Bio 1 Chapter 19

restriction enzymes

Foreign DNA can be identifies as such and cut up (destroyed) by cellular enzymes called _____

bacteria, viruses

Go back and forth between ____ having the upper hand and ___ having the upper hand

infections

Have to have vaccine before _____

lysogenic cycle steps

1. Phage DNA becomes integrated into bacterial chromosome = prophage 2. Prophage is copied with bacterial chromosome and splits making a daughtercell (many cell divisions create many infected bacteria 3. Daughter cell with prophage is made

virulent phage

A phage that reproduces only by the lytic cycle is called a _____

Lytic cycle steps

1. Attachment 2. Entry of phage DNA and degradation of host DNA (injected) 3. Synthesis of viral genomes and proteins (following directions of phage DNA) 4. Self-assembly 5. Release -Cell bursts, releasing the newly formed viruses that may now go out and effect other cells

Viral replicative cycle

1. Entry and uncoating (infection) 2. Replication 3. Transcription and manufacture of capsid proteins 4. Self-assembly of new virus particles and their exit from cell

CRISPR-Cas system steps

1. Infection by a phage triggers transcription of the CRISPR region of the bacterial DNA 2. THE RNA transcript is processed into short RNA strands 3. Each short RNA strand binds to a Cas protein, forming a complex 4. Complementary RNA binds to DNA. The Cas protein cuts the phage DNA 5. Phage DNA can no longer replicate

vaccine

A _____ is a harmless derivative of pathogenic microbes that stimulate the immune system to mount defenses against the harmful pathogen -Elicites an immune response in our bodies so when we are infected by the virus, out immune system already recognizes it and deals with it appropriately

Nucleic acid, capsid, genes

A virus is a very small infectious particle consisting of:

symptoms

Body response to the virus leaving the cell causes _____ of the viral infection

inhibiting synthesis, interfering with viral assembly

Drugs help treat an infection by _______ and _____ but will not kill it

prophage

During the lysogenic cycle ______ may fly under the radar

lytic cycle

During the lysogenic cycle, an environmental signal can trigger the virus genome to exit the bacterial chromosome and switch to the _____ , where the bacterial cell will ultimately die

host range

Each virus has a______, a limited number of host cells that it can infect -Types of cells that can infect EX. Messel virus can only affect humans while west nile virus can effect humans, birds, mosquitos and horses

mutate

Existing viruses can _____ (especially RNA viruses) this leads to different viral strains -Why influenza vaccine is different every year

bacterial mutants

Natural selection favors ______ that can withstand viral infection

double, single

Nucleic acid in a virus can be ______- or ______- stranded DNA or RNA (classifies virus as DNA or RNA virus)

viral proteins

Once the viral genome has entered a cell, the cell begins to manufacture _____ -Once the genome is inside the host cell, it hijacks the cellular machine of the host and the host starts to unwillingly follow the genetic instructions on the viral genome

the lytic cycle and the lysogenic cycle

Phages have two alternative reproductive mechanisms:

temperate phages

Phages that use both the lytic and lysogenic cycle are called _____

prophage, provirus

Prophage and provirus are similar but the difference is that a _____ can be removed from a bacterial chromosome where _____ remains a permenant fixture of the host cells genome

Cas

Resulting RNAs are cut into pieces and bound by ____ proteins

reverse transcriptase

Retroviruses use ______ to copy their RNA genome into DNA -reverse transcription (RNA to DNA instead of DNA to RNA) -EX. HIV

nucleic acid

Since viruses can replicate only within cells, they probably evolved as bits of cellular ____

accessory structures

Some viruses have ______ on the protein coat that help them infect hosts -glycoprotein spikes help to attach virus to host cells

genome

The Cas protein cuts the DNA destroying the ____ of the invading virus, protecting the bacteria from the virus

Phage related RNA

The Cas proteins use the _____ to target the invading phage DNA because this RNA is complimentary to the DNA of the invading phage it can bind to that DNA

lytic cycle

The _____ is a phage replicative cycle that culminates in the death of the host cell

lysogenic cycle

The ______ replicates the phage genome without destroying the host

CRISPR

The attempt of the phage to reinfect the cell triggers transcription of the ______ region (DNA turned to RNA during transcription)

animals

The broadest variety of RNA genomes is found in viruses that infect ____

regenerate

The damage a virus inflicts depends partly on the ability of the infected tissue to ______ by cell division -Some cells are regenerating themselves regularly while others are not. -EX. Easily coming back from a cold but nerve cells not easily replaced (polio)

death

The lytic cycle ends with the _____ of the host cell (virus bursts the cell)

provirus

The viral DNA that is integrated into the host genome is called _____

Injection, endocytosis, or fusion of the viral envelope to the hosts plasma membrane

The viral genome enters the host cell in a variety of ways:

before, after

There is controversy about whether viruses evolved _____ or _____ cells

obligate intracellular parasites

Viruses are ______, which means they can replicate only within a host cell -Also lack metabolic enzymes and equipment for making proteins

living, nonliving

Viruses are in the grey area between ____ and _____

cells

Viruses are not ____

reproduce, metabolism

Viruses cannot ____ or go through ____ outside of a host cell (properties of life)

living organisms

Viruses do not fit our definition of _____

damage, kill

Viruses may ____ or ____ cells

antibiotics

We take _____ for bacterial infections

both

Whereas few bacteriophages have an envelope (viral envelope) or an RNA genome, many animal viruses have _____

Phages

____ are the best understood of all viruses

Bacteria

____ have their own defenses against phages

Glycoproteins

____ help bind the virus to the host cell

Viral envelope

____ is usually derived from the host cells plasma membrane because as they leave the cell through exocytosis, it is packed up inside the hosts own plasma membrane

Viral nucleic acid, capsid proteins

_____ and _____ are going to self-assemble into new viruses that can then leave the cell (protein coats and genome)

Viral infections

_____ cannot be treated after the fact, and not treated by antibiotics

HIV (human immunodeficiency virus), AIDS (acquired immunodeficiency syndrome)

_____ is the retrovirus that causes ______

CRISPR-Cas system

_____: we can utilize this system to go in and change nucleotide sequences, changing the genetic code to help organisms have more disireable traits etc.

Animal viruses

______, typically have an RNA genome, about ¾ of new viral disease in humans spread from existing viruses in other animals -Ex. Bird flu, swine flu, covid-19

Bacteriophages

also called phages, are viruses that infect bacteria (infect prokaryotic bacteria) -Spider like form facilitates attaching to and infecting host cell

reinfected

bacteria who survives an infection cannot be _____ by the same kind of phage again

virus

is an infectious particle consisting of genes packaged in a protein coat -much simpler in structure than even prokaryotes

capsid

is the protein shell that encloses the viral genome

3-2,000

viruses have between ______ genes in their genome while bacteria contain about 200- a few thousand genes