Genetics : Central Dogma of Biology

Study concepts, example questions & explanations for Genetics

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Example Questions

Example Question #161 : Genetics

All of the following organisms follow the central dogma except __________.

Possible Answers:

Algae

Deathcap

HIV

Botulism

Correct answer:

HIV

Explanation:

The central dogma of biology reads that DNA goes to RNA which goes to protein. All of the following do that except for HIV, which uses reverse transcriptase in order to convert RNA to DNA which is going in reverse of the central dogma.

Example Question #11 : Central Dogma Of Biology

A gene is the DNA segment necessary to create a protein. 

What sections of the DNA are included in a gene?

Possible Answers:

Length of DNA from a single chromosome

DNA encoding mRNA and promoter region of DNA

Promoter region of DNA

DNA encoding mRNA

Poly-A tail and 5' cap

Correct answer:

DNA encoding mRNA and promoter region of DNA

Explanation:

Given the definition that a gene is the segment of DNA necessary to create a protein, we can immediately eliminate the choices of "Poly-A tail and 5' cap" and "Length of DNA from a single chromosome." Neither of these choices correspond to a segment of DNA: the first corresponds to segments of processed mRNA, and the second to the entire length of the DNA unsegmented. Neither "DNA encoding mRNA" or "Promoter region of DNA" can be correct, as they cannot function without the other, with the promoter region allowing proteins to prepare for transcription of the DNA-encoding mRNA to be produced. 

Example Question #12 : Central Dogma Of Biology

What is the role of the promoter region of DNA in transcription?

Possible Answers:

To open DNA downstream of the promoter region

To be a template for the mRNA strand to be transcribed.

To open DNA upstream of the promoter region

To initiate transcription of a particular gene

To change the conformation of the DNA (i.e. double helix to parallel)

Correct answer:

To initiate transcription of a particular gene

Explanation:

The promoter region of DNA does not interact with the shape of the DNA around it, eliminating all choices where change in DNA shape occurs. This leaves the answer choices of "To be a template for the mRNA strand," and "To initiate transcription of a particular gene." The promoter region is not transcribed to the mRNA that it initiates, leaving the correct answer, "To initiate transcription of a particular gene." The promoter region does this by attracting transcription factors necessary for recruitment of RNA polymerase. 

Example Question #13 : Central Dogma Of Biology

Where does transcription take place?

Possible Answers:

Inside of the mitochondria

Inside of the rough endoplasmic reticulum

Inside of the nucleus

On ribosomes

On the outer cell membrane of the nuclear envelope

Correct answer:

Inside of the nucleus

Explanation:

The central dogma of biology occurs inside of the nucleus from DNA to modified mRNA transcripts prepared to be exported to the cytoplasm. Since the nucleus is an organelle separated from the endoplasmic reticulum and the mitochondria, those answers can be eliminated. Translation occurs on ribosomes, not transcription. It is an important distinction that transcription occurs entirely within the membranes of the nucleus, and would not be found on the outer membrane of the nuclear envelope.

Example Question #14 : Central Dogma Of Biology

Which of the following is NOT true?

Possible Answers:

DNA and RNA are made of nucleotides.

DNA is transcribed to RNA.

RNA is transcribed into proteins.

Proteins are made of amino acids. 

All answer choices are true.

Correct answer:

RNA is transcribed into proteins.

Explanation:

In the central dogma of biology, DNA is transcribed to RNA, which is then translated to proteins. DNA and RNA are made up of nucleotides, and proteins are made up of amino acids. The only answer choice that does not fit this sequence is "RNA is transcribed into proteins." A correct statement would be that RNA is translated into proteins.

Example Question #15 : Central Dogma Of Biology

In the __________, DNA is __________ to RNA.

Possible Answers:

mitochondria . . . transcribed

nucleus . . . translated

cytoplasm . . . translated

cytoplasm . . . transcribed

nucleus . . . transcribed

Correct answer:

nucleus . . . transcribed

Explanation:

Translation occurs on ribosomes in the cytoplasm or attached to the rough endoplasmic reticulum. No part of transcription or translation occurs in the mitochondria. Transcription occurs in the nucleus of the cell and therefore "nucleus . . . transcribed" is the correct answer. 

Example Question #16 : Central Dogma Of Biology

In the __________, RNA is __________ to protein.

Possible Answers:

nucleus . . . transcribed

nucleus . . . translated

cytoplasm . . . translated

cytoplasm . . . transcribed

mitochondria . . . translated

Correct answer:

cytoplasm . . . translated

Explanation:

Transcription occurs in the nucleus of the cell and is the process of using DNA to build RNA. Translation occurs on ribosomes in the cytoplasm and is the process of using RNA to build protein. No part of transcription or translation occurs in the mitochondria. Therefore "cytoplasm . . . translation" is the correct answer.

Example Question #17 : Central Dogma Of Biology

A transcription factor is a(n) __________ that binds to a specific sequence of __________, thereby controlling the rate of transcription.

Possible Answers:

protein . . . RNA

coactivator . . . DNA

corepressor . . . DNA

protein . . . DNA

RNA sequence . . . DNA

Correct answer:

protein . . . DNA

Explanation:

A transcription factor is a protein that binds to a specific sequence of DNA, thereby controlling the rate of transcription. Transcription factors work by binding to DNA prior to transcription and act to either increase or decrease the rate of subsequent transcription processes. Transcription factors bind to enhancer or promoter regions and may attract corepressor or coactivator proteins to the binding site, but corepressors and coactivators are not themselves transcription factors.

Example Question #18 : Central Dogma Of Biology

What is the main enzyme that transcribes DNA into RNA?

Possible Answers:

DNA Polymerase I

DNA Polymerase III

RNA Polymerase

Helicase

Primase

Correct answer:

RNA Polymerase

Explanation:

Both DNA polymerase I and DNA polymerase III play a role in the replication of DNA, but not in its transcription. Helicase acts to unwind the DNA strand. Primase synthesizes the RNA fragments necessary for DNA replication. RNA polymerase binds to DNA at the promoter region and builds mRNA along the template, therefore "RNA polymerase" is the correct answer.

Example Question #19 : Central Dogma Of Biology

What is the first amino acid in every protein made in a eukaryotic cell?

Possible Answers:

Glutamic Acid

Glycine

Alanine

Methionine

Cysteine

Correct answer:

Methionine

Explanation:

While all of the answer choices are amino acids, only one corresponds to the "start" codon. All start codons correspond to the amino acid methionine, the most common being "AUG." Due to corresponding with the start codon, methionine will be the first amino acid laid down in every protein made in a eukaryotic cell.

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