Nucleic Acid , ATP, Water Flashcards
What does DNA and RNA stand for?
Deoxyribonucleic acid and ribonucleic acid
What is the monomer of DNA?
Nucleotide
Structure of a nucleotide
Formation of polynucleotide (DNA)
Condensation, which is the removal of a water molecules between phosphate group of one nucleotide and pencil sugar of another nucleotide forming a phosphodiester bond
Name the two scientists that came up with a DNA model
Watson and crick
Describe the structure of DNA
DNA
1. Polymer of nucleotides
2. Each nucleotide formed from deoxyribose, a phosphate group and an nitrogenous base
3. Phosphodiester bonds between adjacent nucleotides;
4. 2 strands held by hydrogen bonds to make a double helix.
5. complementary base pairing is H bonding between adenine, thymine and cytosine, guanine
Describe the structure of chromosomes
DNA associated with histone proteins
The visible structure of DNA during mitosis as each chromosome consists of two sister chromatids joined at a centromere.
Describe how the structure of DNA relates to its function.
Sugar-phosphate backbone so provides strength
2. large molecule so can store lots of information
3. Helix so compact
4. base sequence codes for amino acids
5. Double stranded so strands can act as templates
6. Complementary base pairing (Adenine to thymine and guanine to cytosine) so accurate replication
7. Weak hydrogen bonds for so strands easily separated
8. Many weak hydrogen bonds so stable/strong molecule
Describe semiconservative replication
DNA helicase breaks H bonds between the strands
Each stand acts as a template
Free DNA nucleotides attach by complementary base pairing (thymine and adenine or guanine and cytosine) with template by H bonds reforming
DNA polymerase joins up free adjacent DNA nucleotides with
phosphodiester bonds in a condensation reaction.
New DNA molecule contains one old strand and one new
strand.
Describe the three models that meselson and stahl came up with for DNA replication
- Conservative model.= an entirely new molecule synthesis for my DNA template.
- Semi -conservative model= each new molecule consist one new DNA strand and one original strand
- Dispersive model= new molecules made of segment of new and all DNA
Draw the structure of ATP
Two uses of ATP
- Hydrolysis Provides energy for bodily processes such as active transport.
- Phosphorylation which is making substances more reactive
How is ATP formed?
Condensation off ADP + Pi forming ATP catalyse by ATP synthase during respiration/ photosynthesis
How is ATP hydrolysed?
Hydrolysis of ATP into ADP catalysed by ATP hydrolase
Describe what ATP is useful in biological processes?
-releases energy in small amounts
-break single bond down in one step to release energy rapidly.
-phosphorylates substances to make them more reactive.
-can easily be reformed in one step.
Explain the properties that make water important for organisms
- a metabolite in condensation/hydrolysis reactions.
- a solvent so allowing transport of substances
- high specific heat capacity so buffers changes intemperature (takes a lot of heat energy to change temperature) .
- large latent heat of vaporisation so provides cooling effect
- cohesion (hydrogen bonding) so supports columns of water
- cohesion (hydrogen bonding) so produces surface tension supporting small organisms.
