Lecture 4: Molecular composition of the cell Flashcards
What are the major atomic constituents in the body?
O C H & N
What are the building blocks( monomers)? What macromolecules(polymers) do they form?
amino acids - proteins
nucleotides - nucleic acids DNA & RNA
carbohydrates - complex carbohydrates
lipids - lipids ( non polymers)
What are the four levels of carbohydrates?
monosaccharides - single building block e.g glucose, fructose
disaccharides - 2 monosaccharides e.g suncrose, lactose
oligosaccharides - 3-10 linked monosaccharides
polysaccharides - many > 10 linked
Glucose monomers are linked together by:
Alpha 1-4 glycosidic bonds ( starch & glycogen)
Beta 1-4 glycosidic bonds (cellulose)
we don’t have enzymes which break down the beta bonds to use cellulose as an energy source
What are the function of carbohydrates?
1) Cell recognition
2) Energy/fuel - storage
3) structural
What are the functions of lipids
1) Structural : cholestrol & phospholipids in cell membrane
2) Regulatory: hormones such as testosterone & oestrogen
3) Energy - triacylgcerols if not used we store them as fat
What lipid types are there?
1) triacylgycerols: glycerol & 3 fatty tails
2) phospholipid: hydrophilic head & hydrophobic tail
3) Steriods: four fused rings with chemical groups attached
What is the function of nucleic acids?
Contains hereditary/genetic info
What is the structure of RNA & DNA
RNA - ribose sugar
- A U C G
DNA - deoxyribose sugar
- A T C G
Proteins are polymers of amino acids. How many different amino acids are there?
20
How do proteins differ in arrangement?
differ by their R group
What are the functions of proteins?
- structural protiens; collagen in skin
- regulatory: insulin
- Contractile: actin & myosin
- Transport: Haemaglobin
- Storage
- Catalytic
- Protective
