Chapter 1: Viruses and Bacteria

Compare and Contrast: Parasite & Host ~

-Parasite: Organisms that live in / on other living organisms; they cause harm to / kill host. -Host: Living organisms that parasites need in order to survive.

Compare and Contrast: Viroid & Prion~

-Viroid: Extremely simple & smaller than a virus. Consists of small circular molecules of RNA & no protein coat. -Prion: Disease causing particles that do not contain DNA or RNA, they are tiny bits of protein.

Compare and Contrast: Virus & Retrovirus~

-Virus: nonliving infectious particle that requires a host. -Retrovirus: Viruses that have RNA as their genetic information instead of DNA.

What is a close and permanent relationship between two organisms called?

A Symbiotic Relationship

How does a bacteriophage attach to a host cell?

A bacteriophage attaches to a host cell through a virus's tail fibers.

What is a photoautotroph? What is a chemoautotroph?

A photoautotroph makes its own food using light energy from the sun to convert CO2 & water to make oxygen. A chemoautotroph makes its own food by use of energy from inorganic reactions to build molecules.

What is a vaccine? What does it do to our body?

A weakened or killed form of the pathogen that stimulates the body's immune system to produce antibodies.

In what two kingdoms are the bacteria classified?

Archaebacteria and Eubacteria

Bacteria that are capable of making their own food are called?

Autotrophs

What is the name given to a virus that only infects bacterial cells?

Bacteriophages

What is the type of asexual reproduction where the bacterial cell divides to form two identical daughter cells?

Binary Fission

Compare and Contrast: The Lytic Cycle & The Lysogenic Cycle~

Both may occur when a virus enters a host cell. -The Lytic Cycle: Always causes cell to burst, killing it. 1.) Attacks original host cell 2.)Replicated DNA inside of the cell 3.) Uses bacteriophage to infiltrate the cell, killing it. -The Lysogenic Cycle: 1.) Viral DNA is incorporated into the cell, forming a prophage. 2.) Many cell divisions occur, producing a large population of the host cell that are infected with the prophage 3.) The host cell infinitely produces contaminated cells.

What is the name of the protein coat that surrounds the virus?

Capsid

Barnacles are mollusks that attach themselves to the skin of whales. The movement of water across the barnacles carries food to them. The barnacle provides no service to the whale what type of relationship is this?

Commensalism

What is the type of bacterial "reproduction" that occurs when two bacterial cells are connected in order to exchange genetic material?

Conjugation

All viruses posses what two parts?

DNA & RNA surrounded by a protein coat.

In what two ways can bacteria cause diseases?

Either physically growing and invading cells or by releasing toxins into the body.

What are the structures that are formed on the inside of a bacterium in response to adverse environmental conditions? (The contents of the cell draw together and form a thick protective wall around the outside.)

Endospores

Describe the bacterial chromosome. How is this different that the chromosomes found in eukaryotic cells?

Eukaryotes have two or more chromosomes, prokaryotes -such as bacteria- only have a single chromosomes composed of double-stranded DNA in a loop.

What is the comparison in size between eukaryotic cells, prokaryotic cells, and viruses?

Eukaryotes ~ Largest Prokaryotes ~ Middle Viruses ~ Smallest

True or False? Antibiotics are effective against viruses.

FALSE

True or False? There is no cure for any of the viral diseases.

FALSE

True or False? Viruses can grow, reproduce, and carry out respiration.

FALSE

True or False? ALL bacteria are harmful and are capable of causing diseases.

FALSE, only some are capable of causing diseases, some help.

True or False? The EUBACTERIA are an ancient form that can live in very extreme environments.

FALSE, the archaebacteria are ancient forms that can live in very extreme environments.

True or False? A small circular piece of DNA that is separated from the chromosomal DNA is known as MESOSOMES.

False it is called PLASMID

A bacterium that is capable of movement does so by means of a long, whip-like structure known as?

Flagella

Define: Endospore~

Formed inside of a cell when growth conditions for bacteria become unfavorable. Function to ensure survival of the bacteria.

What contribution was made to the study of viruses by Martinus Beijerinck?

He proved there was something smaller than bacteria causing the Tobacco Mosaic Virus. He also is considered the founder of Virology.

What always happen to the host cell at the end of the Lytic Cycle?

It bursts and dies.

Some viruses have an enzyme called reverse transcriptase. What is the role of this enzyme?

