Unit 10

Bacteria,

Viruses &

Disease

KINGDOMS:Eubacteria

AND

Archaebacteria

REVIEW… Cladogram of Domains

Which is the oldest domain in this cladogram?• Domain Bacteria

Pathology

Is defined as the scientific study of the nature

of disease and its causes, processes,

development, and consequences.

A pathogen is a disease causing agent, such

as bacteria, viruses, fungi or parasites.

Prokaryotic cell characteristics

• Free floating genetic materialinside cell

• Cell body enclosed by cell wall

• Small, unicellular organism

• DOES NOT contain specialized membrane bound organelles(lacks nucleus)

• Until recently, bacteria were placed into one Kingdom. As a result, sometimes bacteria are referred to as Monerans.

Kingdom Eubacteria & Archaebacteria

Eubacteria (True Bacteria)

Tend to be smaller

Found throughout the environment

Can be pathogenic

Classified according to their mode of getting nutrients,

mechanism of movement, and their shape

Archaebacteria (Ancient Bacteria)

Tend to be larger

Thought to be ancestors of eukaryotes, gene sequences are

similar.

Tend to live in extreme environments – sometimes they are

called “Extremophiles”

Archaebacteria

Halophiles – Live in very salty environments;

Great Salt Lake

Acidophiles- live in areas of low pH level

(acidic)

Thermophiles – live in high temperatures

Ex: Thermoacidophiles – sulfur hot springs;

hydrothermal vents found deep in the oceans

Methanogens – cannot live in the presence of

oxygen; sewage treatment plants, swamps, bogs

Diversity: Interaction with Oxygen

Obligate Aerobes - require oxygen for

cellular respiration, need oxygen to make ATP

energy for growing and surviving

Obligate Anaerobes - must avoid oxygen,

they will die in its presence

Facultative Anaerobes - can live with or

without oxygen

Diversity: Metabolic (energy usage)

Heterotrophs- get energy by consuming organic

compounds made by other organisms (eat)

Chemoheterotrophs- an organism that gets

“nourishment from others and from using chemicals”

Ex. Lactobacillus “good” bacteria found in yogurt

Photoheterotrophs- an organism that gets

“nourishment from others and from using light”

Ex. Cyanobacteria (makes up pioneer lichens)

Diversity: Metabolic

Autotrophs- make their own food from

inorganic molecules

Chemoautotrophs- an organism that makes

energy for itself using inorganic material such

as sulfur or iron

Ex. archaea living in hostile environments such

as deep sea vents

Photoautotrophs- an organism that gets

“nourishment for itself using light and CO2”

Identification: Diversity of Bacteria Naming

□Cocci – sphere

□Bacilli – rods

□Spirilla – spirals

Prefixes:

□Diplo – in pairs

□Staph – in

clusters

□Strep – in chains

Diversity: Structural Adaptations to Survive Hostile

Environments

Capsules (slime layers) - help evade immune

system and adhere to surfaces

Pili – hair-like projections

Endospores – dormant, tough outer structure for

protection until conditions become favorable

Flagella - one or more long tail-like structures

Diversity: Gram Stain

Stains used to identify bacteria based chemical

differences in their cell walls.

Bacterial species with walls containing small amounts

of peptidoglycan are Gram-negative and turns pink.

Bacteria with walls containing relatively large

amounts of peptidoglycan are Gram- positive and

turns purple.

Gram-Negative & Gram-Positive

Reproduction: Binary Fission

One cell splits into two

cells (asexual)

Offspring are

genetically identical to

parent

Quick, fast reproduction

time

Reproduction: Conjugation

Sexual reproduction

with exchange of

genetic information

before dividing

Offspring have new

genes genetically

different to parents

Increase diversity

Bacteria: Friend or Foe?

Lactobacillus

acidophilus turns

milk into yogurt.

Escherichia coli live

in your gut and

help you digest

food.

