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CHAPTER 2 - DISCOVERING LIFE

All living things are characterized by:

BASIC CHEMISTRY

Compounds can be broken down into __________________, which cannot be broken down into another kind of substance.

EX: Water

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:

  1. Protons: Positively charged particles in the center of the nucleus (+)
  2. Neutrons: Uncharged particles in the center of the nucleus
  3. Electrons: Negatively charged particles in the center of the nucleus (-)

(# PROTONS = # ELECTRONS)

The number of ____________________ in the outer energy shell determines the way atoms react.

 

Periodic Table/ Element Chart

6
C
Carbon
12.011

 

Electron Model

General Info

Example

 

 

 

 

 

 

 

 

Electron Dot Model

 

General Info

Example

 

 

 

 

 

 

 

 

 Counting Atoms

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.

  1. Covalent Bond - _________________________of electrons between two atoms.
  2. EX: H2O

     

     

     

     

     

     

  3. Ionic Bond - __________________________ of electrons by atoms in order to stabilize outer electron shells.

EX: NaCl

 

 

 

 

 

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.

EX: water

H2O

H+ OH-

PH Scale - How we measure the hydrogen ion (H+) level of a solution

0
1 HCl
2
3 Vinegar
4 Tomato
5 Urine
6
7 Blood
8
9
10 Milk of Magnesia
11
12
13 Hair Remover (Nair)
14    NaOH

____________________ - 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).

FUNCTIONS:

 

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.

DNA

RNA

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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