Amino Acids, Proteins and DNA: DNA Flashcards
Define the term nucleotide
- Monomers used to form nucleic acids
Describe the structure of a nucleotide
- Pentose sugar, 2-deoxyribose
- Phosphate group
- Base
What are the four different bases found in nucleotides?
- Adenine
- Thymine
- Cytosine
- Guanine
Identify which atoms on the bases bond with the 2-deoxyribose molecule
- CGP textbook, pg 485
- Atom on base that bonds to 2-deoxyribose
Draw the simplified structure of a nucleotide
Describe which components bond together in a nucleotide
- Phosphate ion bonded to 2-deoxyribose
- 2-deoxyribose bonded to base
What does DNA stand for?
- Deoxyribonucleic acid
What type of polymer is a single strand of DNA?
- Polynucleotide linked by covalent bonds between the phosphate group of one nucleotide and the 2-deoxyribose of another nucleotide
- Results in sugar-phosphate backbone with bases attached to sugars in the chain
How is the sugar-phosphate backbone formed?
- Formed by condensation polymerisation
- Molecule of water lost
- Covalent phosphodiester bond formed
Describe the structure of DNA
- Formed from 2 complementary polynucleotide strands
- 2 strands spiral together to form double helix, held together by hydrogen bonds between the bases
Which bases can bond together?
- Adenine bonds with thymine
- Cytosine bonds with guanine
How do hydrogen bonds form?
- Forms when a δ+ hydrogen is attached to an electronegative atom
- Hydrogen bond forms between δ+ hydrogen and a lone pair of electrons on a nearby oxygen, nitrogen or fluorine atom
How many hydrogen bonds do adenine and thymine form between each other?
- 2 bonds
Draw adenine and thymine to show how they are bonded together
- CGP textbook, pg 488 to see charges
- Adenine and thymine bonds
How many hydrogen bonds do cytosine and guanine form together?
- 3 bonds
Draw cytosine and guanine to show how they are bonded together
- CGP textbook, pg 488 to see charges
- Cytosine and guanine bonds
