Biology Chapter 20 Questions

What occurs during conjugation?

A hollow bridge forms between two bacterial cells, and genes move from one cell to the other.

What is a virus

A virus is a nonliving particle made of proteins, nucleic acids, and sometimes lipids. Viruses can reproduce only by infecting a host's living cell

A person has a low helper-T cell count. They most likely have the viral disease ________________. A person has blister-like lesions on the skin. They most likely have the viral disease __________

AIDS chicken pox

What are some human diseases caused by viruses?

AIDS, influenza, and the common cold

_______ are rod-shaped. _________ are spherical. __________ are spiral or corkscrew-shaped. Most prokaryotes are ______________. Others are autotrophs. Autotrophs may be _____________ or ___________

Bacilli Cocci Spirilla heterotrophs photoautotrophs or chemoautotrophs

How are the causes of tuberculosis and diphtheria similar? How are they different?

Both are caused by bacteria. However, the bacteria that cause tuberculosis break down tissue, whereas the bacteria that cause diphtheria release toxins.

Describe the similarities and differences of antibiotics and disinfectants.

Both kill bacteria. Antibiotics are compounds that kill bacteria in an organism. Disinfectants are chemical solutions that kill bacteria on surfaces.

Why should meat be cooked until it is well-done?

Cooking meats until they are well done raises the temperature of the meat to a point at which bacteria are killed.

Describe three different ways that humans use bacteria.

Humans use bacteria to produce foods, such as yogurt; to synthesize drugs and chemicals; and to clean up waste.

Suppose you were studying an infectious unicellular organism with a cell wall under a microscope. How could you confirm that the organism was a prokaryote? How could scientists determine whether it should be classified in domain Bacteria or domain Archaea?

If the organism were a prokaryote, it would not have a nucleus. Its DNA would be in its cytoplasm. If the organism were a member of the domain Bacteria, its cell wall would have peptidoglycan.

What occurs in the process of binary fission?

It is a type of asexual reproduction in which a prokaryote grows to nearly double its size, replicates its DNA, and divides in half, producing two identical "daughter" cells.

How can we prevent bacterial and viral diseases from spreading

Many bacterial and viral diseases can be prevented by stimulating the body's immune system with vaccines,fighting infections with antibiotics, and maintaining clean and healthy habits.

Why is the process of nitrogen fixation important?

Nitrogen fixation by bacteria converts nitrogen into a form that can be used by plants or that can be attached to amino acids that all organisms use.

Describe how different prokaryotes obtain energy: photoautotroph

Organism that carries out photosynthesis in a manner similar to that of plants

Describe how different prokaryotes obtain energy: chemoautotroph

Organism that obtains energy directly from chemical reactions

Describe how different prokaryotes obtain energy: Heterotroph

Organism that takes in organic molecules and then breaks them down

Describe how different prokaryotes obtain energy: Photoheterotroph

Organism that uses light energy in addition to processing organic molecules

What would happen to plants and animals if decomposers did not recycle nutrients?

Plants would drain the soil of minerals and die, and animals that depend on plants for food would starve.

What are prokaryotes and why are they important

Prokaryotes are unicellular organisms that lack a nucleus. Prokaryotes are essential in maintaining every aspect of the ecological balance of the living world.In addition, some species have specific uses in human industry.

In an analogy why is the outlaw locking up the sheriff instead of the other way around like a virus

The outlaw is locking up the sheriff because, like a virus, the outlaw has come in and taken over. The sheriff is basically hostage to the outlaw—as is a cell's DNA once a virus has entered a cell.

In a lysogenic infection, how can one virus infect many cells?

The viral DNA is inserted into the host cell's DNA. It remains there and is copied each time the cell multiplies.

What would happen to a virus that never came in contact with a living cell? Explain

The virus would never reproduce. Viruses do not have the structures necessary to metabolize, grow, repair damages, or reproduce without a host.

What are antibiotics

They are compounds that block the growth and reproduction of bacteria

How do antiviral medications work? Why don't they also kill host cells?

