BIOLOGY
CH. 17 NOTES 
Taxonomy: Study of Classification
Early Systems:
Aristotle developed a system of taxonomy based on habitat for animals,
structure for plants.
Animals
Water
air
Plants
land
shrubs
trees
herbs
Another system: useful, harmful, unnecessary
CAROLUS LINNAEUS:

Father of modern taxonomy

18th Century

Two-name naming system or binomial nomenclature

Latin (unchanging)

Genus species or Genus species

example: Homo sapiens or H. sapiens

Genus is a noun and the species identifier is an adjective
THREE-DOMAIN SYSTEM
Fig. 18-11. By comparing ribosomal RNA, an estimate of how long ago
pairs of different organisms shared a common ancestor can be
determined.
The phylogenetic tree drawn from these data shows that living things
seem to fall naturally into three broad groups, or domains.
BACTERIA
Eubacteria
ARCHAEA
Archaebacteria
EUKARYA
Protista
Plantae
Fungi
Animalia
Six-Kingdom Classification System
Obj. 1 Bacteria have been subdivided to account for fundamental
differences between them.
Archae
Bacteria
Eukarya
Autotrophs/
heterotrophs
A/H
Archaebacteria
Eubacteria
Fungi
Plantae
Animals
prokaryotes
unicellular
Protista
eukaryotes
A/H
multicellular
H
A/H
H
Kingdom Archaebacteria: archae means ancient

Some autotrophic but NOT photosynthetic—
chemosynthetic (methanogens-produce CH4)
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Their waste products may contain methane.
Harsh environments: extremes of:
o salt (halophiles)
o temperature (thermoacidophiles).
o pH
(phile means to love / phobic means to hate)

Flourished before there was oxygen on earth.

Kingdom Eubacteria: eu means true.

Includes most common bacteria we are familiar with.

Most use oxygen but (aerobic)

a few die in the presence of O2 (obligate anaerobes)
Obj. 2
Similarities
Differences
Archea
Extreme living cond.
distinctive cell membranes
Eu
Ideal cond.
genetic properties
properties similar to eukaryotes
Today: Most abundant living thing on Earth
First living things on Earth
Reproduce by binary fission
Can recombine genes
Short generation time
Kingdom Protista:
Mostly single-celled organisms.
Multicellular examples lack specialized tissue (Kelp)
Membrane-bound nucleus with linear chromosomes (no plasmids)
Most have genetic recombination
Miscellaneous category: all eukaryotes not plants, animals or fungi.
Examples: euglena and amoeba
Kingdom Fungi:
Heterotrophic unicellular and multicellular eukaryotic organisms.
Absorb nutrients rather than ingest
Probably have genetic recombination
Examples: mushrooms, puffballs, rusts, smuts, mildews, molds
Kingdom Plantae:
Multicellular plants
autotrophic using photosynthesis (except parasitic plants)
reproduction involves meiosis (crossing-over for recombination)
Examples: mosses, ferns, conifers, flowering plants
Kingdom Animalia:
Eukaryotic, multicellular heterotrophic organisms.
Symmetrical body organization and move around
Reproduction involves meiosis and recombination
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Modern Biology
Bacteria 23-1 Notes
Obj. 1 Define bacteria, eubacteria, and archaebacteria, and note
relationships between them. See Ch. 17 notes
Obj. 2 Describe the methods used to classify bacteria. See Ch. 17
notes. Eubacteria may be referred to as bacteria.
Archaebacteria. See Ch. 17 notes as well as below.

Have unusual lipids (fats) in cell membranes.

Absence of peptidoglycan in cell walls. Present in eubacteria.

May be more common than first expected.
(Obj. 3 Name and describe three known types of Archaebacteria)

Methanogens: autotrophic using chemosynthesis
H 2 + CO2
 CH4
Oxygen is a poison to them.

Extreme Halophiles: very high salt concentrations like the Great
Salt Lake and the Dead Sea. Use salt to make ATP.

Thermoacidophiles: Extremely high temp and low pH such as hot
springs and volcanic vents on land or hydrothermal vents on the
ocean floor that leak scalding acidic water.
Kingdom Eubacteria:
Shapes:

Bacilla are rods

Spirilla are spirals

Cocci are spheres:
o chains are called streptococci
o clusters called staphylococci
Gram Stain:

Eubacteria can be grouped into two categories according to how
they take a stain. See fig. 24-3.
o Gram+: retain stain and look purple
o Gram- : don’t take the stain but take a second stain;
pink.

A thicker layer of peptidoglycan in cell wall allows bacteria to take
the stain and are Gram+. See fig. 24-4.

Gram Stain is useful because of differences between + and –
bacteria:

Different susceptibilities to antibacterial drugs

Produce different toxic materials

React differently to disinfectants
Gram Stain Procedure:
1. Small amount of bacteria in drop of water on
slide.
2. Heat fixing: use hot plate (level 2 about 10
sec.)
3. application of crystal violet dye (20 sec.)
This will permanently stain your clothes!
4.
Wash (2 sec.) with distilled water
5. Gram’s iodine added to slide
6.
Decolorize with alcohol (10-20 sec.) or until
alcohol flows colorless.
7. Wash (2 sec.) with distilled water
8. Safranin dye (20 sec.)
9. Wash (2 sec.) with distilled water
10. Gently blot dry
Results:
Gram+ is purple-blue in color
Gram – is reddish/pink in color
Biology
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Bacteria
Ch. 23-2 Notes
Structure:
Cell wall made with peptidoglycan (amino acids and carbohydrates)
Gram negative bacteria

cell wall has outer covering of lipids and sugars. Protects
these bacteria against some kinds of antibiotics.
Prokaryotes

bacteria do not contain membrane-bound organelles.

