Living Environment

Topic I: Similarities and Differences Among Living Organisms

Life functions that characterize living organisms:

1. Nutrition- all the activities by which an organism obtains materials from its environment.a. Ingestion- taking in of foodb. Digestion- breakdown of food moleculesc. Egestion- removal of food materials

2. Transport- absorption and circulation of materials throughout the organism

3. Respiration- the chemical processes by which organisms obtain energy from food

4. Excretion- removal of waste products5. Synthesis- building larger molecules

from smaller ones6. Regulation- control and coordination of

various activities of an organism7. Growth- using products of synthesis to

increase cell size and/or # of cells of an organism

8. Reproduction- production of new individuals to maintain the species

METABOLISM- all the chemical processes by which an organism carries on life functions

HOMEOSTASIS- maintaining a stable internal environment

Diversity of Life• Scheme of Classification:• The system that is used today was developed by a

scientist named Linnaeus. All organisms are placed into the following groups: (use human beings as an example)

King Kingdom Animalia BroadPhillip Phylum Chordata GroupingsCame Class MammaliaOver Order PrimatesFor Family HominidaeGreat Genus Homo Narrow, Specific,Spaghetti Species sapiens More diverse

The classification system used here utilizes six kingdoms:

1. Eubacteria

2. Archeabacteria

3. Protist

4. Fungi

5. Plant

6. Animal

Monera

• Prokaryote- No nucleus or organelles• Eukaryote- Nucleus and organelles

• Sessile (Nonmotile) - stationary• Motile- move on own

• Autotroph- makes own food (photosynthesis)• Heterotroph- cannot make own food

Kingdom Phylum Distinguishing Characteristics

Examples

Monera Eubacteria,Archeabacteria,Cyanobacteria (photosynthesize)

Unicellular,Autotrophs (some heterotrophs),Cell wall

E. coli

Protists Protozoa, Algae,Slime molds

Unicellular or multicellular,Autotrophs (some heterotrophs),Cell wall (Chitin)

Paramecium, amoeba, euglena; kelp

Fungi Unicellular or multicellular,Heterotrophs, Cell wall (chitin)

Yeast, bread mold, mushrooms

Plants Bryophytes, Tracheophytes

Multicellular,Autotrophs,Cell wall (cellulose)

Mosses;Ferns, flowering plants, evergreen

Animals Coelenterarates,Annelids,Arthropods,Vertebrates

Multicellular,Heterotrophs

Hydra, earthworm, grasshopper, frogs, humans

ProkaryoteNonmotile/Motile

Eukaryote

Motile

Unicellular or Multicellular

Nonmotile

Nonmotile

Motile

This system is based upon the following criteria:

• The presence (eukaryotic organism) or absence (prokaryotic organism) of a nuclear membrane within the cell.

• Unicellularity vs. Multicellularity• Type of nutrition-autotrophic vs.

heterotrophic• Type of Reproductions (asexual vs. sexual)• Etc.

• Most classification systems suggest relationships among organisms which may indicate common ancestry.

• The modern system of naming organisms is based upon binomial nomenclature. The first part is the genus and the second part is the species. Ex- Homo sapiens

Ex-Felis domesticaSpecies- a group of organisms that are

similar in structure, can mate and produce fertile offspring.

Taxonomy- the science of classifying organisms.

Chemistry of Living Organisms1. Chemical Elements in Living Matter.

CHON• The elements found in the greatest

percentage in living matter are Carbon, Hydrogen, Oxygen, and Nitrogen. Other important elements which are found in smaller quantities include sulfur (S), phosphorus (P), magnesium (Mg), iodine (I), iron (Fe), calcium (Ca), sodium (Na), chlorine (Cl), and potassium (K).

• Element- substances that cannot be broken down chemically. Ex: Hydrogen

• Empirical/Molecular formula- shows the symbols of elements in a compound followed by subscripts for ratio of atoms.Ex: H2O - 2 Hydrogen, 1 Oxygen

2. Chemical compounds in living matter.Compound- chemical combinations of 2 or

more elements.• Ionic bond- atoms combine to form

compounds by transferring electrons.• Covalent bond- atoms combine to form

compound by sharing electrons. (pictures pg 9)

A. Inorganic CompoundsInorganic- Do Not contain BOTH Carbon and Hydrogen.Principal inorganic compounds found in living things:• Water- 60-90% of living things; transport materials,

chemical activities, solvent.• Salts- maintain osmotic (fluid) balance and supply ions

for chemical reactions.• Acids and Bases- used by cells to maintain a balance of

hydrogen ion concentration.The pH scale:

1 3 5 7 9 11 13 14Strong acid neutral Strong base

Greater H+ conc. Greater –OH conc.

Lemon juice, hydrochloric acid

Water, blood

Soaps, bleach, ammonia

B. Organic CompoundsOrganic- contain both carbon and hydrogen

1. See Table on pg 15

1. Carbohydrate (-ose)Monosaccharidesex: glucose, fructoseDisaccharidesLactose, sucrose, maltosePolysaccharidesanimal→glycogenplant →starch, cellulose

Building BlocksSimple Sugars

ElementsC:H:OH:O2:1

Function• Quick energy• Cell structure• Often carbon rings

Structure

2. Lipids

Fats, oils, waxes

Ex: cholesterol,corn, peanut, sesame oils

Building Blocks3 fatty acids1 glycerol

ElementsC:H:O

H:O>2:1

FunctionStored energyCell Structure

Long carbon chains

3. Proteinspeptide → C-N bonddipeptide →2 amino acidspolypeptide → 3 or more

amino acids

Ex: insulin, enzymes, hemoglobin

Building BlocksAmino Acids

≈20

ElementsC:H:O:N

(and sulfur)

FunctionEnzymes

Build & Repair body partsCell Structures

Carboxyl group

Amino group

4. Nucleic Acids

DNA, RNA

Building BlocksNucleotides

• DNA Double Helix• Very Complex Molecules

ElementsC:H:O:N:P

FunctionGenetic Info.

