Unit 1 trimester 2

Biology

Pathogens

microorganism that cause disease

Communicable diseases

A disease that can be spread

Direct contact

Coming into contact with saliva, mucus, blood, or feces containing germs

Indirect contact

Coming into contact with areas that have been contaminated by germs

Vector-Borne

Being bitten by a tick or mosquito carrying a disease-causing agent

Foodborne

Eating food contaminated with germs

Waterborne

Drinking or coming into contact with contaminated water

Types of pathogens

Bacteria, Fungi, Viruses, and protist

Microorganisms (Microbes)

A living organism that’s so small it can only be seen through a microscope. Either beneficial or harmful

Four types of Microorganisms

Bacteria, Algae, Protist, Fungi

Bacteria (prokaryotes)

a single-celled prokaryotic organism that can exist in animals and plants

Eubacteria

Larger kingdom of bacteria; usually surrounded by a cell wall (pepitidoglycan)

Archaebacteria

lack peptidoglycan and have different membrane lipids

Four characteristics of Bacteria (prokaryotes)

their shape, chemical nature of their cell walls, their movement, and the way they obtain energy

Shape

Bacilli, Cocci, Spirlla

Bacilli

bacillus, rod shape

Cocci

coccus, spherical

Spirlla

spirillm, spiral and corkscrew-shaped

Gram-positive

Violet stain, thick pepitidoglycan walls

Gram-negative

red or pink stain, thinner walls inside an outer

Heterotroph

need to consume

Autotrph

make their own food

Aerobe

needs oxygen

Anaerobe

doesn’t need oxygen

Binary Fission

Bacteria has grown up to double its size

Conjugation

Exchange genetic info

Spore formation

Need to survive extreme conditions

Decomposers

Help the ecosystem cycle all nutrients. In sewage systems: break down human waste, descard food, and chemical waste

Importance of Bacteria

Decomposers, Nitrogen Fixers, and Human Use

Nitrogen Fixers

Help in converting nitrogen gas into a form that plants can use

Human Use

Digest petroleum. Help mine minerals used to synthesize drugs. Natural bacteria in human bodies

How Bacterial Diseases Start

Using cells for Food and realeasing toxins

Using cells for Food

bacteria damage the cells and tissues of the infected organism directly by breaking down the cells for food

Releasing Toxins

Bacteria release toxins that travel throughout the body interfering with the normal activity of the host.

Vaccine

preparation of weakend or killed pathegons

Antibiotics

compounds that block the growth and reproduction of bacteria

How to control bacteria growth

Sterilization by heat, Disinfectants, and food storage and processing

Sterilization by heat

Can destroy all bacteria since most bacteria cannot survive high temperature for a long time

Disinfectant

Chemicals/solutions that can kill pathogens

Food storage and processing

Refrigeration and preservatives

Viruses

Composed of a core of DNA or RNA surrounded by a protein coat. Can only reproduce by infecting living cells and can be seen using electron microscope

Lytic Infection

Virus enters a cell, makes copies of itself and causes the cell to burst

Lysogenic infection

virus integrates its DNA into the DNA of the host cell, then the cell replicates

Retroviruses

Use RNA as their genetic info; their RNA is copied into DNA; remain format for some time then becomes active

Viroids

Strands of RNA w/o protein coat

Prions

Misfolded protein w/o DNA or RNA. Can convert other normal proteins into prions

Protist

group of eukarotic, most single-celled organisms. They have features that belong to animals, plants, and fungi. Can be classified based on how they obtain nutrition

Protozoans

Heterotrophs, disease examples: malaria. 4 phyla distinguised by their means of movement

Zooflagellates

Swim using flagella, absorb food through their cell membrane. Live in lakes and streams and absorb nutrients from decaying organic material. Live within bodies of organisms. Reproduce asexually

Sarcodines

Use pseudopods for movement and feeding. Capture and digest particles of food and other cells.

Food vacuole

A small cavity inside sarcodines to store food

Ciliates

Use cilia for movement and feeding, found in fresh and salt water. Most are macronucleus. Produce asexually. When stressed, they undergo conjugation.

Trichocysts

Small bottle-shaped parts for defense

Sporozoans

Don’t move on their own. Reproduce by means of sporzites.

Parasitic

They take or use nutrients of other organisms

Algae

Autotrophs. Many contain chlorophyll. Moves freely. Major food source and oxygen resource. 7 major phyla: unicellular algae and multicellular

Euglenophytes

Have 2 flagella, no cell wall, found in ponds and lakes.

Chrysophytes

Have gold colored chloroplast

Diatoms

Produce thin, delicate cell walls rich in silicon

Dinoflagellates

Have 2 flagella, wrapped between plates and cellulose

Red Algae

Can live in great depths, highly efficient in harvesting sunlight, chlorophyll A (phycoblins)

Brown Algae

Contains chlorophyll, A and C (fucoxanthin), mostly complex, and found in shallow coasts.

Green Algae

Very similar with plants (pigments and cell wall), chlorophyll A and B, found in fresh and salt water

Molds (funguslike Protist)

Heterotrphs, absorbs nutrients from dead or decaying organic matter, unlike fungi, they have centrioles and chitin walls

What are the 3 types of molds

Cellular slime, acellular slime, and water

Slime Molds

Key role in recycling organic material, found primarily in rotting woods or compost piles,

Cellular slime

Individual cells remain distinct (separated by cell membranes)

Acellular Slime

Cell fuse to form large cells with many nuclei

Water molds (aka Oomycetes)

Thrive on dead or decaying matter in water, some are plant parasites on land, produce thin filaments called phyae

Fungi

Fungi are living things with cells that have chitin cell walls. They absorb food after breaking it down outside their bodies. Most feed on dead plants and animals, some are parasites, most are multicellular, and they reproduce sexually and asexually.

Classification of Fungi

Zygomycetes, Ascomycota, Basidiomycota, and Deuteromycota.

Zygomycetes

Common black mold

Ascomycota

aka sac fungi, produces sac sponsor inside

Basidiomycota

Mushroom fungi, spores produced, underneath the “club”

Deuteromycota

If it’s not those 3 funges, they consider it a Deuteromycota

The immune system

Fighting infections through the production of cells that inactivate foreign substance

Foreign Sustance

Anything not actually present in the body. The immune system should recognize it shouldn’t be there.

Antigen

Anything that triggers an immune response. Immune system recognizes specific ones based on what’s on their surface

Antibodies

Proteins that recognize and bind to antigens. Used to neutralize and destroys antigens

Interferons

Proteins made by virus-infected cells to interfere with virus growth

Immune System responds in either of 2 ways

Specific or non- specific

Nonspecific Defenses

Physical and chemical barriers that don’t discriminate between one threat and another

First Line of defense

Keep pathogens out of the body

Second Line of Defense

Inflamation

Epidermis

Out layer that you can see or feel

Keratin

(tough, fibrous protein)

Melanin

from melanocytes

Dermis

layer under the epidermis

Hair

serves as protection

Head

Protects scalp from UV rays and provides insulation from the cold

Hair follicles

close contact with sebaceous (oil) glands; oils maintain hair’s quality

Sweat glands

Makes sweat, controls body temp, components prevent some microbes from entering the body.