3.4.2 DNA and protein synthesis

What is the genome?

• The full range of proteins a cell can produce

• The complete set of genes in a cell

• The structure of mRNA

• The process of protein synthesis

Answer explanation

The genome refers to the complete set of genes in a cell, which contains all the information necessary for the development and functioning of that organism. This distinguishes it from proteins, mRNA structure, and protein synthesis processes.

What does the term 'proteome' refer to?

• The set of all DNA in a cell

• The full range of proteins a cell is able to produce

• The process of transcription

• The structure of tRNA

Answer explanation

The term 'proteome' refers to the full range of proteins a cell is able to produce, distinguishing it from DNA and other processes like transcription or tRNA structure.

Which molecule carries the genetic code from DNA to the ribosome?

• tRNA

• mRNA

• DNA polymerase

• ATP

Answer explanation

mRNA (messenger RNA) is the molecule that carries the genetic code from DNA to the ribosome, where proteins are synthesized. tRNA brings amino acids to the ribosome, but it does not carry the genetic code.

What is the main function of transfer RNA (tRNA)?

• To carry amino acids to the ribosome during translation

• To carry genetic information from the nucleus to the cytoplasm

• To synthesise DNA

• To splice pre-mRNA

Answer explanation

The main function of transfer RNA (tRNA) is to carry amino acids to the ribosome during translation, where proteins are synthesized. This is essential for translating the genetic code into functional proteins.

What is transcription?

• The production of proteins from amino acids

• The production of mRNA from DNA

• The splicing of pre-mRNA

• The breakdown of proteins

Answer explanation

Transcription is the process where the genetic information in DNA is copied to produce messenger RNA (mRNA). This mRNA then serves as a template for protein synthesis, making it the correct choice.

Which enzyme is responsible for joining mRNA nucleotides during transcription?

• DNA polymerase

• RNA polymerase

• Ligase

• Helicase

Answer explanation

RNA polymerase is the enzyme that synthesizes RNA by joining mRNA nucleotides during transcription, making it the correct choice. DNA polymerase is involved in DNA replication, while ligase and helicase have different roles.

In prokaryotes, what is the direct result of transcription?

• Pre-mRNA

• mRNA

• tRNA

• Ribosomes

Answer explanation

In prokaryotes, transcription directly produces mRNA, which serves as the template for protein synthesis. Pre-mRNA is a eukaryotic term, while tRNA and ribosomes are involved in translation, not transcription.

In eukaryotes, what is produced immediately after transcription?

• mRNA

• Pre-mRNA

• tRNA

• Ribosomes

Answer explanation

In eukaryotes, transcription produces pre-mRNA, which is an initial transcript that undergoes processing to become mature mRNA. Therefore, the correct answer is pre-mRNA.

What process converts pre-mRNA into mature mRNA in eukaryotes?

• Translation

• Splicing

• Replication

• Transcription

Answer explanation

Splicing is the process that removes introns and joins exons in pre-mRNA, converting it into mature mRNA. This is essential for proper gene expression in eukaryotes, while transcription and translation are different processes.

What is translation?

• The production of mRNA from DNA

• The production of polypeptides from the sequence of codons carried by mRNA

• The splicing of pre-mRNA

• The replication of DNA

Answer explanation

Translation is the process where ribosomes synthesize polypeptides by reading the sequence of codons on mRNA. This is distinct from transcription, which produces mRNA from DNA.