Friend: Helpful Bacteria

1. Decomposers – recycles dead organisms/nutrients

to soil

2. Help digest food as well as produce vitamins

3. Nitrogen-fixing bacteria: transforms

atmospheric nitrogen and allows it to be absorbed

by plant nodules for growth (proteins)

4. Food – helps ferments milk, cheese, yogurt

5. Clean oil spills (purify water)

6. Antibiotics – bacteria fighting bacteria

Foe: Harmful Bacteria

How do bacteria cause disease?

a) By breaking down the cells and tissue for food

Ex: Mycobacterium tuberculosis (tuberculosis), tooth

decay/cavities

b) Releasing toxins that can move through the body

Ex: Streptococcus- strep throat

Ex: Borelia burgdorferi- Lyme disease

c) Spores are formed and inhaled, can be fatal

Ex. Bacillus anthracis- Anthrax

Found in sheep and cattle

Controlling Bacterial Growth1. Freezing: stops growth

for most bacteria

2. Refrigeration:

-Slows growth / takes

longer to multiply

-Does not kill bacteria

3. Canning/ Jarring:

-Heat & seals out air

-Some endospores may

still survive

Controlling Bacterial Growth

4. Cooking:

High temperature

kills bacteria

5. Drying: no moisture/ dehydrate

6. Salting: if enough will kill bacteria

due to placing cells in osmotic

hypertonic environment

B. Controlling Bacterial Growth

7. Sterilization:

-Using high temperatures for long periods

Autoclave (High heat and pressure)

-Chemical action

8. Disinfectant:

-Chemical solutions ex. alcohol

- Used to clean surfaces

Virus = Virion

1. Living characteristics of viruses: They contain genetic material (DNA or RNA) never both!!

2. Nonliving characteristics of viruses They are acellular / not cells (they contain no cytoplasm

or organelles).

They do not metabolize energy

ONLY replicate using the host cell's machinery.

They do not grow and divide. Instead, new viral components (proteins) are synthesized and assembled within the infected host cell.

They are NOT alive!!!

Structure of a Virus

A virus particle, or virion, consists of the following:

a. Nucleic acid - set of genetic instructions, either DNA

or RNA

b. Coat of protein (capsid) - surrounds the DNA or RNA

to protect it

c. Lipid membrane aka envelope- surrounds the protein

coat (found only in some viruses such as influenza/flu

virus)

Specificity: To Host Cells

Viruses are specific to their hosts.

□ Virus have surface proteins that

can only match to exact receptor

sites on a host cell like a lock & key

Ex. Rabies virus only attacks brain cells

Ex. HIV only attacks helper T-cell in the

immune system

Ex. Influenza only attacks cells of the

respiratory track

Virus A will attack which cell?

Bacteriophage

Viruses that infect ONLY bacteria.

Have a protein "tail" attached to the capsid

(protein coat that envelopes the genetic

material), which is

used to infect the

host bacteria.

Viruses cannot

reproduce on their

own, and must infect

a host cell in order

to create more

viruses.

Replication

Use their own genetic material and the host cell's machinery

1. Penetration - surface proteins bind to host, and release genetic material

(RNA or DNA) into the cytoplasm

2. Replication - the viral genetic material is copied

3. Transcription - the genetic material is used as a blueprint, for the cell to

make messenger RNA which is used to make viral proteins

4. Protein Synthesis – translation occurs in the cytoplasm (ribosomes), viral

proteins are made

5. Viral Assembly - the viral genetic material (from replication) is

surrounded by the newly made viral proteins

6. Release - viruses emerge from the cell by "budding" from the cell

membrane or bursting out of the cell (this causes the cell's death)

Lytic and Lysogenic Pathways

Lytic Pathway :

a. Rapid replication of the virus, ending in cell lysis (bursting of host).

b. More phages are released to infect other cells.

c. Effects of illness are immediate- within hours/days

Lysogenic Pathway:

a. The virus integrates DNA into host’s DNA becoming a prophage

b. Stays inactive within the cell and is copied when cells reproduce **no illness or symptoms for months/years

c. Changes in environment or health of host can trigger the prophage to activate in lytic cycle

HELP me from viruses!

A vaccine can be used to prevent a viral disease.

A vaccine can help your immunesystem become stronger and respond faster with viral recognition.

Vaccines prevent the virus from attaching to a host cell

Antibiotics will NOT work against viruses.

