2.1.3 Nucleotides and Nucleic Acids – The Structure of DNA Flashcards
(16 cards)
What does DNA stand for?
Deoxyribonucleic acid.
Where do we find DNA?
DNA is found within the nucleus of a cell.
What is the major structure and shape of DNA known as?
A double helix
How many sugar phosphate backbones does DNA have?
Two
In what direction do the sugar-phosphate backbones run in relation to each other?
Antiparallel
What does the term antiparallel mean?
When the two strands run in opposite directions parallel to one another.
What are the complementary base pairings in DNA?
Adenine paired with thymine, and guanine paired with cytosine.
What bond holds nitrogenous bases together?
Hydrogen bonds
How many hydrogen bonds are there between base pairs cytosine and guanine?
3
How many hydrogen bonds are there between base pairs adenine and thymine?
2
What is a good fruit to try and extract DNA from?
A kiwi
When extracting DNA what is the purpose of using a pestle and mortar?
To break up the cells.
What is the purpose of adding washing up liquid in the DNA extraction from fruit?
To break down cell surface membranes.
What is the purpose of adding salt when extracting DNA from fruit?
It binds to DNA causing it to clump together.
Why is it important to raise the temperature when extracting DNA from fruit?
It denatures the enzymes that would otherwise break down the DNA.
Why do we add alcohol as the final step to extract DNA from fruit?
It forms a DNA precipitate.
