7.1 The Structure Of DNA Flashcards
The importance of DNA:
- Holds genetic information of living things
- All of the body cells contain exactly the same DNA because the DNA is copied
DNA stands for…
Deoxyribose nucleic acid
DNA is a…
Polymer made up of many repeated units called nucleotides
A nucleotide is made up of…
A five carbon sugar
A phosphate group
An organic base
Five carbon sugar is always…
Deoxyribose
Organic base can be…
Adenine
Guanine
Cytosine
Thymine
Phosphate and sugars of adjacent nucleotides join together to form a…
Long polynucleotide strand
DNA is made up of…
Two polynucleotide strands, one upside down relative to the other
Complementary base pairing - adenine bonds with…
Thymine
Complementary base pairing-
Cytosine with…
Guanine
adenine and thymine have…
2 hydrogen bonds
Cytosine and guanine have…
3 hydrogen bonds
Pyrimidines are …
Thymine and cytosine
Purines are…
Adenine and guanine
Sequence of bases allows the DNA to…
Carry coded information for making proteins
DNA is a very long molecule so it can…
Store a lot of information
Functions of DNA:
- Storage of genetic information
- Self-duplication and inheritance
- Expression of the genetic message
Major function of DNA is…
To code for proteins: information coded in the order of the nitrogenous bases (change of nitrogenous bases = change of amino acids)
Structure related to its functions:
- Sugar-phosphate backbone makes the molecule stable
- Molecule coils up so that it is compact - store a lot of information
- Sequence of bases allows it to carry coded information for making proteins
- Double helix makes the molecule stable, as the base pairs are on the inside of the molecule where they are less likely to be damaged
- Bases are held together by weak hydrogen bonds, which allow the molecule to ‘unzip’ easily when it replicates