HIV (causes AIDS) Transmission (spread

by)

Bodily fluid exchange

No cure / No vaccine

HIV damages Helper T cells in the immune system

Without T cells body cannot fight other infections (bacterium, flu virus) and your body is left with no immune defense

Other examples of Viruses

Cold

Zika

West Nile

Herpes

Warts

Polio

Measles

Chicken pox

Oncogenic Virus: virus that can

cause cancer (HPV)

Describe the effects of

antibodies on viruses.

Antibodies will ____________

Unit 6 – Protists

Remember this chart?????

Compare

Genetic

material

Structure Obtain

energy?

Living?

Prokaryotes DNA and

RNA

Unicellular,

simple

YES YES

Eukaryotes DNA and

RNA

unicellular or

multicellular,

complex

YES YES

Viruses DNA or RNA

not both

(nucleic acid)

No cells:

Protein,

nucleic acid

NO NO

I. The Kingdom Protista

Protist characteristics

Eukaryotic – have a nucleus, membrane

bound organelles

Found in fresh water & ocean water

Most are unicellular, some are multicellular

Some have chloroplasts and cell wall made

of cellulose

Most are heterotrophic, some autotrophic

Protista is the Greek word for “the very first”

II. Classification of Protists

Protists are categorized according to

how they obtain energy

Heterotroph

Autotroph

Decomposer

II. Classification of Protists

3 main groups of protists (how they obtain

energy)

1. Animal-like (heterotrophs)

2. Plant-like (autotrophs)

3. Fungus-like (decomposers)

III. Animal-like Protists

(AKA: protozoans)

Classified by locomotion (how they move)

1. Flagella – whip-like tail

III. Examples of Animal-like

Protists that move with flagella

Trichonympha – lives in

gut of a termite and

helps digest wood

Giardia –-causes diarrhea if you

don’t boil or treat water

III. Animal-like Protists

2. Cilia - Short hair-like projections

III. Example of Animal-like

Protists that move with cilia

Paramecium

III. Animal-like Protists

3. Pseudopod “false feet”– temporary

projections of cytoplasm for amoeboid

movement

Animal-like Protists that move with

pseudopods (false feet)

Entamoeba – causes

amoebic dysentery or the

“revenge” (a bad case of

diarrhea)

Amoeba

III. Animal-like Protists

4. Nonmotile - “no movement”, do not move

Example – Plasmodium

Causes Malaria

IV. Plant-like Protists

Contain chloroplasts and perform

photosynthesis

Plant-like Protista produce OXYGEN, making

them one of the most important groups of

organisms.

Can be Unicellular or Multicellular

Examples of Unicellular

Plant-like Protists

Euglena Golden Algae

Diatoms

cell walls of Silicon

used as an abrasive

in toothpaste

Examples of Unicellular

Plant-like ProtistsKarenia & Gonyaulax

Cause “Red Tide”,produce nerve toxin that kills fish/humans (eutrophication)

Eutrophication

• Caused by the addition

of excess nutrients to a

body of water

• Can lead to depleted

oxygen levels & “dead

zones”

• Remember the saying:

“Too much of a good

thing can be bad!”

Examples of Multicellular

Plant-like Protists

Red Algae Brown Algae

Examples of Multicellular

Plant-like Protists

Sargassum Kelp

Examples of Multicellular

Plant-like Protists

Green Algae species

Volvox Spirogyra

V. Fungus-like Protists

Heterotrophs that absorb nutrients from dead or

decaying organic matter (decomposer)

