What is Biology?

Biology• Definition:

– “bio-” = – “-logy” =

– This includes the structure, function, growth, origin, evolution and distribution (where they live and how they get around) of living organisms.

Book referencepages16-22

Anything that is or once was alive is….

LIVING!!!

5 Characteristics of Life1. Organization

– Specialized for a purpose– Ex. Cells, tissues, organs, organ

systems– The cell is the smallest unit capable of

life function

5 Characteristics of Life2. Reproduction

– Asexually vs. Sexually– Within a species

5 Characteristics of Life3. Energy

– Light, nutrients – ATP – adenosine triphosphate: a

molecule in muscle tissue that is the major source of energy for cellular reactions

5 Characteristics of Life4. Growth & Development

– Change in size– Change in shape/form

5 Characteristics of Life5. Response and Adaptation

– Response to an environmental stimulus– Adaptation is change in a population of

same organisms in response to changes in the environment

Origin of Life - 2 Theories1. Spontaneous Generation

– Life from non-life (since at least 4 BC)– Franscesco Redi’s experiment (1668)– Louis Pasteur experiment (1864)

2. Biogenesis– “bio-” = – “-genesis” =– Life comes from life– Reproduction occurs within the same species

Redi’s Experiment

Origin of Life - 2 Theories1. Spontaneous Generation

– Life from non-life (since at least 4 BC)– Franscesco Redi’s experiment (1668)– Louis Pasteur experiment (1864)

2. Biogenesis– “bio-” = – “-genesis” =– Life comes from life– Reproduction occurs within the same species

P H E

OC

Problem

Hypothesis

ExperimentSafetyMaterialsProcedureData

Observation

Conclusion

Problem & HypothesisObservation: I have a headache.P: How do I get rid of my head ache?H: If I…

Observation: My car won’t start.P: Why won’t my car start?H:

Observation: Plants seem to grow towards the window.

P: Do plants grow towards artificial light?H:

Terms• Variable = factor that changes in an experiment

– You should only test ONE variable in an experiment!! Why?

• Experimental Group = factor being tested• Control Group = “normal” condition or condition

that you are comparing against• Constants = conditions that remain the same

between experimental group and control group• Independent Variable = It’s the variable “I

control”• Dependent Variable = effect caused by

changes in the independent variable, what you observe

Example• Problem:

– How does excess fertilizer affect the growth of of a houseplant

• Hypothesis:– If excess fertilizer is added then the plant will grow taller

• Variable = • Experimental Group =• Control Group =• Constants =• Independent Variable = • Dependent Variable =

Data

Day

No Fertilizer

Height (cm)

Recommended amount of fertilizer

Height (cm)

Excess Fertilizer

Height (cm)

1 0 0 0 3 0 0.5 1 5 0.5 2 4 7 0.9 4 8 9 2 5 8

11 2.5 6 8.5 15 4 8 9 19 5 11 9 22 6 13 9.5

10 Levels of Organization1.Cell

– Basic unit of living things

2.Tissue– Made up of cells working together for the

same function

3.Organ– Made up of tissues working together for the

same function

10 Levels of Organization4. Organ System

– Made up of organs working together for the same function

5. Organism– All living things

6. Population– A group of organisms of the same species– Ex. Turtles in a pond

10 Levels of Organization7.Community

– All populations living/working together– Biotic

8.Ecosystem– Living and non-living parts of a community– Biotic and abiotic

10 Levels of Organization9. Biome

– A large group of similar ecosystems, determined by climate

10.Biosphere – Thin layer of air, land and water that is home

to living things

Chemistry of Life• Atom = smallest particle of an

element– proton– neutron– electron– isotope

• form of the element with different amount of neutrons; usually unstable and radioactive

Chemistry of Life– atomic mass:

• average mass of an atom of an element - sum of protons and neutrons in nucleus

– atomic number: • proton number

– symbol:• one or two letters used internationally

Chemistry of Life• Periodic Table

Model of an Atom

Chemistry of Life• Bohr Model vs. Electron Cloud Model

Chemistry of Life• Bonding = energy is exchanged

when bonds break/form– ex. Na+ Cl- NaCl– ex. H2O

• Molecule – two or more atoms

• Compound – molecule of two or more elements

Properties of H2O• Cohesion

• Adhesion

• Surface tension

• Capillary action

Chemistry of LifeWater strider

Chemistry of LifeGreen Basilisk Lizard

Organic Compounds• Organic compounds contain carbon

– Ex. Carbon skeleton– Monomer

• “one” unit– Dimer

• “two” units– Polymer

• “many” units

4 Compounds Found in Living Things

1. Carbohydrates

2. Protein

3. Lipid

4. Nucleic Acid

4 Compounds Found in Living Things

1. Carbohydrates– Starch (Iodine Test)– Sugar (Benedict’s Test)– Cellulose

2. Protein– Nitric Acid Test

3. Lipid– Smear test

4. Nucleic Acid

Carbohydrates• Starch (Iodine Test)

– Long lasting energy– ex. Potato, pasta

• Sugar (Benedict’s Test)– Short term energy– ex. Candy, glucose

• Cellulose– Gives structure– Found in plants

Protein (Nitric Acid Test) • Polymers of amino acids (20)

• Provide structure (muscles, skin)– ex. Eggs, meat

Lipids (Smear Test)• Fat

– Insulation– Long lasting energy

• Waxes– Waterproofing– Water storage

• Steroids– Growth & development

• Phospholipid– Cell membrane

Nucleic Acid• DNA

– Genetic code

• RNA– Makes proteins

Chemical Reaction• Process that changes one set of

chemicals into another set of chemicals

• Ex. CO2 + H2O H2CO3

H2O2 H2O + O2

Energy• Bonds broken/formed

• Activation Energy– Energy to get a reaction started – Energy absorbed (endergonic) vs.

Energy released (exergonic)

Endergonic reaction requires energy to start reaction and absorbs the energy

If you touched a beaker in which an endergonic reaction was occurring, what would you feel?

Exergonic reaction needs a small amount of energy to start but releases energy as part of the reaction

If you touched a beaker in which an endergonic reaction was occurring, what would you feel?

Endergonic reaction requires energy to start reaction and absorbs the energy

Exergonic reaction needs a small amount of energy to start but releases energy as part of the reaction

Enzymes• Proteins that act as catalysts

– Catalyst = speeds up the rate of a chemical reaction

• Lower activation energy

Enzyme lowers the activation energy:

EA = activation energy

Enzymes• Enzymes provide a site where reactants

can be brought together to react• Substrate = the reactants of enzyme-

catalyzed reactions

Enzymes• Lock-and-Key Fit• Active Site

Enzymes• Enzyme is not used up in reaction, can

start again after product is released

• Things That Affect Enzymes• pH (how acid or basic the environment is)• Temperature (hot vs. cold)

• What is the optimal condition for enzymes in the human body?

Review1. What are the 4 compounds that make up

living things?2. What do they all have in common?3. What are the three types of carbohydrates?4. How are they related?5. What is a protein made up of?6. How do the 20 amino acids compare to the

26 letters in the alphabet?7. How are lipids beneficial?

Review7. Where are lipids found in living things?8. What are nucleic acids?9. What role do they play in living things?10.What foods contain carbohydrates?11.What foods contain lipids?12.What foods contain proteins?13.Where are proteins found in our bodies?