Viruses &

Bacteria1

A)Students will derive the relationship between single-celled and multi-celled organisms and the increasing complexity of systems.

B) Compare how structures and function vary between the six kingdoms.

C) Examine the evolutionary basis of modern classification systems.

d) Compare and contrast viruses with living organisms.

UNIT GOALS

Understanding Viruses Clip

A virus is a nonliving particle with a simple structure.Composed of a nucleic acid (DNA or RNA) surrounded by a protein coat. Virus

that infects

bacteria

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Capsid - The capsid is the protein shell that encloses the nucleic acid; Three functions:

1) it protects the nucleic acid from digestion by enzymes, 2) contains special sites on its

surface that allow the virus to attach to a host cell, and

3) Allow virus nucleic acid penetrate the host cell’s membrane and, in some cases, to inject the infectious nucleic acid into the cell's cytoplasm.

Envelope - Surrounds the capsid. Composed of two lipid layers interspersed with protein molecules

Or RNA

Or RNA

Virus Virus StructureStructure

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Viral Nucleic AcidViral Nucleic Acid •The nucleic acid of each virus encodes the genetic information for the synthesis of all proteins. •Only a few groups of viruses use DNA. •Most viruses maintain all their genetic information with the single-stranded RNA.

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Viruses, such as the influenza virus, that have RNA as their genetic material mutate more often that DNA viruses.

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Retrovirus

• Has an RNA genome that is converted to DNA in the host cell

• HIV• Reverse

transcription ANIMATION

•How does a virus infect a cell?

•Clip

1.1.The virus The virus attaches to a attaches to a host cell and host cell and injectsinjects its nucleic its nucleic acid into the cell.acid into the cell.

2.2.The viral nucleic The viral nucleic acid is acid is immediately immediately replicatedreplicated, , eventually eventually causing the host causing the host cell to cell to burstburst, , releasing new releasing new viral particles. viral particles.

3.3.These new These new viruses then viruses then attack other attack other cellscells..

Lytic CycleLytic Cycle

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Animation

Lysogenic CycleAfter the virus

embeds its nucleic acid into the chromosome of the host cell, the viral nucleic acid is replicated along with the host cell’s DNA. Then the virus becomes dormant, sometimes for years without the host knowing.The virus may suddenly become active, resuming the lytic cycle, which will eventually destroy the host cell.

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Animation

Overview: Lytic and Lysogenic

cycles

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Are viruses alive?• Can They:

– Reproduce? – Obtain and use

energy? – Grow, develop,

and die? – Respond to the

environment?

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Do they meet the

criteria for

life?

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Vaccines

•Made from parts of a virus.

•Then when our bodies see the virus

again it recognizes and fights the

virus.

•Antibiotics do not work on viruses!

•Most vaccines contain purified

fragments taken from killed bacteria

or viruses.

•Some vaccines contain live viruses,

but in a very weak form that dos not

cause disease.

stimulates the body’s immune response

"teach" the immune system

how to recognize and fight

bacteria and viruses 13

Clip on next slide

EXTRAS

• PrionPrion-is a type of infectious agent made only of protein.

• Chronic wasting disease, (in deer and elk), mad cow disease

• All of these diseases affect the structure of the brain or other neural tissue, and all are untreatable and fatal.

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Viroids• small naked single-

stranded RNA molecules that infect plant cells and cause disease.

• Smaller than viruses, viroids are not enclosed in a protein coat of any kind.

• They generally consist of less than 400 nucleotides and do not contain any genes. 1

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Compare and contrast viruses with living organisms.

Examples to include:

-Mode of nutrition?-Characteristics of living things-Reproduction-Structure-Homeostasis?- Cell structures?

Viruses 6 kingdomsof

Living things

Diseases Caused by VirusesDiseases Caused by Viruses

•Influenza

•Measles

•Chickenpox

•Polio•HIV•Mumps

•Rabies

•Hepatitis

•Common

cold

•Smallpox•Ebola•Hantavirus•Herpes•Lassa Fever•Mononucleosis

•West Nile•Yellow fever•Cancer

Influenza

1918 1918 pandemic pandemic 20 20 to 40 million peopleto 40 million people

contagious respiratory illness

More people died of influenza in a single year than in four-years of the Black Death Bubonic Plague from 1347 to 1351. Known as "Spanish Flu" or "La Grippe" the influenza of 1918-1919 was a global disaster

Polio• Polio is a contagious, historically

devastating disease that was virtually eliminated from the Western hemisphere in the second half of the twentieth century. Although polio has plagued humans since ancient times, its most extensive outbreak occurred in the first half of the 1900s before the vaccination, created by Jonas Salk, became widely available in 1955.

