Chapter 20 Biology Test Miller and Levine (Not including virus presentations or specific book viruses)

How do viruses reproduce?

Viruses can reproduce only by infecting living cells.

What happens after a virus infects a cell?

Inside living cells, viruses use their genetic information to make multiple copies of themselves. Some viruses replicate immediately, while others initially persist in an inactive state within the host.

virus

particle made of proteins, nucleic acids, and sometimes lipids that can replicate only by infecting living cells

capsid

protein coat surrounding a virus

bacteriophage

kind of virus that infects bacteria

lytic infection

type of infection in which a virus enters a cell, makes copies of itself, and causes the cell to burst

lysogenic infection

type of infection in which a virus embeds its DNA into the DNA of the host cell and is replicated along with the host cell's DNA

prophage

The combination of the host's genetic material and the viruses' genetic material

retrovirus

RNA virus that contains RNA as its genetic information and is lysogenic

What are all viruses considered to be? Define it.

All viruses care considered to be obligate intracellular parasites

The feed off their host cell and reproduce off it, they are within the host cell, and the word obligate means that the other two words are a must for the virus.

What does a parasite do?

A parasite feeds off and reproduces off other cells and are never positive

Ex.

Tapeworm - steals food from you in your intestine

What are pathogens?

A virus that causes a disease

What is a positive that comes out of viruses? Name and example

They are used for genetic research in which good DNA is put into a virus to help the body.

Ex.

In gene therapy they put good DNA in hepatitis and send it in your body to help your liver

What are 7 characteristics of a virus?

Viruses are smaller than bacteria (1 millionth of an inch)

Not living, but have some characteristics of being alive when in host

No nucleus

No cytoplasm

No organelles

No cell membrane

No carrying out cellular function

- need cells to reproduce

- not alive because you need to reproduce, but instead they use other cells to reproduce

What are the two must haves for viruses?

Viruses must have genetic material (DNA or RNA), and they must have proteins.

How do viruses cause disease?

Viruses cause disease by directly destroying living cells or by affecting cellular processes in ways that upset homeostasis.

What can genetic material be?

DNA or RNA, and can be single stranded or double stranded

What is the most common TYPE of genetic material in viruses? What is the least?

Double stranded DNA and single stranded RNA and the most common, while single stranded DNA and double stranded RNA are the least common

What is the most common FORM of genetic material in viruses? What is the least?

70% of viruses have RNA while only 30% have DNA, thus RNA viruses are more common than DNA viruses

What two shapes can genetic material be in?

Genetic material can be in a linear or circular shape

What are 5 shapes of capsids? Give one example for each.

Helix

- TMV

- measles

Bullet shaped

- rabies

Naked (no protein coat)

- ebola

Icosahedral

- adenovirus

- herpes

- chicken pox

-polio

-zika

Spherical

- influenza

Are capsids optional?

Yes

Are envelopes optional?

Yes

What are envelopes made out of? Give examples of viruses with envelopes

They are made out of lipids, and they are made out of the host's cells membrane, which allows the virus to slip into the host cell

Ex.

- chickenpox

- HIV

- influenza

- herpes

What are glycoproteins? What are glycoproteins attached to

Glycoproteins are little bumps on the envelope surface that are used to attach to the host cell. Their root is attached to the capsid. They are the 'key' to the specific cell surface proteins, the 'locks'.

Are glycoproteins optional?

Yes

What are reverse transcriptase? What does the prefix mean? What does the prefix defenition mean? What are they doing and why?

Reverse transctipase is the enzyme in retroviruses that converts RNA back into DNA. the prefix 'ase' in transcriptase means enzymes, and enzymes speed up reactions. The normal process is changing DNA to RNA to proteins, but instead they are changing RNA to DNA to enter the host cell, and then changing it into RNA to proteins.

What is a vaccination?

A shot given to a patient to cause an immune response

Who invented the first vaccination? What was it?

Edward Jenner invented the first vaccination by injecting a boy with cowpox, and the boy never got smallpox

How many types of vaccinations are there?

7

What are the two main vaccinations? List 3 facts about each.

"Live" Attenuated vaccine

contains the pathogen, a weaker version

difficult to make

can't be given to immune compromised people

can last a life time

Ex: MMR, Oral Polio, Flu mist, H1N1,chickenpox, shingles do not develop fullblown symptoms, but trigger immune response

Inactive Vaccine

pathogen is inactive

not very long lasting (need booster)

Ex: Polio, Influenza, Rabies

- do not develop fullblown symptoms, but trigger immune response

How do viruses move?

Viruses have no mode of movement, but they can travel in air, water, food, or body fuids

What are the two things that DNA viruses do to the host cell?

some DNA viruses use host cell to make proteins directly

some DNA viruses incorporate DNA into host DNA

What are the two things that RNA viruses do to the host cell?

some RNA viruses use host cell to make proteins directly

some RNA uses an enzyme called reverse transcriptase to make RNA into DNA and slip the new DNA into the host's DNA (retrovirus)

What cycles does HIV use and how? What type is it?

HIV does the lysogenic cycle, then the lytic cycle. It is RNA also so it uses reverse transcriptase, thus it is a retrovirus

What cycle does chickenpox use? What does its genetic material become?

