DNA encodes protein structure through a process called gene expression, which involves two main steps: transcription and translation. In transcription, the genetic information in a specific segment of DNA is copied into messenger RNA (mRNA). The mRNA sequence, composed of codons (triplets of nucleotides), is then translated into a sequence of amino acids during translation, occurring at the ribosome. Each codon specifies a particular amino acid or a stop signal, with the start codon (AUG) marking the beginning of protein synthesis. The sequence of nucleotides in the DNA determines the order of amino acids in the protein, ultimately defining its structure and function. This precise encoding ensures the production of functional proteins vital for cellular processes.
How does DNA encode the structure of a protein?
DNA encodes the structure of a protein through the sequence of nucleotides, which is transcribed into mRNA and then translated into a sequence of amino acids that form the protein.
What is a codon?
A codon is a triplet of nucleotides in mRNA that specifies a particular amino acid or a stop signal during protein synthesis.
Which molecule carries the genetic code from the nucleus to the ribosome?
Messenger RNA (mRNA) carries the genetic code from the nucleus to the ribosome.
What is the role of transfer RNA (tRNA) in protein synthesis?
Transfer RNA (tRNA) transports specific amino acids to the ribosome and matches them to the corresponding codons on the mRNA using its anticodon.
What happens during the process of translation?
During translation, the sequence of codons in mRNA is read by the ribosome, and tRNA brings the appropriate amino acids to form a polypeptide chain.
What is the central dogma of molecular biology?
a) Protein -> RNA -> DNA
b) RNA -> DNA -> Protein
c) DNA -> RNA -> Protein
d) Protein -> DNA -> RNA
Answer: c) DNA -> RNA -> Protein
What is the process by which an RNA copy of a gene is produced from DNA?
a) Translation
b) Transcription
c) Replication
d) Transformation
Answer: b) Transcription
Which of the following enzymes is primarily responsible for catalyzing the synthesis of RNA from a DNA template during transcription?
a) DNA polymerase
b) RNA polymerase
c) Primase
d) Ligase
Answer: b) RNA polymerase
A sequence of three nucleotides in mRNA that codes for a specific amino acid is known as a:
a) Anticodon
b) Codon
c) Promoter
d) Primer
Answer: b) Codon
Which type of RNA molecule carries amino acids to the ribosome for incorporation into a polypeptide chain?
a) mRNA
b) rRNA
c) tRNA
d) snRNA
Answer: c) tRNA