2.1.3: Nucleotides And Nucleic Acids Flashcards
What must occur before new cells are created?
All the DNA in a cell must be replicated
This ensures each new cell contains the full amount of DNA.
In which phase of the cell cycle does DNA replication occur?
S-phase
S-phase is part of interphase.
What are the two ends of a DNA strand called?
3’ end and 5’ end
These refer to the carbon positions in the deoxyribose sugar.
What is the role of DNA helicase in DNA replication?
Breaks the hydrogen bonds between complementary bases
This action unwinds the double helix and separates the strands.
What aligns opposite their complementary base during DNA replication?
Free-floating DNA nucleotides
Hydrogen bonds form between the base pairs.
What enzyme joins adjacent nucleotides together during DNA replication?
DNA polymerase
It forms a phosphodiester bond between nucleotides.
Fill in the blank: The enzyme that catalyzes DNA replication is _______.
DNA polymerase
What is a phosphodiester bond?
A bond formed between adjacent nucleotides in a DNA polymer chain
It connects the phosphate group of one nucleotide to the deoxyribose sugar of another.
What are the stages of DNA replication?
- DNA helicase unwinds the double helix
- Free-floating nucleotides align with template strands
- DNA polymerase forms a new polymer chain
These stages ensure accurate DNA replication.
What happens during the G1 phase of the cell cycle?
Growth
G1 is the first gap phase before DNA synthesis.
What occurs during the G2 phase of the cell cycle?
Growth and preparation for mitosis
G2 is the second gap phase after DNA synthesis.
What is the significance of the 3’ end during DNA replication?
The enzyme can only attach to the DNA at this location
This ensures the proper directionality of DNA synthesis.
True or False: DNA replication is a conservative process.
False
DNA replication is semi-conservative, meaning each new DNA molecule contains one original and one new strand.
