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GVSU / Biology / BIOL 212 / How did microbiology develop?

How did microbiology develop?

How did microbiology develop?

Description

School: Grand Valley State University
Department: Biology
Course: Introduction to Microbiology
Term: Summer 2015
Tags: Microscopy, methodology, Bacteria, and eukaryotes
Cost: 50
Name: Microbiology Exam 1 Study Guide
Description: This is a study guide created by combining notes from the readings with notes from the in class power points and the points from Professor Thomas' study guide. I have organized it in a way that makes m
Uploaded: 01/29/2017
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Unit 1 1/28/17 7:29 PM


How did microbiology develop?



Microbiology: study of organisms too small to be seen without  magnification

Microorganisms include:

• Bacteria

o Prokaryotic  

o Cells made of polysaccharide (peptidoglycan)

o Reproduce asexually

o Most much smaller than eukaryotic cells

o Live alone, in pairs, clusters, chains

o Live anywhere w/enough moisture

• Viruses

o Smaller than the smallest prokaryote

o Acellular (not made of cells)

o Has little genetic material

• Fungi  

o Eukaryotic


What is the history and scope of microbiology?



o Get food from other organisms

o Have cell walls

o Microscopic Fungi: Molds & Yeasts  

▪ Molds  

???? Multicellular

???? Long filaments, intertwine

???? Reproduce w/sexual and asexual spores (make  

new individual w/out fusing to another cell)  

▪ Yeasts

???? Unicellular  

???? Oval – round

???? Reproduce by asexual budding (the daughter cell  

grows off the mother), some by sexual spores

• Protozoa  

o Single cell eukaryotes


What are the i's in microbiology?



If you want to learn more check out What are the social cognitive processes and their purposes?

o Similar to animals in nutritional needs & cell structure  

o Capable of locomotion

▪ Cilia: Many short protrusions that propel the  

microorganism

▪ Flagella: few extensions, whip-like motion

o Live in water, & inside animal hosts

o Most reproduce asexually, some sexual

• Helminths (worms)

o A parasite that can be seen by the naked eye, studied by  microbiologists because eggs are microscopic

• Algae  

o Unicellular & Multicellular

o Photosynthetic eukaryotes = make their own food from  CO2 + water + energy from sunlight  If you want to learn more check out What are biological molecules?
We also discuss several other topics like What is fiscal federalism?

o Large Algae: kelp and seaweeds, found in oceans, Agar used  in lab media comes from these Don't forget about the age old question of What is nonresponse bias?

o Small Algae: found in freshwater and oceans

• Archaea

o Prokaryotic

o Cell walls lack peptidoglycan  If you want to learn more check out What are the 3 classes of animal domestication that made my archaeozoologist?

o Reproduce asexually

o Live alone/in pairs/chains/clusters  

o Live in extreme conditions

▪ Highly saline and arsenic rich Mono Lake CA

▪ Acidic Hot Springs of Yellowstone National Park  Don't forget about the age old question of Why does the world need financial accounting information?

▪ In oxygen depleted mud at bottom of swamps

Microbiology led to:

• Immunology: Study of bodies defense against pathogens • Public Health Microbiology

• Epidemiology: study of the occurrence, distribution, spread of  disease in humans

o John Snow studied Cholera spread

• Food, Dairy, Aquatic Microbiology (Food Spoilage)

• Agricultural Microbiology: water pollution caused by microbes • Biotechnology

• Genetic Engineering & Recombinant DNA Technology: Microbes in  cheese making, alcohol, microbes interaction with immune system • Environmental Microbiology: Study of Microbes in soil, water, other  habitats

• Bioremediation: Use living bacteria, fungi, & algae to detox.  Polluted environments

• Industrial Microbiology: Microbes used to make products o Pasteurization: Heat something to kill contaminating bacteria Microbes are also involved in flow of Energy and Nutrients • Photosynthesis: convert CO2 to organic material

• Decomposition: Breakdown dead matter & wastes into simple  compounds

Microbes involved in infectious diseases

• Pathogens: microorganisms that harm (this is the minority of  microorganisms)

o 2,000 dif. Microbes cause harm

o 10 billion new infections worldwide per yr.

o 12 million deaths by infections per yr.

Science according to the organism studied

• Bacteriology: The study of Bacteria

• Phycology: The study of Algae

• Mycology: The study of Fungi

• Protozoology: The study of Protozoa

• Parasitology: The study of Parasites

• Virology: The study of Viruses

History Of Microbiology

• Prominent Discoveries

o Microscopy

o Scientific Method

▪ Make observation

▪ Generate question

▪ Generate hypothesis

▪ Experiment (w/control groups)

▪ Accept, reject, or modify the Hypothesis

▪ If hypothesis repeatedly verified = Theory or Law (ex:  Theory of Evolution or Selective Pressure)

o Developed Medical Microbiology

o Microbiology Techniques

• Lifestyle of Microorganisms

o Exist freely in soil, water, surface

o Relatively harmless or even beneficial (decomposition)

o If associated with other organisms considered parasites and  live in a host

• Early Microscopy

o Robert Hooke - 1660

▪ First compound microscope (microscope w/2 lenses)  ▪ Saw cells of cork first and reminded him of a monk’s  quarters which were called a “cell” – how we got the  

name “cell”

