Structure of Bacteriophage

-protien coat

-Dna

-sheath

- core

-spiderlike

Virus Structure (more general)

-nucleic acid enclosed within a protein structure(coat)

-can only survive by infecting a living cell

-common parts: head(dna or rna), tail, tail fibers

Pathogen and 4 types

-disease causing microorganism
-virus

-bacteria

-fungi

-protists 

Characteristics of Life and Non-Life in Viruses

L- genes, highly organized

NL- not cellular, cannot reproduce on own

Lytic Cycle

-dna injected by virus into host cell immediately highjacks the cell to produce copies of virus

1. phage injects dna

2. phage dna circulizes

3.new phage dna and protiens synthesized

4. phages assemble

5.cell lyses and releases phages

Lysogenic Cycle

-dna injected by virus into host cell incorporates the viral dna into host cell dna passing dna to future generations without making copies of the virus

1.phage attaches and injects dna

2.phage dna integrates into bacterial dna

3.the bacteria cell replicates

-can switch to lytic cycle if triggered

Lytic vs. Lysogenic

BOTH

-bacteriophages

-phage injects dna & dna circulizes (2 steps)

DIF

-lytic=short, lyso=long

-lytic=lyses, lyso=divides/replicates

Plant Viruses

-stunt plant growth

-most are rna

-to infect need to get past plant epidermis

-people have create plant breeds resistent to the viruses

Animal Viruses

-many have outer envelope made of phospholipid membrane with protien spikes

-most rna

ex. hiv, mumps, common cold, SARS, polio, measles

Typical Bacteria Cell and its Shapes

-no nucleus

-most have cell walls

-no organelles

-50% mobile

-cocci-sphere, bacilli-rod, spirochete-spiral

Interferon

-protiens produced by virus infected body cell which bind to nearby uninfected cells stimulating them to produce antiviral protiens which inhabit growth of other viruses

-signal to nearby cells when under attack to stop virus from replicating

How Do Bacteria Reproduce

-binary fission

-can reproduce at a phenominal rate if conditions are favorable

Exotoxins and Endotoxins

-poisonous protiens secreted by bacterial cells

-cause vomiting and diarrhea

-ex. botulism, staph infections

-chemical components of cell wall bacteria

-cause fever, aches, drop in BP

-ex. food poisoning, typhoid fever

Antibiotics

-leave a zone of inhibition which can be measured

-for bacteria?

First Line of Defense

-external barriers

-nonspecific

-ex. hair and mucus, sweat, saliva, tears

-flushing of the body

2nd Line of Defense

-nonspecific

-internal defenses that depend on white blood cells(leukocytes)

1.neutrophils

2. macrophages

3. natural killer/cytotoxic t cells

4. complement proteins

4. interferons

2nd line: Inflammatory Response

-when tissue is damaged, the body responds with a coordinated set of nonspecific defenses

-causes injury to become red, swollen, and warm

1. release of chemical signals such as histamine

2. dilation and increased leakiness of local blood vessles, phagocytes migrate to area

3.phagocytes engulf bacteria and cell debris, tissue heals

Players is 2nd Line Inflammatory Response

-Histamine: chemical that causes vessels to dilate and leak fluid into the wounded tissue, causing it to swell

-Prostaglandins: chemical that increases blood flow to wound area causing it to turn red and warm

-Pyrons: chemicals that travel to hypo..(brain) that cause fever

Third Line of Defense

-specific

-the immune system recognizes and attacks specific kinds of invading microbes

-antigen, antibody, lymphocytes, B cell, T cells

Antibodies

-defensive protiens produced by the immune system when it detects antigens

- Y shape of 4 protien chains

- recognize and bind to certain antigen  and counter antigens affect

-mark invaders by neutralization, agglutination, precipitation, activation of complement protiens

Vaccine

Active immunity when a small non harmful part of  disease is injected into your bloodstream to teach your body how to fight the disease

3rd Line: Primary Immune Response

-first exposure of lymphocytes to an antigen

-takes several days to produce antibodies through clonal selection

-memory cells produced to remember anitgen , are located in lymph nodes, live for decades

-think about a graph

3rd Line: Secondary Immune Response

-when same antigen is encountered again, memory cells rapidly multiply, producing lymphocytes which produce antibodies.

-faster, more effective that primary response, often symptom-free

-could confer lifelong immunity

-think about graph

Lymph Nodes

-"swollen glands" in neck, when lymph nodes fill with lymphocytes

-have memory cells located in nymph nodes

T cells in 3rd Line of Defense

-Memory Cells

-mature in Thymus and attack infected body cells

-Helper T cells

-Natural Killer (2nd)

-Cytoxic T cells

-Supressor T cells

B Cells

-mature in bone marrow, secrete antibodies

-antigen binds with b cells (lymphocytes) that have complementary receptors

-B cells are activated- grow and divide and differentiate into effector cells which create antibidoes for that specific antigen

-B cells respond to free antigens in body fluids

Antigen

-molecules on the surface of viruses or foreign cells

-specific defense

-enter body and binds with B cells that have complementary receptors

-bodies remember antigens wwe have encountered

HIV/AIDS

-attackes helper T cells, which activate T and B cells

-Acquired Immune Deficiency Syndrome

-since 1981 has killed more than 20 million people

-40 million are living with it

Leukocytes

-white blood cells produced in bone marrow

-Neutrophils- engulf bacteria and viruses in infected tissue

-Macrophages-large phagocytic amoeboid WBC's

-natural killer cells- destroy infected body cells

-part of imflammatory response

Lymphocytes

-produce immune response

-originate from stem cells in bone marrow

-B Cells & T Cells

Phagocytes

-engulf foreign cells or substances

Neutrophils & Macrophages

Cytoxic T Cells

-3rd line

-identify infected body cells and bind to it

-discharges perforin (protien) that creates a hole in infected cell's membrane

-other T cell protiens enter cell and cause cell death

Natural Killer Cells

-2nd line

-attack virus infected body cells, causing them to burst

Active Immunity

-body produces antibodies in its own defense

-by having disease or by vaccination

Passive Immunity

-3rd line

-by recieving pre-made antibodies

-through mothers blood stream

-by shot containing antibodies produced by another organism

Humoral Immunity & Cell Mediated

HUM -provided by B cells

-defend primarily vd. bacteria and viruses present in body fluids

C: produced by T cells

-attacking body cells that have been infected

Histamine

-is released and causes allergy symptoms

Steps of Allergic Reactions

1. Allergen (ex. pollon) enters blood stream

2. B cells make antibodies

3. Antibodies attach to mast cell

4. Allergen binds to antibodies on mast cell

5. Histamine os released and causes allergy symptoms