Unit 1 KA-2 Flashcards
What is a chromosome?
Rod like structure that contains the genetic material of an organism encoded into DNA.
What is DNA?
A molecule that holds the genetic code for living organisms.
What is DNA Polymerase?
Enzyme that unwinds and unzips DNA: adds free nucleotides during DNA replication.
What is DNA Ligase?
Enzyme that joins up DNA fragments.
What is a nucleotide?
Component of DNA consisting of deoxyribose sugar, a phosphate group and a base.
What is a primer?
Short complementary strand of DNA
Define PCR.
Method of amplifying sequences of DNA.
What is the Leading strand.
DNA strand that is replicated continuously.
What is the Lagging Strand?
DNA strand that is replicated in fragments.
AT the Golf Course
Adenine - Thymine
Cytosine - Guanine
Bases are held together by…
Weak hydrogen bonds
Complimentary strands of DNA run in the _________ direction to each other they are said to be__________
Complimentary and antiparrallel
At want prime end is deoxyribose present?
3’ end
At what prime end is phosphate present?
5’ end
Prior to cell division, what is DNA replicated by and why?
DNA polymerase to ensure that all genetic information is passed on to all new cells.
For DNA replication to occur it is essential to have:
- A template strand of DNA to be replicated
- A primer (short strand of nucleic acid)
- DNA polymerase
- Ligase
- ATP
Stages of DNA replication.
- DNA double helix unwinds
- Weak hydrogen bonds between base pairs break (forming 2 template strands)
- DNA template strands become stabilised and expose their bases at a Y-shaped replication fork.
- One strand of the replication fork is a template for the leading strand and the other is the template for the lagging strand
How are the nucleotides held together?
Strong chemical bonds form between the deoxyribose sugar of one nucleotide and the phosphate group of the next. This gives each strand a Sugar-Phosphate backbone.
