Macromolecules #3Macromolecules #3

LIPIDS!!!LIPIDS!!!

LipidsLipids

used for long term energy storageall lipids do not dissolve (insoluble) in

water (hydrophobic)

used for long term energy storage all lipids do not dissolve (insoluble) in water (hydrophobic)

4 Kinds of Lipids4 Kinds of Lipids

1.1. TRIGLYCERIDETRIGLYCERIDE Most body fat stored in form of Most body fat stored in form of

triglycerides (adipose tissue in our triglycerides (adipose tissue in our bodies)bodies)

Excellent source of Excellent source of energy – stores more energy – stores more energy than CHOenergy than CHO

Helps keep your Helps keep your body warm (insulation)body warm (insulation) Women have a Women have a thickerthicker layer of fat than layer of fat than

men for men for child bearingchild bearing

Structure of a Triglyceride:Structure of a Triglyceride:

Contains 4 subunits: Contains 4 subunits: glycerol + 3 fatty acidsglycerol + 3 fatty acids GlycerolGlycerol: : 3-carbon molecule with a hydroxyl 3-carbon molecule with a hydroxyl

group attached to each carbon atomgroup attached to each carbon atom Fatty acidsFatty acids: : long chains of carbon and hydrogen long chains of carbon and hydrogen

atoms, with a carboxyl group at one endatoms, with a carboxyl group at one end

Simple triglyceride: Simple triglyceride: all 3 fatty acids are the all 3 fatty acids are the samesame

In a mixed triglyceride: In a mixed triglyceride: 3 fatty acids are 3 fatty acids are differentdifferent

Diagram of A TriglycerideDiagram of A Triglyceride

4 Kinds of Triglycerides cont.4 Kinds of Triglycerides cont.

2. 2. FATTY ACIDSFATTY ACIDS:: Long chains of carbon and hydrogen Long chains of carbon and hydrogen

atoms, with a carboxyl group at one endatoms, with a carboxyl group at one end Can be:Can be:

SaturatedSaturated – contains all single bonds – contains all single bonds between it’s carbon atoms so chain is straightbetween it’s carbon atoms so chain is straight E.g. E.g. steric acidsteric acid

UnsaturatedUnsaturated – – contains at least one double contains at least one double or triple bond between it’s carbon atoms so or triple bond between it’s carbon atoms so chain is bentchain is bent e.g. e.g. oleic acidoleic acid

Saturated TriglycerideSaturated Triglyceride(saturated fats):(saturated fats):

Contains Contains fatty acids with only single fatty acids with only single bondsbonds

Less healthy form of fatLess healthy form of fat SolidSolid at room temperature at room temperature Diets high in saturated fats can lead to Diets high in saturated fats can lead to

clogged arteries which increase risk of clogged arteries which increase risk of heart attack and strokeheart attack and stroke e.g. animal fats – used to make lard and fats e.g. animal fats – used to make lard and fats

in butterin butter

Diagram of Saturated TriglycerideDiagram of Saturated Triglyceride

Unsaturated TriglycerideUnsaturated Triglyceride(unsaturated fats):(unsaturated fats):

Contains Contains fatty acids fatty acids with more than one with more than one double bonddouble bond

Healthier form of fatHealthier form of fat LiquidLiquid at room at room

temperaturetemperature E.g. vegetable oils E.g. vegetable oils

made from plants such made from plants such as sunflowers, as sunflowers, canolas, olives, canolas, olives, grapeseedgrapeseed

Diagram of Unsaturated Diagram of Unsaturated TriglycerideTriglyceride

4 Kinds of Lipids cont.4 Kinds of Lipids cont.

3. 3. STEROIDSSTEROIDS:: Lipid molecules made of Lipid molecules made of 4 carbon rings4 carbon rings

e.g.e.g. Male and female sex hormonesMale and female sex hormones::

testosterone, estrogen, progesteronetestosterone, estrogen, progesterone

Steroid examples continuedSteroid examples continued

CHOLESTEROLCHOLESTEROL::- Steroid found in Steroid found in cell membranes (causes cell membranes (causes

membrane to be “fluid”)membrane to be “fluid”)- There is no cholesterol in There is no cholesterol in plantsplants- Reducing Reducing saturated fatssaturated fats in your diet helps to in your diet helps to

reduce your reduce your blood cholesterol levelsblood cholesterol levels- High concentration of High concentration of cholesterolcholesterol in blood stream in blood stream

can clog your arteries and increase your risk of can clog your arteries and increase your risk of heart attack and strokeheart attack and stroke

- HDL – “good cholesterol”HDL – “good cholesterol”- LDL – “bad cholesterol”LDL – “bad cholesterol”

Diagram of Cholesterol MoleculeDiagram of Cholesterol Molecule

4 Kinds of Lipids cont.4 Kinds of Lipids cont.

4. 4. PHOSPHOLIPIDSPHOSPHOLIPIDS Main component of Main component of cell membranescell membranes Determine what is allowed to enter and leave Determine what is allowed to enter and leave

cellcell Lipid molecules similar to Lipid molecules similar to triglyceridestriglycerides, but a , but a

phosphate groupphosphate group replaces one of the replaces one of the fatty fatty acidsacids

Have aHave a hydrophilic (water-loving, polar) headhydrophilic (water-loving, polar) head Hydrophobic (water-hating, non-polar) tailHydrophobic (water-hating, non-polar) tail

Diagram of Phospholipid:Diagram of Phospholipid:

FLUID MOSAIC MODEL OF CELL FLUID MOSAIC MODEL OF CELL MEMBRANEMEMBRANE

Represents a structure of the cell Represents a structure of the cell membrane which is made of many parts membrane which is made of many parts that are free flowing, yet stay togetherthat are free flowing, yet stay together

FMMFMM

The Cell Membrane is Composed of:The Cell Membrane is Composed of: Phospholipid bilayerPhospholipid bilayer: hydrophilic on the : hydrophilic on the

outside and hydrophobic on the insideoutside and hydrophobic on the inside Cholesterol moleculesCholesterol molecules: maintain the fluid : maintain the fluid

condition of the phospholipid bilayer by condition of the phospholipid bilayer by separating the phospholipid moleculesseparating the phospholipid molecules

Embedded proteins:Embedded proteins: Integral proteins:Integral proteins: span entire width of phospholipid span entire width of phospholipid

bilayer and act as channels for molecules to pass into bilayer and act as channels for molecules to pass into and out of the celland out of the cell

Peripheral proteins:Peripheral proteins: sit on outside membrane and sit on outside membrane and act as recognition receptors for the cellact as recognition receptors for the cell

Recall: Function of Cell MembraneRecall: Function of Cell Membrane

Separates the cell contents from it’s Separates the cell contents from it’s environmentenvironment and allows for and allows for selective passageselective passage of materials in and out of the cellof materials in and out of the cell

Substances that:Substances that: Can enter cell membrane:Can enter cell membrane:

Water and other small moleculesWater and other small molecules Large, hydrophobic moleculesLarge, hydrophobic molecules

Cannot enter cell membrane (need to enter Cannot enter cell membrane (need to enter through protein channels in membrane):through protein channels in membrane):

Large hydrophilic molecules (glucose)Large hydrophilic molecules (glucose) Ions (charged atoms: NaIons (charged atoms: Na++, Cl, Cl--, K, K++