Question 1

One of the genes affected in Diamond-Blackfan Anemia is called RPS19. This gene plays a role in maturation of the 40S subunit. Your sister tells you she heard that protein synthesis can occur normally if the large ribosomal subunit is present, even if the small subunit is not because the large subunit is the part that decodes the information. You tell her that this is

Accepted Answer

Protein synthesis cannot occur normally if the small ribosomal subunit is missing because it plays a crucial role in decoding the messenger RNA (mRNA) and aligning it with the transfer RNA (tRNA) carrying the correct amino acid. The large subunit is important for the peptide bond formation between the amino acids, but it cannot function without the small subunit. Therefore, both subunits are necessary for protein synthesis to occur.

Question 2

Your sister asks you what the difference is between protein synthesis and translation. You explain to your sister that the process of generating proteins in a cell is called translation because the information for the protein is in the form of ________ but proteins are composed of ________.

Accepted Answer

The information for the protein is in the form of nucleic acids (specifically, mRNA), but proteins are composed of amino acids. This means that the process of generating proteins in a cell is called translation, which involves reading the information in the mRNA in order to assemble the correct sequence of amino acids that will make up the protein.

Question 3

Your patient took biology many years ago. You remind her of the structure of DNA and RNA. Which statement is NOT correct?

Accepted Answer

RNA contains the nucleobases adenine, guanine, uracil, or cytosine, not thymine. Thymine is a nucleobase found only in DNA.

Question 4

You explain to your sister that ribosomes are the site of ________ in cells.

Accepted Answer

Ribosomes are responsible for making new proteins by translating the genetic information in mRNA molecules into chains of amino acids. This process is called protein synthesis.

Question 5

You tell your patient that the genetic code is used when translating mRNA to synthesize protein. You explain that the code is degenerate and that this is important because

Accepted Answer

The answer of You tell your patient that the genetic...

Question 6

Your patient tells you she didn't get the flu vaccine either because she heard that she would have to get it every year. She doesn't understand why this is that case. You explain that flu viruses have two types of glycoprotein spikes that have a role in flu virus pathogenesis. Every year, minor changes occur in the genes that code for these spikes, resulting in slight changes in their amino acid sequence. These changes to the spikes on the surface of the virus is an example of ________.

Accepted Answer

Antigenic variation refers to changes in the antigenicity of a pathogen, which occur due to genetic changes in the pathogen's genes. In the case of the flu virus, these changes occur in the genes that code for the glycoprotein spikes on the surface of the virus, resulting in slight changes in their amino acid sequence. This is why a new flu vaccine is needed every year, as the vaccine must be developed to target the specific strains of the virus present in that particular year.

Question 7

When E. coli is placed in a medium containing both glucose and lactose, why does cell growth stop temporarily when the glucose is used up?

Accepted Answer

Once glucose is depleted, the cell must use the lactose; before it can do this, it must express the lac operon and synthesize the enzymes needed to use lactose, which takes time. This temporary stop in growth is known as the diauxic shift.

Question 8

Which of the following statements would NOT be good information for your sister?

Accepted Answer

Although this statement is technically true, it would not be helpful information for your sister as it does not provide any new or relevant information. The other statements explain the structure and function of ribosomes and protein synthesis, which would be more useful for a beginner's understanding of this topic.

Question 9

Your patient somewhat remembers the details of replication but can't really recall what role various enzymes play in the process. You give her the information. Which of the following would you NOT tell her?

Accepted Answer

DNA ligase is responsible for joining Okazaki fragments on the lagging strand during DNA replication, not for joining the antiparallel strands of DNA together. The antiparallel strands are held together by hydrogen bonds between complementary base pairs.

Question 10

Ribosomes are involved in generating proteins in a cell. The other components directly needed for this process to occur are

Accepted Answer

Ribosomes use mRNA as a template to synthesize proteins by linking amino acids together. tRNA molecules bring the appropriate amino acids to the ribosome based on the genetic code carried by the mRNA. Therefore, mRNA, tRNA, and amino acids are the other components directly needed for protein synthesis along with ribosomes. Nucleic acids and DNA polymerase are not directly involved in protein synthesis, and a nucleus or nucleolus is not required for protein synthesis to occur in prokaryotic cells.

Question 11

Why is the position of the first AUG after the ribosome binding site critical?

Accepted Answer

The position of the first AUG after the ribosome binding site is critical because it establishes the correct reading frame for translation. The ribosome will begin reading the mRNA sequence from this AUG codon, and if it is in the incorrect position, the resulting amino acid sequence would be completely different. Every polypeptide does not necessarily have to start with methionine or end with methionine or arginine. Therefore, options A, B, C, and E are incorrect.

Question 12

You give your patient some general information on gene expression in cells. You explain that when cells divide, two processes are involved: replication and gene expression. Gene expression includes two related events: (i) copying the information encoded in DNA into RNA, a process called ________, followed by (ii) the interpretation of the information carried by the RNA to synthesize the encoded protein in a process called ________.

Accepted Answer

When cells divide, two processes are involved: replication (copying of DNA) and gene expression. Gene expression includes two related events: (i) copying the information encoded in DNA into RNA, a process called transcription, followed by (ii) the interpretation of the information carried by the RNA to synthesize the encoded protein in a process called translation. Therefore, the correct answer is (A) transcription followed by translation.

Question 13

You remind your patient that information for proteins is encoded in DNA ________. These are copied into ________ in the mRNA.

Accepted Answer

Information for proteins is encoded in DNA as triplets of nucleotides (three nucleotides in a sequence). These triplets are copied into codons (three nucleotides in a sequence) in the mRNA.

Question 14

You explain that transcription starts at a particular region on the DNA template called the ________, and ends at a sequence called the ________.

Accepted Answer

Transcription begins at the promoter region on the DNA template and ends at the terminator sequence. The start codon (AUG) is involved in translation, not transcription. The stop codon (UAA, UAG, or UGA) is important in translation where it signals the end of the protein-coding sequence. The terms "initiator" and "stop" are not commonly used to refer to the regions where transcription begins and ends.

Quiz 7: The Blueprint of Life, From Dna to Protein

Your sister asks you what the difference is between protein synthesis and translation. You explain to your sister that the process of generating proteins in a cell is called translation because the information for the protein is in the form of but proteins are composed of .