Q: Which of the following is true regarding the directionality of nucleic acid synthesis?

Both DNA and RNA are synthesized in the $$5' \to 3'$$ direction.

Question 1

Which of the following best describes the relationship between genotype and phenotype in a bacterial cell?

Accepted Answer

Genotype is the genetic makeup, and phenotype is the observable expression of that genetic makeup.

Question 2

A scientist isolates a nucleic acid from a virus and finds it contains uracil but no thymine. Which type of nucleic acid is this most likely to be?

Accepted Answer

RNA

Question 3

Which of the following statements about prokaryotic and eukaryotic genomes is correct?

Accepted Answer

Prokaryotic genomes are usually circular and found in the nucleoid region.

Question 4

Which enzyme is responsible for unwinding the DNA helix during replication?

Accepted Answer

Helicase

Question 5

If a DNA molecule contains 20% guanine, what percentage of cytosine would you expect to find?

Accepted Answer

$$20\%$$

Question 6

Which of the following is NOT a component of a DNA nucleotide?

Accepted Answer

Amino acid

Question 7

During DNA replication, which enzyme replaces RNA primers with DNA nucleotides?

Accepted Answer

DNA polymerase I

Question 8

Which of the following best explains why DNA is more stable than RNA?

Accepted Answer

DNA has a deoxyribose sugar, which lacks a hydroxyl group at the 2' position.

Question 9

A mutation in the gene encoding for DNA ligase would most directly affect which step of DNA replication?

Accepted Answer

Sealing of nicks in the sugar-phosphate backbone

Question 10

Which of the following scenarios best illustrates the concept of phenotype being influenced by environmental factors?

Accepted Answer

Serratia marcescens produces a red pigment at $$28^\circ C$$ but not at $$37^\circ C.$$

Question 11

Which of the following is a function of plasmids in prokaryotic cells?

Accepted Answer

They often carry genes that confer a survival advantage, such as antibiotic resistance.

Question 12

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 13

Which of the following is true regarding the directionality of nucleic acid synthesis?

Accepted Answer

Both DNA and RNA are synthesized in the $$5' 	o 3'$$ direction.

Question 14

Which of the following is a correct pairing of DNA and RNA nitrogenous bases?

Accepted Answer

Guanine pairs with cytosine in both DNA and RNA.

Question 15

Which of the following is NOT a function of RNA polymerase during transcription?

Accepted Answer

Proofreading and correcting DNA replication errors

Question 16

A bacterial cell is exposed to a new antibiotic. After several generations, some cells survive due to a gene found on a plasmid. This is an example of:

Accepted Answer

Horizontal gene transfer

Question 17

Which of the following best describes the role of tRNA in protein synthesis?

Accepted Answer

It brings the correct amino acid to the ribosome by matching its anticodon to the mRNA codon.

Question 18

Which of the following is a key difference between prokaryotic and eukaryotic DNA replication?

Accepted Answer

Eukaryotes have multiple origins of replication per chromosome.

Question 19

Which of the following best explains why the number of chromosomes does not determine organismal complexity?

Accepted Answer

Chromosome number varies independently of gene number and organism sophistication.

Question 20

Which of the following is a real-life example of gene expression being regulated by environmental factors?

Accepted Answer

Streptococcus mutans produces a sticky slime layer only in the presence of sucrose.

Microbial Genetics: Structure, Function, and Expression

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