UNIT 3: MATTER ENERGY LIFE

objectivesStudents can:1. Describe matter, atoms and molecules and give simple

examples of the four major kinds of organic compounds in living cells

2. Describe the difference between ionic and covalent bonds in chemical reactions

3. Explain the difference between kinetic and potential energy

4. Know the principles of the conservation of matter and energy

5. Describe the BGC Cycles (BioGeoChemical): how water, carbon, nitrogen, and phosphorus cycle between Earth Systems

6. Understand the reciprocal nature of photosynthesis and respiration in capturing and using energy

7. Discuss food chains, webs, and trophic levels; explain why there are pyramids of energy, biomass, and individuals

vocab Covalent, Ionic Archaea, Extremophile Nucleic Acid, Nucleotide Diffuse Logarithm Oxidize reduce

Elements of life Matter is anything that takes up space and

has mass Law of Conservation of Matter: it cannot

be created or destroyed, but it can be transformed”

Elements cannot be broken down into simpler substances by chemical reactions,

Atoms are the smallest whole particle of an element, consisting of a nucleus (containing protons and neutrons) and orbiting electrons

facts about atoms Atomic number = # of protons the atom

contains (usually equals the # of electrons) Atomic mass = # of protons + # of

neutrons Atoms with a different number of neutrons

are known as isotopes Ions are charged atoms that have lost or

gained electrons (during chemical reactions)

Ions and inorganic chemical reactions Oxidation – many elements can

react with oxygen. They lose electrons to oxygen (LOX = loss of electrons)because oxygen is an effective electron grabber

Metals reacting with non-metals create ionic bonds (involving loss and gain of electrons)

Acids, bases and salts are inorganic ionic compounds

Water H2O is the medium in which acids, bases and salts dissolve.

Acids and bases are measured on the pH scale

Organic Chemistry Four elements make up 96% of the mass of

most living organisms: carbon hydrogen oxygen Nitrogen

In contrast to inorganic compounds, organic compounds form covalent bonds. These compounds tend to be more stable, less reactive, and require more energy for reactions to occur.

Organic ChemistryThese (and 3 other) elements cycle continuously between living and non-living systems.

Four major categories of organic compounds Carbohydrates – glucose, cellulose, fructose Proteins – enzymes, structures Lipids – cell membranes, fats, oils, waxes Nucleic acids – DNA, RNA

Cells

All living organisms are composed of cells Cells are composed of lipids (cell

membranes), proteins (structures and enzymes), nucleic acids (DNA and RNA), and carbohydrates furnish the energy for functioning

Cells

Photosynthesis transforms energy from the sun into stored sugars (carbohydrates)

6CO2 + 6H2O C6H12O6 + 6O2 Metabolism is the energy-releasing

reactions performed during respirationC6H12O6 + 6O2 6CO2 + 6H2O

Non-photosynthesizers Extremophiles (also known as Archaea)

transform chemicals or heat energy into their energy supply through chemosynthesis

They live in places like hot springs, heat vents at divergent boundaries on the sea floor, and high concentration salt, acid, or base solutions.

Energy Defined: the ability to do work or cause

heat transfer Potential energy: stored (by position, in

chemical bonds) Kinetic energy: exhibited by movement

of objects (atoms, molecules, gross matter)

Food is a form of potential energy that is released when we digest it

Laws of Conservation of Energy1. Energy cannot be created or

destroyed; it can only be transformed2. Every time energy is transformed from

one type to another, some energy is lost as heat.

It can no longer perform useful work It is referred to as “low-quality” Entropy is the term describing disorder,

Energy Cycle Species – a group of individual organisms

that can reproduce only with each other Population – group of a single species Community – groups of populations

interacting Ecosystem – communities interacting in

their physical environment Feeding relationships describe how

energy moves through an ecosystem

Food Chains / Webs

Feeding relationships

Illustration of 2nd law of thermodynamics NOTE: Only

10% of consumed energy is passed from one trophic level to the next.

Cycling of Matter Carbon cycle Water (Hydrologic) cycle Oxygen cycle Nitrogen cycle Phosphorus cycle Sulfur cycle

Carbon cycle

Water cycle

Nitrogen cycle

Driven largely by bacteria in the soil, that:• Capture N2 from the atmosphere and make it usable

for plants• Break down waste and dead organic matter, to release

nitrogen either back to the soil or back to the atmosphere

• Can live in plant roots• Will be assimilated into new living things once it’s

been taken up by plants

Phosphorus cycle

Phosphorus never reaches the atmosphereIt is carried by water (weathering, erosion, fertilizer)Can cause “eutrophication in water bodiesUltimate effect is a “dead zone”