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Chapter 2:  Chemistry of Life

Page history last edited by Shelly Turner 10 years, 11 months ago

Chapter 2 – The Chemistry of Life

 

 

 

Chapter 2 Notes

 

I.      Section 1: The Nature of Matter

II.    Atoms: the smallest particle of an element that has the properties of that element

A.   Parts of an atom:

1.    Protons – positively charged, found in core

2.    Neutrons – no charge, found in core

3.    Electrons – negatively charged, found in a cloud around the core   

 

              

B.   Atoms bond together to form compounds

1.    Types of bonds:

a)  Covalent Bonds – (electron sharing) – formed when electrons are shared between two elements – strongest type of bond  

Ex.  H + Cl  =  HCl

b)      Ionic Bonds – (electron donating) – electrons from one atom are donated to another creating an ion(atoms that are positively charged due to the loss of electrons or negatively charged due to addition of electrons) - positive and negative atoms are attracted to each other creating the bond 

Ex. Na + Cl  =  Na+Cl- 

c)      Hydrogen Bonds – (weak electrical attractions) – larger Oxygen molecules pull smaller Hydrogen molecules closer – “almost” share an electron          

 Ex. 2H + O = H2O

 

 

 

III.  Section 2: Water and Solutions

A.  Properties of Water

1.    Water stores heat efficiently

2.    Water is cohesive – water molecules stick together

3.    Water is adhesive – Water molecules stick to other substances

4.    Water is polar – it has a positive and negative side

a)    Solution – substance(s) dissolved in water (Ex. Salt water)

b)    Polar molecules can dissolve in water creating a solution

c)     Non-polar molecules (like oil) can not dissolve in water and do not create a solution

B.  Acids and Bases

1.    Acids – form hydrogen ions when dissolved in water

2.    Bases – reduce hydrogen ions in water

3.    Ph Scale 

IV.   Section 3: Chemistry of Cells

A.   Organic Molecules/Compounds – combinations of atoms containing carbon

B.   There are 4 major types of organic compounds found in living things

1.    Carbohydrates – Made of carbon, hydrogen, and oxygen in the proportion of 1:2:1; main source of energy; provide structure in plants

a)      3 Types of Carbohydrates

(1)   Monosaccharide (simple sugars) – the building blocks of carbohydrates  Ex. Glucose and Fructose (fruit sugars)

(2)   Disaccharides (double sugars) – 2 or more monosaccharides put together Ex. Sucrose (table sugar) and Lactose (milk sugar)

(3)   Polysaccharides (many sugars) – 3 or more monosaccharides put together Ex. Rice, potatoes, beans, corn, pasta, bread

(a)     Examples of polysaccharide groups

(i)   Starches: plants store energy (extra glucose) in this form

(ii)  Glycogen: animals store energy (extra glucose)in this form in two areas, the muscles and liver, when these are full the remaining energy is stored in fats.

(iii)  Cellulose – used in the structure of the cell wall of plants.  Cannot be digested by humans but is essential for digestive health.

2.    Lipids – insoluble organic compounds (do not dissolve in water); made of fatty acids and glycerol in the proportion of 1:3; held together by hydrogen bonds; store a lot of energy

a)      Contain almost 2x the energy found in carbohydrates (9 calories VS 4 calories)

b)      4 Types of Lipids

(1)   Fats and oils – provide long term energy storage and act as insulation to keep animals warm

(a)  Fat is solid at room Temp, oils liquid

(b)  Saturated fats – stick butter, lard, that whitish waxy looking stuff that forms on a steak or hamburger in the refrigerator; unhealthy fats, effect heart/liver functions, weight gain, and cholesterol levels

(c)  Unsaturated fats – olive oil, fish oil, etc are much better for you and can even raise your level of “good” cholesterol.

(2)   Waxes – provide protection by repelling water (Ex. Cuticle of plants; naturally occur on fruits and vegetables to prevent dehydration

(3)   Phospholipids – make up the cell membrane

(4)   Steroids – serve structural and control functions in the body(Ex. Hormones such as Estrogen, Testosterone, and fats such as Cholesterol that is produced by the body) 

3.    Proteins – large complex molecules made of amino acids (20 amino acids are used to make a variety of protein combinations); how the amino acids are arranged is key to biodiversity

a)    6 Major Protein Functions:

(1)  Movement – actin and myocin are proteins needed for contraction and relaxation of muscle fibers and therefore muscle movement

(2)  Structure – collagen is the most abundant protein in the human body, it gives elasticity and firmness to skin; forms bones, tendons, ligaments, and cartilage.

(3)  Defense – antibodies are proteins that help animals fight off invasion by viruses and bacteria

(4)  Transport – hemoglobin is the protein in red blood cells that carries oxygen through the bloodstream; a lack of red blood cells is called anemia

(5)  Nutrition – casein is a protein in breast milk that stores amino acids for use by newborn mammals; many proteins are used to build muscles and repair injuries

(6)  Regulation – enzymes catalyze (speed up) chemical reactions in the cells; we get them from eating raw vegetables (note the verb catalyze is from the non catalyst – a chemical that speeds a chemical reaction without being altered itself)

4.    Nucleic Acids – large complex molecules that contain hereditary or genetic information

a)    2 Types of nucleic acids

(1)  DNA (deoxyribonucleic acid) – caries instructions that control the activities of the cell

(2)  RNA (ribonucleic acid) – responsible for protein synthesis

 

 

C.  One more important biological molecule – ATP

1.    adenosine triphosphate

2.    energy currency of the cell; contains 2 extra energy storing phosphate groups

3.    cells need a steady supply of ATP to function 

V.  Section 4: Energy and Chemical Reactions

A.  Energy – the ability to move or change matter; many types including chemical, light, heat, mechanical, and electrical

1.    Energy can be stored or released in a chemical reaction

2.    Chemical reactions are processes in which chemical bonds between atoms are broken and new ones formed producing one or more new substances; summarized as …       reactants   →   products

3.    Metabolism – all the chemical reactions that occur within an organism

4.    Activation Energy – energy needed to start a reaction (like the first push to get a large object rolling downhill)

5.    Enzymes – act as a catalyst to speed up reactions once started

a)    Enzymes affect specific substances (ex. Amylase affects starch & glucose) and are affected by factors like temperature and pH

b)    Steps in an Enzyme Action

(1)  Coordinating enzyme and substrate are available

(2)  Substrate binds to enzyme’s active site

(3)  Chemical bonds in substrate break; substrate is converted into its products

(4)  Products are released; enzyme is unchanged

                      

Elements and Symbols to know…

 

H

Hydrogen

Cu

Copper

O

Oxygen

Zn

Zinc

Li

Lithium

Au

Gold

Na

Sodium

Ag

Silver

K

Potassium

Pt

Platinum

Be

Beryllium

Hg

Mercury

Mg

Magnesium

B

Boron

Ca

Calcium

Al

Aluminum

Ba

Barium

Pb

Lead

Fe

Iron

Sn

Tin

Mn

Manganese

Si

Silicon

U

Uranium

C

Carbon

Ni

Nickel

N

Nitrogen

P

Phosphorous

As

Arsenic

S

Sulfur

F

Fluorine

Cl

Chlorine

Br

Bromine

I

Iodine

R

Radon

Ar

Argon

Ne

Neon

He

Helium

Ra

Radium

 

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