Lab 10

What is the monomer of a nucleic acid?

Nucleotide

What are the three components of a DNA nucleotide?

• Deoxyribose sugar

• Phosphate group

• Nitrogenous base

What type of bond occurs between deoxyribose & phosphate?

Covalent bond

What type of bond joins nitrogenous base pairs?

Hydrogen bond

Which bases pair together?

• A ↔ T

• G ↔ C

What functional group is located on the 3' end? On the 5' end?

• 3' = Hydroxyl (-OH)

• 5' = Phosphate

Describe the antiparallel design of DNA.

• One strand runs 5'→3'

• The other runs 3'→5'

Histones vs. Nucleosomes

• Histones = proteins

• Nucleosomes = DNA wrapped around histones

When does DNA replication occur?

S phase of Interphase

What does semi-conservative mean?

Each new DNA molecule contains:

• 1 old strand

• 1 newly made strand

Enzymes and molecules

• Helicase → unzips DNA

• Binding proteins → keep strands apart

• Primase → makes RNA primer

• RNA primer → starting point for DNA polymerase

• DNA polymerase → adds nucleotides and proofreads

• Ligase → seals Okazaki fragments together

• Leading strand

  • Made continuously

  Lagging strand

  • Made in pieces called Okazaki fragments

In which direction does DNA replication always occur?

5' → 3'

What must be synthesized before DNA polymerase can attach?

RNA primer

Be able to label:

• Helicase

• Binding proteins

• Primase

• RNA primer

• DNA polymerase

• Ligase

• Leading strand

• Lagging strand

• Okazaki fragments

• Replication fork