Structure and Replication of DNA: Key Area 1.2 Flashcards
What is DNA?
DNA is a substance that encodes genetic information of heredity in a chemical language
What is the structure of DNA?
DNA is a very long double stranded molecule in the shape of a double helix. Each strand is made up from chemical units called nucleotides.
What is a nucleotide made up of?
- Deoxyribose sugar
- A Phosphate sugar
- A Base
What do deoxyribose molecules have?
Five carbon atoms which are numbered 1-5
What are the 4 different DNA bases called?
A - Adenine
T- Thymine
G - Guanine
C - Cytosine
How is genetic information encoded?
In the sequence of bases along the length of one of the strands of a DNA molecule
What are base pairs held together by?
Hydrogen bonds
What does each strand have?
• Sugar phosphate backbone with a 3 prime end that starts with a deoxyribose molecule and a 5 prime end that finishes with a phosphate
Why are the two strands of a DNA molecule described as being anti parallel?
They run in opposite directions to each other.
What do chromosomes consist of?
Tightly coiled DNA, which is packaged with associated proteins.
What is replication?
The process by which DNA molecules can direct the synthesis of identical copies of themselves
What end does DNA polymerase add complementary DNA nucleotides?
3 prime end.
What does DNA polymerase require to start replication?
Primers
What are primers?
Short, complementary sequences of nucleotides that allow binding of DNA polymerase
What are nucleotides added as on the lagging strand?
Fragments
