1B - More Biological Molecules Flashcards
What is the job of RNA?
- transfers genetic information from DNA to ribosomes
What is a nucleotide made of?
- pentose sugar
- nitrogen-containing organic base
- phosphate group
What is the sugar in DNA called and what are the 4 possible bases?
- deoxyribose
- adenine (A)
- thymine (T)
- cytosine (C)
- guanine (G)
What is the sugar in RNA called and what base replaces thymine?
- ribose
- uracil (U)
What reaction is used to form polynucleotides?
- condensation
- between phosphate group and sugar
What bond is formed between polynucleotides?
- phosphodiester bond
What is structure of DNA?
- double helix
- complementary base pairing (A-T, C-G)
- 2 hydrogen bonds between A and T
- 3 hydrogen bonds between C and G
- antiparallel strands twist to form double helix
What is structure of RNA?
- short polynucleotide chain
What happens in semi-conservative replication?
- DNA helicase breaks hydrogen bonds (helix unwinds)
- free floating DNA nucleotides attract to their complementary bases
- condensation joins new strands together (catalysed by DNA polymerase)
- hydrogen bonds form
What are the properties of water?
- metabolite in condensation and hydrolysis reactions
- high latent heat of vaporisation (lots of energy needed to break hydrogen bonds)
- high specific heat capacity
- good solvent (polarity makes ions dissolve)
- very cohesive (great at transporting substances)
What is the structure of water?
- H2O
- covalently bonded
- partial negative charge on one side and partial positive charge charge on the other
What is ATP and how is it made?
- immediate source of energy in a cell
- glucose released through respiration is used to make ATP
- diffuses to the part of the cell that needs energy
- energy is stored in high energy bonds between phosphate groups
What is ATP made of?
- adenine, ribose sugar and 3 phosphate groups
What happens to ATP when a cell needs energy?
- broken down into ADP and P (inorganic) using hydrolysis
- catalysed by ATP hydrolase
- ATP hydrolysis can be coupled to other energy-requiring reactions in the cell
- inorganic phosphate can be added to a compound to make it more reactive (phosphorylation)
- ATP can be re-synthesised in condensation by ATP synthase
What is an ion with a positive charge called?
- cation
What is an ion with a negative charge called?
- anion
What makes an ion ‘inorganic’?
- does not contain carbon
What does the iron ion (Fe2+) bind to in haemoglobin?
- oxygen
- temporarily becomes Fe3+ until oxygen is released
What is the rule of hydrogen ions and pH?
- the higher the concentration of hydrogen, the lower the pH
Sodium ions help transport what across membranes?
- glucose and amino acids
DNA, RNA and ATP all contain what inorganic ion?
- phosphate ions (PO4 3+)
- allow nucleotides to join up and make polynucleotides
