Mastering the Fundamentals of DNA and Genetics Quiz

1. Garrod hypothesized that "inborn errors of metabolism" such as alkaptonuria occur because.

It is caused by environmental factors such as diet and lifestyle choices.

The affected individuals have a psychological aversion to certain types of food.

Genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

It is a result of mutations in non-coding regions of the DNA.

Garrod's hypothesis regarding inborn errors of metabolism focuses on genetic defects affecting enzyme production, not environmental factors, psychological aversions, or mutations in non-coding regions of DNA.

Explanation

Garrod's hypothesis regarding inborn errors of metabolism focuses on genetic defects affecting enzyme production, not environmental factors, psychological aversions, or mutations in non-coding regions of DNA.

2. Which of the following provides evidence that RNA probably evolved before DNA?

DNA is double-stranded while RNA is single-stranded.

DNA lacks the 2'-hydroxyl group found in RNA.

DNA polymerase uses primer, usually made of RNA.

DNA contains thymine while RNA contains uracil.

DNA polymerase using RNA primer indicates that RNA is likely older in evolution than DNA due to the reliance on RNA in the replication process.

Explanation

DNA polymerase using RNA primer indicates that RNA is likely older in evolution than DNA due to the reliance on RNA in the replication process.

3. The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?

Genes from one organism cannot be transferred to another organism.

Organisms with different genetic codes are unable to reproduce.

All organisms have the same physical traits.

A gene from an organism can theoretically be expressed by any other organism

The genetic code being the same for all organisms means that the basic language of DNA is universal, allowing for genes to be expressed by different organisms despite their variations in physical traits or genetic codes. This is the foundation of genetic engineering and gene expression studies.

Explanation

The genetic code being the same for all organisms means that the basic language of DNA is universal, allowing for genes to be expressed by different organisms despite their variations in physical traits or genetic codes. This is the foundation of genetic engineering and gene expression studies.

4. What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'?

Phe-glu-lys-leu-arg-lys

Met-ser-ser-leu-ser-leu

Thr-gly-arg-ile-ser-pro

Ala-arg-leu-tyr-ala-lys

The correct answer is met-ser-ser-leu-ser-leu. The mRNA codon sequence corresponds to the amino acid sequence as per the genetic code table. The incorrect answers do not align with the codon sequence provided.

Explanation

The correct answer is met-ser-ser-leu-ser-leu. The mRNA codon sequence corresponds to the amino acid sequence as per the genetic code table. The incorrect answers do not align with the codon sequence provided.

5. A simple metabolic pathway is shown below. A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?

An increase in production of B and C

No impact on the production of B and C, but an increase in production of A

An accumulation of A and no production of B and C

A decrease in production of A and an increase in production of B and C

The mutation resulting in a defective enzyme A would lead to an accumulation of A due to the inability to convert A into B and C. This would disrupt the metabolic pathway as enzyme A plays a crucial role in the production of B and C.

Explanation

The mutation resulting in a defective enzyme A would lead to an accumulation of A due to the inability to convert A into B and C. This would disrupt the metabolic pathway as enzyme A plays a crucial role in the production of B and C.

6. The nitrogenous base adenine is found in all members of which group?

Cytosine, Ribose, Thymine

Lipids, Amino Acids, Carbohydrates

ATP, RNA, and DNA

Chlorophyll, Starch, Collagen

Adenine is a nitrogenous base that is commonly found in molecules such as ATP, RNA, and DNA. It is one of the four main bases found in nucleic acids.

Explanation

Adenine is a nitrogenous base that is commonly found in molecules such as ATP, RNA, and DNA. It is one of the four main bases found in nucleic acids.

7. Which of the following nucleotide triplets best represents a codon?

A triplet containing a stop codon

A triplet in the same reading frame as an upstream AUG

Any three random nucleotides in the DNA sequence

Three consecutive nucleotides in a different reading frame

A codon is a sequence of three nucleotides that corresponds to a specific amino acid or stop signal during protein synthesis. The correct answer states that a codon should be in the same reading frame as an upstream AUG to accurately represent a specific amino acid during translation of mRNA.

Explanation

A codon is a sequence of three nucleotides that corresponds to a specific amino acid or stop signal during protein synthesis. The correct answer states that a codon should be in the same reading frame as an upstream AUG to accurately represent a specific amino acid during translation of mRNA.

8. If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme B would be capable of growing on which of the following media?

Minimal medium supplemented with A and C.

Minimal medium supplemented with C only

Complete medium with only A and B.

Complete medium with only C.

In this scenario, since the gene-encoding enzyme B is mutant, the strain would be capable of growing on minimal medium supplemented with C only because A and C are still required for growth. Complete medium with only A and B or only C would not provide the necessary components for growth in this case.

Explanation

In this scenario, since the gene-encoding enzyme B is mutant, the strain would be capable of growing on minimal medium supplemented with C only because A and C are still required for growth. Complete medium with only A and B or only C would not provide the necessary components for growth in this case.

9. If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A would be able to grow on which of the following media?

Minimal medium supplemented with nutrient B only

Minimal medium without any additional supplements.

Minimal medium supplemented with nutrient A only.

Minimal medium supplemented with nutrient C only.

In this scenario, since gene-encoding enzyme A is mutant, the strain would require nutrient A to be supplemented in the medium in order to grow.

Explanation

In this scenario, since gene-encoding enzyme A is mutant, the strain would require nutrient A to be supplemented in the medium in order to grow.

10. During translation, what is the function of the tRNA molecule?

It carries genetic information from DNA to the ribosome.

It acts as the site where ribosomes are assembled.

It transports amino acids to the ribosome and matches them to the correct codon on mRNA.

It synthesizes mRNA from a DNA template.

tRNA (transfer RNA) carries specific amino acids to the ribosome and pairs its anticodon with the corresponding codon on the mRNA, ensuring the correct sequence of amino acids in the growing polypeptide chain.

Explanation

tRNA (transfer RNA) carries specific amino acids to the ribosome and pairs its anticodon with the corresponding codon on the mRNA, ensuring the correct sequence of amino acids in the growing polypeptide chain.