Biochemistry of Cells ORGANIC MOLECULES: Normally found in living systems Contain C (carbon) Usually...
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Transcript of Biochemistry of Cells ORGANIC MOLECULES: Normally found in living systems Contain C (carbon) Usually...
ORGANIC MOLECULES:
• Normally found in living systems
• Contain C (carbon)
• Usually in rings or long chains
• Often attached to other atoms such as Hydrogen, Oxygen and Nitrogen.
Uses of Organic Molecules• Canadians consume
an average of 140 pounds of sugar per person per year
Cellulose, found in plant cell walls, is the most abundant organic compound on Earth
Uses of Organic Molecules
• A typical cell in your body has about 2 meters of DNA
A typical cow produces over 200 pounds of methane gas each year
(see video)
cowsandmethane.rm
Touching on Water• About 60-90 percent of an
organism is water
Water is used in most reactions in the bodyWater is called the universal solvent
Carbon-based Molecules
• Although a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules
Organic chemistry is the study of carbon compounds
Carbon is a Versatile Atom
• It has four electrons in an outer shell that holds eight
Carbon can share its electrons with other atoms to form up to four covalent bonds
Carbon can use its bonds to::
• Attach to other carbons
Form an endless diversity of carbon skeletons
Large Hydrocarbons:
• Are the main molecules in the gasoline we burn in our cars The
hydrocarbons of fat molecules
provide energy for our bodies
Shape of Organic Molecules
• Each type of organic molecule has a unique
three-dimensional shape
The shape determines its function in an
organism
Functional Groups are:• Groups of atoms that give properties to the
compounds to which they attach
Gained Electrons Lost Electrons
Giant Molecules - Polymers
• Large molecules are called polymersPolymers are built from smaller molecules called monomersBiologists call them macromolecules
Most Macromolecules are Polymers
• Polymers are made by stringing together many smaller molecules called monomers
Nucleic Acid
Monomer
Linking MonomersCells link monomers by a
process called dehydration synthesis (removing a
molecule of water)
This process joins two sugar monomers to make a double
sugar
Remove H
Remove OH
H2O Forms
Breaking Down Polymers
• Cells break down macromolecules by a process called hydrolysis (adding a molecule of water)
Water added to split a double sugar
Macromolecules in Organisms
• There are four categories of large molecules in cells:Carbohydrates
Lipids
Proteins
Nucleic Acids
•CARBOHYDRATES1. Energy
2. Fuel for CNS
3. Fuel for the Muscular System
4. Spare Proteins
5. Supply Dietary Fiber
Carbohydrates• Carbohydrates include:• Small sugar molecules
in soft drinks• Long starch molecules
in pasta and potatoes
Characteristics of Carbohydrates
• Consist of carbon, hydrogen, & oxygen• Energy containing molecules• Some provide structure• Basic building block is a monosaccharide
(CH2O)n ; n = 3,5,6
• Two monosaccharides form a disaccharide
• Many form polysaccharides!
Monosaccharides:• Called simple sugars
Include glucose, fructose, & galactoseHave the same chemical, but different structural formulas
C6H12O6
Monosaccharides• Glucose is found in
sports drinksFructose is found in fruitsHoney contains both glucose & fructoseGalactose is not found in nature
Isomers• Glucose &
fructose are isomers because they’re structures are different, but their chemical formulas are the same
Disaccharides• A disaccharide is
a double sugarThey’re made by joining two monosaccharides
Involves removing a water molecule (dehydration)
Disaccharides
• Common disaccharides include:
Sucrose (table sugar) Lactose (Milk Sugar) Maltose (Grain sugar)
Disaccharides• Sucrose is composed of
glucose + fructose
Maltose is composed of glucose + glucoseLactose is made of galactose + glucose
GLUCOSE
Polysaccharides
• Complex carbohydratesComposed of
many sugar monomers linked togetherPolymers of monosaccharide chains
Starch
• Starch is an example of a polysaccharide in plants
Plant cells store starch for energy
Potatoes and grains are major sources of starch in the human diet
Glycogen• Glycogen is an example of a
polysaccharide in animals• 2/3 muscles; 1/3 liver• Acts as a carb reserve!
Cellulose
• Cellulose is the most abundant organic compound on Earth
It forms cable-like fibrils in the tough walls that enclose plants
It is a major component of wood
It is also known as dietary fiber
Dietary Cellulose
• Most animals cannot derive nutrition/energy from fiberThey have
bacteria in their digestive tracts that can break down cellulose
Another important Polysaccharide:
• CHITIN:• Glucose subunits• Partly derived from
non-sugars (nitrogen)• Composes
exoskeletons of insects
• Similar in structure to cellulose
Sugars in Water
• Simple sugars and double sugars dissolve readily in water
They are hydrophilic, or “water-loving”
WATER MOLECULE
SUGAR MOLECULE
INTERACTIVE CARBOHYDRATES:
• RECAP: Let’s Take another LOOK!
• http://www.bbc.co.uk/education/asguru/biology/02biologicalmolecules/index.shtml
Carb Digestion: (1-4 hrs) Cracker
• In the Mouth: • Saliva (salivary amylase) hydrolyzing starch to shorter
polysaccharides and maltose• Do you think much carb digestion takes place in the
mouth?• In the Stomach:• Bolus is continually broken down by acid, but its juices
contain no enzymes to digest carbohydrates.• Fibers linger in the stomach (satiety)• In the Small Intestine – PERFORMS MOST OF THE
WORK!!• Pancreatic amylase enters and breaks down further.
Digestion cont…
• On the Outer Membranes of the Intestinal Cells:• SPECIFIC ENZMES DISMANTLE DISACCHARIDES!• Maltase breaks maltose into • _________ +________• Sucrase breaks sucrose into • ___________ + _______• Lactase breaks lactose into • ___________ + ________• At this point, all polysaccharides and disaccharides
are broken down into mono’s – mainly glucose (but some fructose and galactose as well)
Carb Absorption
• Nutrient absorption takes place in the SI
• Glucose and galactose leave the cells lining the SI by active transport
• Fructose leaves by facilitated diffusion, which slows its entry and produces a smaller rise in blood sugar.