Chicken pox uses the lysogenic cycle then the lytic cycle. Its DNA is called a prophage

What is a bacteriophage?

A virus that infects only bacteria

What is the most studied type of bacteriophage?

The most studied one is T-phage

What shape is the head of a bacteriophage?

The head of the bacteriophage is icosahedral

What genetic material does a bacteriophage has?

RNA or DNA

How does a bacteriophage insert its genetic material into the host and what does it use? What is the inserter attached to?

It has a tail that helps inject the nucleic acid into the host. The tail is attached to the base where tail fibers emerge

What is the lytic cycle?

Virus reproduces itself by using the host cell's chemical machinery. It destroys the cell

What are the viruses that use the lytic cycle called?

virulent viruses

What is the first step of the lytic cycle? Give examples

Attachment to the host

tail fibers link up to receptor sites on host cell surface 'lock and key'

Ex

hepatitis - liver cells only

influenza - lung cells only

HIV - T-cells of the immune system

What is the second step of the lytic cycle?

Entry into host cell

Enzymes eat away a spot on the cell wall. Presses sheath against cell and ONLY injects nucleic acid.

What is the third step of the lytic cycle?

Replication

Virus parts are replicated by the host cell, the protein coat called the capsid is made, and the DNA is replicated

What is the fourth step of the lytic cycle?

Assembly

Newly made virus parts are assembled in the cytoplasm or the nucleus

What is the fifth step of the lytic cycle?

Release

The abundance of newly made viruses and enzymes disinitegrating the host cell (lysis) causes the cell to burst releasing the newly made viruses to go infect new cells

Enveloped viruses steal parts of the cell's membrane to "wear" as a disguise

What is the lysogenic cycle?

Virus that infects host cell without immediately killing it

Incubation takes days, months, or years

What are viruses that preform the lysogenic cycle called?

Temperate virus

What is the first step of the lysogenic cycle?

Attachment to the host

tail fibers link up to receptor sites on host cell surface 'lock and key'

What is the second step of the lysogenic cycle?

Injection

Releases DNA into host cell, but does not immediately make RNA and proteins

What is the third step of the lysogenic cycle?

Integration

Virus DNA gets incorporated into host DNA at a specific site called a Prophage

What is the fourth step of the lyogenic cycle?

Cell multiplication

Cell preforms binary fission and the prophage is replicated along with the cell.

What is the fifth step of the lysogenic cycle?

Radiation and chemicals can trigger a temperate virus to become viral. Chocolate and stress can also cause it to trigger

What are retroviruses alway?

Retroviruses are always in the lysogenic cycle first.

What is the quickest virus to kill a human?

Ebola is the fastest virulent virus

Who discovered viruses?

Dutch scientist Martinus Beijerinck discovered them

What are viruses named after?

Viruses are named after the latin word for poision, they were named by Martinus Beijerinck

What is the structure of a virus?

What is the genetic code of a virus?

DNA or RNA

How do viruses grow and develop?

They don't, they do not grow and develop (trick question)

How do viruses obtain and use energy?

They don't, they do not obtain and use energy (trick question)

How do viruses respond to their enviroment?

They don't, they do not respond to their enviroment

Do viruses change over time?

Yes

How does the common cold virus infect its host?

The common cold virus infects its host by entering the host, normally through the nose, having the viral protein make viral RNA, the viral RNA is mistaken to be the host's own and translates it into capsids and other viral protein, and then they assemble the parts and release hundreds of new viral particles.

Define a retrovirus. Are there more retroviruses or non-retroviruses? How do retroviruses communicate with their host cell?

A retrovirus is a RNA virus that contains RNA as its genetic information. There are more retroviruses than non-retroviruses, 70% to 30%, and they communicate with their host cell by making a DNA copy of its RNA and putting it in a host cell, in which it stays inactive for many cell cycles until activated (similar to prophage in bacteria for they too stay inactive until activated by the enviroment).

Which viruses have a vaccine variable?

HIV, Human Papillomavirus, Anthrax, Chicken Pox, Zika

Human Papillomavirus, Anthrax, and Chicken Pox all have a vaccine avaliable

List 3 effective personal hygiene behaviors

Wash your hands

Avoid contact with sick individuals

Coughing or sneezing into a tissue or your sleeve

Define: emerging disease. What emerging diseases are found in Africa (3 of them)?

An emerging disease is an unknown diseases that appears in a population for the first time, or a well-known disease that suddenly becomes harder to control. 3 emerging diseases found in Africa are Ebola, Cholera, and Zika.

Name 2 diseases that are airborne transmitted

The Common Cold and Influenza can be airborne transmitted.

What are prions? Where were they first found?

Protein infectious particles, formed when a protein known as PrP is improperly folded. They were first found in the brain of sheep.

Name the four steps of PrP proteins

Nerve cell produces PrP protein

Prions are made from misfolded PrP proteins, which arise spontaneously from misfold or are introduced in food

Prions cause additional PrP proteins to misfold, thereby producing more prions

Eventually so many prions accumulate that cells become damaged and cease to function