Upload
elijah-conley
View
221
Download
0
Tags:
Embed Size (px)
Citation preview
How are organic compounds different from inorganic compounds?
Why is water so important to living things?
Inorganic Compounds – derived from nonliving things
Organic Compounds – derived from living things and contain “C” - “H” & “O”
So, what would water (H2O) be??
1. A source of hydrogen & some oxygen
2. A medium for dispersal & transport
3. Most common solvent
Water’s biological functions stem from its chemical structure
In a water molecule the 2 hydrogen atoms are covalently bonded to the oxygen atom
Although electrons are shared, they are not shared equally
The oxygen atom has 8 protons in its nucleus to attract electrons
The hydrogen atom only has one proton
The nucleus of the oxygen atom more strongly pulls the shared electrons
As a result the electrical charge is unevenly distributed
The 3 atoms in a water molecule are not arranges in a straight line
The 2 hydrogen atoms bond with the oxygen atom at an angle
The total electrical charge on the molecule is zero
But the area where oxygen is located is slightly negative and the areas where the 2 hydrogens are located are slightly negative
Makes water effective at dissolving many other substances› Sugars› Some proteins› Ionic compounds**NaCl – ionic compound that dissociates
into Na+ ions and Cl- ions in water. **Important for essential body functions
such as muscle contraction and the sending of nerve impulses
Polar water molecules are attracted to eachother
A hydrogen bond forms between a slightly positive H atom in one water molecule and a slightly negative oxygen atom in another water molecule
So, water clings to itself and to other substances
Cohesion – attractive force between particles of the same kind
Water molecules are cohesive The hydrogen bonds cause water to
act as if it has a skin on its surface This is called surface tension Water appears to bulge from the
sides of objects
Adhesion is the attractive force between unlike substances
Capillary Action - Adhesion + Cohesion allows water molecules to move up through narrow tubes against the force of gravity
You can observe the flow of colored water up through a stem and into a flower
Contain carbon atoms that are covalently bonded to other carbon atoms
Carbon atoms are usually bonded to other atoms as well – H, O and N
The chemistry of carbon is the chemistry of life
Has four electrons in outer shell:
It wants to fill its outer shell with 8 electrons
It can form four covalent bonds with itself or other elements
It can combine in many ways(chains, branches, and rings)
It can form double or triple bonds Functional groups – clusters of atoms
attached to the carbon determine the characteristics of a compound (OH)
Large molecules are built up from smaller molecules – monomers
Monomers bond together to form polymers (larger molecules of repeated, linked units)
Large polymers are called macromolecules
Monomers link together to form polymers in a chemical reaction called a condensation reaction or a dehydration synthesis reaction
As the monomers link together, a molecule of water is released
The breakdown of a complex molecule or polymer occurs through a hydrolysis reaction
This is the reverse of a condensation reaction
Water must be added to separate the monomers
Life processes require a constant supply of energy
Adenosine triphosphate (ATP) has 3 phosphate groups attached to each other by covalent bonds
When bond that holds the last phosphate group is broken – lots of energy is given off
This energy drives the chemical reactions within each cell
Complete carbon compounds activity
Finish for homework if not completed in class
Why is carbon so commonly bonded to itself and other atoms?
What type of reaction results in the formation of polymers?
What type of reaction breaks down polymers?
THERE ARE “FOUR” DIFFERENT CLASSES OF ORGANIC COMPOUNDS› Carbohydrates› Lipids› Proteins› Nucleic Acids
Organic compounds of C, H and O
Used as energy sources in cells
Also found in several cellular structures such as bacterial capsules
They are synthesized from water and carbon dioxide during photosynthesis
Monosaccharides are the simplest carbohydrates
They are the building blocks for the larger carbohydrates (polysaccharides)
Glucose, galactose and fructose are examples of isomers – they have the same chemical formula C6H12O6
But their structures and properties are different
Represents the basic supply of energy in the world
Half of the world’s carbon exists as glucose
Double sugars – composed of two monosaccharides held together by covalent bonds
They are made from glucose molecules through dehydration synthesis – water is removed as the new bonds are formed
Examples are:› maltose – found in barley and used to ferment beer› lactose – found in milk and digested by bacteria to
form yogurt, sour cream› Sucrose – table sugar and is the starting point in
wine fermentation and may be a cause of tooth decay
Complex sugars
Large compounds formed by joining together 100’s or 1000’s of glucose molecules› Starch – used by bacteria as an energy
source› Cellulose – a component of the cell walls of
plants and molds and also used as an energy source by microorganisms
What are the 4 classes of organic compounds?
