Upload
sofiapazm
View
811
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Molecules of Life or Organic Molecules, for 9th grade
Citation preview
THE MOLECULES OF LIFE
Chapter 2 (chapter 5 in the book)
Like all matter, life is built from atoms — the basic units of matter that link together to form molecules.
Organic molecules are the molecules of life and are built around chains of carbon atoms that are often quite long.
There are four main groups of organic molecules that combine to build cells and their parts: carbohydrates, proteins, lipids, and nucleic acids.
Definition
CARBON IS THE MAIN INGREDIENT
OF ORGANIC MOLECULES
2.1 Concept
Carbon based molecules are called organic molecules.
Non-carbon based molecules—
water, oxygen, and ammonia are inorganic molecules.
ORGANIC vs. INORGANIC
2.1.1 Atomic Structure of Carbon
Carbon has 4 electrons in outer shell.
Carbon can form covalent bonds with as many as 4 other atoms (elements).
Usually with C, H, O or N.
Example:CH4(methane)
Two or more atoms held together by
covalent bonds.
# and types of atoms in a molecule
# and types of atoms in a molecule
How atoms are linked by bonds
review MOLECULES STRUCTURE
Atoms and complexes connected by non-covalent bonds such as hydrogen bonds or ionic bonds are generally not considered single molecules
Types of carbon backbones:
- A) straight chain
- B) branched chain
- C) can form ring structures
2.1.2 CARBON BACKBONES(SKELETONS)
CARBON SKELETONS
Group of atoms within molecules—determine properties of organic molecules
React in predictable ways with other molecules
Hydrophilic molecules: molecules that are attracted water
Hydrophobic molecules: molecules that do not mix with water
2.1.3 FUNCTIONAL GROUPS
4 most common functional groups:
1) hydroxyl group: (OH)
2) carbonyl group: (C=O)
3) carboxyl group: (O=C-OH)
4) amino group: (H-N-H)
2.1.3 FUNCTIONAL GROUPS
Most biological molecules are large and are made up of smaller subunits
Monomer: molecular subunit that is building block of a larger molecule
Polymer: long chain of monomers
2.1.4 MONOMERS & POLYMERS
Also called condensation reaction Links monomers together forming
polymers or making polymer chains longer
Water molecule is removed in forming a polymer or making it longer
Same type of reaction occurs regardless of type of monomers being linked or type of polymer produced
2.1.5 DEHYDRATION REACTION
2.1.5 DEHYDRATION REACTION
Chemical reaction where polymers are broken down to their monomers
Large polymers must be broken down to make monomers available to cells
Hydrolysis breaks the chemical bonds in polymers by adding water molecules reverse of dehydration/condensation
2.1.6 HYDROLYSIS REACTION
2.1.6 HYDROLYSIS REACTION
http--faculty.pingry.org-thata-pingry_upload-movies-water_macromolecules-condensation.mov.url
DEHYDRATION & HYDROLYSIS
Short polymer MonomerHydrolysis
Dehydration
Longer polymer
Summary:
Dehydration: water is removed to build a polymer
Hydrolysis: Water is added to break down a polymer
DEHYDRATION vs. HYDROLYSIS
CARBOHYDRATES PROVIDE FUEL AND BUILDING
MATERIAL
CONCEPT 2.2
Sugars contain carbon, hydrogen, and oxygen in the following ratio:
1 carbon : 2 hydrogen : 1 oxygen
Molecular formula of any carbohydrate is a multiple of the basic formula CH2O
2.2.1 CARBOHYDRATES ARE MADE UP OF SUGAR MOLECULES
Main fuel supply for cellular work
Other uses: - Provide raw material to make other organic molecules such as fats
- Used to make energy stockpiles
- Serve as building materials
2.2.2 HOW CELLS USE SUGARS
Sugars that contain just one sugar unit or monomer
Examples: - glucose - fructose - galactose
2.2.3 MONOSACCHARIDES
“double sugars”
Produced in dehydration reactions from two monosaccharides
Most common disaccharide is sucrose – table sugar—formed by linking glucose and fructose molecules
2.2.3 DISACCHARIDES
3 common types all glucose polymers:
Starch: found in plant cells—glucose storage molecule
Glycogen: found in animal cells—glucose storage—abundant in muscle and liver cells
Cellulose: used by plant cells for building material—makes up cell walls—not digestible by humans forms “bulk” in our diet
2.2.4 POLYSACCHARIDES
