And a Little Taxonomy too!

The science of classification of living organisms. So we can identify and understand

relationships between organisms.

Method of grouping organisms based on their evolutionary history. Uses shared characteristics that reflect

evolutionary history. What are some shared characteristics used?

First developed by Carolus Linnaeus (1707-1778). Method of classifying things in a

hierarchical structure from most general to most similar.

Binomial System (2 names) Domain

Kingdom (most general) Phylum or Division Class Order Family Genus Species

Ex. Eschericia coli

or E. coli

CR4. 2007. http://cr4.globalspec.com/blogentry/2067/Happy-Birthday-Carolus-Linnaeus

Domains constitute a level of classification above the kingdom.

Domains are further subdivided into kingdoms etc.

1. Archaea 2. Bacteria 3. Eukarya - animals- plants- algae- protozoa- fungi

Prokaryotes Eukaryotes

Based on similar morphology, geographic distribution, and if multicellular, the ability to interbreed.

Bacteria

A phylogenetic tree based on rRNA data showing Woese’s three domain system. Retrieved from http://en.wikipedia.org/wiki/Kingdom_%28biology%29

Another system for classifying Prokaryotes.

Still use kingdom, division or phylum, class, order, family, genus, species.

Classification based on similar morphological and biochemical characteristics.

How are they different and how are they the same?

It is the fundamental unit of all living matter.

Has all characteristics of life. Can live independently of other cells.

Enzymes A protein that speeds up a chemical reaction.

DNA – deoxyribonucleic acid A large molecule that stores genetic

information. RNA – ribonucleic acid

A large molecule involved in protein synthesis.

ATP – adenosine triphosphate The main energy currency of a cell.

Amino Acids Proteins are composed of basically the same

20 amino acids.

Possess membrane-bound organelles. 10-30µm in diameter. Eukaryote = “true nucleus”

Their DNA is enclosed by a double membrane.

Cell Membrane Phospholipid (fatty chain with a phosphate)

bi-layer with different types of proteins interspersed.

Separates inside of cell from external environment.

It has selective permeability. Only certain things can get in and out.

Other organelle membranes are similar in structure.

Nucleus Controls the functions of the cell (“the

control center). Nuclear membrane – surrounds nucleus. Nucleoplasm – gelatinous matrix. Chromosomes – linear DNA molecules and

proteins. Gene – specific DNA segment on the

chromosome that contains the information for making a gene product, usually a protein.

Nucleolus – where rRNA is made and is used to make a structure called ribosomes.

Cytoplasm A semi-fluid, gelatinous, nutrient matrix. Contains storage granules and cell organelles. Most of cell’s metabolism occurs. Often called the cytosol.

Endoplasmic Reticulum (ER) An irregular maze of spaces enclosed by a

membrane. “Assembly Line” Rough ER

Contains ribosomes Involved in making proteins

Smooth ER Does not contain ribosomes Involved in lipid metabolism (fat storage)

Ribosomes Are important in protein synthesis. Are found in the Rough ER.

Golgi Complex “packaging plant.” Stacks of flattened, membranous sacs. Completes and packages newly formed

proteins and lipids. Packages them so that they are ready for

storage within the cell or outside of the cell.

Lysosomes “garbage disposal system” 1 µm diameter Contain lysozyme and other enzymes that

break down foreign material. Particles may enter cell by phagocytosis. Also involved in programmed cell death called

autolysis or apoptosis. Peroxisomes

Membrane-bound vesicles that generate and break down hydrogen peroxide (a dangerous and highly reactive chemical).

Used to break down lipids (fats) and destroy toxic molecules.

Mitochondria “the power plant of the cell” 0.5 – 1 µm in diameter, 7 µm in length Where ATP (adenosine triphosphate) is

formed. ATP is the energy currency of the cell.

ATP is formed during a reaction called cellular respiration.

ATP is formed from our food sources.

Plastids Site of photosynthesis. Contain photosynthetic pigments.

Photosynthesis – converting light energy into a source of chemical energy for organism.

Chloroplasts – type of plastid that contains chlorophyll. Chlorophyll – a green photosynthetic pigment.

micro.magnet.fsu.edu/cells/plants/plantmodel.html

Cell Wall External structure that provides rigidity,

shape, and protection. May be composed of cellulose, pectin, lignin,

chitin, and some mineral salts. Usually simpler than prokaryotic cells.

Cells stained green (DNA) and red (keratin)

www.newworldencyclopedia.org/entry/Cell_(biology

Illustration by Robert Hooke (c.1665)

askabiologist.asu.edu/.../rhooke.html

Plant Cells

Cell Walls

Present

•Plants

•Algae (protists)

•Fungi

•Most Bacteria

Absent

•Animals

•Protozoa (protists)

•Mycoplasma species (type of bacteria)

Flagella An organelle of movement. Long, thin structure that moves like a whip to

propel organism through liquid environment. Can be found in some species of protozoa,

spermatozoa, and algae. Cilia

Organelle of locomotion. Usually short, hair-like structures that beat in

coordinated, rhythmic movement. Can be found in some species of protozoa and

types of cells that line respiratory tract.