• People who have abortive polio or nonparalytic polio usually make a full recovery. However, paralytic polio, as its name implies, causes muscle paralysis - and can even result in death. In paralytic polio, the virus leaves the intestinal tract and enters the bloodstream, attacking the nerves (in abortive or asymptomatic polio, the virus usually just stays in the intestinal tract). The virus may affect the nerves governing the muscles in the limbs and the muscles necessary for breathing, causing respiratory difficulty and paralysis of the arms and legs. Although the acute illness usually lasts less than 2 weeks, damage to the nerves could last a lifetime.

•What's the Future of Polio?Through intensive vaccination programs, a coalition of organizations in 1999 decided to work toward world eradication of polio by 2005. Between 1988 and 1998, wild-type polio was eliminated from North America, South America, and Europe. But polio still exists in Africa, as well as India and some of its neighboring countries. Clip

Ebola Virus 

The onset of illness is abrupt

and is characterized by fever,

headache, joint and muscle

aches, sore throat, and

weakness, followed by

diarrhea, vomiting, and

stomach pain. A rash, red

eyes, hiccups and internal and

external bleeding may be

seen in some patients.

People can be exposed to Ebola virus from direct contact with the blood and/or secretions of an infected person: contact with objects, such as needles, that have been contaminated with infected secretions

native to the African continent.

Human Immunodeficiency Virus

AIDS means 'acquired immune

deficiency syndrome'. It is a

condition that sets in when the

HIV virus has killed so many T-

helper cells that the immune

system is no longer able to

recognize and react to attacks

from everyday infections.

HIV attacks some of the cells that are vital to a healthy immune system, including the white blood cells known as T-helper cells or CD4 cells.

Lassa Fever

West Africa

single-stranded

RNA virus and is

animal-borne.

The number of Lassa virus infections per year in West Africa is estimated at 100,000 to 300,000, with approximately 5,000 deaths. In some areas of Sierra Leone and Liberia, it is known that 10%-16% of people admitted to hospitals have Lassa fever, which indicates the serious impact of the disease on the population of this region.

The Mastomys rodents shed the virus in urine and

droppings. Lassa fever may also spread through person-

to-person contact. This type of transmission occurs

when a person comes into contact with virus in the

blood, tissue, secretions, or excretions of an individual

infected with the Lassa virus.

Signs and symptoms of Lassa

fever typically occur 1-3 weeks

after the patient comes into

contact with the virus. These

include fever, retrosternal pain

(pain behind the chest wall), sore

throat, back pain, cough, abdominal pain, vomiting, diarrhea, conjunctivitis, facial

swelling, proteinuria (protein in

the urine), and mucosal bleeding.

The most common

complication of Lassa

fever is deafness. 1%

of infections with result

in death.

Chickenpox• Chickenpox is a very

contagious viral disease that causes an itchy outbreak of skin blisters.

• The chickenpox virus spreads from person to person by direct contact with fluid from broken chickenpox blisters.

• Chickenpox is usually a mild disease. However, in adults and children with weakened immune systems, chickenpox can cause serious complications and even death.

• A vaccine is now available to prevent chickenpox.

Hantavirus

The first symptoms are fever, chills, muscle aches, and sometimes nausea, vomiting, and abdominal pain. The muscle aches are often severe, and occur in the thighs, hips, back and sometimes the shoulder. Some patients will develop coughing and shortness of breath within a few days. Others may go for as long as a week with the other symptoms before developing a cough and shortness of breath, followed by the abrupt onset of respiratory distress, often severe and fatal.

A person may be exposed

to hantavirus by

inhaling dust after

disturbing nests or

breathing in closed

spaces inhabited by

infected mice.

The deer mouse

(Peromyscus

maniculatus) is the

main carrier of

hantavirus; however,

other wild rodents can

cause problems as

well.

Mortality is about

40 to 50 percent

Measles• Diseases of childhood that causes a skin rash.  • Serious complications, such as pneumonia, croup

or encephalitis, can occur.• The disease starts with a cold, fever, cough,

conjunctivitis (red eye) and fatigue.  Three days later, a red blotchy rash starts on the face - then spreads to the rest of the body, including the feet.  The fever starts to go down on the second or third day of the rash.  There may be some fine peeling of the skin after the rash fades. Most patients are ill for about seven days;

• IS IT CONTAGIOUS?VERY. It is most common in late winter and early spring.  Most people have been exposed to the disease 10-12 days before they have any symptoms. Spread by coming in contact with the saliva of someone who has the disease through coughing, kissing or sharing of eating utensils.

