DNA Structure, Replication, Transcription, and Mutations: Key Concepts for Biology

What are the three components of a nucleotide?

Sugar (deoxyribose), phosphate group, and nitrogenous base (A, T, C, G)

What is the structure of DNA?

A double helix formed by two strands held together by hydrogen bonds between complementary bases.

Which nitrogenous bases pair together in DNA?

Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

What is the backbone of the DNA structure composed of?

A sugar-phosphate chain.

What is the semi-conservative model of DNA replication?

Each new DNA molecule consists of one old strand and one new strand.

What enzyme unwinds the double helix during DNA replication?

DNA helicase.

What is the role of DNA polymerase?

It adds complementary nucleotides during DNA replication.

What does DNA ligase do?

It seals fragments of DNA during replication.

What is transcription?

The process of converting DNA into mRNA.

Where does transcription occur?

In the nucleus.

What is the role of RNA polymerase?

It builds mRNA using the DNA template.

What is translation?

The process of converting mRNA into protein.

Where does translation occur?

In ribosomes.

What are codons?

Triplets of bases in mRNA that specify amino acids.

What is the role of tRNA in translation?

It brings amino acids to the ribosome.

What is the start codon in the genetic code?

AUG (methionine).

What are the stop codons in the genetic code?

UAA, UAG, UGA.

What is a substitution mutation?

A point mutation where one base is replaced by another.

What is a frameshift mutation?

A mutation caused by insertion or deletion of bases that shifts the reading frame.

What are the effects of a silent mutation?

No change in the protein produced.

What can a missense mutation cause?

A different amino acid to be incorporated into the protein.

How can mutations drive evolution?

They can cause changes that may be beneficial for survival and reproduction.

What is the role of viruses in relation to DNA?

Viruses use DNA or RNA as genetic material and hijack host cells to replicate.

Give an example of a virus that uses DNA.

HIV or Zika.