It produces DNA from an RNA template.

What are the "living" and characteristics of a virus?

Living Characteristics: 1.) They can reproduce (but only in living cells) 2.) They can mutate / change 3.) They have DNA / RNA

What contribution was made to the study of Viruses by Wendell Stanley?

Living organisms do not crystalize, meaning that viruses are not alive and therefore CAN crystalize and be stored indefinitely until introduced to a living host.

Define: Flagella~

Long and whip-like structure that works as a means of movement for some bacteria.

A lichen is a relationship between an alga and a fungus. The alga provides food to the fungus; the fungus provides water to the alga. What type of relationship is this?

Mutualism

What are the "nonliving" characteristics of a virus?

Nonliving Characteristics: 1.) They are non-cellular 2.) They have no metabolism 3.) They can be crystalized & dehydrated & stored indefinitely.

Define: Facultative Aerobe~

Organisms that can survive with or without oxygen.

Define: Obligate Anaerobe~

Organisms that do not require oxygen and are killed by its presence.

Define: Obligate Aerobe~

Organisms that require a constant supply of oxygen in order to live.

A tapeworm in the intestine of a mammal thrives living off of the food from the host, but the host loses weight and becomes lethargic. What type of relationship is this?

Parasitic

What term is used to describe bacteria that are capable of causing diseases?

Pathogenic

What are disease causing agents known as?

Pathogens

One of the major differences in Eubacteria and Archaebacteria is in the cell wall. True bacteria have what type of polysaccharide in the cell wall?

Peptidoglycan ("true" bacteria are known as Eubacteria)

Short, stiff structures found on the outside of bacterial cells that are used to attach bacteria to a food source or to one another are known as what?

Pili

Describe the importance of the nitrogen-fixing bacteria.

Plants and animals must have nitrogen to build amino acids, but they are not capable of using nitrogen gas directly. Bacteria can convert it into a usable form (nitrates)

The term "virus" comes from the Latin word meaning what?

Poison

Define: Capsule~

Present in some bacteria (prokaryotes), it is composed of a gluey polysaccharide and enables the cell to adhere to their substrate or to other individuals in the colony, some shield pathogenic bacteria from attacks by their host's immune system while others keep the cell from becoming dehydrated.

Infectious particles made up of proteins rather than DNA or RNA are called what?

Prions

What is the term for a cell that has no nucleus or membrane bound organelles?

Prokaryotic

What is the name given to viral DNA that is embedded in the host cell's DNA?

Prophage

Viruses have the ability to infect a specific type of cell because they recognize:

Protein receptor sites on the outside of the host cell.

Bacteria have the ability to "fix" nitrogen into composed other organisms can use. Why is nitrogen so important to all living things?

Proteins

What might happen to cause a prophage to become virulent?

Radiation & certain chemicals

What is the name given to a virus that contains RNA as its genetic material?

Retrovirus.

What type of bacteria lives on dead organic matter?

Saprophytes

True or False? Viruses cause chicken pox

TRUE

True or False? Viruses cause strep throat.

TRUE

True or False? Viruses need a host in order to survive.

TRUE

Describe the two ways that a virus might reproduce inside a cell.

The Lytic Cycle and The Lysogenic Cycle. The Lytic Cycle kills the host cell by causing it to burst. The Lysogenic Cycle allows the cell to indefinitely reproduce viral infected cells.

In the reproductive process of conjugation, there is no increase in numbers of cells produces. What is the purpose of this process?

The cells redistribute the genetic information which increases genetic diversity in future populations.

Describe what happens to the host cell at the end of The Lysogenic Cycle.

The host cell makes copies of the viral genetic material indefinitely.

Viruses are placed into groups based on:

The type of organism they infect

Why do we have to get a new flu shot every year to ward off the flu? Why doesn't one shot provide protection year after year?

There are different strands of the flu

What is the primary importance of bacteria in an ecosystem?

They act as decomposers.

Give two reasons why bacteria are so successful.

They are successful because of their rapid cell division (reproduction.) And their great metabolic diversity. They can double their numbers every 20 minutes and live in environments that support no other forms of life.

What must viruses do in order to reproduce themselves?

They must infiltrate a host cell and reprogram it to reproduce viral parts rather than cell parts.

Viruses pose a challenge to the human immune system because:

They mutate so quickly

What do all viruses have in common with one another?

