Week 1: Building blocks of the cell: proteins, carbs and lipids Flashcards
Messenger protein function
Transport signals inside cells and from cell to cell.
E.g: hormones
Enzymatic protein function
Accelerate chemical reactions in the body
E.g: digestive enzymes in stomach
Structural protein function
Forms the structure of molecules and cells
E.g: keratin is the main structural component in hair, nails and skin
Defensive protein function
Protects the body from disease
E.g: antibodies
Transport protein function
Carry other molecules around a cell or the body
E.g: haemoglobin carrying oxygen around the body from lungs
Storage protein function
Binds to other proteins and prevents their use
E.g: ferritin that stores iron
Toxin protein function
Toxins are substances created by plants and animals that are poisonous (toxic) to humans
E.g: Tetanus toxin causes tetanus disease
What are amino acids?
Building blocks of proteins (monomer = amino acid)
Joined together by peptide bonds in a linear chain
Polymers = polypeptide
Order dictates shape size and function
Structure of amino acid
What are R groups and what do they determine
20 different R groups, therefore 20 different amino acids
Side chains determine:
* Folding
* Charge (positive/negative)
* Polarity of side chain
Non-polar amino acids (Hydrophobic = Water insoluble)
Polar amino acid (Hydrophilic = Water soluble) Neutral (uncharged)
What are N and C terminus?
N-terminus: free amine end of the chain
C-terminus: free carboxylic end of the chain
Chemically different so have different chemical properties
What are the different protein structure types?
Primary: simple chains
Secondary: alpha helix or beta pleated sheet
Tertiary: Complexly folded
Quaternary: more than 1 chain
Combo of monomers creates different macromolecules for different biological functions
What are non-polar amino acids
Hydrophobic R group (doesn’t interact with water)
Found in centre of a molecule
What are polar amino acids
Hydrophilic R groups. Surface of a protein
What are aromatic amino acids
Often comprise key portions of protein-protein or protein-ligand interaction interfaces on protein surface
What are charged amino acids?
Salt bridges formed by interaction of closely located positively and negatively charged side chains
Membrane bound proteins
Polar amino acids generally line interior pores to create hydrophilic channels
Non-polar amino acids located on regions of the surface in contact with membrane
Enzyme structure and function
Active site depends on the location and distribution of polar and non-polar amino acids
Hydrophobic/philic interactions can play a role in substrate binding to active site
What are conformational changes affected by?
- Correct sequence of a.a (e.g: sickle cell anaemia)
- Chemical conditions of protein’s environment
- pH and temperature
- Other proteins in environment (e.g: inhibitors, co-activators)
Carbohydrate structure
General formula: (CH2O)n
Monomer = monosaccharide
Polymer = complex carbohydrates
How they’re joined = different function
Function of carbohydrates
- Serves as fuel and building materials
- Carbs covalently linked to proteins (glycoproteins) or lipids (glycolipids) are part of cell membranes, and function as adhesion and address loci for cells
- Structural support
Disaccharide examples
- Glucose + Fructose = sucrose
- galactose + glucose = lactose
- glucose + glucose = maltose
What are oligosaccharides?
- 3-10 monomers
- Common on cell membranes and surfaces as cell markers
What are lipids?
- Organic: C, H and little O
- Hydrophobic
- Varied in structure and function
Function of Lipids
- Energy storage
- Insulation
- Building blocks (phospholipids and glycolipids)
- Targeting molecules (direct to appropriate place)
- Messenger molecules
Phospholipid structure
Polar head (hydroophilic) and non polar tail (hydrophobic)
Complex macromolecule examples
- Lipopolysaccharides (lipid and carb)
- Proteoglycans (protein and carb)
- Glycoproteins (protein is made, then carbs added)
- Lipoproteins (lipid and protein)
- Glycolipids
What is the lipid bilayer?
Acts as a barrier to protect the cell against various environmental insults and enables multiple cellular processes to occur in subcellular compartments.
