microbiology

magnification

the number times larger an image appears under a particular lens
objective lens have different powers

low power

4x

medium power

10x

high power

40x

ocular lens

eyepiece of microscope

ocular lens power

10x

resolving power

the ability to distinguish between two objects that are very close together

micron

a millionth of a metre (1x10^-6m =1μm)

depth of field

how much your image is in focus

illumination

the amount light in brightness
low power has highest illumination, high power has lowest illumination

field of view (field diameter)

the circle area you can see when looking into a microscope
depends on which lens you are using

cell theory

the cell is the basic unit of life
all living things are made of one or more cells
all cells come from other living cells

cell shape

depends on its function

cell size

cells are small because:
cells are limited in size by the ratio of their surface area to their volume
processes such as diffusion are slow and inefficient over large sitances which limits nucleus ability to control large cells and efficiency of nutrient exchange within the cell

cell membrane

covering that separates the inside of the cell from its surroundings
controls movement of material into and out of the cell
has two thin layers of fat molecules (lipids) with proteins on outside of cell
found in both plant and animal cells

lipid

fat molecules

cell wall

tough rigid structure that surrounds the cell membrane and gives a rectangular box lik shape to the cell
made of cellulose and protects/provides structural support
straight stiff lines around the edge of a cell
found in plant cells

cytoplasm

jelly like substance that surrounds the other organelles and gives the cell shape. most chemical activities within the cell takes place here
found in plant and animal cells

nucleus

control activities in the cell and contains dna and chromosomes
contains nucleolus that makes ribosomes
found in plant and animal cells

mitochondria

powerhouse of the cell, produces energy through cellular respiration
food (glucose) C6H12O6 + O2 -> CO2 + H2O + energy
can reproduce inside the cell if more energy is needed
found in plant and animal cells

ribosomes

usually located in the cytoplasm or attached to endoplasmic reticulum
makes proteins
found in plant and animal cells

endoplasmic reticulum

next to the nucleus, transport proteins within the cell
rough er has ribosomes and smooth er does not
found in plant and animal cells

golgi apparatus

sorts and packs proteins into vesicles for shipping into or outside the cell
found in plant and animal cells

vesicles

small membrane sacs that carry proteins, nutrients, and water in and outuof the cell
found in plant and animal cells

lysosomes

little sacs of digestive enzymes that break down unwanted parts of the cell like old organelles, breaks down food particles and cell wastes
circular sac, sometimes with small dots inside
suicide sacs: explode and kill the entire cell (apoptosis)
found only in animal cells

vacuoles

used for storage of water, food, sometimes waste
large membrane sacs
found in both plant and animal cells (larger in plant cells)

chloroplast

green organelle responsible for photosynthesis
CO2 + H2O + light -> C6H12O6 + O2
changes light to chemical energy
found only in plants

mitosis

a form of cell division used by cells that make copies of themselves

daughter cells

exact copies of parent cell

asexual reproduction advantages

large numbers of offspring produce quickly
large number can allow species to survive if conditions/number of predators change
large colonies can outcompete other organisms
no energy needed to compete or find a mate

asexual reproduction disadvantages

low genetic diversity, not good in a change environment. vulnerable to disease and often have to compete with own offspring for resources (space, sunlight, nutrients, etc)

meiosis

the form of cell division used to create sex cells (sperm and egg) in organisms that undergo sexual reproduction
daughter cells have half the genetic information as the parent cells

diploid

two chromosomes

haploid

one chromosome

sexual reproduction advantages

fusion of gametes from each parent allow for genetic diversity
allows organisms to adapt to a changing environment

sexual reproduction disadvantages

lots of energy used in finding mate
more likely to have a mutation
not as fast and produces fewer offspring

kingdom monera

lack of nucleus and membrane bound organelles, including domain bacteria and archaea. does not exist anymore

thermoacidophiles

archaea that live in hot acidic environments

halophiles

archaea that live in salt environments

methanogens

archaea that are obligate anaerobes that use carbon dioxide to give off methane as waste product
can be found in sewage treatment plants, swamps, bogs, near volcanic vents and help with mammals intestine

obligate anaerobes

microorganisms that cannot live in the presence of oxygen

archeans and mammals

some archaeans have a symbiotic (close) relationship with mammals
methanogens metabolize organic matter to produce methane in mammals intestines to promote healthy digestion
archaea are not known to be pathogenic (disease causing)

difference between bacteria and archaea

bacteria cell walls contain peptidoglycan
different lipids in their plasma membranes
different ribosomal proteins and RNA

nucleoid

large, circular region containing genetic material

plasmid

smaller piece of DNA that most prokaryotes have

capsule

some prokaryotes produce a layer of polysaccharides around the cell wall
prevents the cell from drying out and attach to surfaces in its enviornment
also helps prevent he bacteria from being engulfed by white blood cells and shelters cell from effects of antibiotics

pili

hairlike structures that are made of protein
help attach to surfaces and serves as a bridge between cells

how to identify bacteria

1. cell shape
2. cell wall
3. movement
4. metabolism (how they obtain energy)
5. reproduction
6. energy production (respiration)

cell shape

round (coccus, cocci)
elongated (bacillus, bacilli)
spiral (spirillium, spirilli)

