Nucleic Acids Flashcards
what does RNA stand for?
Ribonucleic acid
What does DNA stand for
Deoxyribonucleic acid
What are the three components of a nucleotide
A pentose sugar
A phosphate group
A nitrogen containing organic base
What are the 5 nitrogen containing organic bases
Cytosine Thymine (DNA) Uracil (RNA) Adenine Guanine
How are the pentose sugar, phosphate group an organic base joined?
Condensation reactions
Phosphodiester bond (between nucleotides)
What is the pentose sugar in RNA
Ribose
What bonds are formed between nitrogenous bases?
Hydrogen bonds
What are the base pairings?
Adenine - Thymine/Uracil
Guanine - Cytosine
How is a DNA molecule stable?
Phosphodiested backbone protects more chemically reactive organic bases
Hydrogen bonds link the organic base pairs
Strongest in C-G pairings
How is DNA adapted to carry out its function
Stable Rarely mutates Hydrogen bonds easily separated in replication Large - more genetic information Backbone protects base pairings Base pairing allows replication to mRNA
Outline the four requirements of semi conservative replication
Four types of nucleotide each with their base pair must be present
Both stands of DNA act as a template for attachment of nucleotides
The enzyme DNA polymerase
Chemical energy
Outline the process of semi conservative replication
DNA helicase breaks the hydrogen bonds
Double helix separated into two strands
Exposed poly nucleotides acts as template
DNA polymerase joins nucleotides in condensation reaction
Each new DNA molecule contains one original DNA strand and one new strand
Outline the supporting evidence provided by Watson and Crick in the semi conservative model
Heavy N15 DNA was cultivated
When placed into a N14 culture
The following generation provided one N14 and one N15 strand
Showing up half way between the two lines of DNA in the tubes
Cultivated in bacteria
Outline the structure of ATP
Adenine
Ribose
Three phosphate groups
Outline the equation for ATP energy release
ATP + H2O > ADP + P + Energy
Outline the function of ATP hydrolase
Acts as a biological catalyst
For the hydrolysis
Of ATP into ADP
Outline the function of ADP synthase
Acts as a biological catalyst
For the condensation
Of ADP into ATP
What are the three ways ATP is synthesised from ADP
Photosynthesis
Respiration (eukaryotes)
Transfer of phosphate groups from donor molecules to ADP (substrate-level phosphorylation)
Outline the main role of ATP
Immediate energy source
How is ATP adapted to its function
Weak bonds between phosphate molecules Cannot be stored Easily produced Lots of mitochondria Reversible reaction
Outline the processes cells use ATP for
Metabolic - building macromolecules (eg starch)
Movement - Muscle contraction
Active Transport - changes carrier protein shape
Secretion - form lysosomes
Phosphorylation - more reactive molecules
List the properties of a water molecule
Dipolar Hydrogen bonding Specific heat capacity Latent heat of vaporisation Cohesion and surface tension
Describe dipolar property (biology)
Oxygen is more negative
Hydrogens are more positive
Describe hydrogen bonding (biology)
Negative oxygen attracts positive hydrogen
Positive hydrogen attracts negative oxygen
Creating a weak inter molecular force
Describe the specific heat capacity of water
Hydrogen bonding makes molecules stick together
More energy is required to separate them
Increasing the boiling point of water
Making water act as a buffer to heat changes
Describe the latent heat of vaporisation of water
Hydrogen bonding
Requires a lot of energy to evaporate 1g of water
Describe cohesion and surface tension in water
Water molecules stick together (cohesion)
Allow it to be pulled up without energy
Pulled back into water rather than into air
Making water surface act like a strong “skin”
Outline how water is used metabolically
Break down molecules in hydrolysis
Produced in condensation reaction
Chemical reactions occur aqueous conditions
Raw material for photosynthesis
Outline how water is used as a solvent
Dissolves gases (eg oxygen and CO2)
Dissolves harmful waste material (eg urea)
Dissolves inorganic ions for transport
Dissolves enzymes for aqueous conditions
Outline how water is used by animals for external conditions
Evaporates to cool animals
Provides support for hydrostatic skeletons
Transparent allowing aquatic plants to photosynthesise
Surface tension to allow animals to sit atop
Cohesion allows pull up a xylem