Protein Synthesis

pg. 13

2. Hydrolysis- complex organic compound is broken down into simpler substances through addition of water.

3. Dehydration synthesis- complex substances formed from simpler ones.

Reactants Products

Chemical Control• Role of enzymes- regulators of most

chemical activity in living systems, and are often referred to as organic catalysts.

• Enzymes are not changed during the reaction and therefore can be reused.

-Each chemical reaction requires a specific enzyme.-Enzymes modify the rate of reactions.

• Enzymes are large complex proteins consisting of one or more polypeptide chains whose names end in “-ase”. Enzymes are often names for the substrate (chemical being acted upon).

Ex. Maltose is hydrolyzed by Maltase.Lipids are hydrolyzed by Lipase.Proteins are hydrolyzed by protease.

All enzymes are exclusively proteins or are proteins with non-protein parts known as coenzymes. Coenzymes are usually vitamins.

Enzymes act upon an active site.

The Lock and Key Model and the formation of an enzyme-substrate complex.

Enzyme-Substrate ComplexEnzyme Substrate

Products of Reaction

Enzyme

Factors Influencing Action of Enzymes

1. Shape- Each enzyme must have a specific shape to work correctly. The reaction rate will decrease in proportion to the number of enzymes altered.

Denaturation- enzyme molecules change shape or break apart at high temperatures or in strong acids/bases.

2. Temperature- As temp. increases, enzyme rate reaction increases (to a point.)

Temp (0C)37

Enzyme rate

Denaturation

370C=98.60F

3. pH- usually pH 7 provides optimum environment. Enzymes vary at different pH’s.

Enzyme Rate

1 7 14

Pepsin (stomach)

Trypsin (intestinal)

4. Relative Amounts of Enzymes and Substrate- the reaction speeds up until a certain amount of excess substrate is added.

Enzyme Rate

Substrate Concentration

Unity of LifeCELL THEORY:1. Cells basic unit of structure and function in

living things.2. Cells come from preexisting cells.3. All living things made of cells.

HISTORICAL BACKGROUNDAnton Van Leeuwenhoek- discovered one-celled

organisms in water by using a simple one lens microscope (1632-1723)

Robert Hooke- used a two lens microscope to examine tree bark, empty cork “cells” (1635-1703)

Robert Brown- discovered a body, which he called a nucleus, at the center of most cells (1773-1858)

Matthias Schleiden- determined plants composed of cells (1804-1881)

Theodor Schwann- determined animals composed of cells (1810-1882)

Louis Pasteur- proved tiny microbes (microscopic organisms) caused disease (1822-1895)

Ruldolph Virchow- stated that cells arise from pre-existing cells (1821-1902)

The cell• Organelles-specialized structures in the cell

Organelles and function:• Plasma membrane (Cell Membrane)- semipermeable-

allows certain materials to pass in/out of cell. Consists of a 2 layer film made of lipids with proteins embedded.

• Cytoplasm- fluid-like material inside P.M., outside of nucleus where many biochemical processes occur. Moves organelles.

• Nucleus- contains chromosomes and DNA, carries hereditary info. And directs biochemical activities of cell.

• Nucleolus- (In nucleus) produces RNA found in ribosomes.

• Chromosomes- contain DNA/hereditary material (inside nucleus).

• Endoplasmic Reticulum (E.R.)- network of channels in cytoplasm that function in synthesizing, transporting and storing substances.

• Ribosomes- synthesize proteins. (free or attached to E.R.)

• Mitochondria- sites of aerobic cellular respiration for ATP (energy) production.

• Golgi complex- membrane-bound channels where materials are synthesized and packaged. Ex: modify proteins

• Lysosomes- contain digestive enzymes for digestion of food materials. *usually only in animal cells

lysosomesmitochondria

• Vacuoles (large in plants)-membrane spaces in cytoplasm that contain water and other materials (digestive enzymes in plants)

• Centrioles- cylindrical structures outside nuclear membrane in animals for cell division

Plastids:a. Chloroplasts- in plant cells, algae and some

protists. Contain pigment to absorb sunlight and are sites of photosynthesis.

b. Chromoplasts- contain pigments that absorb light chlorophyll cannot; orange carotene, yellow xanthophyll and red anthocyanin.

c. Leucoplasts- store food such as starches, proteins and lipids.

• Cell Wall (nonliving)- in plant cells, made of cellulose. Surround cell, giving it strength and support. Pores allow water and dissolved substances to enter/leave.

leucoplastschloroplast

Centrioles

Exceptions to the Cell Theory:• Since all cells come from pre-existing

cells, what produced the first cell?• Viruses are not composed of cells and do

not carry on most cellular activities.• Mitochondria and chloroplasts can

reproduce independently inside the cell but are considered organelles even though they contain their own genetic material.

Organization• Cells-the basic unit of structure

and function in living organisms.• Tissues-group of specialized cells

that perform a specific function.• Organs-different kinds of tissues

combined to perform a specific function.

• Organ System- several organs that work together to perform a major bodily function.

• Organism- multiple organ systems working to maintain life functions.