Biology Unit 3 - 25.3

A gene is expressed (or “turned on”) when:

• it is transcribed into RNA and translated into a protein.

• it is replicated during cell division.

• it is mutated and causes a genetic disorder.

• it is deleted from the genome.

Answer explanation

A gene is expressed when it is transcribed into RNA and translated into a protein, which are essential steps in gene expression. The other options do not represent the process of gene expression.

Tags

NGSS.HS-LS1-1

The roles of RNA molecules (mRNA, tRNA, and rRNA) in gene expression include:

• mRNA carries the genetic information from DNA to the ribosome.

• tRNA translates the genetic code into proteins.

• rRNA forms the core of the ribosome's structure and catalyzes protein synthesis.

• All of the above.

Answer explanation

All roles of RNA are crucial in gene expression: mRNA transports genetic info to ribosomes, tRNA translates this code into proteins, and rRNA is essential for ribosome structure and function in protein synthesis.

Gene expression involves several key events. Which of the following correctly summarizes these events?

• Transcription and translation

• Replication and transcription

• Translation and replication

• Mutation and selection

Answer explanation

Gene expression consists of two main processes: transcription, where DNA is converted to mRNA, and translation, where mRNA is used to synthesize proteins. Thus, the correct summary is 'Transcription and translation'.

The movement of information from nucleus to a functional protein is described by which of the following processes?

• Transcription and Translation

• Replication and Transcription

• Translation and Replication

• Transcription only

Answer explanation

The correct choice is 'Transcription and Translation' because transcription converts DNA to mRNA in the nucleus, and translation synthesizes proteins from mRNA in the cytoplasm, completing the flow of genetic information.

Determine amino acid sequences given the mRNA sequence.

• Translate the mRNA sequence to amino acids.

• Transcribe the mRNA sequence to DNA.

• Replicate the mRNA sequence.

• None of the above.

Answer explanation

To determine amino acid sequences, you must translate the mRNA sequence into amino acids using the genetic code. The other options do not achieve this goal.

mRNA processing involves several steps. Which of the following is NOT a step in mRNA processing?

• 5' capping

• Polyadenylation

• Splicing

• Translation

Answer explanation

Translation is the process of synthesizing proteins from mRNA, not a step in mRNA processing. The actual processing steps include 5' capping, polyadenylation, and splicing.

The genetic code is said to be degenerate because:

• each amino acid is coded by multiple codons.

• it is universal across all organisms.

• it is composed of nucleotides.

• it is a triplet code.

Answer explanation

The genetic code is considered degenerate because multiple codons can code for the same amino acid, allowing for redundancy in the genetic code. This ensures that mutations may not always affect protein synthesis.

The process of using a gene sequence to synthesize a protein is called:

• Transcription

• Translation

• Replication

• Mutation

Answer explanation

The process of using a gene sequence to synthesize a protein is called translation. During translation, the mRNA produced from transcription is decoded to build the corresponding protein.

Tags

NGSS.HS-LS1-1

Which type of RNA is responsible for carrying the genetic information from DNA to the ribosome?

• Messenger RNA (mRNA)

• Transfer RNA (tRNA)

• Ribosomal RNA (rRNA)

Answer explanation

Messenger RNA (mRNA) carries genetic information from DNA to the ribosome, where proteins are synthesized. Transfer RNA (tRNA) and ribosomal RNA (rRNA) have different roles in protein synthesis.

Which type of RNA is involved in the translation process by bringing amino acids to the ribosome?

• Messenger RNA (mRNA)

• Transfer RNA (tRNA)

• Ribosomal RNA (rRNA)

Answer explanation

Transfer RNA (tRNA) is the type of RNA that brings amino acids to the ribosome during translation, facilitating the assembly of proteins. Messenger RNA (mRNA) carries the genetic code, while ribosomal RNA (rRNA) forms part of the ribosome.