lipids and proteins

Question 1

what are triglycerides made of and how are they formed

Answer 1

one glycerol molecules and 3 fatty acids
- formed by a (3) condensation reaction between then and joined by 3 ester bonds. water molecule lost between each fatty acid and part of glycerol attaching to it (3 H2O)

Question 2

what are the 2 different structures of fatty acids

Answer 2

saturated - no double bonds between carbon atoms (only single bonds in hydrocarbon chain)

unsaturated - at least one double bonds between the carbon atoms

Question 3

what is the function of triglycerides and how do their result in their function

Answer 3

energy store
-due to large ratio of energy storing carbon:hydrogen bonds compared to the number of carbon atoms(a lot fo energy is stored in the molecule)
- high ratio of hydrogen:oxygen atoms which acts as metabolic water source (release water if oxidised - camels in desert env)
-dont effect water potential and osmosis - large and hydrophobic = insoluble in water
-lipids have low mass, meaning a lot can be stored w/o increasing the mass

Question 4

what is a phospholipid made of and how are they formed

Answer 4

made up of 2 fatty acids, glycerol molecule and a phosphate group
- formed by a (2)condensation reactions, joined by 2 ester bonds

Question 5

what are the properties of phospholipids

Answer 5

phosphate group has a negative charge (hydrophilic head) meaning they attract water and repel lipids

fatty acids dont have charge - hydrophobic tail, repelling water but ix with fats and lipids

= phospholipid BILAYER membrane structure (makes up plasma membrane)

Question 6

how are dipeptides formed

Answer 6

when two amino acids join together by a condensation reaction joined by peptide bonds

Question 7

how are polypeptides formed

Answer 7

condensation reactions of many amino acids joined by peptide bonds

Question 8

what is the primary structure of a protein

Answer 8

the order of amino acids in a polypeptide chain - polymer

Question 9

what is the secondary structure of a protein

Answer 9

primary structure (sequence of amino acids) folded
- alpha helix or beta pleated sheet created
- held by hydrogen bonds

Question 10

what is the tertiary structure of a protein

Answer 10

further folding of secondary structure - unique 3D shape
- held in place by ionic, hydrogen and disulphide bonds - determine how it folds (primary structure which determines the location of bonds)

Question 11

what is the quaternary structure of a protein

Answer 11

same unique 3D shape as tertiary structure
- protein made up of more than one polypeptide chain

Question 12

what are the 5 properties of water

Answer 12

high high heat capacity - can buffer temp changes since it takes a lot of energy to boil water (molecules can absorb a lot of energy) - inside body temp is kept stable

• good solvent; water’s polarity is useful solvent; metabolic reactions are ionic (made from one positively charged atom and one neg charged) so the positive end of water mol attracts the neg atom and the neg end attracts the positive atom
• high latent heat of vaporisation; a lot of energy is needed to evaporate water (break the hydrogen bonds) = living organisms can lose water through evaporation to cool down w/o losing too much water
• strong cohesion; water molecules have a strong attraction between each other and therefore are very cohesive (stick together) because they are polar
• important metabolite; used in condensation and hydrolysis reactions in the body (hydrolysis requires water to break a bond and condensation releases a water molecule as it forms a new bond)