• Once you have had a case of measles you have lifetime immunity (protection) to the disease.

Mumps

Mumps is an infectious disease that causes

swelling of the saliva-producing glands near the

ears. 

Can last 7-10 days The most common symptom is painful swelling

in front of and below the ears.  Often, there is

pain when eating or moving the jaw.  Some

people have headaches, loss of appetite, fever

and a tired feeling about a day before the swelling.  One side of the face usually swells

before the other.  In males past puberty, a

problem that is associated with mumps is orchitis (swelling of the testicles).

Mumps is spread by

contact with the saliva of

someone who has the

disease.  It is contagious

until all the swelling is

gone.  Mumps occurs year-

round, but is more common

in the winter and spring.

Rabies

RNA virus.

Most often transmitted through the bite of a rabid animal

•Infects the central nervous

system, causing encephalopathy

and ultimately death. Early

symptoms in humans are

nonspecific, consisting of fever &

headache.

•As the disease progresses,

neurological symptoms appear

and may include insomnia,

anxiety, confusion, slight or

partial paralysis, excitation,

hallucinations, agitation,

hypersalivation, difficulty

swallowing, and hydrophobia.

Death usually occurs within days

of the onset of symptoms.

The principal rabies

hosts today are wild

carnivores and bats..

Rabies immune globulin and

five doses of vaccine given

over a 4-week period typically

SmallpoSmallpoxx• Infection usually occurred by

inhalation of virus • acute, with fever, malaise, headaches,

and backaches. The initial toxemia phase lasted 4-5 days. On about the third or fourth day, the characteristic rash appeared. First, it appeared on the buccal and pharyngeal mucosa, the face, and the forearms. Within a day, it spread to the trunk and lower limbs.

• The lesions usually protruded from the skin and are firm to touch. About 8 weeks after onset of the rash, the lesions dried up and became crusted by day 14. By the end of the third week, most crusts had fallen off, with the exception of the palms and the soles. The outcome of infection was either death or recovery with immunity.

In 1966, the World Health Organization started a program for the worldwide eradication of smallpox.Through intensive case finding and vaccination of direct and indirect contacts, the disease was finally eradicated on December 9,1979.

HepatitisHepatitis is a disease that impairs liver function either temporarily or permanently, sometimes even leading to death. It can be initiated by a host of factors, but primarily by viruses. Drugs also can cause hepatitis but when the specific drug is discontinued, the liver usually returns to normal.

Hepatitis Amainly transmitted by

contaminated food and water.

Hepatitis BThis type is essentially a blood-borne virus with other bodily fluids being infectious, notably semen and saliva, and is often transmitted from mother to fetus.

Hepatitis CHepatitis CBefore a blood test was discovered in 1989 to screen for HCV, this was the most frequent hepatitis to be acquired from blood transfusions and blood products. Up to half of those with chronic disease will go on to develop liver failure and need a transplant. Each year, 8,000 to 10,000 people die in the United States because of hepatitis C-related cirrhosis or HCV-related liver cancer.

Herpes• Infection caused by the Herpes

Simplex Virus (HSV), which resides in the nerve ganglia after the initial exposure to the virus.

• Because the virus is so effective at "hiding out" in the nerve cells, the body is never able to eliminate the herpes virus completely. Instead, after the initial infection, the body produces antibodies which show up in the blood stream.

• Blood tests which indicates the presence or lack of these antibodies.

• The antibodies make it easier for the body to recognize and attack the virus when it re-emerges from the nerve cells in the form of an outbreak.

• For this reason, out breaks following the primary outbreak usually diminish in frequency and intensity over time.

• Some people may never have another outbreak.

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MONERA

EUBACTERIA ARCHAEABACTERIA

1.Largest2.Unicellular 3.Prokaryotic 4.Most use oxygen but some are anaerobic.

1.Unicellular 2.Prokaryotic 3.Ancestors of Eukaryotes4. Lives in harsh environments.

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Round

Shape

sRod Spiral

Different kinds

of bacteria

have different

shapes.3

Structur

e

4

Flagella

Cell membrane

Ribosome Pili

Plasmids

Chromosome

Cell Wall

Method scientist use to determine cell wall type in

bacteria

Gram Gram StainingStaining

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PiliHelps the

bacteria

stick to

surfaces.