They use the machinery of the host cell to reproduce to make more viruses.

True or False The cytoplasm of a prokaryotic cell is filled with many ribosomes.

True

True or False? Antibiotics are effective in killing and destroying disease causing BACTERIA.

True

True or False? Bacteria can rapidly increase their numbers by a type of cell division known as BINARY FISSION.

True

What is a weakened or killed form of a pathogen that stimulates the immune system to produce antibodies?

Vaccine

What is the best defense that humans have against viruses?

Vaccines

Define: Pili~

Very short and sticky, (shorter than flagella, they are like tiny hairs) They serve to attach bacteria to: 1.) A food source 2.) The surface of a liquid 3.) Another bacteria during reproduction

What name is given to small, circular molecules of RNA that have no protein coats that are known to cause plant diseases?

Viroids

A bacteriophage that reproduces only by the lytic cycle is called what?

Virulent phage.

Are viruses "living" or "nonliving"?

Viruses are nonliving.

What makes viruses so highly specific for the type of cell they infect?

Viruses just bind precisely to proteins on the cell surface.

Which of the following are true concerning viruses? 1.) Viruses do not grow. 2.) Viruses do not maintain homeostasis. 3.) Viruses have no energy requirements.

all of the above are true

Name the five stages of the Lytic Cycles.

~1.) Attachment ~ tail fibers are used to attach to receptors sites on the surface of the host cell. 2.) Entry ~ Phage DNA is injected. Empty capsid remains outside. Host cell DNA is destroyed. 3.) Synthesis ~ the host cell is directed to produce viral genomes and protein capsid. 4.) Assembly ~ the viral DNA or RNA is assembled inside the protein coat. 5.) Release ~ the cell swells, bursts, and releases 100's of new viruses .

What cellular organelles are found in a bacterial cell?

1.) Cell Wall 2.) Membrane 3.) Ribosome 4.) Cytoplasm 5.) Flagella

What are the three basic shapes of bacteria?

1.) Cocci ~ Spherical 2.) Bacillus ~ Rod Shaped 3.) Spirilla ~ Spiral Shaped

Describe three methods of movement in prokaryotes:

1.) Flagella 2.) Lash / snake forward 3.) Glide slowly over secreted slime

Name three actives that are carried out by cells but not viruses.

1.) Growth and Development 2.) Obtain and use energy 3.) Respond to their environment

What are five diseases caused by viral infections?

1.) Herpes 2.) AIDS 3.) Flu 4.) Measles 5.) Polio

What are four structures found in cells that are not found in viruses?

1.) Membrane bound nucleus 2.) Mitochondria 3.) Endoplasmic Reticulum 4.) organelles in a cytoplasmic bound membrane(?)

List three types of archaea. Describe the habitat in which each group lives.

1.) Methanogens -They must live in anaerobic environments such as deep fresh water, marine mud, swap mud, and sewage. Also thrive in digestive tracts of cows and termites. 2.) Halophiles -Live in high salt concentrations, such as the Great Salt Lake and the Dead Sea. 3.) Thermophiles -Live in very acidic areas that have high temperatures, such as the hot springs in Yellowstone National Park. Thrive in temps of 110 C and pH of less than 2. Found near "black smokers" which are hydrothermal vents that leak very hot, dark colored acidic water.

List 5 cell organelles that are never found in bacteria and explain why they are not found in bacteria.

1.) Nucleus - 2.)Lysosomes - 3.)E.R. (smooth endoplasmic reticulum) - 4.)R.R. (rough endoplasmic reticulum) - 5.) Golgi Body -

Name four ways prokaryotes can be identified

1.) Shape 2.) The materials composing their cell wall 3.) The way they move 4.) The way they obtain energy

Bacteria can undergo binary fission as rapidly as every 20 minutes. What four factors prevent them from overpopulating?

1.) The exhausting of food supply 2.)Poisoned by their own metabolic waste. 3.) Competition from other microbes 4.) Being consumes by other microbes.

Name the stages of the Lysogenic Cycle ~

1.) Viral genome enters the cell 2.) Viral DNA integrates into host cell DNA 3.) Host cell DNA copies viral chromosomes 4.) Cell divides, and viral chromosomes are transmitted to cell's daughter cells 5.) Process may repeat indefinitely.

List three reasons why bacteria are important to man.

1.)Decomposers 2.)Nitrogen fixation 3.)Make food