Chapter 2The Chemistry of Life

2.1 The Nature of Matter, 2-2 Properties of Water, 2-3 Carbon

Compounds, 2-4 Chemical Reactions and Enzymes

2.1 The Nature of Matter

Key ConceptsWhat three subatomic particles make up atoms?

How are all of the isotopes of an element similar?

What are the two main types of chemical bonds?

2-1 Atoms

The study of chemistry begins with the basic unit of matter, the atom.

AtomIncredibly small

If placed side by side, 100 million atoms would make a row only about 1 centimeter long.

Contain subatomic particles

2.1 Atoms

The subatomic particles that make up atoms are protons, neutrons, and electrons.

http://www.youtube.com/watch?v=pV822HfqT44

2.1 Atoms

Protons and neutrons have about the same mass (or weight).

However, protons have a positive charge and neutrons carry no charge or are neutral. Very strong forces bind protons and neutrons together to form the nucleus, which is the center of the atom.

2.1 Atoms

Electrons are negatively charged particles with are extremely small.

They are in constant motion. They are attracted to the positively charged nucleus but remain outside of it because of the energy of their motion.Because atoms have equal numbers of electrons (-) and protons (+), and because these subatomic particles have equal but opposite charges, atoms are neutral

2.1 ElementA chemical element is a pure substance that consists entirely of one type of atom.

More than 100 known elements, but only 24 are commonly found in living organisms

Represented by one or two-letter symbol

2.1 Element

Atomic Number- number of protons and electrons in an atom

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2.1 Isotopes

Atoms of an element can have different numbers of neutrons in their nucleus

Atoms of the same element that differ in the number of neutrons they contain are known as isotopes.

2.1 IsotopesMass Number- The sum of the protons and neutrons in the nucleus of an atom

Isotopes are identified by their mass numbers

Isotopes still have the same number of electrons and protons

They still have the same chemical properties

2.1 Radioactive Isotopes

Some isotopes are radioactiveTheir nuclei are unstable and break down at a constant rate over time

They give off radiation

2.1 Radioactive Isotopes

Scientific purposes for Radioactive Isotopes

Geologists can determine the ages of rocks and fossils by analyzing the isotopes found in them

Radiometric Dating

Radiation from certain isotopes can be used to treat cancer and kill bacteria that cause food to spoil

Radiation

2.1 Radioactive Isotopes

http://www.youtube.com/watch?v=W_ClcBF6a0I&feature=related

2.1 Chemical Compounds

In the natural world, most elements are found combined with other elements in compounds.

Therefore, a compound is a substance formed by the chemical combination of two or more elements in definite proportions.

2.1 Chemical Compounds

Scientists show the composition of compounds by a kind of shorthand known as a chemical formula

What is the chemical formula for water? Carbon dioxide?

2.1 Chemical Compounds

The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed

ExampleHydrogen and oxygen, which are gases at room temperature, can combine explosively and form liquid water

2.1 Chemical Bonds

A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei.

There are two main kindsIonic Bonds

ions

Covalent Bondsmolecule

2.1 Chemical Bonds

Van der Waals forces- occur when molecules are close together, and a slight attraction can develop between the oppositely charged regions of nearby molecules.

Not nearly as strong as ionic or covalent and can easily be broken

Hold large molecules together

2.1 Chemical BondsGecko

Feet covered with half a million tiny hairlike projections that are further divided into hundreds of flat fibers

Van der waals forces form between molecules on the surface of the gecko’s foot and molecules on the surface of the wall

2.2 Properties of Water

Key ConceptsWhy are water molecules polar?

What are the properties of water?

What are acidic solutions?

What are basic solutions?

2.2 The Water Molecule

Like all molecules, a water molecule (H2O) is neutral.

It has 10 protons (+) and 10 electrons (-) that balance each other out

2.2 The Water Molecule

A water molecule is made of:One oxygen atom that has 8 electrons and protons

2 hydrogen atoms that each have one electron and one proton

2.2 The Water Molecule

It has a bent shapeThe oxygen atom at one end and the two hydrogen's at the other end

As a result, the oxygen has a slightly negative charge and the hydrogen's have a slightly positive charge

A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms

2.2 Hydrogen Bonds

Because of the positive and negative charges of the water molecule, hydrogen bonds occurHydrogen bonds are not nearly as strong as covalent or ionic bondsThese hydrogen bonds are the reason for:

CohesionAdhesion

2.2 Hydrogen BondsCohesion- is an attraction between molecules of the same substance

Water’s cohesion causes molecules on the surface of water to be drawn inwards

Cohesion also explains why some insets and spiders can walk on a pond’s surface.

2.2 Hydrogen BondsAdhesion- is an attraction between molecules of different substancesAdhesion between water and the chromatography paper causes water to rise in a narrow action.In nature, you can see this in plants. Capillary action is one of the forces that draws water out of roots of a plant and up into its stem and leaves

2.2 Solutions and Suspensions

Water is often found as a mixture, a mixture is a material composed of two or more elements or compounds that are physically mixed together but not chemically combined

2.2 Solutions and Suspensions

If you add sugar or salt to water, the water eventually becomes a solution

A solution is a mixture where all the components are evenly distributed

In a saltwater solution, the salt is the solute (substance that is dissolved) and the water is the solvent (substance in which the solute is dissolved in)

2.2 Solutions and Suspensions

Some materials, such as oil, do not dissolve when placed in water

Such mixtures of water and nondissolved material are known as suspensions, since the nondissolvable particles separate and do not settle out

2.2 Acids, Bases, and pHA water molecule can react to form ions. This reaction can be summarized by a chemical equation in which double arrows are used to show that the reaction can occur in either direction