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Moveme

nt

1.Flagella

2.“Snake” or spiral 3.Glide on slime4.Non-motile

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NutritionNutrition--obtaining obtaining energyenergy

1.1.HeterotrophicHeterotrophic

2.2.AutotrophicAutotrophic **PhotoautotrophiPhotoautotrophicc

**ChemoautotrophiChemoautotrophicc

3.3.PhotoheterotrophPhotoheterotrophicic

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Releasing Energy

Obligate Aerobes

Facultative Anaerobes

Obligate Anaerobes

Must Have Oxygen

With or Without Oxygen

Cannot Have Oxygen

9.1

Take in “food” and Eliminate Waste

• Take in “food” by endocytosendocytosisis

• Eliminate waste through the cell membrane by exocytosisexocytosis..

9.2

Bacteria Reproduction

Sexual Asexual

Conjugation Binary Fission

Exchange DNA Split

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E. coli undergoing conjugation

Conjugation tube

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duplication of the chromosome followed by the bacterial cellsplitting into two cells.

Binary

fission

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CLIP

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The spores may remain dormant for years until conditions become favorable. In favorableconditions, the spore splits open and the bacteria rapidly reproduce.

Some bacteria can form

endospores that allow

them to wait out harsh

environmental

conditions.

Endospores are a method of survival.

Some disease causing

bacteria (like Anthrax)

are capable of causing

an infection 1300 years

after forming their

endospore!

ENDOSPORE

S

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ENDOSPORE FORMATION

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BACTERIABACTERIAHELPFUL HARMFUL

Soil---decomposing

Plants---nitrogen fixation

Humans---digestive system

Humans---Food:cheese, yogurt,

sauerkraut, & soy sauce.

Diseases

Photosynthesis produces oxygen

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Humans---Genetic

Engineering

•Cholera

•Diphtheria

•Leprosy

•Lyme

disease

•Meningitis

•Cat-scratch

•Streptococc

us•Scarlet

Fever

•Plague•Pneumonia•Syphilis•Tetanus•Tuberculosis•Typhoid fever•Salmonella•Rocky Mountain Spotted Fever

Diseases caused by Bacteria

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Bacterial DiseasesBacterial Diseases

release poisons release poisons that Harmthat Harmthe bodythe body

breaking down breaking down Tissues for Tissues for

foodfood

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TreatmentsTreatments–VaccinesVaccines

»Before infectionBefore infection

–Antibiotics»After infectionAfter infection

Alexander Fleming

Discovered Penicillin19

antibiotics can be used to

destroy bacterial cells

Usually inhibits cell wall growth or protein synthesis

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CLIP

Different ways to preventprevent a bacterial infectionbacterial infection.

1) Sterilization:Uses heat or chemicals to kill

bacteria from objects.

2.Skin and surfaces that have been in contact with raw meat should be washedwashed thoroughly, food should be cookedcooked properly, and contaminated water should be boiledboiled.

2.2.Avoid contactAvoid contact with an infected organism or organisms that carry disease-causing microorganisms. • Plague swept across Europe in the

Middle Ages, half of the population died.

• Bacteria transmitted through the bite of a flea.21

Why do we refrigerate our food?

• Slows down the growth of bacteria.– Slows down spoilage.

EOCT QUESTIONS

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The outer layer of The outer layer of a virus is made ofa virus is made ofA) carbohydratesA) carbohydrates

B) lipidsB) lipids

C) nucleic acidsC) nucleic acids

D) proteinsD) proteins

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Meningitis is an

infection within the

spinal fluid that

may be caused by

eitherviruses or bacteria.

Which of the

following would be

a treatment for

bacterialmeningitis but

NOT for viral

meningitis?

A vaccinationsB blood transfusions

C vitamin CD antibiotics

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Influenza

measles,

and chickenpox

are diseases

caused by

A bacteriaB fungiC protozoaD viruses

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Why is food preserved by canning in glass containers normally safe for

later consumption?

A The glass allows solar radiation to kill the bacteria that were in the food.B Bacteria are destroyed by extreme heat in the glass container.C Bacteria are removed from the food before it is placed in the glass container.D The glass container prevents oxygen. 26

• Microorganisms such as bacteria are able to change and adapt much more quickly than other organisms.

• Bacterial populations, for example, are able to build a resistance to antibiotics within months, whereas compounds that are toxic to animals remain toxic to animals for many years.

• One reason for their rapid adaptability is that microorganisms

A are highly motileB have a short life spanC have specialized organellesD are chemosynthetic

Recognize the role of evolution to biological resistance

Which statement is true about viruses?

A. They can reproduce. B. They are autotrophs. C. They contain organelles. D. They are living organisms.

Understandin

g Bacteria

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