More biological molecules Flashcards
What are the monomers of DNA + RNA?
Nucleotides
What are nucleotides made from?
- Nitrogen containing organic base
- Pentose sugar
- Phopshate group
Outline the structure of DNA nucleotide
- Pentose sugar: deoxyribose
- Has phosphate group
- Bases: adenine, cytosine, thymine + guanine
Outline the structure of RNA nucleotide
- Pentose sugar: ribose sugar
- Phosphate group
- Base: uracil
What bond forms between a phosphate group + sugars?
Phosphodiester bond
What is the chain of sugars + phosphates known as?
Sugar-phosphate backbone
Outline the structure of DNA
- 2 DNA polynucleotide strands joined together by H bonds btw bases
- W/ complimentary base pairing
- Joined during condensation reaction
- 2 H bonds btw A + T
- 3 H bonds btw C + G
- Double helix
- Strands are antiparallel
Outline the structure of RNA
- Single polynucleotide chain
- Shorter than DNA polynucleotides
Outline DNA replication by semi-conservative replication
- DNA helicase breaks H bonds btw bases, helix unwind
- OG strand acts as template
- Free floating DNA nucleotides attracted to complimentary base pair on template strand using complimentary base pairing
- Condensation reaction joins nucleotides catalysed by DNA polymerase, H bonds form
- Each DNA strand contains 1 OG strand + new strand
Outline the study for the evidence for semi-conservative replication
- 2 samples of bacteria grown, 1 nutrient containing light N + 1 in heavy, as bacteria reproduced they took up N to help make nucleotides
- Sample of DNA taken from bacteria + spun in centrifuge, DNA from heavy settled lower down centrifuge tube
- Bacteria grown in heavy put into broth containing light N, left for 1 round of DNA replication, sampled + centrifuged
- If SC, bacteria would contain 1 old heavy + new light so DNA will settle in middle
What are the properties of water?
- Metabolite - condensation + hydrolysis
- High latent heat of vaporisation - lots of energy to break H bonds, useful bc living organisms can use water loss through evapouration to cool down w/o losing too much
- High specific heat capacity - H bonds absorb alot of energy, useful bc living organisms don’t experience rapid temp changes, help maintain constant body temp
- Good solvent - bc water is polar, +ve end attracted to -ve ion, totally surrounded by water so dissolves
- Cohesive due to polarity - helps water flow so good as transporting substances, also high surface tension w/ air
Outline the structure of ATP
- Adenine base
- Ribose sugar
- 3 phosphate groups
When energy is needed by a cell, what happens to ATP?
- Broken down into ADP + Pi
- Hydrolysis reaction
- Phosphate bond broken + energy released
- Catalysed by ATP hydrolase
How is ATP re-synthesised?
- Condensation reaction
- Btw ADP + Pi
- During respiration + photosynthesis
- Catalysed by ATP synthase
What are the products from the hydrolysis of ATP used for?
- ATP hydrolysis coupled to other energy requiring reactions rather than lost as heat
- Pi added to another compound making it more reactive
What is an ion w/ a +ve charge?
Cation
What is an ion w/ a -ve charge?
Anion
Outline the functions of inorganic ions
- Iron ion - heamoglobin carries O2 round body in RBC, made up of 4 polypeptide chains each w/ iron ion which binds to O2, Fe2+→ Fe3+ until O2 is released
- H ion - determine pH
- Sodium ions - transport glucose + aa via co-transport
- Phosphate ion - bonds btw phosphate groups store energy in ATP, in DNA + RNA they allow nucleotides to join forming polynucleotides