2.2.5 POLYSACCHARIDES
LIPIDS INCLUDE FATS AND STEROIDS
CONCEPT 2.3
Commonly known as fats and oils
Are hydrophobic do not mix with water
Simplest fats are triglycerides
Chain of 3 fatty acids (hydrocarbon molecules) bonded to a glycerol molecule
LIPIDS
http--faculty.pingry.org-thata-pingry_upload-movies-water_macromolecules-triglyceride.mov.url
TRIGLYCERIDE: SIMPLE LIPID
Act as a boundary—they are a major component of cell membranes
Circulate in the body acting as chemical signals to cells—some are hormones
Used to store energy in the body
Act to cushion and insulate the body
FUNCTIONS OF LIPIDS
All the carbon atoms in fatty acid chains contain only single bonds
Include animal fats such as butter
Solids at room temperature
SATURATED FATS
Have at least one double bond between the carbon atoms in one of the fatty acid chains
Found in fruits, vegetables, fish, corn oil, olive oil, and other vegetable oils
Liquids at room temperature
UNSATURATED FATS
SATURATED vs. UNSATURATED
Carbon skeleton forms four fused rings
Classified as lipids are hydrophobic
Some act as chemical signals or hormones estrogen and testosterone
Some form structural components of cells cholesterol
STEROIDS
EXAMPLES OF STEROIDS
Essential molecule found in all cell membranes
Serves as base molecule from which other steroids are produced
Has bad reputation cholesterol containing substances in blood are linked to cardiovascular disease
CHOLESTEROL
PROTEINS PERFORM
MOST FUNCTIONS IN
CELLS
CONCEPT 2.4
Form structures—hair, fur, muscles
Provide long-term nutrient storage
Circulate and defend the body against microorganisms (antibodies)
Act as chemical signals—hormones
Help control chemical reactions in cells--enzymes
FUNCTIONS OF PROTEINS
Polymers formed from monomers called amino acids
Amino acids bond together to form chains called a polypeptides
Sequence of amino acids makes each polypeptide unique
Each protein is composed of one or more polypeptides
PROTEIN STRUCTURE
AMINO ACID STRUCTURE
Figure 5-12: All amino acids consist of a central carbon bonded to an amino group, a carboxyl group, and a hydrogen atom. The fourth bond is with a unique side group – called the “R” group. Differences in side groups convey different properties to each amino acid.
Functional proteins consist of precisely twisted, coiled, and shaped polypeptides
Proteins cannot function correctly if shape is altered
Sequence and types of amino acids in the polypeptides affect protein shape
Surrounding environment—usually aqueous—plays a role in protein shape
PROTEIN SHAPE
Denaturation: loss of normal protein shape
Changes in temperature, pH, or other environmental conditions may cause proteins to become denatured
If the protein shape is changed, protein cannot function normally
DENATURATION
ENZYMES ARE PROTEINS THAT
SPEED UP SPECIFIC
REACTIONS IN CELLS
CONCEPT 2.5
Activation energy: minimum energy required to start chemical reaction
Chemical bonds in reactants must be weakened to start most reactions
Catalysts: compounds that speed up chemical reactions
Enzymes: proteins that act as catalysts for chemical reactions in organisms
ACTIVATION ENERGY
Provide a way for reactions to occur at cell’s normal temperature
Enzymes lower energy requirement for a chemical reactions in cells so they can occur at normal cell temperatures
Each enzyme catalyzes a specific kind of chemical reaction
ENZYMES
Substrate: specific reactant acted on by an enzyme
Active site: specific region of the enzyme that the substrate fits into
Substrate binds to enzyme’s active site where the substrate undergoes a change
HOW ENZYMES WORK
Shape of an enzyme fits the shape of only specific reactant molecules
As substrate enters, active site of enzyme changes slightly to form snug attachment
Attachment weakens chemical bonds in substrate lowering activation energy required for reaction to proceed
HOW ENZYMES WORK
ACTIVE SITE MODEL
Once products of chemical reaction are released, enzyme’s active site is ready to accept another reactant molecule
Recycling is a key characteristic of enzymes—they are not “used up” catalyzing a single reaction
HOW ENZYMES WORK
HOW ENZYMES WORK
Enzyme Activity.url
THE END