They attack specific viral enzymes. Hosts do not have these enzymes.

How do decomposers help the ecosystem recycle nutrients when a tree dies?

They feed on and digest the dead tissue, breaking it down into its raw materials, which are released back into the environment.

What kind of relationship do many plants have with nitrogen-fixing bacteria?

They have a symbiotic relationship

Why do all organisms need nitrogen?

They need nitrogen to make proteins and other molecules.

RNA viruses have shown an ability to evade antiviral drugs. How do you suppose this is possible, when viruses are not alive? How may the reproductive methods of viruses help the process

Viruses reproduce quickly, so their genetic makeup can also change quickly. The DNA of RNA viruses must be translated by the host cell. This allows the opportunity for mutations to occur. Also, many RNA viruses are made inside one cell before bursting forth. They may exchange genetic information at that time. This genetic variation allows them to evolve.

In 1935 the American biochemist _____________ _____________ isolated a virus for the first time. A _____________ is a particle made of nucleic acid, protein, and, in some cases, lipids. A typical virus is composed of a core of DNA or RNA surrounded by a protein coast called a _____________. Viruses that infect bacteria are called _________________. They enter living cells and once inside, use the machinery of the infected cell to produce more viruses

Wendell Stanley virus capsid bacteriophages

What is a bacteriophage

a virus that attacks bacteria

What is a capsid

a virus's protein coat

The rod-shaped bacteria are ___________________ and the spherical bacteria are called ____________. Whiplike structures on a bacterium that produce movement are called _____________

bacilli cocci flagella

Prokaryotes reproduce asexually by ____________ _________, which results in two identical "daughter" cells. Many prokaryotes can form ____________ when conditions are unfavorable in order to protect their DNA. They can also exchange genetic information by ______________

binary fission endospores conjugation

How is the common cold like the HIV virus?

both RNA viruses

A protein coat surrounding a virus is a _______________. Viruses that have RNA as their genetic material are called ____________________. Some bacteria exchange genetic material through the process of ______________. SARS, MRSA, Ebola, and bird flu are all examples of __________________

capsid retroviruses conjugation emerging disease

One way bacteria can cause disease is by breaking down and damaging _____________ of the infected organism. Bacteria can also cause disease by releasing __________ that harm the body. A ________ is a disease causing agent

cells (or tissues) toxins pathogens

Prokaryotes are vital to maintaining the ecological balance of the living world. Some are _____________ that break down dead matter. Others are producers that carry out ____________. Some soil bacteria convert natural nitrogen gas into a form plants can use through a process called ___________ ____________. Human use bacteria in industry, _________ production, and other ways

decomposers photosynthesis nitrogen fixation food

Many bacterial pathogens can be controlled by washing, using _____________, preparing and storing food safely, or ___________ exposed items. Bacterial diseases can be prevented and treated through the following methods

disinfectants sterilizing

An unknown disease that appears in a population for the first time or a well-known disease that suddenly becomes harder to control is called an ___________ ____________. The increase of worldwide travel and food shipments is one reason new diseases are spreading. Another is virus and bacteria ____________. Scientists are struggling to keep up with changes. They recently discovered _______, which are disease-causing forms of proteins. They cause disease in animals, including humans

emerging disease evolution prions

Archaea are more closely related to _____________than ______________.Some bacteria have a second ____________outside the cell wall.

eukaryotes bacteria membrane

Pathogens are able to ______________ over time. A ____________ disease is an unknown disease that appears in a population for the first time. The widespread use of ______________ has led to the emergence of resistant strains of bacteria.