Unlike true fungus, they do not have cell walls made

of chitin

Ex: Slime molds

IV. Fungus-like Protist examples

Water molds - white fuzz growing on fish

in aquariums

Kingdom Fungi

UNIT 10

Classification of Living OrganismsDomain Bacteria Archaea Eukarya

Kingdom Eubacteria Archaebacteria Protista Fungi Plantae Animalia

Cell type Prokaryote Prokaryote Eukaryote Eukaryote Eukaryote Eukaryote

Cell

Structure

Cell walls with

peptidoglycan

Cell walls without

peptidoglycan

Cell walls of

cellulose in

some; some

have

chloroplasts

Cell walls of

chitin

Cell walls

of cellulose; chloroplasts

No cell walls

or

chloroplasts

# of

cells

Unicellular Unicellular Most

unicellular;

some

colonial;

some

multicellular

Most

multicellular

some

unicellular

Multicellular Multicellular

Mode

of Nutrition

Autotroph or

heterotroph

Autotroph or

heterotroph

Autotroph or

heterotroph

Heterotroph Autotroph Heterotroph

Ex.Streptococcus,

Escherichia coli

(E. coli)

Methanogens, halophiles Amoeba,

Paramecium,

slime molds,

giant kelp

Mushrooms,

yeasts

Mosses,

ferns,

flowering

plants

Sponges,

worms, insects,

fishes, mammals

Kingdom Fungi Characteristics

• Eukaryotes- NUCLEUS

• Heterotrophs- cannot make own energy

(NO photosynthesis)

• Decomposers or Parasites

• BOTH unicellular (ex. yeast) AND

multicellular (ex. mushroom)

• Cell walls made of chitin

Application

What KINGDOM would an organism belong

to if it had the following characteristics?

• Eukaryotic

• Heterotrophic

• Multicellular

• Cell wall made of chitin

Role of fungi in environment• Decomposers

– convert organic waste into compounds

usable by plants (break down dead

organisms)

All organisms that die will become organic waste!

Fungi Structures• Hyphae

– thin filaments that make up the fungus body

Fungi Structures• Mycelium

– Big mass or group of hyphae below ground

Fungi Structures• Mushroom

– Fruiting body or reproductive structure,

usually above ground

Fairy Ring

Fungi Reproduction

• Asexual Reproduction

– No exchange of genetic material

– Fruiting body/reproductive structure

produces spores that are dispersed by wind,

water & animals

• Sexual Reproduction

– Exchange of genetic material

– Increases a population’s variation

– Increases chances of surviving & evolving

SEXUAL REPRODUCTION

ASEXUAL REPRODUCTION

Classification of Fungi

• Common Molds

• Sac Fungi

• Club Fungi

• Imperfect Fungi

Common Molds

• Rhizopus (common bread mold)

–Rhizoids – root-like hyphae that

penetrate the bread’s surface &

anchor it to the bread

–Stolons – stem-like hyphae that run

along the surface of bread

Sac Fungi

• Reproductive structure resembles a cup

• Yeast

–only unicellular fungi

–Reproduce asexually by budding

–Thrush: yeast infection of the mouth due to overuse of antibiotics

THRUSH

Club Fungi

• Reproductive structure

resembles a club

• Ex. Pigskin poison puffball, stinkhorn,

shelf fungus, bird’s nest fungi, common

mushroom, fly agaric (poisonous)

CLUB MUSHROOMS

BRACKET FUNGI

GILLS

Imperfect Fungi

• Do not have an observable sexual phase in life cycle

• Penicillium notatum (antibiotic penicillin)

• Parasites – Athlete’s foot & ringworm

ATHLETE’S FOOT

RINGWORM

MOLDY

ORANGE

Penicillium

Penicillium

Symbiotic RelationshipLichens

• A relationship between fungusand a photosynthetic organism

• Fungus collects water & minerals and protects autotrophs

• Algae or cyanobacteria provides food (performs photosynthesis)

• What type of eukaryotic organism is algae? – plant-like protist

• What type of symbiotic relationship is this?– Mutualism

• Often a pioneer organism

Lichens

Lichen Anatomy

Symbiotic RelationshipMycorrhizae

• A relationship between plant roots and fungi mycelia

• Roots provide products of photosynthesis, which are…? – Glucose and oxygen

• Fungi help plant absorbmore water, minerals & other nutrients

• Which type of symbiotic relationship?

– Mutualism

MYCORRHIZAE

Benefits of

Mycorrhizae

Plant with

mycorrhizae

on the right

Plant without

mycorrhizae

on the left

Other fun fungus facts

FUNGUS EATING ROUND WORM

Parasitic fungi

Cordyceps video