Question 1

The structures of the four bases in DNA are given in Figure 5-42.  
Figure 5-42
A.Which are purines and which are pyrimidines?
B.Which bases pair with each other in double-stranded DNA?

Accepted Answer

The answer of The structures of the four bases in...

Question 2

Gene A, which is normally expressed, has been moved by DNA recombination near an area of heterochromatin.None of the daughter cells produced after this recombination event express gene A, even though its DNA sequence is unchanged.Explain this observation.

Accepted Answer

The answer of Gene A, which is normally expressed, has...

Question 3

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
bands extended kinetochore
chromatin homologous nonhomologous
chromosomes hybridization
condensation karyotype
In eukaryotic __________, DNA is complexed with proteins to form __________.The paternal and maternal copies of human Chromosome 1 are __________, whereas the paternal copy of Chromosome 1 and the maternal copy of Chromosome 3 are __________.Cytogeneticists can determine large-scale chromosomal abnormalities by looking at a patient's __________.Fluorescent molecules can be used to paint a chromosome, by a technique that employs DNA __________, and thereby to identify each chromosome by microscopy.

Accepted Answer

The answer of For each of the following sentences, fill...

Question 4

Match between columns Premises: All functional DNA sequences inside a cell code for protein products. Gene sequences correspond exactly to the respective protein sequences produced from them.
Each strand of DNA contains all the information needed to create a new double-stranded DNA molecule with the same sequence information.
Gene expression is the process of duplicating genes during DNA replication.

Accepted Answer

The Answer of False and True is...

Question 5

Because hydrogen bonds hold the two strands of a DNA molecule together, the strands can be separated without breaking any covalent bonds.Every unique DNA molecule "melts" at a different temperature.In this context, T_m (melting temperature) is the point at which two strands separate, or become denatured.Order the DNA sequences listed below according to relative melting temperatures (from lowest T_m to highest T_m).Assume that they all begin as stable double-stranded DNA molecules.Explain your answer. A.GGCGCACC B.TATTGTCT C.GACTCCTG D.CTAACTGG

Accepted Answer

The answer of Because hydrogen bonds hold the two strands...

Question 6

Match between columns Premises: In many eukaryotic genomes, genes contain additional, interspersed, noncoding sequences.
Chromosomes of different length emit different wavelengths of light, making them appear colored under the microscope. Eukaryotic genes are distributed across multiple DNA molecules, which can be packaged into linear or circular chromosomes.
For the majority of genes in the eukaryotic genome, the final product is an RNA molecule.

Accepted Answer

The Answer of True and False is...

Question 7

Origins of replication typically have a relatively high number of A-T base pairs.How does this sequence feature relate to the function of these DNA regions?

Accepted Answer

The answer of Origins of replication typically have a relatively...

Question 8

A.Define a "gene."
B.Consider two different species of yeast that have similar genome sizes.Is it likely that they contain the same number of genes? A similar number of chromosomes?

Accepted Answer

The answer of A.Define a "gene."
B.Consider two different species of...

Question 9

Explain the differences between chromosome painting and the older, more traditional method of staining chromosomes being prepared for karyotyping.Highlight the way in which each method identifies chromosomes by the unique sequences they contain.

Accepted Answer

The answer of Explain the differences between chromosome painting and...

Question 10

Match between columns Premises: Comparing the relative number of chromosome pairs is a good way to determine whether two species are closely related. Eukaryotic chromosomes contain many different sites where DNA replication can be initiated. Chromosomes exist at different levels of condensation, depending on the stage of the cell cycle.
The telomere is a specialized DNA sequence where microtubules from the mitotic spindle attach to the chromosome so that duplicate copies move to opposite ends of the dividing cell.

Accepted Answer

The Answer of False and True is...

Question 11

For each of the following sentences, choose one of the options enclosed in square brackets to make a correct statement about nucleosomes.
A.Nucleosomes are present in [prokaryotic/eukaryotic] chromosomes, but not in [prokaryotic/eukaryotic] chromosomes.
B.A nucleosome contains two molecules each of histones [H1 and H2A/H2A and H2B] as well as of histones H3 and H4.
C.A nucleosome core particle contains a core of histone with DNA wrapped around it approximately [twice/three times/four times].
D.Nucleosomes are aided in their formation by the high proportion of [acidic/basic/polar] amino acids in histone proteins.
E.Nucleosome formation compacts the DNA into approximately [one-third/one-hundredth/one-thousandth] of its original length.

Accepted Answer

The answer of For each of the following sentences, choose...

Question 12

Early studies of chromosome structure relied on isolating chromatin from cells followed by nuclease treatment in vitro, followed by analysis of the products of this treatment.Demonstrate your understanding of this process by answering the questions below:
A.How can nucleosome core particles be isolated from chromatin?
B.What molecular components were identified after this treatment was complete?
C.What portion of the nucleosome was destroyed/removed during this treatment and what function does it normally serve?

Accepted Answer

The answer of Early studies of chromosome structure relied on...