The cell membrane contains the enzymes for cellular
respiration.

Also has folds called thylakoids like chloroplasts.

Bacterial DNA is a single, closed loop plus some have
plasmids.
Capsule

polysaccharides (starch) that cling to outside surface and
protect cell from drying or harsh chemicals or host’s white
blood cells. If capsule is fuzzy/sticky with sugars its called
glycocalyx which helps it stick to host cells.
Pili:

Short hairlike protein structures on surface.

Help bacteria adhere and also used to

transfer genetic material to another bacterium.
Endospores:

dormant structure

produced by some Gram-positive bacteria

exposed to harsh conditions

Made of thick outer covering around cell’s DNA

NOT reproductive cells

When conditions favorable again, endospore opens and
bacterium emerges and begins reproducing.
Movement Structures:

Flagella: propel with “run-and-tumble” motion.

Single, both ends, tufts, all over.
Nutrition and Growth:
Saprophytes: Hetertrophic bacteria feed on dead and decaying matter
Photoautotrophs: Autotrophic bacteria use sunlight or
Chemoautotrophs minerals for energy.
Obligate anaerobes cannot live in presence of oxygen. C. tetani
Facultative anaerobes live with or without oxygen. E. coli
Obligate aerobes must have oxygen. M. tuberculosis
Genetic Recombination: table 24-3
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Chapter 23-3 Notes
Bacteria and Humans
Bacteria and Disease:
Pathology is the study of disease.
Toxins are made by bacteria and can cause disease.

Exotoxins: made from protein by Gram-positive bacteria. C. tetani
These toxins are produced continuously.

Endotoxins: made of lipids and carbs on outer membrane of Gramnegative bacteria like E. coli. These toxins produced only when cell
dies causing fever, body aches, and weakness can damage blood
vessels.
Antibiotics: combat bacteria by inhibiting various cellular functions (see
table 24-5).

Many antibiotics protect bacteria and fungi from other microscopic
invaders.

Some antibiotics are synthesized in labs.

Broad spectrum antibiotics affect a wide variety of organisms.

Examples: Penicillin, ampicillin, bacitracin, cephalosporin,
tetracycline, streptomysin, sulfa drugs, rifampin, quinolines.)
Antibiotic Resistance:
1. When bacteria are treated with antibiotic, most die.
2. If even one survives and reproduces it creates a strain of antibiotic
resistant bacteria.
3. Overuse of antibiotics causes easily treatable diseases to become
difficult to treat. See fig. 24-6
Useful Bacteria:

Decompose waste, recycle nutrients, create organic compounds.

Bacteria ferment sugar in milk (lactose) to make sour cream,
buttermilk, yogurt.

Bacteria digest protein in milk produce unripened cheese (ricotta)

Fermented foods like cabbage > sauerkraut / cucumbers > pickles
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Biology
“Viruses”
Ch. 24-1 “Viral Structure and Replication”
STRUCTURE

Viruses are non-living particle.

Composed of nucleic acid (DNA or RNA) and a protein coat.

Cause many diseases.

Useful in genetic research because they change the way cells
work.

Virology is the study of viruses.
Virology:

Wendell Stanley crystallized the tobacco mosaic virus.

Suggested that viruses were chemicals not cells.

See table 24-1.
Characteristics of Viruses:

Some of the smallest biological particles capable of causing
disease.

Absent: nucleus, cytoplasm, organelles, or cell membrane and can
only reproduce (replicate) by infecting cells and taking over.
Viral Structure:

Nucleic acid (DNA or RNA) and a

Protein Coat called a capsid.

Envelope is membrane-like layer outside capsid. Stolen from hostcell membrane during replication. It helps virus infect new host
cells. Examples: influenza, chickenpox, herpes simplex, and HIV

see fig. 24-1 to ID parts

glycoprotein: On surface of envelope are projections made of
glycoprotein that the virus uses to attach to a host cell.
Viral Shape: May be determined by its capsid or nucleic acid.

Icosahedron:
o shape with 20 triangular faces determined by capsid.
o Examples: herpes simplex, chickenpox, and polio.

Helix:
o coiled spring shape determined by nucleic acid.
o Examples: rabies, measles, and tobacco mosaic viruses.
Grouping Viruses: 24-1 cont’d

Based on their shape and structure.

The presence of a capsid structure and an envelope.

Whether they contain DNA or RNA and whether its

single-stranded or double-stranded. Examples: see table 24-2
Virus Types:
o DNA type:
o can directly produce its own RNA
o then makes more viral proteins or
o can join the host cell’s DNA to direct the synthesis of new
viruses.
o RNA type:
o enters host cell
o viral RNA released into cytoplasm where it uses the host
cell’s ribosomes to produce new viral proteins.
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Retroviruses

another RNA type

Reverse transcriptase to use its own RNA as a pattern (template) to
make an RNA transcript of itself.

This RNA is then used to make protein.

(normal transcription: DNA>RNA>Protein)

(Reverse: RNA>DNA>RNA>Protein
Viroids and Prions: Even simpler than viruses.

Viroids:
o smallest known particles able to replicate (reproduce).
o Made of short, single strand of RNA and has no capsid.
o See fig. 24-3 Damage crops.

Prions:
o abnormal forms of proteins that clump together inside a
cell.
o Clumping eventually kills cell.
o Made of about 250 amino acids (building blocks of
proteins) but no nucleic acid (DNA or RNA).
o Examples:

scrapie in sheep

mad cow disease. Similar to

CJD (Creutzfeld Jakob) in humans.
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