Viruses and Bacteria

AP Biology

Virulent reproductive cycle

replicate using the lytic cycle and destroy the host cell

Temperate reproductive cycle

can use both modes of reproduction in a bacterium (lytic and lysogenic)

Phages infect what type of cells?

Bacterium

Transformation

a change in genotype due to the assimilation of external DNA by a cell

Transduction

a type of gene transfer in which phages carry bacterial DNA from one host to another

Conjugations

the direct transfer of DNA between the two cells that are temporarily joined. Can be of the same or different species.

restriction enzymes

identifies phage DNA as foreign in bacterium cells and destroys it

DNA in prokaryotes

found in a single, circular chromosome located in the cytoplasm of a nucleoid

DNA in eukaryotes

DNA is organized into multiple linear chromosomes that is located in the nucleus

Attachment in the Lytic Cycle

uses tail fibers to bind specific receptor sites on E-Coli

Entry in the Lytic Cycle

Phage DNA enters the host cell, and the host DNA is degraded

Synthesis in the Lytic Cycle

Viral genomes and proteins. Phage DNA directs the production of phage proteins.

Assembly in the Lytic Cycle

separate sets of proteins self assemble to make heads, tails, and tail fibers. The genome is packaged inside the capsid as the head forms.

Release in the Lytic Cycle

an enzyme is produced that damages the cell wall that will let fluids enter. The cell swells and bursts (hypotonic)

Obligate parasite

An organism that can only survive and reproduce within a host

Reverse Transcription

Proteins →RNA→DNA

Transcription

DNA→RNA→Proteins

How do Viruses reproduce?

Reproduce by invading a host cell and using it to replicate their genetic material

How do Bacteria reproduce?

Reproduce through binary fission. One cell divides into 2 identical daughter cells.

How do Prions reproduce?

Reproduce by converting normal proteins into the misfolded prion forms

How do Viroids reproduce?

Reproduce by replicating within the plant cells using the hosts RNA polymerase

Horizontal Transmission

When a disease spreads from one individual to another through direct contact, air, water, etc.

Vertical Transmission

When a disease is passed down from parent to offspring

viral genome

consists of single or double RNA or DNA and is organized as a single linear or circular molecule of nucleic acid

capsid

a protein shell that encloses the genome and is made of capsomeres

viral envelope

surrounds the capsid of some viruses and contains host cell phospholipids and membrane proteins

lysis

host cell bursts open and releases viruses

budding

new viruses “bud” off from the host cell membrane and take part of it to act as their viral envelope. This does not necessarily kill the cell.

viroid

plant pathogen made of a molecule of nake, circular RNA that is 100s of nucleotides long. Causes abnormal development and stunted growth

prion

infectious agent that is a misfolded version of a protein. It increases the number by converting correctly folded versions of the protein into misfolded versions to make more prions.

transposition

movement of DNA sequences from one location to another in a genome

cell wall

made of peptidoglycan

capsule

protective layer that helps stick to surfaces

Fimbriae

hair-like appendages that help it st

Sex pili

links one cell to another at the start of conjugation (conjugation pilus)

gram staining

the stain will stick to the bacteria cell wall, depending on the kind of structure it has

plasmid

small, circular, double stranded DNA molecules that carry accessory genes separate from the bacterial chromosome. It only carries a few genes

Nucleoid

a dense region of DNA in a prokaryotic cell

photo

light

auto

self

troph

nourish

hetero

other

chemo

CO2

how does bacteria prevent itself from being inefected

they have phage defense genes encoded on the cell surfaces

peptidoglycan

a type of polymer in bacterial cell walls consisting of modified sugars that are cross-linked by short polypeptides

F-factor

a piece of DNA that enables the ability to donate DNA during conjugation. contains about 25genes

Hfr cell (high frequency of recombination)

a cell with the F factor built into its chromosome

obligate aerobe

an organism that required O2 for cellular respiration and cannot live without it

obligate anaerobe

an organism that only carries out fermentation or anaerobic respiration

facultative anaerobe

an organism that makes ATP by aerobic respiration when O2 is present, but can switch to anaerobic respiration or fermentation if O2 is not present

nitrogen fixation

the conversion of atmospheric nitrogen to ammonia

extreme halophiles

an organism that lives in a highly saline environment

extreme thermophiles

an organism that thrives in hot environments

methanogen

an organism that obtains energy using CO2 to oxidise Hydrogen, producing methane as a byproduct

pathogen

an organism that causes disease

exotoxin

a toxin protein secreted by a pathogen and produces specific symptoms, even if the bacteria is no longer present

endotoxin

a toxic coponent of the outer membrane in gram-negative bacteria thats release

bioremediation

the use of organisms to detoxify and restore polluted/degraded e