Week 1: Building blocks of the cell: proteins, carbs and lipids

Question 1

Messenger protein function

Answer 1

Transport signals inside cells and from cell to cell.
E.g: hormones

Question 2

Enzymatic protein function

Answer 2

Accelerate chemical reactions in the body
E.g: digestive enzymes in stomach

Question 3

Structural protein function

Answer 3

Forms the structure of molecules and cells
E.g: keratin is the main structural component in hair, nails and skin

Question 4

Defensive protein function

Answer 4

Protects the body from disease
E.g: antibodies

Question 5

Transport protein function

Answer 5

Carry other molecules around a cell or the body
E.g: haemoglobin carrying oxygen around the body from lungs

Question 6

Storage protein function

Answer 6

Binds to other proteins and prevents their use
E.g: ferritin that stores iron

Question 7

Toxin protein function

Answer 7

Toxins are substances created by plants and animals that are poisonous (toxic) to humans
E.g: Tetanus toxin causes tetanus disease

Question 8

What are amino acids?

Answer 8

Building blocks of proteins (monomer = amino acid)
Joined together by peptide bonds in a linear chain
Polymers = polypeptide
Order dictates shape size and function

Question 9

Structure of amino acid

Answer 9

Question 10

What are R groups and what do they determine

Answer 10

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)

Question 11

What are N and C terminus?

Answer 11

N-terminus: free amine end of the chain
C-terminus: free carboxylic end of the chain
Chemically different so have different chemical properties

Question 12

What are the different protein structure types?

Answer 12

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

Question 13

What are non-polar amino acids

Answer 13

Hydrophobic R group (doesn’t interact with water)
Found in centre of a molecule

Question 14

What are polar amino acids

Answer 14

Hydrophilic R groups. Surface of a protein

Question 15

What are aromatic amino acids

Answer 15

Often comprise key portions of protein-protein or protein-ligand interaction interfaces on protein surface

Question 16

What are charged amino acids?

Answer 16

Salt bridges formed by interaction of closely located positively and negatively charged side chains

Question 17

Membrane bound proteins

Answer 17

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

Question 18

Enzyme structure and function

Answer 18

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

Question 19

What are conformational changes affected by?

Answer 19

• 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)

Question 20

Carbohydrate structure

Answer 20

General formula: (CH2O)n
Monomer = monosaccharide
Polymer = complex carbohydrates
How they’re joined = different function

Question 21

Function of carbohydrates

Answer 21

• 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

Question 22

Disaccharide examples

Answer 22

• Glucose + Fructose = sucrose
• galactose + glucose = lactose
• glucose + glucose = maltose

Question 23

What are oligosaccharides?

Answer 23

• 3-10 monomers
• Common on cell membranes and surfaces as cell markers

Question 24

What are lipids?

Answer 24

• Organic: C, H and little O
• Hydrophobic
• Varied in structure and function

Question 25

Function of Lipids

Answer 25

• Energy storage
• Insulation
• Building blocks (phospholipids and glycolipids)
• Targeting molecules (direct to appropriate place)
• Messenger molecules

Question 26

Phospholipid structure

Answer 26

Polar head (hydroophilic) and non polar tail (hydrophobic)

Question 27

Complex macromolecule examples

Answer 27

• Lipopolysaccharides (lipid and carb)
• Proteoglycans (protein and carb)
• Glycoproteins (protein is made, then carbs added)
• Lipoproteins (lipid and protein)
• Glycolipids

Question 28

What is the lipid bilayer?

Answer 28

Acts as a barrier to protect the cell against various environmental insults and enables multiple cellular processes to occur in subcellular compartments.