Chapter 2: Nucleic Acids Flashcards
What are nucleic acids?
Nucleic acids are a group of important molecules, most commonly DNA and RNA. They are information carrying molecules.
What are ribosomes made from and where are they found?
Ribosomes are molecules made from RNA and proteins which transfer information from DNA to ribosomes.
What are the 3 components of a nucleotide?
1) A pentose sugar
2) A phosphate group
3) A nitrogen-containing organic base
What is the reaction which forms nucleotides?
Condensation reaction
What is the bond which forms between two nucleotides joined to each other?
Phosphodiester bond
What are the 4 DNA organic bases? Why do they pair together?
Adenine Thymine Cytosine Guanine The base pairs are complementary
What are the 4 RNA organic bases?
Adenine Guanine Cytosine Uracil
Describe the structure of DNA:
- Two DNA strands curled in a double helix formation. - Sugar and phosphate form a ‘sugar-phosphate backbone’. - Opposite bases are joined by hydrogen bonds.
Who worked out the structure of DNA?
James Watson Francis Crick (Following the work of Rosalind Franklin)
What is the function of DNA and where is it found?
DNA is a hereditary material which is responsible for passing genetic information between cells and generations.
How is DNA adapted to carry out its function?
- Very stable structure
- 2 seperate strands joined by hydrogen bonds (so they can separate during replication)
- Extremely large molecule
- Base pairs ‘protected’ by helica cylinder
- Base pairing makes DNA replicatin and transfer of information easier and more efficient
Define nuclear division:
The process by which he nucleus divides. This includes mitosis and meiossis.
Define cytokinesis:
The process following nuclear division in which the whole cell divides.
What is semi-conservative DNA replication?
Repliation of a double stranded molecule of nucleic acid, separating into single strands which serve as a replicaion template for the formation of another complementary strand onto each original strand.
What are the four requirements for semi-conservative replication?
- Four types of nucleotide (A,T,C,G)
- Both strands of the DNA molecule act as a template
- The enzyme DNA polymerase
- A source of chemical energy