Question 13

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
10,000 chromosome mitosis
100 different nuclear envelope
1000 DNA nucleolus
cell cycle dynamic proteins
cell wall interphase similar
chromatin lipids static
Each chromosome is a single molecule of __________ whose extraordinarily long length can be compacted by as much as __________-fold during __________ and tenfold more during __________.This is accomplished by binding to __________ that help package the DNA in an orderly manner so it can fit in the small space delimited by the __________.The structure of the DNA-protein complex, called __________, is highly __________ over time.

Accepted Answer

The answer of For each of the following sentences, fill...

Question 14

In principle, what is the minimum number of nucleotides necessary to code for each amino acid? Keep in mind there are twenty different naturally-occurring amino acids, and that each amino acid is encoded by the same number of nucleotides.

Accepted Answer

The answer of In principle, what is the minimum number...

Question 15

Evidence suggests that the replication of DNA packaged into heterochromatin occurs later than the replication of other chromosomal DNA.What is the simplest possible explanation for this phenomenon?

Accepted Answer

The answer of Evidence suggests that the replication of DNA...

Question 16

Given the sequence of one strand of a DNA helix (below), provide the sequence of the complementary strand and label the 5′ and 3′ ends.
5′-GCATTCGTGGGTAG-3′

Accepted Answer

The answer of Given the sequence of one strand of...

Question 17

The human genome comprises 23 pairs of chromosomes found in nearly every cell in the body.Answer the quantitative questions below by choosing one of the numbers in the following list: 23 69 >200 46 92 >10⁹ A.How many centromeres are in each cell? What is the main function of the centromere? B.How many telomeres are in each cell? What is their main function? C.How many replication origins are in each cell? What is their main function?

Accepted Answer

The answer of The human genome comprises 23 pairs of...

Question 18

Describe the mechanism by which heterochromatin can spread, once it has been established in one region of the chromosome.

Accepted Answer

The answer of Describe the mechanism by which heterochromatin can...

Question 19

Match between columns Premises: Histone proteins have a lower-than-average number of lysines and arginines in their polypeptide chains.
Interphase chromosomes represent a physical state of the chromatin with the highest order of packaging. The histone proteins that constitute the core nucleosome include tetramers of histones H2A, H2B, H3, and H4.
Linker histones help compact genomic DNA by influencing the path of the DNA after it has wrapped about the nucleosome core.

Accepted Answer

The Answer of True and False is...

Question 20

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; each word or phrase should be used only once.
$\begin{array}{lll}
\text { 30-nm fiber } & \text { heterochromatin } & \text { linker } \
\text { active chromatin } & \text { histone } \mathrm{H} 1 & \text { loops } \
\text { axis } & \text { histone } \mathrm{H} 3 & \text { more } \
\text { beads-on-a-string } & \text { histone } \mathrm{H} 4 & \text { synaptic complex } \
\text { euchromatin } & \text { less } & \text { zigzag }
\end{array}$

Interphase chromosomes contain both darkly staining __________ and more lightly staining __________.Genes that are being transcribed are thought to be packaged in a __________ condensed type of euchromatin.Nucleosome core particles are separated from each other by stretches of __________ DNA.A string of nucleosomes coils up with the help of __________ to form the more compact structure of the __________.A __________ model describes the structure of the 30-nm fiber.The 30-nm chromatin fiber is further compacted by the formation of __________ that emanate from a central __________.

Accepted Answer

The answer of For each of the following sentences, fill...

Quiz 5: DNA and Chromosomes

The structures of the four bases in DNA are given in Figure 5-42. Figure 5-42 A.Which are purines and which are pyrimidines? B.Which bases pair with each other in double-stranded DNA?

Gene A, which is normally expressed, has been moved by DNA recombination near an area of heterochromatin.None of the daughter cells produced after this recombination event express gene A, even though its DNA sequence is unchanged.Explain this observation.

Indicate whether the following statements are TRUE or FALSE.If a statement is false, explain why it is false.

Indicate whether the following statements are TRUE or FALSE.If a statement is false, explain why it is false.

Origins of replication typically have a relatively high number of A-T base pairs.How does this sequence feature relate to the function of these DNA regions?

A.Define a "gene." B.Consider two different species of yeast that have similar genome sizes.Is it likely that they contain the same number of genes? A similar number of chromosomes?

Explain the differences between chromosome painting and the older, more traditional method of staining chromosomes being prepared for karyotyping.Highlight the way in which each method identifies chromosomes by the unique sequences they contain.

Indicate whether the following statements are TRUE or FALSE.If a statement is false, explain why it is false.

In principle, what is the minimum number of nucleotides necessary to code for each amino acid? Keep in mind there are twenty different naturally-occurring amino acids, and that each amino acid is encoded by the same number of nucleotides.

Evidence suggests that the replication of DNA packaged into heterochromatin occurs later than the replication of other chromosomal DNA.What is the simplest possible explanation for this phenomenon?

Given the sequence of one strand of a DNA helix (below), provide the sequence of the complementary strand and label the 5′ and 3′ ends. 5′-GCATTCGTGGGTAG-3′

Describe the mechanism by which heterochromatin can spread, once it has been established in one region of the chromosome.

Indicate whether the following statements are TRUE or FALSE.If a statement is false, explain why it is false.