IMMUNE SYSTEM BENCHMARK STUDY GUIDE

What is a PATHOGEN? Anything that causes disease Can be a bacteria, virus,

fungi, parasites Bacteria produce toxins Viruses lyse cells

What is a VIRUS? A non-living particle that requires a

host to replicate Can cause disease Found in soil, water, air, surfaces

What happens during the LYTIC CYCLE?

Attachment Entry DNA Replication and Virus Protein

Production Assembly Lysis

What happens during the LYSOGENIC CYCLE?

Attachment Entry Provirus – Viral DNA is incorporated into

host DNA Cell DNA with virus DNA is replicated

What adaptations allow bacteria to survive in different environments?

Cell Walls Can withstand harsh environments Endospores Aerobic or anaerobic respiration

What are some useful uses for bacteria?

Make cheese and yogurt Clean spills Make antibiotics Nitrogen fixation Recycle nutrients/decomposers

Describe how Robert Koch explained the cause of disease. Steps?

Pathogen is isolated from a host Pathogen is grown/cultured Pathogen is introduced to another

host New host becomes ill, must have

same symptoms Pathogen is isolated – must be same

pathogen as original

What are the causes of… Malaria – plasmodium parasite on

mosquitoes Mosquito is a vector

HIV – Virus Passed through exchange of body

fluids

Shingles – Virus Passed on by contact/droplets

Define INNATE IMMUNITY First line of defense

Barriers and Mucus Non-specific defense Skin Mucus membranes Tears and Saliva

Lysozyme enzyme – breaks down bacterial cell walls and membranes

What is INFLAMMATION? Non-specific defense 2nd Line of Defense

Entry of pathogen Mast cells release histamine

Histamine triggers – pain, heat, swelling, redness

Dilate red blood vessels to allow phagocytes to damage site

Phagocytes (macrophages, monocytes, neutrophils) digest pathogens

Pus

How does the body react to viral infections?

Virus infected cells release INTERFERONS

Interferons (chemicals) tell neighboring cells to make antiviral proteins Viruses cannot enter neighboring cells

What is the function of white blood cells?

Basophils – make histamine Macrophage – digest invading cells

Describe 2 ways bacteria can reproduce?

Binary fission Asexual reproduction One bacteria replicates DNA and

divides into two cells

Conjugation Sexual reproduction One bacteria passes on a plasmid or

new DNA to another bacteria through pili

What is ACQUIRED IMMUNITY? 3rd Line of Defense Build up resistance Specific Immunity Body uses T and B cells against a

specific pathogen Cellular Immunity Antibody Immunity

Cellular Immunity1. Pathogen is engulfed by macrophage

2. Macrophage presents digested pathogen to Helper T Cell

3. Helper T cell activates Cytotoxic T cells

4. Cytotoxic T cells signal infected cells to commit “suicide”

5. Memory Cytotoxic T cells are made

Antibody Immunity Pathogen (bacteria) is engulfed by

macrophage Macrophage presents digested bacteria

to Helper T cell Helper T cell activates B cell B cell turns into plasma cell Plasma cell makes Antibodies

Antibodies circulate through blood stream to find and collect bacteria

What is PASSIVE IMMUNITY? Receive Antibodies by injection or

breast feeding Passive – you DON’T make

antibodies yourself Temporary

What is ACTIVE IMMUNITY Occurs Naturally – You build up

immune system You have to get sick Body makes memory B and T cells

What is an ANTIBIOTIC? Most come from penicillin Target – bacterial infections CANNOT be used on viruses Break down the cell walls

What is RESISTANCE? When a bacteria is no longer

sensitive to antibiotics