evolving emerging antibiotics

They damage the cells and tissues of the infected organisms directly by breaking down the cells for ____________. They release __________ (poisons) that travel throughout the body, interfering with the normal activity of the ___________

food toxins host

Viruses produce disease by directly destroying living cells or by affecting cellular processes in ways that disrupt __________. In many viral infections viruses attack and destroy certain ________ cells, causing the symptoms of the disease. Viral diseases in humans include the common cold, influenza, AIDS, chicken pox, and measles. Viruses produce other serious diseases in other animals and in plants. Protection against viruses either by ____________ or vaccination, is the best way to avoid viral illness. A handful of _____ drugs have been developed that help reduce they symptoms of specific viruses

homeostasis body hygiene antiviral

Slight genetic changes would be needed for the bird flu virus to become infectious to _____________. Scrapie is most likely caused by pathogens known as _____________

humans prions

What organs do the bacteria that cause tuberculosis typically damage?

lungs

In a ______________ _____________, a virus integrates part of its DNA called a ___________ into the DNA of the host cell. The viral genetic information replicated along with the host cell's DNA. Eventually the prophage will remove itself from the host cell DNA and make new virus particles

lysogenic infection prophage

Viruses have two methods of infection once inside a host cell. In a ____________ _____________, a virus enters a cell, makes copies of itself, and causes the cell to burst, releasing a new virus particles that can attack other cells. In the case of the bacteriophage _______, viral DNA directs the synthesis of new viruses using materials in the cell

lytic infection T4

Prokaryotes that require a constant supply of oxygen to live are called ______________ ___________. Those that cannot survive in oxygen are called __________ ___________. Organisms that can survive without oxygen when necessary are called ___________ ____________.

obligate aerobes obligate anaerobes facultative anaerobes

What occurs when viruses get inside cells

once inside, the viral genes are expressed. This may lead to the cell's destruction

What are viruses

particles of nucleic acid, protein, and in some cases lipids that can reproduce only by infecting living cells

Microorganisms that cause diseases are known as _____________. Bacterial pathogens can produce many diseases that affect humans and other animals. They do so in one of two general ways: They destroy living cells and tissues _________ or by causing an _________ response that destroys tissue

pathogens directly immune

Prokaryotes can be surrounded by a cell wall, which contains _______________. Inside the cell wall is a cell membrane surrounding the ____________. Archaea look similar to bacteria but are genetically closer to ________________. Archaea lack peptiodoglycan and have different membrane ___________ than bacteria

peptidoglycan cytoplasm eukaryotes lipids

What is the bacterial control method- -Washing hands:___________ -Boiling soup:______________

physical removal safe food processing

The smallest and most common microorganisms are ____________, which are unicellular organisms that lack a nucleus. Prokaryotes are classified either in domain __________ or domain ________________

prokaryotes Bacteria Archaea

Unicellular organisms that lack a nucleus are called _____________. The two different domain of prokaryotes are _____________ and ______________. A cell wall made of _____________ protects some bacteria from damage

prokaryotes Bacteria and Archaea peptidoglycan

In a ___________, the genetic information is copied backward= from RNA to DNA instead of from DNA to RNA. The virus that causes the disease ___________ is a retrovirus. Viruses must infect a living cell in order to reproduce. Although viruses are ____________, they are not made of cells and are not considered living things

retrovirus AIDS parasites

What is the bacterial control method- -Putting milk in a refrigerator:______________ -Using bleach to clean a countertop:______________ -Using boiling water to clean dishes:____________

safe food storage disinfectant sterilization by heat

Prokaryotes are identified by the characteristics such as ________, the chemical nature of their ________ _________, they way they __________, and the way they obtain ____________

shape cell walls move energy

One way to control bacterial growth is by subjecting the bacteria to high temperatures during a process known as ___________. A ______________ is a preparation of weakened or killed pathogens or inactivated toxins that can prompt the body to produce immunity to a disease.

sterilization vaccine

How does a typical virus get inside a cell

the capsid proteins "trick" the cell by binding to receptors on its surface

A ______________ is a preparation of weakened or killed pathogens or inactivated toxins. A vaccine can prompt the body to produce the immunity to the disease. Immunity is the body's natural way of killing ___________. When a bacterial infection does occur, _____________ can be used to fight the disease. They are compounds that block the growth and reproduction of the bacteria

vaccine pathogens antibiotics