Genetics test 3 real

Intercalating agents such as ethidium bromide function as mutagens to
A. promote transitions
B. attach to purines, causing distorion
C. remove amine groups
D. fit between stacked bases and disrupt replication
E. add ehyl or methyl groups

The components of a chromosome include one long DNA molecule and
A. carbohydrates
B. steroids
C. phospholipids
D. RNA
E. proteins

Sometimes a part of the genome moves from chromosome to chromosome. This is known generally as a
A. duplication
B. translocation
C. inversion
D. transposable element
E. deletion

Which of the following is not true about DNA polymerase?
A. it can only travel in the 5 to 3 direction
B. it can reconstruct the 3 end of each newly made DNA strand.
C. It cannot begin 5 end of a new strand without a primer
D. It can replace RNA primer with DNA at the 5 end.

An integrated copy of a termperate bacteriophage is called a prophage.
a. True
b. False

The duplication of the triplet sequence CGG resultin in elongation or breakage of the X-chromosome is termed
A. rhys syndrome
B. unequal crossing over
C. Fragile X syndrome
D. Huntington's disease
E. Barr-eyed

Which of the following are properties of telomeres?
A. All of the choices are correct
B. prevent the loss of DNA throught incomplete replication
C. consist of special repetitive DNA sequence
D. cap the ends of each chromosome
E. number of repeats varies with cell type

Robertsonian translocations result from which of the following?
A. unequal crossing over occurs during meiosis
B. fusion of two small chromosomes end-to-end such that a double centromere occurs
C. breaks occur at or near the centromeres of two acrocentric chromosomes, followed by the reciprocal exchange of broken parts
D. a part of one chromosome becomes attached to a non-homologous chromosome

Individuals who are deletion heterozygotes have a greatly increased risk of losing both copies of certain genes and developing cancer. One such disease in humans is
A. retinoblastoma
B. triplolethal
C. scarlet eyes
D. cataracts

Chromosome banding patterns can be used for which of the following?
A. to locate genes
B. to reveal the cause of certain genetic diseases
C. to analyze chromosomal differences between species
D. All of the choices are correct

The enzyme that some organisms use to replicare DNA at the 5' ends of chromosomes is called
A. DNA ligase
B. telomerase
C. replicase
D. DNA polymerase

A mutation in which parts of two nonhomologous chromosomes change places is called a
A. translocation
B. deletion
C. transition
D. insertion
E. transversion

Which of the following is not usually seen when a cell loses telomerase activity?
A. Telomeres shorten slightly with each cell division
B. In the immune system, certain capacity for protection is gradually lost.
C. After 30-50 divisions, cells show signs of senescence and then die.
D. Many normal somatic cells gain the ability to divide indefinitely.

By weight, chromatin consists roughly of
A. 1/3 dna and 2/3 acidic proteins
B. 1/4 dna, 1/4rna, 1/4 histones, 1/4 nonhistones
C. 1/3 dna, 1/3 histones, and 1/3 basic proteins
D. 1/3 dna, 1/3 histones, and 1/3 nonhistones

We spread 10⁹ bacteria on a plate with 25ug streptomycin/ml. four colonies grew. These colonies contain bacteria that are
A. wild type
B. resistant to streptomycin
C. resistant to all antibiotics
D. able to grow in unusual circumstances
E. None of the above

The hydrolysis of a purine base from the deoxyribose-phosphate backbone is called
A. deletion
B. depurination
C. replica plating
D. excision repair
E. deamination

Histones and DNA have a strong attraction for each other because
A. DNA is positively charges and histones are negatively charges
B. both DNA and proteins are hydrophobic
C. DNA is negatively charges and histones are positively charges
D. like substances share common charges
E. None of the above

Down syndrome can result from
A. three copies of chromosome 21
B. a translocation of a part of chromosome 21
C. a reciprocal translocation between any two autosomes
D. both A and B
E. A,B, and C are all correct

From DNA research, sites of transcription and therefore most of the genes along the length of the chromosome appear to be found in
A. centromeric regions
B. constitutive heterochromatin
C. euchromatin
D. heterochromatin

Which of the following is not an aneuploidy?
A. tetraploid
B. trisomy
C. monosomy
D. tetrasomy

Electroporation is the use of high-voltage and high calcium salt to force foreign DNA into bacteria.
a. True
b. False

Choose the statement that is most correct regarding the rII- strain of T4 that Benzer studied.
A. produces smaller plaques than wild type
B. produces smaller plaques; grows in E. coli K, not in E. coli B
C. produces larger plaques; grows in E. coli K, not in E. coli B
D. produces larger plaques, grows in E. coli B, not in E. coli K
E. produces larger plaques, grows in both E. coli K and E. coli B

