Lipids and glycogen COPY Flashcards
What does a triglyceride consist of and draw the diagram? (also briefly describe the bonding)
a molecule of glycerol with three fatty acids attached to it. each fatty acid forms an ester bond with glycerol in a condensation reaction
As the glycerol molecule in all triglycerides are the same, where does the differences in the properties of different fats and oils come from?
the variations in the fatty acids
What is a fatty acid molecule?
a long chain of carbon atoms with an acid group (-COOH) at one end. Hydrogen atoms are attached to the carbons.
What does it mean if a fatty acid is saturated?
It means that every carbon atom in the chain is joined by a single bond
What does it mean if a fatty acid is unsaturated?
It means if on or more of the bonds that every carbon atom is joined by is a double bond
What does it mean if a fatty acid is polyunsaturated?
It means it has many double bonds
Why are unsaturated and polyunsaturated lipids liquid (oils) at room temperature?
Because the double bonds cause the molecules to bend, hence they cannot be packed together closely
Describe more in detail about the structure of triglycerides and how this is related to its property
high ratio of energy-storing carbon-hydrogen bonds to carbon atoms = excellent source of energy
low mass to energy ratio = making them good storage molecules, as much energy can be stored in a small volume. Benefits animals as it reduces mass they have to carry
large, non-polar molecules = insoluble in water = their storage does not affect osmosis in cells or the water potential of them
high ratio of hydrogen to oxygen atoms -= release water when oxidized = provide an important source of water = useful to organisms living in dry deserts.
What are phospholipids, describe the components and draw the diagram?
a class of lipids that has two fatty acid chains and a phosphate group. hydrophilic head (phosphate), which interacts with water but not fat.
Hydrophobic fatty acid tails
How do phospholipids position themselves when they are placed in water?
hydrophillic heads are as close to the water as possible
hydrophobic tails are as far away from the water as possible
What are cell membranes made out of?
a double layer of phospholipids
How do phospholipids affect the properties of the cell membrane?
contribute to the flexibility of membranes
transfer of lipid-soluble substances across them
What are the roles of lipids and how does it carry out its role? (4)
Source of energy = when oxidised, provide morethan twice the enrgy as the same mass of carbohydrate and release valuable water
waterproofing = insoluble in water. In plants & insects: waxy cuticle to conserve water. In mammals: produce oil secretion from sebaceous glands in skin
Insulation = Fats are slow conductors of het and when stored beneath the body surface, they help retain body heat. Also acts as electrical insulators in the myelin sheath around the nerve cells
protection = stored around delicate organs such as the kidneys
How is the structure of phospholipids related to their properties
polar molecules due to the hydrophobic and hydrophilic components = in an aqueous environment phospholipid molecules form a bilayer within the cell-surface membrane = hydrophobic barrier is formed between the inside and outside of a cell
hydrophilic phosphate heads of phospholipid molecules help to hold at the surface of the cell-surface membrane
phospholipid structure allows them to form glycolipids by combining with carbohydrates within the cell-surface membrane. glycolipids important in cell recognition
Draw a triglyceride (chemical formula version)
Draw a glycerol (chemical formula version)
Draw a triglyceride