coccus/cocci

round cell

bacillus/bacilli

elongated cell

spirillium/spirilli

spiral cell

diplo

prefix for pairs

staphylo

prefix for clusters

strepto

prefix for chains

two types of bacteria

one with an outer layer of lipid, and one without

grams stain

technique used to identify the type of bacteria
contains 2 dyes: crystal violet and safranin

grams positive

appears purple when stained
thick protein (carbohydrate layer absorbs crystal violet stain)

gram negative

appear red when stained
has a lyaer of cabohydrate and lipid surrounding cell membrane that picks up safranin stain

movement of bacteria

moves by flagella
glide on slimes that they have secreted
may spiral or lash forward

how bacteria obtain energy

heterotroph
photoautotroph
chemoautotroph

photoautotroph

organism that convert light energy into chemical energy

chemoautotroph

organism like archeabacteria that obtain their energy by oxidizing inorganic compounds like hydrogen sulphide or ammonia

binary fission

the division of a cell into two genetically identical cells
not mitosis because they are no nucleus and only have one chromosome
exact copies are produced
can occur every 20 minutes

exponential growth

starting with a single bacteria, a colony will grow over 1 million bacteria in under 8 hours

vertical gene transfer

transfer of genetic information from parent to offspring

horizontal gene transfer

bacteria can transfer DNA from one cell of the same generation to another

conjugation

transfer of circular DNA called plasmid by cell to cell contact through a pillus

transformation

bacteria takes up DNA from their enviornment
DNA usually comes from dead bacteria releasing genetic contents to surroundings

transduction

transfer of DNA from one cell to another by a virus (bacteriophage)

bacteriophage

viruses that infect and replicate only in bacterial cells

endospores

if conditions become unfavorable, some bacteria will form endospores “inner seed”

respiration

uses oxygen and breaks down food molecules to produce energy

aerobic bacteria

use oxygen for respiration

obligate aerobes

bacteria that need oxygen

facultative aerobes

bacteria that use oxygen but not dependant

anaerobic bacteria

do not need oxygen for respiration

facultative anaerobes

bacteria that do not need oxygen but are not harmed by it

fermentation

produces energy without the use of oxygen (sugar -> alcohol + carbon dioxide + energy, sugar -> lactic acid + energy

nitrogen fixation

certain plants with a symbiotic relationship with bacteria
the bacteria can remove nitrogen gas and convert it into a form that can be taken up by plants and we can eat the plants to get nitrogen

digestion

found in large intestine, necessary to break down food and produce vitamin K

defence

bacteria in your mouth and skin act as defense, prevents more damaging bacteria from attacking

bacteria that cause diseases

quickly multiply at infection site before immune system can destroy them
serious infection can spread to other parts of body
bacteria produces a harmful toxin

normal flora

bacterial that live in or on you they are harmless

virus

microscopic particle that cen infect the cells of a living organism
are 5 to 300 nanometers big
composed of protein and DNA (or RNA)
cannot reproduce without the aid of a hotst cell and are considered parasitic
can infect eukaryotes, prokaryotes, and even other viruses

bacteria evidence of living

reproduce
contain enzymes
contain proteins
have genetic material (DNA or RNA)
can evolve (natural or artificial selection
affect other living things

bacteria evidence of non living

non cellular
no metabolism
do not grow
do not respond to stimuli
cannot reproduce on their own
can be crystalized (like chemicals)

progressing or escape hypothesis

viruses arose from genetic elements (DNA/RNA) that gained the ability to ove between cells

regressive or reduction hypothesis

viruses came from parts of cells

virus-first hypothesis

viruses predate or coevolve with their cellular host

virion

virus particle

nucleic acid in virion

DNA or RNA (cannot be both)

capsid

protein coat that surrounds the DNA or RNA in a virion

lipid membrane coat

membrane around the capsid is present in larger viruses. helps virus enter cells and is often called membranous envelope. made of proteins and lipids

antigen

proteins attached to viruses. allows for recoginition of the virion

adenovirus

causes common cold

bacteriophage

attack bacterial prokaryotic cells
plant viruses attack eukaryotic plant cells ex. tobacco mosaic virus
animal viruses attack eukarotic animal cells ex adenovirus

virophages

small double stranded DNA virus that co infect another virus

lytic cycle

ATTACHMENT
virus attaches itself to the host cell
ENTRY (penetration)
nucleic acid is injected into the host cell
REPLICATION
host cells metabolic machinery makes viral nucleic acid and proteins
ASSEMBLY
viral components are put together to make new viruses
LYSIS AND RELEASE
an enzyme breaks down the cell wall/membrane of the host and the host cell bursts open (lysis) and dies. the viral particles exit and go on to attach other cells
lytic cycle virus produce active infections like common cold and influenza
symptoms from active infections appear 1-4 days after exposure

lysogenic cycle

starts the same way as lytic cycle, attachment and entry
instead of taking over the cell to replicate itself, the nucleic acid will become part of the host cells chromosome in a stage called INTERGRATION
the viral nucleic acid is now called a provirus
virus remains in latent (inactive) form
the host cell will continue to replicate itself with provirus as part of its chromosomes
provirus will continue to be replicated every time the host cell divides (every copy of that host cell contains the provirus)
the provirus can be activated any time due to change in temperature, pH, stress, diet, etc
once activated, the provirus will enter into the lytic cycle, destroying the host and causing symptoms of infection