Question 1

On average,how much of a gene sequence is removed as introns,leaving the exons to be spliced together and translated into protein?&#10;A) 100%&#10;B) 95%&#10;C) 50%&#10;D) 1%

Accepted Answer

On average, about 95% of a gene sequence is removed as introns, leaving the exons to be spliced together and translated into protein. This process is known as RNA splicing, and it is essential for producing mature mRNA molecules that can be used to make proteins. The introns themselves do not code for proteins and are instead removed by the splicing machinery before the mRNA is sent to the ribosome for translation. This allows for greater flexibility in gene expression and enables different protein isoforms to be produced from a single gene.

Question 2

Polymorphic DNA sequences that are short tandem repeats 1 to 13 base pairs in length are referred to as:&#10;A) microsatellites.&#10;B) minisatellite DNA.&#10;C) long tandem repeats.&#10;D) transposable elements.

Accepted Answer

Polymorphic DNA sequences that are short tandem repeats 1 to 13 base pairs in length are commonly referred to as microsatellites. They are also known as simple sequence repeats (SSRs) or short tandem repeats (STRs).

Question 3

In the following sequences,the normal amino acid sequence is given first followed by the sequence that is produced by a sequence alteration.Identify the type of sequence alteration that most likely causes the altered amino acid sequence. Normal Sequence: Phe-Asn-Pro-Thr-Arg
Mutated Sequence: Phe-His-Pro-Thr-Arg
What type of sequence alteration most likely caused the mutation?

A) Indel
B) Missense
C) Nonsense
D) There is no alteration.

Missense

Accepted Answer

The mutated sequence differs from the normal sequence by a single nucleotide substitution, which causes a change in the amino acid at position 2 from asparagine (Asn) to histidine (His). This type of alteration is called a missense mutation.

Question 4

Which one of the following is a similarity between bacterial and human genomes?&#10;A) Number of chromosomes&#10;B) Structure of chromosomes&#10;C) Number of genes&#10;D) Presence of double-stranded DNA

Accepted Answer

Both bacterial and human genomes contain double-stranded DNA as their genetic material. While the structure and number of chromosomes and genes vary significantly between bacteria and humans.

Question 5

If you were interested in studying plasmid structure,which one of the following cell types would be appropriate for you to examine?&#10;A) Human cells&#10;B) Fungal cells&#10;C) Bacterial cells&#10;D) All cell types

Accepted Answer

Plasmids are small, circular pieces of DNA that can be found in many bacterial cells. Therefore, if you are interested in studying plasmid structure, it would be appropriate to examine bacterial cells. Human cells and fungal cells do not typically contain plasmids, so they would not be useful for studying plasmid structure. While plasmids can technically be found in all cell types, examining bacterial cells would be the best choice for specifically studying plasmid structure.

Question 6

An example of epigenetic variation that affects gene expression would be:&#10;A) heteroplasmy.&#10;B) chromosomal translocation.&#10;C) copy number alteration.&#10;D) histone modifications.

Accepted Answer

Histone modifications are a type of epigenetic variation that can affect gene expression. Changes in histone modification patterns can lead to changes in the accessibility of DNA to transcription factors, affecting the rate of gene expression.

Question 7

Copy number variants comprise approximately what percent of the human genome?&#10;A) 75%&#10;B) 50%&#10;C) 10%&#10;D) 0.5%

Accepted Answer

Copy number variants (CNVs) account for about 10% of the human genome. CNVs are large areas of the genome that have been duplicated or deleted, and they can vary from one individual to another, contributing to genetic diversity and sometimes to disease.

Question 8

Which one of the following statements regarding the human genome below is correct?&#10;A) Mobile genetic elements (transposons)comprise almost half of the human genome.&#10;B) An intron is located within a transposon segment of a chromosome.&#10;C) Genes that contain instructions for making proteins are located in transposons.&#10;D) Unique sequences that code for protein make up only 10% of the human genome.

Accepted Answer

Mobile genetic elements, also known as transposons, make up about 45% of the human genome. This is the only option that accurately describes the presence and proportion of transposons in the human genome.

Question 9

In the following sequences,the normal amino acid sequence is given first followed by the sequence that is produced by a sequence alteration.Identify the type of sequence alteration that most likely causes the altered amino acid sequence. Normal Sequence: Phe-Asn-Pro-Thr-Arg
Mutated Sequence: Phe-His-Pro-Thr-Arg
What type of sequence alteration most likely caused the mutation?

A) Indel
B) Missense
C) Nonsense
D) There is no alteration.

Missense

Accepted Answer

Nonsense mutation is most likely the cause of the altered amino acid sequence because it introduces a premature stop codon, leading to a truncated protein, as seen in the mutated sequence where the sequence ends abruptly after Pro.

Question 10

The major difference between single nucleotide variants (SNVs)and copy number variants (CNVs)is that:&#10;A) SNVs are duplicated in tandem and involve complex gains or losses of homologous sequences,whereas CNVs involve simple sequence changes.&#10;B) CNVs occur in stretches of DNA ranging from 100 to millions of bases in size,whereas SNVs involve single base changes.&#10;C) SNVs are always associated with disease,whereas CNVs are not.&#10;D) SNVs are involved in gene amplification by producing more than two functional genes in a genome.

Accepted Answer

The major difference between SNVs and CNVs is that SNVs involve single base changes, whereas CNVs occur in stretches of DNA ranging from 100 to millions of bases in size. This means that CNVs can result in the duplication or deletion of entire genes or regions of the genome, whereas SNVs typically only affect a single nucleotide.

Question 11

A single nucleotide variant (SNV)that produces a misplaced termination codon in a polypeptide chain is called a:&#10;A) missense variant.&#10;B) transposon.&#10;C) copy number variant.&#10;D) nonsense variant.

Accepted Answer

The answer of A single nucleotide variant (SNV)that produces a...

Question 12

A virus does not need as much nucleic acid for the production of protein as bacteria do because:&#10;A) viruses use the DNA of the cells that they infect to produce protein.&#10;B) viruses contain high sequence variation.&#10;C) there are no introns in the viral genome.&#10;D) it uses plasmids to synthesize protein instead of DNA.

Accepted Answer

The answer of A virus does not need as much...

Question 13

Polymorphic repeated DNA sequences that are sometimes referred to as minisatellite sequences and are between 14 and 500 base pairs in length are called:&#10;A) transposons.&#10;B) a variable number of tandem repeats.&#10;C) a restriction endonuclease.&#10;D) short tandem repeats.

Accepted Answer

The answer of Polymorphic repeated DNA sequences that are sometimes...

Question 14

Approximately what percentage of genomic DNA is required to maintain the structure of chromosomes as centromeres and telomeres?&#10;A) 75%&#10;B) 50%&#10;C) 20%&#10;D) 2%

Accepted Answer

The answer of Approximately what percentage of genomic DNA is...

Question 15

A single nucleotide variant that produces a misplaced termination codon in a polypeptide chain results in:&#10;A) a frameshift mutation.&#10;B) premature polypeptide chain termination.&#10;C) chromosomal translocation.&#10;D) a trinucleotide repeat.

Accepted Answer

The answer of A single nucleotide variant that produces a...

Deck 49: Genomes and Nucleic Acid Alterations