2.Nucelic Acids Flashcards
Facts about ribonucleic acid (RNA)
Single short strand
Ribose sugar
A G C U
Three forms-messenger transfer and r
Facts about deoxyribonucleic acids (DNA)
Double long strand
Deoxyribose
A C G T
What’s the structure of a nucleotide
What’s the reaction that forms them and what’s the bond formed
Phosphate group, pentose sugar, organic base
Condensation reaction
Phosphodiester bond between carbon 3 and phosphate of next nucleotide
Chain is called polynucleotide
Facts about base pairing
Bases of DNA attach to eachother by hydrogen bonds
Complementary base pairing
C-G has 3 hydrogen bonds, the more c-g bonds the stronger and more stable
What increases the stability of DNA
Phosphodiester sugar backbone protects the chemically reactive organic bases
Hydrogen bonds when numerous are strong
What’s the function of dna
Responsible for passing on genetic information cell to cell
Many variations in base sequences = genetic variation of species/organisms
How is DNA suited to its function
Stable structure-rarely mutates
Hydrogen bonds-allow for replication and protein synthesis
Large molecule-lots of genetic information
Sugar Phosphate backbone-protects the organic bases
Base pairing-DNA can be replicated
What are the two stages of DNA Replication
Nuclear division-nucleus divides
Cytokinesis-whole cell
Process of semi conservative replication
1-enzyme DNA helicase causes two strands of dna to unwind by breaking jt ehydrogen bonds between the complimentary base pairs
2-each strand acts as a template for DNA replication
3-free activated nucleotides bind specifically to their complimentary base
4-DNA polymerase then catalysed the condensation reaction which forms the phosphodiester bonds between nucleotides. Forming a polynucleotide chain with a sugar phosphate backbone
5-Now two DNA molecules, each with an original strand and a newly synthesised strand
Evidence for semi conservative dna replication
1-bacteria was grown in a median containing n14, this was incorporated into the dna bases
2-bacteria transferred to median containing n15 and then incorporated into half the dna
3-when our in centrifuge half the dna was lighter
N14 is lighter than N15 so it will separate out-
What is energy
And when did it originally come from
Ability to do work
Originally from sun
What’s ATP and what’s the reaction for it
Adenine triphosphate
ATP + H2O ——> ADP + energy
What is ATP made of
Adenine
\
Ribose — phosphate — phosphate — phosphate
How does ATP store energy
- The bonds between phosphates are unstable and have low activation aenergy
- easily broken
- when broken releases large amount of energy
- normally only terminal phosphate is removed
Synthesis of ATP
Reversible reaction
ATP is hydrolysed by ATP hydrolase to for ADP and an inorganci phosphate
ADP is condestationed by ATP synthase which adds the iP to adp
What is phosphorylation
The addition of a phosphate group to a molecule
What are the 3 ways ATP is synthesised from ADP
1-photo phosphorylation-happens in chlorophyll containing plant cells during photosynthesis
2-oxidative phosphorylation-in plant and animal cells during respiration
3-substrate Keven phosphorylation-when phosphate groups are transferred from donor molecules to ADP in plant and animal cell
What’s the role of ATP
Immediate energy source-cells don’t store it
Releases less energy-manageable
Single reaction-quick release
Energy requiring processes that require ATP
Metabolic-energy to build up macromolecules
Movement-energy for muscle contraction
Active transport-Energy to change shape of carrier proteins
Secretion-needed to form lysosomes
Activation of molecules-inorganic phosphate used to phosphorylase other compounds
Why is water dipolar
Oxygen has a stronger electrostatic pull, pulls the electrons closer to it, causing it to be slightly negatively charged
Subsequently hydrogen is left as slightly positively charged.
Water is dipolar as its poles are oppositely/separately charged
What does the hydrogen bonding do between water molecules
Hydrogen bond forms between a slightly positive hydrogen and a slightly negative oxygen of another molecule
Helps stick the water molecules together
What is specific heat capacity
Due to water being extensively hydrogen bonded
More heat energy is required to break the bonds
Therefore higher boiling point
Creates thermostable environment as vast amount of energy is needed to change the temperature
What is latent heat of vapourisation
Hydrogen bonding of water molecules means it requires a lot of heat energy to evaporate 1g of water
Evaporation of a small volume of water creates a huge cooling effect
What is cohesion and surface tension
Due to hydrogen bonding water has large cohesive forces that allow it to be pulled up a tube (xylem)
When water molecules meet air they are pulled into the body of after creating surface tension, surface tension is strong enough to hold small organisms
Why is water a metabolite
Used to break down complex molecules (hydrolysis)
Used to form complex molecules (condensation)
Chemical reactions take place in it
Major raw material in photosynthesis
Why is water a solvent
It readily dissolves substances eg
Gases
Wastes
Inorganic ions
Enzymes