What would happen if a transposon were to "jump" into the origin of replication of the bacteria genome?
A. Transposon would express its gene constituitively.
B. Transposon would be replicated like the genome.
C. None of the choices would occur.
D. Transposon would inactivate the origin and no DNA replication would be possible
E. Transposon would "jump" to another location

Indicate the correct order for one round of infection by bacteriophase T4.
1. Lysis of host cell.
2. Phage proteins and DNA synthesized, host DNA degraded.
3. Assembly of phage within host cell.
4. Phage body enters host cell.
5. Phage injects DNA into host cell.
A. 5,1,2,3
B. 4,2,3,1
C. 1,2,3,4,5
D. 5,2,3,1
E. 4,5,3,1

Which of the following is not a role ascribed to nonhistone proteins found in chromatin?
A. chromosome segregation
B. replication
C. nucleosome packers
D. structural

Sometimes a piece of one chromosome attaches to another chromosome. This is known as
A. inversion
B. duplication
C. deletion
D. translocation
E. None of the above

Specialized transduction allows phages to pick up only adjacent DNA from the host chromosome during the transition from the lysogenic to the lytic cycle.
a. True
b. False

Down syndrome is an example of triplody
a. True
b. False

The results of the Luria Delbruck experiment indicated that
A. a low level of any bacterial population is naturally resistant to phage
B. bacteria are naturally resistant to phage
C. bacteria become resistant to phage by random spontaneous mutation prior to exposure
D. phage mutate to produce large plaques with sharp edges
E. bacteria become resistant to phage by mutation when exposed to phage

In mammalian cells, replication proceeds
A. unidirectionally from many origins
B. bidirectionally from only one origin
C. unidirectionally
D. bidirectionally

____ are small circular pieces of DNA frequently found in bacteria.
A. transposons
B. centromeres
C. baceriophage
D. plasmids
E. insertion sequences

Red-green-color-blindness is more common in males than females because
A. the red pigment gene is on the X chromosome; the green is on an autosome
B. the green pigment gene is on the X chromosome; the red is on an autosome
C. the rhodopsin gene is on the X chromosome
D. both the red and the green pigment genes are on the X chromosome
E. both the red and the green pigment genes are on the autosome

Which of the following grows on minimal media only if supplemented?
A. auxotrophic
B. cistron
C. prototrophic
D. transposable element

In the Luria Delbruck experiment, the bacteria +phage plates showed
A. all plates had the same number of resistant colonies
B. some plates had no resistant colonies; the plates that had resistant colonies all had the same number of resistant colonies
C. all plates had some resistant colonies; some had very many
D. some plates had no resistant colonies; a few plates had very many resistant colonies
E. phage cause mutation to occur in some of the plates but not in others

The first level of compaction of DNA consists of
A. histones, DNA, and nonhistones covalent bonding
B. tight coiling of DNA with nucleosomes into higher order structure
C. DNA winding around histones to form small nucleosomes
D. high level compaction into metaphase-type chromosomes

rhizobia are bacteria that live symbiotically in the roots of leguminous plants. It has been proposed that some enzymes in the bacteria were derived from the plant. What mechanism would most likely have been involved in this?
A. generalized transduction
B. transformation
C. conjugation
D. specialized transduction

The conseqeuence to a bacterial cell of a mutation that inactivated the enzyme that methylates the A of the sequence GATC in newly made DNA would be
A. failure to carry out replication
B. failure to distinguish old and new DNA during mismatch repair
C. inactivation of certain metabolic genes
D. failure to correct thymine dimmers
E. decrease in the mutation rate

Cohesins are a multisubunit protein complex that functions to
A. hold sister chromatids together
B. ensure that proper chromosome arm length is maintained
C. allow easy karyotyping
D. develop meiotic chromosome replication
E. all of the above

Which of the following adds material to the genome?
A. inversions
B. duplications
C. deletions
D. translocations
E. None of the above

Two bacteria grow together. One appears to donate DNA to the other. One of the bacteria contains a bacteriphage that is normally quiescent but occasionally forms a plaque. What sort of genetic exchange is more likely to be occuring?
A. conjugation
B. electroporation
C. transduction
D. transformation

The lysogenic cycle of phage production results in bacterial cell lysis.
a. True
b. False

The structure of a protein that involves the interaction between two distinct polypeptide chains is
A. primary structure
B. secondary structure
C. tertiary structure
D. quaternary structure

Which of the following removes materials from the genome?
A. inversions
B. duplications
C. deletions
D. translocations
E. None of the above

Unequal crossing over results in
A. a production of eggs containing Y chromosomes
B. an exchange between nonhomologous chromosomes
C. a repair of UV-induced damage
D. a creation of deletions and duplications