Question 1

Only sixty- one of the sixty- four codons specify an amino acid. In what process do the other three codons function?

Accepted Answer

The other three codons function as stop codons, which signal the termination of translation by indicating the end of the amino acid sequence of the protein.

Question 2

Identify which of the following includes three possible components of a RNA nucleotide?

Accepted Answer

RNA nucleotides consist of a ribose sugar, a phosphate group, and one of four nitrogenous bases: adenine, cytosine, guanine, or uracil. Choice E correctly identifies ribose and adenine as components of an RNA nucleotide, while thymine is not found in RNA.

Question 3

What is the sequence and polarity of the DNA strand complementary to the strand 5' AAATGTCCATGC 3'?

Accepted Answer

The complementary DNA strand is formed by pairing adenine (A) with thymine (T) and cytosine (C) with guanine (G). The sequence is also antiparallel, so the complementary strand to 5' AAATGTCCATGC 3' is 3' TTTACAGGTACG 5'.

Question 4

What kind of bond is formed between complementary base pairs to join the two DNA strands into a double helix?

Accepted Answer

Hydrogen bonds form between complementary base pairs (adenine-thymine and cytosine-guanine) to join the two DNA strands into a double helix.

Question 5

Retroviruses carry their genetic information in the form of RNA, which is subsequently coded into DNA after the virus enters its host cell. What enzyme does the retrovirus use to produce this initial DNA?

Accepted Answer

Retroviruses use the enzyme reverse transcriptase to convert their RNA genome into DNA once they have entered the host cell. This process is essential for the integration of the viral genome into the host's DNA, allowing the virus to replicate.

Question 6

What kind of bond is formed between the 5' phosphate group of one nucleotide and the 3' hydroxyl (OH) group of the adjacent nucleotide?

Accepted Answer

Phosphodiester bonds are the type of bonds that link the 5' phosphate group of one nucleotide to the 3' hydroxyl group of another nucleotide in nucleic acids, forming the backbone of DNA and RNA strands.

Question 7

The movement of DNA or RNA in gel electrophoresis is often a matter of molecular weight alone. Which of the following molecular parameters usually influence the movement of protein?

Accepted Answer

The movement of proteins in gel electrophoresis is influenced by their weight, charge, and shape. These factors collectively determine how a protein migrates through the gel matrix.

Question 8

Messenger RNA (mRNA) is__________ .

Accepted Answer

Messenger RNA (mRNA) carries the genetic information copied from DNA in the form of a series of codons, each of which specifies a particular amino acid, and serves as a template for protein synthesis in the ribosomes.

Question 9

If a eukaryotic chromosome was composed of 20% adenine, how much cytosine should theoretically be present in that same chromosome?

Accepted Answer

According to Chargaff's rules, in DNA, the amount of adenine (A) equals thymine (T), and the amount of cytosine (C) equals guanine (G). If adenine is 20%, then thymine is also 20%. This leaves 60% for cytosine and guanine combined, so cytosine would be 30%.

Question 10

Modern genetics consists of three major branches. Which of these branches, also known as "transmission genetics," involves the study of the transmission of traits and characteristics in successive generations?

Accepted Answer

Mendelian genetics, named after Gregor Mendel, focuses on the principles of heredity and the ways in which traits are passed from one generation to the next, which is why it is also referred to as "transmission genetics."

Question 11

What chemical group appears on the 5' carbon of a DNA nucleotide?

Accepted Answer

The 5' carbon of a DNA nucleotide is attached to a phosphate group, which is a key component of the nucleotide's structure, allowing nucleotides to link together to form the DNA backbone.

Question 12

Sexual reproduction uses________ to generate___________ gametes, which join at fertilization.

Accepted Answer

Sexual reproduction involves meiosis to produce haploid gametes, which ensures genetic diversity and halves the chromosome number to be restored at fertilization.

Question 13

You identify a new unicellular organism with multiple chromosomes organized by proteins within the cell's nucleus. Into which of the three domains of life might this organism fit?

Accepted Answer

The presence of a nucleus and chromosomes organized by proteins indicates that the organism belongs to the domain Eukarya. Only eukaryotic cells have a defined nucleus and complex chromosome organization involving proteins like histones.

Question 14

What kind of bond is formed between successive amino acids during translation?

Accepted Answer

Peptide bonds are formed between the amino group of one amino acid and the carboxyl group of another during protein synthesis (translation), linking amino acids together in a polypeptide chain.

Question 15

Watson and Crick used evidence from several studies to determine the structure of DNA. What conclusion were they able to draw from Rosalind Franklin's X- ray diffraction data, specifically?

Accepted Answer

Rosalind Franklin's X-ray diffraction data provided critical evidence that DNA is a duplex, with two strands forming a double helix structure. This was a key piece of evidence used by Watson and Crick in determining the overall structure of DNA.

Question 16

What is the process of synthesizing single- stranded RNA from template DNA?

Accepted Answer

The process of synthesizing single-stranded RNA from template DNA is called transcription. This is a fundamental aspect of gene expression, where the DNA sequence of a gene is copied into RNA.

Question 17

What is the process of synthesizing proteins from mRNA sequences?

Accepted Answer

The process of synthesizing proteins from mRNA sequences is called translation. This occurs in the ribosome where the mRNA is decoded to produce a specific protein.

Question 18

When a diploid cell divides by mitosis, the result is___________ .

Accepted Answer

Mitosis results in two identical diploid cells, each having the same number of chromosomes as the original cell.

Question 19

Use the data in the following table to determine which nucleic acid sample can be ALL of the following 4 types: double- stranded DNA, single- stranded DNA, double- stranded RNA, or single- stranded RNA. $$\begin{array} { | l l| } 
\hline \text { Nucleic Acid Sample } & \text { Data } \
\text { Sample } 1 & 25 \% \text { of the bases are thymine } \
\text { Sample } 2 & 35 \% \text { of the bases are adenine } \
\text { Sample } 3 & 25 \% \text { of the bases are uracil } \
\text { Sample } 4 & 55 \% \text { of the bases are cytosine } \
\text { Sample } 5 & 50 \% \text { of the five- carbon sugars are } \
& \text { deoxyribose }\\hline
\end{array}$$

Accepted Answer

The answer of Use the data in the following table...

Question 20

What are the DNA regulatory sequences recognized by RNA polymerase called?

Accepted Answer

Promoters are specific DNA sequences that RNA polymerase recognizes and binds to initiate the transcription of a gene.

Quiz 1: The Molecular Basis of Heredity, Variation, and Evolution