KA : 1.1 Structure of DNA Flashcards
What is DNA?
DNA is inherited and is the genetic material of living things.
Where is DNA located?
DNA is located within the nucleus of all cells apart from red blood cells.
What is a genotype?
When a DNA sequence differs between individuals.
“A DNA molecule is comprised of __ chains of ______”
A DNA molecule is comprised of 2 chains of nucleotides.
What is a nucleotide made up of?
A phosphate, a deoxyribose sugar and any 1 of the 4 bases.
What are the 4 bases?
Adenine, Guanine, Cytosine and Thymine.
What is the base pairing rule?
Bses are said as being complementary to each other meaning there shapes match up.
Adenine → Thymine
Cytosine →Guanine
What are the bases joined by?
Hydrogen bonds
What forms the sugar phosphate backbone?
Nucleotides in a chain that are held together by strong chemical bonds between the phosphate and sugar make long chains of nucleotides called polynucleotides which form the sugar phosphate backbone.
Why is the 5’ and 3’ used?
The phosphate is attached to the carbon 5 of the deoxyribose sugar.
The base is attached to the carbon 1 of the deoxyribose sugar.
How is the double helix structure formed?
The chains of polynucleotides are joined together by the bases, by hydrogen bonds which is twisted round to create a double helix.
“The double helix is described as having __/_____/____ of nucleotides because one side goes from _’ to _’ and the opposite side goes from _’ to _’.”
The double helix is described as having two
anti-parallel chains of nucleotides because one side goes from 5’ to 3’ and the opposite side goes from 3’ to 5’.
What forms the genetic code?
The base sequence of DNA forms the genetic code.
What is meant by prokaryote?
A prokaryote is when cells lack a nucleus and most organelles.
What is meant by eukaryote?
A eukaryote is when cells have a nucleus and organelles.
