Chapter 2: Nucleic acids Flashcards
DNA has a double helix structure and carries…
Genetic information
A nucleotide is made up of:
- Pentose sugar
- Phosphate group (deoxyribose for DNA)
- Nitrogen-based organic group
The five nitrogen-based organic groups are:
Adenine, Cytosine, Guanine, Thymine and Uracil
Uracil and Thymine are used by which nucleic acid?
RNA uses Uracil
DNA uses Thymine
The phosphate group, pentose sugar and organic base are bonded through which reaction and to make what?
- Condensation reaction
- To make a mononucleotide
Two mononucleotides can join together through what reaction to make what kind of bond?
- Condensation reaction
- To make a phosphodiester bond
The base groups used for RNA are:
Adenine, Guanine, Cytosine and Urasil
DNA is a stable structure because of?
(Two things)
- The phosphodiester bond protects the chemically active base groups in the double helix
- The hydrogen bonds
Why is a DNA structure more stable the more C-G pairs it has?
The C-G pair has three hydrogen bonds which adds more stability than the A-T pair
Cell division occurs in two main stages:
- Nuclear division (Mitosis, meiosis)
- Cytokinesis ( where the whole cell divides_
The four requirements for semi-conservative replication are:
- All base pairs
- The enzyme DNA polymerase
- A source of chemical energy
- Both strands of the DNA molecule
The two enzymes used in DNA replication are and their functions?
- DNA helicase which breaks apart the strands into two
- DNA polymerase which rebinds the strands together
What does DNA helicase do? (Cause and effect)
It breaks apart the hydrogen bonding between the base pairs
This unwinds the double helix into two separate strands
What happens after the helicase unwinds the strands?
The polynucleotide strand acts as a template for free nucleotides to attach to their complementary base pairing.
What is the protein associated with DNA in a chromosomes
Histones
