Lecture 4c - How do molecules of life differ from non-living matter? Flashcards
What is the directionality of polypeptides?
N to C terminus
N terminus = amine group
C terminus = COOH group
How do amino acids from polypeptides?
- joining of COOH and NH2
- condensation reaction eliminating water to form a peptide bond
How can polypeptides be broken down?
hydrolysis with water
Name the 5 different interactions holding polypeptide chains together
- hydrophobic interactions
- disulphide bridge
- hydrogen bonds
- hydrophilic interactions
- ionic bonds
What is a lipid?
a biomolecule that is not souble in water, but is in a non-polar solvent
What are the two classes of lipids?
- fats
- steroids
What are steroids?
- used for signalling
- 4 ring structure
What are fats?
3 fatty acids + glycerol
- forms a triglyceride
- these are a type of fat
What functional group joins together fatty acids to form triglycerides?
ester
what does amphiphilic mean?
that there is a hydrophobic section and a hydrophilic section
What happens of you put phospholipids in water?
they organise themselves so the hydrophobic section is away from water
What is compartmentalisation with phospholipids?
separate environment and separate sections within cells to carry out different functions
What do saturated phospholipids form? and why?
- stiff membrane
- can interact better and pack more closely together
- results in a rigid membrane
What do unsaturated phospholipids form and why?
- fluid membrane
- interact less strongly so pack less efficiently
- results in a fluid membrane
How can a cell regulate if there is a stiff or fluid membrane?
changing the amount of double bonds in the phospholipid
