure.
True
T/F: The S-phase of the cell cycle stands for synapsis.
False
T/F: The mitotic spindle in animals is formed by the centrosome and one type of microtubule.
False
T/F: Except for the production of gametes (sperm/eggs) all cell divisions in your body are by mitosis.
True
T/F: The “wobble hypothesis” states that the genetic code is degenerate.
True
T/F: Women are more likely to get X-linked recessive diseases than men.
False
T/F: DNA repair systems are composed of proteins that detect irregularities in DNA structure and then fix the abnormality to prevent mutation.
True
T/F: Somatic cell mutations are heritable
False
T/F: Mitosis is typically followed by the division of the cell into two cells, a process called metastasis.
False
T/F: Receptors for steroid hormones are transmembrane proteins located on target cells.
True
T/F: Synapsis and crossing over are processes that occur only during meiosis.
True
The centromere_____.
is a region of DNA where sister chromatids associate.
What type of regulatory transcription factor binds DNA and increases the transcription of a gene?
an activator exerting positive control
Genes organized into an operon are beneficial to certain bacteria because the operon allows for _____.
- Differential regulation of individual genes that encode proteins with a common function
- Coordinated regulation of a group of genes that encode proteins with a common function
- Separate regulation of individual genes that encode proteins with different functions
- Coordinated regulation of a group of genes that encode proteins with different functions
- Coordinated regulation of a group of proteins involved in numerous cellular activities
Coordinated regulation of a group of genes that encode proteins with a common function.
Liver cells, mammary cells, and skin cells all contain the same genome; however, their respective proteomes vary drastically. This observation is best explained by what phenomenon?
Gene regulation
A researcher determined that a strain of E. coli is producing a shortened version of a protein required for glucose metabolism. What type of mutation could be responsible for this shorter than normal protein?
Nonsense mutation
Sickle-cell anemia is a human disease that occurs as a result of what type of mutation in the b-globin gene?
Missense
A(n) _______ operon is one whose transcription is kept at low levels by effector molecules.
Inducible
This coats single-stranded DNA, preventing them from reforming a double helix
Single stranded binding proteins
This relaxes supercoils
Topoisomerase I
This catalyzes phosphodiester to covalently link nucleotides
Polymerase
This breaks the hydrogen bonds of ds DNA
Helicase
This synthesizes short RNA primers
Primase
This catalyzes a covalent bond between Okazaki fragments
Ligase
Gametes have
One allele for each gene
Which statement describes a process that is NOT involved in control of the cell cycle?
Cytokinesis involves the formation of cleavage furrow to separate the cells.
Place the following events of mitosis in the correct order.
- Sister chromatids align on the metaphase plate
- The cleavage furrow forms
- The nuclear membrane breaks up
- Sister chromatids condense
- Sister chromatids separate
4, 3, 1, 5, 2
Meiosis I produces ______ cells, and meiosis II produces _____ cells.
Two haploid, 4 haploid
A cell’s ability to control their level of gene expression is called
gene regulation
At the lac operon, when lactose is ABSENT:
Transcription is _______ because the repressor protein is bound to ______.
OFF, THE OPERATOR
Which of the following is TRUE concerning a somatic cell mutation?
Only a small group of cells within the organism is affected by the mutation.
Based on the gene and protein sequences that follow, what type of mutation-polypeptide effect has occurred?
Base addition-frameshift
Which of the following types of physical mutagens produces thymine dimer mutations?
Ultraviolet light
_____ can convert proto-oncogenes into oncogenes.
- Gene amplification
- Retroviral insertions
- Chromosomal translocations
- Missense mutations
- All of these choices are correct
All of these choices are correct.
Which of the following statements is FALSE concerning sister chromatids?
- The formation fo sister chromatids doubles the amount of DNA in a cell
- Sister chromatids consist of two identical copies of a single homologue
- Sister chromatids are held together at the centromere by kinetochore proteins
- Sister chromatids are formed during the S phase of the cell cycle
- Sister chromatids separate during telophase
Sister chromatids separate during telophase …is FALSE.
The formation of the bivalent during meiosis _____?
Contributes to the genetic diversity of a species
