Question 1

Which of the following correctly lists the three components of a nucleotide, as shown in the provided diagram?

Accepted Answer

Phosphate group, pentose sugar, nitrogenous base

Question 2

In double-stranded DNA, which base pairs with guanine, and what type of bond stabilizes this pairing?

Accepted Answer

Cytosine; stabilized by three hydrogen bonds

Question 3

What does the term 'antiparallel' mean in the context of DNA structure?

Accepted Answer

The two DNA strands run in opposite directions, one 5' to 3' and the other 3' to 5'

Question 4

Which of the following best describes the difference between ribose and deoxyribose sugars in nucleic acids?

Accepted Answer

Ribose has a hydroxyl group ($$-OH) at $$the 2' carbon, while deoxyribose has a hydrogen ($$-H) at $$the same position

Question 5

During DNA replication, why is the lagging strand synthesized discontinuously?

Accepted Answer

DNA polymerase can only add nucleotides in the 5' to 3' direction, requiring Okazaki fragments on the lagging strand

Question 6

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

Accepted Answer

Helicase

Question 7

In prokaryotic transcription, what is the role of the sigma factor?

Accepted Answer

It helps RNA polymerase recognize and bind to the promoter region

Question 8

Which of the following statements about mRNA processing in eukaryotes is correct?

Accepted Answer

Eukaryotic mRNA undergoes capping, polyadenylation, and splicing before translation

Question 9

Which of the following best explains why prokaryotic mRNA does not require a 5' cap?

Accepted Answer

Transcription and translation are coupled in the cytoplasm, so mRNA is immediately translated

Question 10

Which of the following is a function of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome by matching its anticodon to the mRNA codon

Question 11

A mutation changes the DNA sequence from $$5'-ATG-3' to$$ $$5'-ATA-3'. $$What is the most likely effect on the protein product?

Accepted Answer

The start codon is lost, potentially preventing translation initiation

Question 12

Which of the following best describes an operon in prokaryotes?

Accepted Answer

A group of genes transcribed together as a single mRNA, allowing coordinated expression

Question 13

Which of the following is true about the central dogma of molecular biology?

Accepted Answer

It describes the flow of genetic information as DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 14

Which of the following is NOT a major class of RNA?

Accepted Answer

dRNA (degradation RNA)

Question 15

During translation, which site on the ribosome does the initiator tRNA bind to first?

Accepted Answer

P site

Question 16

Which of the following codons is a stop codon in translation?

Accepted Answer

UAA

Question 17

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 18

Which of the following best explains the difference between prokaryotic and eukaryotic DNA replication origins?

Accepted Answer

Eukaryotes have multiple origins of replication per chromosome, while prokaryotes typically have a single origin

Question 19

Which of the following is a real-world consequence of plasmid-encoded genes in bacteria?

Accepted Answer

They can confer antibiotic resistance, allowing survival in the presence of antibiotics

Chapter 6

Guida di studio - Domande di pratica