A Summary of How Theories Develop in Science: – based on a series of verifiable observations & measurements. leads to a conclusion based on inductive reasoning.

A Summary of How Theories Develop in Science: – based on a series of verifiable observations & measurements.

leads to aconclusionbased oninductive reasoning

- tests must be...

– other people must be able to repeat and verify or reject tests. a theory arises scientific theories enable researchers tomake...

– that guides research and opens-up new questions.

conclusions drawn on evidence can be tested with an experiment or additional observations.

Unit 2: Matter and Energy

Identify what is wrong with each of the following statements.

1.Everybody knows that gravity exists. There is so much proof for the Law of Gravity that it will not change.

2.Although many scientists believe in evolution, there are still many things that cannot be explained by evolutionary biologists. Therefore, it is just a theory.

3.After completing our lab, we proved that the theory of enzyme activity was right.

– the basic unit of matter• – center of the

atom• – positively

charged particles (+)• – particles that

carry no charge• – negatively

charged particles (-), 1/1840 the mass of a proton (equal, but opposite charge)

Electron configuration of oxygen

– spaces that electrons have the greatest probability of being found

Basic Chemistry

The Periodic Table

Element –

6

CCarbon12.011

Go to Section:

The Element Carbon on the Period Table

Atomic number –

Atomic mass –

Atomic number

Atomic mass

Why is the atomic mass of carbon not exactly twelve?

The 6 most common elements that make up living organisms:

CHONSP or SPONCHThe Periodic Table of

Elements

Elements Found in Biological Organisms

Compounds and Chemical Bonds• Compound –

Two Main Types of Chemical Bonds:• Ionic Bonds –

• Covalent Bonds –

Why Ionic Bonds Are Important to Life

• Break apart easily in water

• The ions are used to transfer positive or negative charges in cells (i.e. allows information, materials, and short-term energy to be exchanged)

Why Covalent Bonds Are Important to Life

• Store energy in the bonds (this energy can be used for growth, movement, etc by an organism)

• Do not break apart in water (the bodies of plants and animals are mostly water – glucose will not release its energy)

• Form the building blocks of life (proteins, fats, etc. are made of covalent bonds)

2-2 Properties of WaterWater is the single most abundant compound in most living things and it possesses many special properties. Water is one of the few compounds that is liquid at the temperatures found over much of the Earth’s surface. When water does freeze, it expands, becomes less dense than liquid water, and floats.

Polarity of Water

• Water is a polar molecule –

• Oxygen has more electrons, so it is more negatively charged (i.e. it is electronegative and pulls electrons to it)

• Hydrogen has fewer electrons, so it is more positive than negatively charged

Hydrogen Bonding in Water

• – weak bond formed with a positively charged hydrogen atom and other negatively charged atoms

• Waters polarity and hydrogen bonds give it unusual properties

• It easily forms a solid (ice), liquid, and gas (vapor).

• Cohesion – a property dependent upon the strength of attractive forces between molecules of the same substance (water to water)

• Adhesion – a property dependent upon the strength of attractive forces between molecules of different substances (water to glass)

Go to Section:

Cl-

Water

Cl-

Na+

Water

Na+

Why Water Is Necessary to Life

Water is a solvent –

Solute –

Water breaks some chemicals apart, allowing atoms to interact and move around, so chemical reactions can take place easily.

Methane Acetylene ButadieneBenzene Isooctane

Figure 2-11 Carbon Compounds

The Chemistry of Carbon

Carbon has 4 valence electrons, allowing it to bond to 4 other atoms

Carbon forms strong covalent bonds

Carbon bonds easily with other carbon atoms, hydrogen, oxygen, nitrogren, sulfur, and phosphorous =

Organic Compounds -

Organic compounds interact to perform the basic functions of life

Macromolecules - Macromolecules are built buy joining smaller molecules together.

Monomers - small unit that joins together with other small units to form polymers.

Polymers - large compound formed from combinations from many monomers.

Carbohydrates

• Carbohydrates - compounds made up of carbon, hydrogen, and oxygen atoms usually in a ratio of 1:2:1.