What 3 elements are carbohydrates made up of?
What carbohydrate is considered a universal source of energy?
Dissolve in organic solvents, but not in water
Like carbohydrates, they are composed of C, H, and O, but with much less O
The best known lipids are fats
Fats are important long-term energy sources for living things
Fats are also components of cell membranes
Fats consist of a 3 carbon glycerol molecule and up to 3 long-chain fatty acids
2 major types of fatty acids:› Saturated – contain the maximum number
of H atoms› Unsaturated – contain less than the
maximum number of H atoms› Unsaturated fatty acids are good for us –
they lower the levels of cholesterol in the blood
Overhead Master #7
What are the facts about saturated fat?
If the carbon atoms (C's) in a fat have all the hydrogen atoms (H's) that they can hold, the fat is saturated.
Lipid molecules are sparingly to insoluble in water. Lipids are hydrophobic because the molecules consist of long, 18-22 carbon, hydrocarbon backbones with only a small amount of oxygen containing groups. Lipids serve many functions in organisms. They are the major components of waxes, pigments, steroid hormones, and cell membranes. Fats, steriods, and phospholipids are very important to the functioning of membranes in cells and will be the focus of this tutorial. Fats (triacylglycerols)
Other types of lipids:› Waxes – long chains of fatty acids
Bee’s wax Plant leaves
› Phospholipids – contain a phosphate group Cell membranes
› Steroids – composed of several rings of carbon atoms with side chains Cholesterol Estrogen Testosterone
What are fats used for in your body? What is the difference between
saturated and unsaturated fats?
Most abundant organic compounds of living things They can be:
› Structural› Enzymes – regulate the rate of chemical reactions
They are composed of chains of amino acids
Each amino acid contains› Carbon atom› Amino group (NH2)› Carboxyl group (COOH)› Functional (R) group - what makes the 20 AA’s different
Amino acids are joined together by peptide bonds› 2 AA’s – dipeptide› More than 2 AA’s - polypeptide
The sequence of amino acids is extremely important because one mistake changes the protein (mutations)
Protein Structure:› Primary – AA sequence› Secondary – AA chain twists into a corkscrew
or sheet pattern› Tertiary – Protein folds back upon itself› Quaternary – Multi-unit cluster
Enzyme - protein that acts as a catalyst
They lower the amount of activation energy needed for a reaction to occur
Depends on a physical fit between the enzyme molecule and its substrate (lock and key)
As they link, the enzyme changes shape and some of the substrate's chemical bonds are weakened
Insulin – protein that regulates the metabolism of carbohydrates and fats
People with diabetes don’t produce enough insulin
If we could understand insulin’s structure, we could make it in the lab as a drug
Frederick Sanger – broke insulin code; used chromatography to identify the kinds and amounts of amino acids
Some of the largest molecules found in organisms› DNA – genetic material in the chromosomes
that carries the genetic code› RNA – cell messenger that functions in protein
construction
Composed of nucleotides – 3 parts› Carbohydrate molecule (ribose or deoxyribose)› Phosphate group› Nitrogenous base
DNA – adenine, guanine, cytosine, thymine RNA – adenine, guanine, cytosine, uracil
DNA is located in the chromosomes of the cell
It passes on the genetic information and directs protein synthesis
DNA molecule consists of 2 single strands of DNA in opposite directions arranged in a double helix ladder:› Sides of ladder – sugar and phosphate› Rungs of ladder – paired nitrogenous bases
DNA in the nucleus carries the genetic code
DNA gets transcribed into messenger RNA (mRNA) in the nucleus
mRNA leaves the nucleus and brings the code out into the cytoplasm of the cell
mRNA gets translated into protein with the help of transfer RNA (tRNA) and ribosomes