1 Nucleic acids Flashcards
what is DNA made up of?
DNA (mono)nucleotides
Componenst of a nucleotide
A pentose sugar
A phosphate group
A nitrogen containing organic base (Cytosine, Uracil, Thymine, Guanine)
Bond formed between the sugar of one nucleotide and phosphate group of another
phosphodiester bond
Difference between RNA and DNA nucleotide
Ribose sugar
Uracil instead of thymine
Base pairs, what type o bond and how many?
C and G (3 H bonds)
A and T (2 H bonds)
Adaptations of DNA
- Stable, passed from generation to generation and rarely mutates
- 2 separate strands only bound by hydrogen bonds (easy to separate for DNA replication)
- large molecules carrying its of genetic information
base pairs are protected by backbone (from outside chemical and physical forces)
Base pairs allow replication and transfer (as mRNA)
DNA helicase
Breaks hydrogen bonds between bases during semi conservative replication
Template strand
the strand to which complimentary free nucleotides join during semi conservative replication
DNA polymerase
joins the free nucleotides (to each other) during semi conservative replication, to form the complimentary polynucleotide strand
what is semi conservative replication?
DNA replication where an original strand acts as a ‘template’ to form a new complimentary polynucleotide strand. The new DNA is made up of one original stand and one new strand.
components of ATP
- Adenine (nitrogen containing organic base)
- Ribose sugar (5C)
- chain of 3 phosphates
how is ADP formed
hydrolysis of ATP by ATP hydrolase
ATP + water –>ADP +Pi (+Energy)
Roles of ATP
- Metabolic processes (e.g. building molecules)
- Movement (e.g. energy for muscle contraction)
- Active transport (changes shape of carrier proteins)
- Secretion (needed to form lysosomes)
- Activation of molecules (phosphorylates other compounds to make them more reactive (adding a phosphate group))
why is water a DIPOLAR molecule adn why is it important
Oxygen is slightly negative
Hydrogen is slightly positive
(but no overall charge)
Forms hydrogen bonds (between + of one molecule and - of another)
Makes water slightly cohesive:
1. allows transpiration and movement through xylem in plants.
2. creates surface tension in bodies of water (strong enough to support small organisms)
What is specific heat capacity of water and why is it important
high specific heat capacity
so a lot of energy needed to heat a given mass
so water acts as a buffer against temperature variations :
1. in aquatic environment
2. in living organisms (as they are made up of water)