CHAPTER 2 - DISCOVERING LIFE
All living things are characterized by:
Compounds can be broken down into __________________, which cannot be broken down into another kind of substance.
H20 = H (element) + O (element)
The 4 elements common to all living things:
Elements are composed of ________________, which are the smallest particles of matter that retain all of the chemical properties of an element.
Each atom has a nucleus containing:
(# PROTONS = # ELECTRONS)
The number of ____________________ in the outer energy shell determines the way atoms react.
Periodic Table/ Element Chart
Electron Dot Model
1. H2O H = _________ O = _________
2. 2 (H2O) H = _________ O = _________
Chemical Bonding - A force that holds 2 atoms together. Consists of interactions between electrons of outer energy levels of atoms. Atoms WANT to fill their outer electron shells in order to be more stable.
An ______________________ is an atom that has gained or lost electrons, and has a ____ or ____ charge.
A _______________________ is a group of atoms held together by covalent bonds. Most consist of more than two atoms.
Ex: Carbon has 4 electrons in the outer energy level, so it can react with up to four other atoms.
Single bond between two atoms: 1 electron is shared
Double bond between two atoms: 2 electrons are shared
Chemical Bonds can be formed in TWO WAYS:
An _____________ is an atom with a + charge or - charge
____________________ is when non-ionic compounds can be converted into ions.
PH Scale - How we measure the hydrogen ion (H+) level of a solution
10 Milk of Magnesia
13 Hair Remover (Nair)
____________________ - A solution has more hydrogen (H+) ions than hydroxide (OH-) ions Ex: (HCl)
____________________ - A solution has less hydrogen (H+) ions than hydroxide (OH-) ions Ex: (MgOH)
____________________ - Regulate & stabilize pH during reactions that release large amounts of ions.
____________________ - Substance that promotes a chemical reaction
____________________ - Highly specialized & specific protein catalysts found in organisms
MOLECULES OF LIFE
Organic Molecules are made of carbon chains.
Molecules join together to make _________________________:
Carbohydrates: Contains C, H, O, usually in a 1:2:1 ratio (C6H12O6). Used for ENERGY STORAGE
Monosaccharides - Simple sugar with 7 or fewer carbons. EX: glucose, fructose. (draw structure)
Disaccharides - 2 Simple sugars. EX: sucrose = fructose + glucose (draw structure)
Polysaccharides - Many simple sugars linked together. EX: cellulose (draw structure)
Animals store glucose in the form of glycogen; Plants manufacture glucose in the form of cellulose.
Lipids: Contain C, H, O. Includes fats, oils, wax, steroids (cholesterol). Used for ENERGY STORAGE. 1 gram of fat has 2X more energy than 1 gram of carbohydrate. WHY? (more C-H bonds than carbs. Energy is held in the electron shared by C-H bonds)
Name one similarity and one difference between carbs & lipids:
Basic structure of a lipid = GLYCEROL + FATTY ACIDS (3)
Saturated Fat - Fatty acids have no carbon double bonds (They are saturated with Hydrogen atoms) - draw structure
Unsaturated Fat - Fatty acids have carbon double bonds; Chains have kinks in them. draw structure
Steroids - Ex: Cholesterol
Proteins: Contain C, H, N, O. Consists of long chains of amino acids (20 exist).
Dipeptide - Two amino acids linked together
Tripeptide - Three amino acids linked together
Polypeptide - Many amino acids linked together
Shape of a protein is determined by the amino acid sequence. Interactions between the amino acids in the protein chain repel or attract one another, causing the protein to bend, twist, curl & fold. This shape is called a protein's tertiary structure, or 3-D shape. This shape only allows certain molecules into the protein, or enzyme for reactions to occur. (A fat could not fit into the enzyme during metabolism)
Nucleic Acids: Contain C, H, O, N, P. Nucleic acids consist of genetic material, DNA and RNA.
Compare and contrast DNA and RNA.
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