DNA Structure
What sugar is found in DNA?
Deoxyribose
What enzyme unzips the DNA double helix?
Helicase
What enzyme is responsible for transcription?
RNA Polymerase
What is the molecule that carries amino acids to the ribosome?
tRNA
What is a mutation?
A change in the DNA sequence.
What are the three parts of a nucleotide?
Sugar, phosphate, nitrogenous base
What is the role of DNA polymerase in replication?
It adds complementary nucleotides to the new DNA strand.
Where in the cell does transcription occur?
The nucleus.
What are the three-letter sequences on mRNA that code for amino acids?
Codons
What is a silent mutation?
A mutation that does not change the amino acid sequence.
What type of bond holds complementary base pairs together
Hydrogen bonds
Why is DNA replication important?
It ensures each new cell gets an exact copy of the DNA.
What happens to mRNA after transcription?
It leaves the nucleus and goes to the ribosome to be translated into a protein.
What is the first amino acid in nearly all proteins?
Methionine (MET), coded by AUG
What is a frameshift mutation?
A mutation caused by insertion or deletion of a nucleotide, shifting the reading frame.
Why is DNA called a "double helix"?
Because it has two strands that twist into a spiral shape.
What would happen if DNA replication did not occur before cell division?
New cells would not have a complete set of DNA, leading to missing genetic information.
What nitrogen base is found in RNA but not in DNA?
Uracil
What type of bond forms between amino acids during translation?
Peptide bond
How can mutations be beneficial?
They can lead to genetic variation and adaptation.
Why is complementary base pairing important in DNA?
It ensures DNA can be copied accurately during replication.
What enzyme proofreads the new DNA strand for mistakes?
DNA polymerase.
What is the function of the promoter region in transcription?
It signals RNA polymerase where to begin transcription.
What would happen if a stop codon appeared too early in translation?
The protein would be too short and might not work properly.
How can a mutation in DNA affect an organism’s traits?
It can change a protein, leading to a different trait, disease, or no change at all.