Euglena – sp. Protozoa. Notice the flagella.www.biologie.uni-erlangen.de/.../fotonm3_eng.htm

Paramecium – sp. Protozoa. Notice the cilia.microbewiki.kenyon.edu/index.php/Paramecium

More simple than eukaryotic cells. Can perform all functions necessary for

life. Prokaryotes comprise all bacteria and

archaeans. Do NOT contain membrane-bound

organelles. Typical E. coli cell is about 1 µm wide and

2-3 µm long.

Bacterial Cell Wall Provides rigidity, strength, and protection. More complex than eukaryote cell walls. Composed of peptidoglycan (polymer of sugars

and amino acids) Gram-positive bacteria

Thick layer of peptidoglycan with some other molecules. Gram-negative bacteria

Thinner layer of peptidoglycan with an outer membrane composed of lipid macromolecules.

Genus Mycoplasma do not have cell walls. Archaens have cell walls but not composed of

peptidoglycan.

Cell Membrane Similar to eukaryotic cells. Contains proteins and phospholipids. Selectively permeable. It is very flexible and thin.

Glycocalyx Thick, slimy, gelatinous material produced by the

cell membrane and secreted outside the cell wall. Some bacteria have it. 2 types of glycocalyx

1. Slime Layer Is not highly organized or firmly attached to cell wall. Allows bacteria to glide or slide along surfaces.

2. Capsule Highly organized and firmly attached to cell wall. Chemical composition allows scientists to determine different

types of bacteria. Prevent bacteria from being phagocytized by phagocytic

white blood cells. Can attach bacteria to a wide array of surfaces.

diverge.hunter.cuny.edu/~weigang/Lecture-syll.

Prokaryotic Chromosome Single, long, supercoiled, circular DNA

molecule. Embedded in cytoplasm. Found in nuclear region of cell. Does not have a nuclear membrane. Contains all the information for carrying out

life processes. Plasmids may also be found in prokaryotic

cells.

Plasmid Small, circular molecule of double-stranded

DNA. Not part of the chromosome.

Called extrachromosomal DNA. Found in the cytoplasm. May contain 10-100s genes. Number varies per cell.

Cytoplasm Semiliquid interior of cells. Consists of water, enzymes, dissolved oxygen

(in some bacteria), waste products, nutrients, proteins, carbohydrates, and lipids.

Everything necessary for its metabolic functions.

Cytoplasmic Particles Ribosomes are found in the cytoplasm. They are important in protein synthesis. Some substances are stored in cytoplasmic

granules. Such as starch, lipids, sulfur, or iron. The type of substance stored depends on the

species of organism.

diverge.hunter.cuny.edu/~weigang/Lecture-syll.

Flagella A mechanism for

movement for some bacteria.

Bacteria can be classified and identified by the arrangement of their flagella.

Nonflagellated bacteria are usually considered to be nonmotile. Although there

are exceptions.

Pseudomonas fluorescens – aerobic soil bacteria.www.scienceclarified.com/As-Bi/Bacteria.html

Pili (Fimbriae) Not associated with motility. Thin, rigid, hair-like structure. Arise in cytoplasm and extend through the

plasma membrane, cell wall, and capsule (if present).

2 types of pili 1. Adhesins - allows bacteria to adhere to

surfaces. 2. Sex pilus

Allows for the transfer of genetic material through a process called conjugation.

One bacteria attaches its sex pilus to another cell and transfers its genetic material to the other cell usually in the form of a plasmid.

Adhesin bacterial cell with pili (fimbriae) ultr23.vub.ac.be/.../fimbrialadhesion.html

Bacterial conjugation with sex pilus. www.cbs.dtu.dk/.../roanoke/genetics980309.html

Spores (Endospores) Bacterial spores called endospores. Usually found in 2 genera: Bacillus and

Clostridium. Form through the process sporulation.

A copy of the chromosome and some cytoplasm is enclosed in a thick protein coat.

This occurs when moisture and nutrients are low.

Endospores are resistant to heat, cold, drying, and most chemicals.

If adequate conditions are present, the endospore can become an active bacteria.

Clostridium difficil forming an endospore.

Associated with antibiotic related diarrhea caused by toxins produced

Red structure is endospore forming. www.chem.wayne.edu/feiggroup/research.htm

Binary Fission One parent cell splits to become 2 daughter

cells. This process produces a clone of the parent

cell. During this process, its chromosome is

replicated in a process called DNA replication. Generation time

The time it takes one parent cell to become 2 identical daughter cells.

www.uic.edu/.../bios100/lecturesf04am/lect06.htm