Chapters 16-18 - Viruses, bacteria, archaea, protists, fungi

Question 1

Are viruses alive? Why or why not?

Answer 1

No

They lack metabolic processes and ability to replicate on their own

Question 2

What is a virus?

Answer 2

Consists of nucleic acids (either DNA or RNA) enclosed by a capsid

Question 3

How do viruses replicate?

Answer 3

They need host cells in order to replicate.

Viruses must inject their genetic material into a host cell and used their hosts to make more copies of the virus.

Question 4

How do viruses enter a host cell?

Answer 4

Some cells have receptors that recognize the virus, and the virus attaches itself to those receptors. It will either:
1. Inject its genetic material into the host cell (if it’s a bacteriophage)
2. Entire the cell completely intact via Endocytosis.

Question 5

The lytic cycle

Answer 5

When the host cell is destroyed at the end of of the viruses replicative cycle.

Once many copies of the virus is generated the host cell bursts (lyses) and releases the viruses to go infect other cells

Question 6

The lysogenic cycle

Answer 6

When the host cell is not destroyed at the end of the viruses replicative cycle.

The virus DNA becomes incorporated into the genome of the host cell. The cell can then divided many times with each daughter cell having bits of the viral DNA in them.

(Sometimes the lysogenic cycle turns into the lytic cycle and all daughter cells burst at once)

Question 7

Viroids

Answer 7

Naked, circular RNA molecules that infect plants, NOT animals

Question 8

Prion

Answer 8

Infectious protein particles that contain no genome, and infect only animals, NOT plants.

Cause other others in brain cells to bring on disease symptoms

Alzheimer’s and Parkinson’s may be associated.

Question 9

Virophages

Answer 9

Viruses that infect other viruses

Question 10

What is an emerging virus?

Answer 10

A virus that appears suddenly, or is new to medical science.

Ex. HIV, Ebola, Covid

Question 11

What are the 3 processes that contribute to emerging viruses?

Answer 11

1. Mutation
2. Contact between species
3. Spread from isolated populations

Question 12

How do you catch a cold?

Answer 12

When viruses are inhaled and make contact with the lining of the upper respiratory tract.

(Usually from a rhinovirus)

Question 13

Can you catch a cold from being cold?

Answer 13

In humans, it was tested that cold people were no more likely to get a virus than warm people.

In other animals, being cold will lower immunity, but not really in humans

Question 14

Can antibiotics help against viruses?

Answer 14

No, because viruses don’t have a cell wall for the antibiotic to attack.

Question 15

What is a strep bacteria type?

Answer 15

Strep refers to bacteria which form in chains.

Ex. if you have streptococci, you have chains of round bacteria.

Question 16

What is a staph bacteria type?

Answer 16

Refers to bacteria which form in clumps.

Ex. Is you have staphylococci, you have clumps of round bacteria

Question 17

Photoautotrophs

Answer 17

Use energy from the sun to make organic molecules from CO2

Ex. Cyanobacteria

Question 18

Photoheterotrophs

Answer 18

Get energy from the sun, but carbon from organic sources

Ex. Purple nonsulphur bacteria

Question 19

Chemoautotrophs

Answer 19

Get energy from inorganic molecules and use carbon from CO2 to make organic molecules.
(Inorganic -> organic)

Ex. Most archaea

Question 20

Chemoheterotrophs

Answer 20

Get both energy and carbon from organic molecules

Ex. Most bacteria

Question 21

Microbiome

Answer 21

The collection of all microorganisms that naturally live in our bodies and helps in developing our immune system.

Question 22

Dysbiosis

Answer 22

A microbial imbalance inside of the body

Caused by use of antibiotics, and poor diet choices

Question 23

Why shouldn’t we use antibacterial soaps?

Answer 23

Most of them contain the antimicrobial Triclosan which will make you more susceptible to become resistant to other antibiotics

Question 24

Archaea are extremophiles, what does this mean?

Answer 24

They live at temperatures, pressures, or pH levels thy would kill other life forms.
(They live in extreme environments)

Halophiles - live in very salty environments
Thermophiles - live in very hot environments (usually near volcanoes)

Question 25

Symbiosis

Answer 25

A physically close association between organisms of two or more species.

Question 26

Mutualism

Answer 26

A relationship in which organisms living in symbiosis both benefit from the relationship.

Question 27

Protist

Answer 27

A eukaryote that is not a plant, animal, or fungus. They are typically unicellular (but there are exceptions.)

Ex. Amoeba, slime molds, algae

Question 28

Mycorrhizae

Answer 28

A symbiotic relationship between a fungus and a plant.

The fungus benefits from a supply of sugar from the host plant. In return the fungus increases the plants surface area for nutrient absorption

This occurs in about 80% of plants

Question 29

Heterokont

Answer 29

A heterokaryotic stage were hyphae of two strains fuse cytoplasm but remain haploid because their nuclei haven’t fused yet.

(Dikaryotic)