carbohydrates & lipids
DESCRIPTION
Carbohydrates & Lipids. September 10 th , 2012. What are Carbohydrates?. Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen that serve as energy sources and structural materials for cells of all organisms. Structure of carbohydrates. - PowerPoint PPT PresentationTRANSCRIPT
CARBOHYDRATES & LIPIDS
September 10th, 2012
WHAT ARE CARBOHYDRATES?
Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen that serve as energy sources and structural materials for cells of all organisms
STRUCTURE OF CARBOHYDRATES
Carbohydrates consist of carbon, hydrogen, and oxygen
They may be monomers or polymers
WHAT ARE MONOMERS?Monomers are molecules that can
be bonded to other identical molecules to form polymers
The monomer form of carbohydrates are known as monosaccharides
Glucose is an example of a monosaccharide
DISACCHARIDESDisaccharides: consist of two
monosaccharides. Ex: maltose & sucrose
Disaccharides form by dehydration synthesis – where a molecular of water is split out as the bond is formed
Disaccharides are broken down into monomers by hydrolysis
WHAT ARE POLYMERS?Polymers are substances that have
a molecular structure built up chiefly or completely from a large number of similar units bonded together
The polymer form of carbohydrates are polysaccharides
Polysaccharides are large carbohydrate molecules that are polymers of monsaccharides
Ex: starch, glycogen and cellulose
Glycogen is a polymer of glucose
Glucose
Glycogen
WHAT IS STARCH?Starch is the energy storage
molecule in plants and a good source of energy for human cells
Produced by all green plants It is the most common carbohydrate
in the human diet and is contained in large amounts in such staple foods as potatoes, wheat, maize (corn), rice and cassava
WHAT IS GLYCOGEN?Glycogen is the short-term energy
storage molecule in human cells
WHAT IS CELLULOSE?Cellulose is the molecule that makes
up plant cell walls in green plants
POLYSACCHARIDES CONTINUED
Differences between the polysaccharides are caused by differences in their molecular structure
Organisms must break down polysaccharides to obtain usable glucose molecules. For example: our body breaks down starch and glycogen by hydrolysis
However, we cannot break down cellulose into molecules of glucose. Instead, cellulose passes undigested through our digestive system
WHAT ARE LIPIDS?Lipids are organic compounds that
include: fats, phospholipids, waxes, and steroids
Long-term energy storage Insoluble in water
FATS In human cells, fats serve as long-
term energy storageUseful long-term energy storage
molecules in both plants and animals – because of the many energy containing carbon-hydrogen bonds
Very concentrated source of energyStored fat helps cushion and protect
important organs such as the kidneys
FATS, CONTINUED…Fats are made up mainly of two types
of molecules: fatty acids and glycerol Fatty acids may be either saturated or
unsaturatedSaturated fatty acids have no double
bonds between their carbon atoms. They are relatively straight structurally
Unsaturated fatty acids have one or more double bonds between carbons and so are not saturated with hydrogen
SATURATED VS. UNSATURATED FATTY ACIDS
SATURATED VS. UNSATURATED FATTY ACIDSWhen referring to the structure of a
fatty acid, wherever you see a double bond, it causes a kink in the molecule
The kinks prevent unsaturated and polyunsaturated fatty acids (more than one double bond) from packing together tightly – therefore these are liquid at room temperature
The linear saturated fatty acids are able to pack together more tightly and tend to be solids at room temperature
SATURATED VS. UNSATURATED FATTY ACIDS Saturated Fatty Acids = Saturated Fats - found in red meat and dairy products - associated with health problems
usually cardiovascular related Unsaturated Fatty Acids = Unsaturated
Fats - Come from plants like: canola, corn and
olives. Also some animals - Some may benefit your health - Linoleic acid is actually essential for
your body!
GLYCEROLGlycerol is an organic molecule with
3 carbons and 3 hydroxyl groupsBonds with 2 or 3 fatty acids to form
a fatGlycerol bonded to 3 fatty acids
TriglycerideTriglycerides – long-term energy
storage in animals. Stored in adipose tissue
Adipose tissue body fat
GLYCEROL CONTINUED…Fat cells usually cannot grow.
Therefore we can’t create new fat cells in our body, instead we can just add to the triglycerides existing in our fat cells
PHOSPHOLIPIDSPhospholipids are an important
part of cell membranes. They help the cell membrane perform its role of monitoring the passage of molecules into and out of the cell
Consist of a hydrophilic phosphate molecule and two hydrophobic fatty acid tails
Hydrophilic – water-lovingHydrophobic – water-hating
STEROIDSSteroids is a group of organic
compounds that include: cholesterol and the sex hormones – estrogen and testosterone
Cholesterol is necessary for many different functions, including the proper formation of cell membranes. However, too much cholesterol can cause for the onset of cardiovascular disease
STEROIDS CONTINUED…Estrogen and testosterone are
present in both males and females It is the amount of estrogen and
testosterone that vary in males and females
Testosterone – more in malesEstrogen – more in females