• Functions as the energy source for most living things• Monosaccharide – simple sugar molecules (glucose, fructose, galactose)• Polysaccharide – chains of monosaccharides

– Glycogen – stored in muscles and the liver of animals– Starch – stored in plants– Cellulose – found in the stalks of plants, provides strength and rigidity

Starch

Glucose

Lipids• Lipids - macromolecule made

mainly from carbon and hydrogen atoms; includes fats, oils and waxes.

• Functions as an energy source and makes up part of the cell membrane and steroid hormones

• Formed when glycerol binds to fatty acids

• Insoluble in water • Saturated fats – lipids that have

the maximum possible number of hydrogen bonds

• Unsaturated fats – lipids that contain some double bonds

Nucleic Acids

• Nucleic acids - macromolecule containing hydrogen, oxygen, nitrogen, carbon, and phosphorous.

• Functions as genetic structure, transmits hereditary information

• Nucleotide – building blocks of nucleic acids

• Types of nucleic acids

• DNA

• RNAStructure of DNA

Proteins

• Proteins macromolecule that contains carbon, hydrogen, oxygen, and nitrogen

• Function as enzymes, hormones, builds the structure in bones, muscle and organs

• Amino acid – the building blocks of proteins

Aminoacids

General structure Alanine Serine

Amino group Carboxyl group

Amino acids - compounds with an amino group (-NH2) on one end and a carboxyl group (-COOH) on the other end.

There are 20 different amino acids that can combine to form proteins. Proteins are made up hundreds of amino acids bonded together and then folded into a particular shape.

Amino Acids

Macromolecules

CarbonCompounds

include

that consist of

which contain

that consist of that consist of that consist of

which contain which contain which contain

Concept Map

Carbohydrates Proteins

Glycerol & Fatty Acids

Carbon,hydrogen,

oxygen

Carbon,hydrogen,oxygen, nitrogen,

phosphorus

Complete the Diagram

Word Bank:

Carbon,hydrogen,oxygen, nitrogen, sulfur Monosaccharides Nucleotides

Nucleic acids Lipids Amino Acids

Carbon,hydrogen,oxygen

Energy-Absorbing Reaction Energy-Releasing Reaction

Products

Products

Activation energy

Activation energy

ReactantsReactants

Chemical Reactions

Example – Photosynthesis (synthesis)

Reactants = CO2 + H2O

Products = C6H12O6 + O2

Example – Cell Respiration (decomposition)

Reactants = C6H12O6 + O2

Products = CO2 + H2O

Chemical Reactions - a process that changes one set of chemicals into another

Metabolism – the sum of all the body’s chemical reactions

CO2 + H2O C6H12O6 + O2 C6H12O6 + O2 CO2 + H2O

Reaction pathwaywithout enzyme Activation energy

without enzyme

Activationenergywith enzymeReaction pathway

with enzyme

Reactants

Products

Energy in Reactions

Activation energy – the amount of energy needed to start a chemical reaction

What is an enzyme?

Enzymes

Enzyme – complex proteins that lower the

activation energy

1. Speed up the chemical reactions in a cell

2. Lower the temperature needed for the reaction to occur

3. Act as catalysts – speed up reactions, but are not used up (can be used over and over)

Factors that Affect Enzyme Action

• Temperature

• Surface Area

• pH

• Explain how each of these might affect the function of an enzyme

The pH Scale

• The pH scale indicates the concentration of H+ ions in solution

• At pH 7, the concentration of H+ ions and OH- ions is equal

• Acid – any compound that forms H+ ions in solution

• Base – any compound that produces OH- ions in solution

• Buffer – a weak acid or base that can react with strong acids or bases to prevent sharp, sudden changes in pH

• Fluids in most cells must be kept between 6.5 and 7.5 or the reactions in cells will be effected

Oven cleaner

Bleach

Ammonia solution

Soap

Sea water

Human bloodPure waterMilkNormalrainfall

Acid rainTomatojuice

Lemon juice

Stomach acid

Neutral

Incr

easi

ngly

Bas

icIn

crea

sing

ly A

cidi

c

How Enzymes Work