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

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

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

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 2

During transcription in eukaryotes, what is the role of the TATA box?

Accepted Answer

It is a promoter sequence crucial for forming the transcription initiation complex.

Question 3

A DNA template strand has the sequence $$3'	ext{-TACGGTACC-}5'. $$What is the corresponding mRNA sequence produced during transcription?

Accepted Answer

$$5'	ext{-AUGCCAUGG-}3'$$

Question 4

Which of the following statements about the genetic code is TRUE?

Accepted Answer

The genetic code is nearly universal among all organisms.

Question 5

What is the function of spliceosomes in eukaryotic cells?

Accepted Answer

They remove introns from pre-mRNA and join exons together.

Question 6

A point mutation changes a codon from $$UAC ($$tyrosine) to $$UAA. $$What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; introduces a premature stop codon

Question 7

Which of the following best explains why insertions or deletions often have more severe effects than substitutions?

Accepted Answer

They can cause frameshift mutations, altering the reading frame for all downstream codons.

Question 8

In prokaryotes, why can translation begin before transcription has finished?

Accepted Answer

Transcription and translation both occur in the cytoplasm without a nuclear envelope.

Question 9

Which enzyme is responsible for attaching the correct amino acid to its corresponding tRNA?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 10

A mutation in the gene encoding a signal peptide would most likely affect which process?

Accepted Answer

The targeting of the polypeptide to the endoplasmic reticulum

Question 11

Which of the following modifications occurs to eukaryotic pre-mRNA before it leaves the nucleus?

Accepted Answer

Addition of a 5' cap and a poly-A tail

Question 12

A researcher introduces a gene from a jellyfish into a mosquito, and the mosquito expresses a fluorescent protein. What does this experiment demonstrate about the genetic code?

Accepted Answer

The genetic code is universal among organisms.

Question 13

During translation, what is the function of the P site of the ribosome?

Accepted Answer

It holds the tRNA carrying the growing polypeptide chain.

Question 14

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation caused by insertion or deletion of nucleotides not in multiples of three, altering the reading frame

Question 15

Which of the following is a post-translational modification that can affect protein function?

Accepted Answer

Glycosylation (addition of a sugar group)

Question 16

A scientist finds a mutation that changes the codon $$GAA ($$glutamic acid) to $$GAG ($$also glutamic acid). What type of mutation is this?

Accepted Answer

Silent mutation

Question 17

Which of the following statements about ribozymes is correct?

Accepted Answer

Ribozymes are RNA molecules with catalytic activity.

Question 18

If a eukaryotic gene undergoes alternative RNA splicing, what is the result?

Accepted Answer

Multiple different polypeptides can be produced from the same gene.

Question 19

Which of the following best explains why polyribosomes are advantageous for cells?

Accepted Answer

They enable a cell to make many copies of a polypeptide very quickly from a single mRNA.

Chapter 17

Guida di studio - Domande di pratica

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