DNA Flashcards
What are DNA strands and what are they made of?
They are polymers made up of lots of repeating units called nucleotides.
What does each nucleotide consist of?
- One sugar molecule.
- One phosphate molecule.
- One ‘base’.
What do the sugar and phosphate molecules in the nucleotides do?
Form a ‘backbone’ to the DNA strands. The sugar and phosphate molecules alternate.
What are the four different bases that can join with sugar?
- A (adenine)
- T (thymine)
- C (cytosine)
- G (guanine)
How many strands does a DNA molecule have?
Two strands coiled together.
What shape are the two strands coiled together in a DNA molecule?
Double helix (double stranded spiral).
How are the bases linked to each other?
Each base links to a base on the opposite strand in the helix.
A is paired with T.
C is paired with G.
This is called complementary base pairing.
How are complementary base pairs joined together?
By weak hydrogen bonds.
What are chromosomes?
Long, coiled up molecules of DNA.
Where are chromosomes found?
In the nucleus of eukaryotic cells.
What is a gene?
A section of DNA on a chromosome that codes for a particular protein.
What makes up an organism’s genome?
All of the organism’s DNA.