Water hydrogen ion + hydroxide ion

2.2 pH ScaleChemists devised a measurement system called the pH scale to indicate the concentration of H+ ions in a solutionpH scale ranges from 0-14

At a pH of 7 the concentration of H+ ions and OH- ions is equalAnything with a pH below 7 is considered acidic because they have more H+ ionsAnything with a pH above 7 is considered basic because they have more OH- ions

2.2 Acids and Bases

Acidic solutions contain higher concentrations of H+ ions than pure water and have pH values below 7

Strong acids are 1-3Hydrochloric acid (stomach acid) ranges from 0-1.5

Basic solutions contain lower concentrations of H+

ions than pure water and have pH values above 7

Strong bases are 11-14

Oven cleaner and bleach

2.2 Buffers

The pH of the fluids within most cells in the human body must generally be kept between 6.5 and 7.5.If the pH is lower or higher, it will affect the chemical reactions that take place within cellsBuffers are weak acids or bases that can react with strong acids or bases to prevent sharp sudden changes in pH.

2.3 Carbon Compounds

Key ConceptsWhat are the functions of each group of organic compounds?

2.3 The Chemistry of Carbon

One of the most abundant elementsFound in most inorganic compounds and ALL organic compounds

Carbon forms strong covalent bondsCarbon atoms can bond to other carbon atomsCarbon has the ability to form millions of different large and complex structures

No other element can come close to matching carbon’s versatility

2.3 Macromolecules

Many molecules in living cells are so large that they are known as macromolecules or “giant molecules”

Made from thousand of even smaller molecules

Monomers-smaller units or single unit

Polymers-made of many monomersEx.// links on a watch, beads of a necklace

2.3 Macromolecules

It would be extremely difficult to study the millions of organic compounds (macromolecules) if they were not classified into groups.4 groups of organic compounds

CarbohydratesLipidsNucleic acidsproteins

2.3 Carbohydrates

Made up of carbon, hydrogen, & oxygenLiving things use carbohydrates as their main source of energy. Plants and some animals also use carbohydrates for structural purposes.

Breakdown of sugars, such as glucose, supplies immediate energy for all cell activities

2.3 Carbohydrates

Single sugar molecules are also called monosaccharides

Large molecules formed from monosaccharides are known as polysaccharides

Many animals store excess sugar in a polysaccaride called glycogen (many glucose molecules)

2.3 Lipids

Lipids are a large and varied group of biological molecules that are generally not soluable in water

Made of carbon and hydrogen atoms

Lipids can be used to store energy. Some lipids are important parts of biological membranes and waterproof coverings

2.3 Lipids

Some lipids are fats, oils, and waxes.

Steroids are lipids as well

2.3 Nucleic Acids

Nucleic acids are macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorusNuclei acids are polymers made up of monomers known as nucleotidesThree parts

5 carbon sugarPhosphateNitrogenous base

2.3 Nucleic AcidsNucleic Acids store and transmit hereditary, or genetic information

2 kindsRNA- ribonucleic acid

DNA- deoxyribonucleic acid

2.3 ProteinsProteins are macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen

Proteins are polymers of molecules called amino acids

2.3 Proteins

Some proteins control the rate of reactions and regulate cell processes. Some are used to form bones and muscles. Others transport substance into or out of the cells or help to fight diseases.

2.4 Chemical Reactions & Enzymes

All living things are made up of chemical compounds (macromolecules)- some are simple some are complex. Everything that happens in an organism- its growth, its interaction with the environment, its reproduction, and even its movement are based on chemical reactions

2.3 Chemical Reactions

A chemical reaction is a process that changes, or transforms, one set of chemicals into another

Chemical reactions always involve changes in the chemical bonds that join atoms in compounds.

2.4 Chemical Reactions

Examples of chemical reactions:

CO2 + H2O H2CO3

The reaction shown above enables the bloodstream to carry carbon dioxide to the lungs. In the lungs the reaction is reversed.

H2CO3 CO2 + H2O

This reverse reaction produces carbon dioxide gas, which is released as you exhale.

2.4 Enzymes

Enzymes are proteins that can act as biological catalysts in chemical reactions

Enzymes speed up chemical reactions that take place in cells

http://www.youtube.com/watch?v=AEsQxzeAry8&feature=related

http://www.youtube.com/watch?v=qDEVBMldiY8&feature=related

Sample Essay Questions

What are the 7 characteristics of life. List all 7 and explain each one. Include important terminology/ vocabulary.

I am using a microscope that has an ocular magnification of 10x, low objective of 10x, medium objective of 40x, and high objective of 100x.

What is the total magnification when I am using the medium powered objective?Show all work, including the equation.

Sample Essay Questions

Explain in 3 steps how to make a proper wet mount of the letter “e”.

What are the two types of chemical bonds you researched? What is the difference between the two?

What are the 5 properties of water we discussed in the H2O Fo Sho lab?

List all 5 then choose 2 and describe them.

Sample Essay Questions

In relation to carbon, there are 4 groups of organic compounds (macromolecules). List all 4 and explain the functions of each one.

What happens to chemical bonds during reactions? How are enzymes related?

Other Test Info.

Make sure you are able to label the parts of the microscope without a word bank.

Know the difference in pictures between SEM and TEM microscopes

Vocabulary Info.Chapter 2 Vocabulary for Vocab portion of the test

AtomIsotopeElementCovalent bondIonic bondCohesionAdhesionAcidBaseMonomerpolymer

MonosaccharidePolysaccharidenucleotideCarbohydrateLipidNucleic AcidProteinEnzyme