▪ He examined living and non-living things

o Anton van Leeuwenhoek – 1632-1723

▪ Traded in linen & wanted to see the quality so made his  own magnifying glasses and achieved the level of  

microscopes

▪ Saw things that moved called them Animalcules

▪ When he died never passed on the secret to making the  lenses and lost ability to see microscopic things

o Edward Jenner – 1796

▪ Developed first vaccine

???? Knew about variolation (when take puss from  

someone w/smallpox & give it to someone else  

they either die or are protected)  

???? Decided when saw milkmaids hands w/something  

that looked like smallpox but they never  

contracted it, to take puss from their hands and  

give it to a boy

???? The boy survived & was given smallpox, he was  

protected, this was considered FIRST  

VACCINATION (“vaca,” from “cow”)

o Joseph Lister – 1867

▪ Founder of antiseptic surgery

▪ Opened field of research in antisepsis & disinfection o Ignaz Semmelweis  

▪ Introduced hand washing  

▪ People not ready for it, didn’t take on even when  

proved it worked

▪ Took on when Lister introduced it further

o Spontaneous Generation (Abiogenesis): Commonly held  theory that things just started growing randomly, until it was  disproved by the following people (proved Biogenesis: creation via biology)

o Louis Pasteur – 1822-1895

▪ Created flasks with bent necks that prevented microbes  from falling into sterile solution

???? If broke neck microbes got in and grew  

▪ Proved that grapes + yeast = alcohol & grapes +  bacteria = acid

▪ Proved Yeast can grow with & w/out oxygen & from  other cells  

o Robert Koch – 1843-1910

▪ Germ Theory: disease is caused by germs

▪ Pioneer of Etiology: How diseases is caused  

▪ Worked w/anthrax in animals & discovered endospores  (the resting stage of bacteria) – this was the 1st time  bacteria proven to cause disease

▪ Man who worked in lab developed Petri Dishes

▪ Walter Hess developed the media from algae – Agar ▪ Created framework to identify Pathogens: Koch’s  Postulates

???? 1. Find evidence of microbe in every case of the  disease

???? 2. Isolate microbe from infected subject & grow in  lab

???? 3. Inoculate healthy subject & cause same  

disease

???? 4. Re-isolate agent from subject

o Alexander Flemming – 1881-1955

▪ Discovered Penicillin 1929 (1st modern antibiotic) ???? Saw that fungi penicillian was killing staph he was  growing  

???? Penicillin enters widespread US – 1941

▪ Discovered Lysozyme from snot dripping & breaking  down bacteria

???? In snot, tears, egg whites

o Selman Waksman – 1944

▪ Discovered Streptomycin – first drug for tuberculosis

▪ Discovered first way to isolate soil bacteria & test  

antibiotics  

▪ Reference to soil bacteria on grave: “The Earth will  

open and bring forth salvation.”

5 I’s of Culturing Microbes

• Inoculation: Introduction of sample into container of media to  produce culture of observable growth

• Isolation: Separate one species from another

• Incubation: placed in a temperature controlled chamber and  microbe multiples for observable growth

• Inspection: Microscopic and Macroscopic Observation, what you can  see upon inspection:

o Pure Culture: growth of 1 single known species

o Mixed Culture: growth of 2 or more identified species

o Contaminated Culture: the mixture was once pure & was  mixed w/unwanted microbes growing in it.

• Identification:  

o Use micro/macroscopic appearance to identify

o Perform biochemical tests to identify

o Use genetic characteristics to identify  

o Use immunological tests to identify

Media to Isolate Microorganisms

• Physical Form of the Media

o Nutrient Agar (made from red algae)  

▪ Solid Agar: Solid at room temp and body temp

▪ Holds moisture & nutrients (beef extract, peptone,  

agar)

▪ Not digestible for most microbes

▪ Semisolid Agars: help determine if the organism is  

motile or not, if it is then it will move in this media  

???? Used in clinical tests

o Nutrient Broth: Liquid medium w/beef extract & peptone

• Different Chemical Compositions of Media

o Complex or Non-synthetic: Media has nutrients released by  partial chemical breakdown by beef, soy, proteins, has at  least 1 ingredient that is not exact (chemically defined)

o Defined: Media in which the exact chemical composition is  known  

o Synthetic: Contains pure organic and inorganic compounds in  an exact amount (chemical formula)

o General Purpose Media: Grows many microbes, considered  non-synthetic

o Enriched Media: complex organic substances (blood, serum,  hemoglobin, and special growth factors that picky microbe  require)  

▪ Used to grow less abundant microbes

• Different Functions of Media

o Selective Media: media that contains nutrients that promote  the growth of one microorganism and inhibit the growth of  others

o Differential Media: media made so there is a change in  appearance of media or the organisms that helps the  

microbiologists tell the difference between different bacteria  ▪ Agar has dye that changes color based on pH

o Blood Agar considered a differential and complex  medium

Isolation Techniques

• Streak Plate: Serial dilution on a solid surface, use loop to spread  on one quadrant then go on to quadrant 2 and go back into  quadrant 1 slightly to dilute the bacteria, repeat 2 more times • Pour Plate Technique:

o Serial dilution of liquids

o Allows growth of different types of microbes because of  different environment

o Used for fewer colonies

Colonies: Culture visible on the surface

CFU: Colony Forming Unit which pure culture comes from (comes from a  single progenitor)

How to Dispose of Cultures

• Steam Sterilization

• Incineration

Key Characteristics of a Microscope

• Magnification: ability to enlarge objects

• Resolving Power: ability to show detail (Resolution)

o If particle size is smaller it has a better resolution

Compound Microscope  

• Hooke used

• Binocular – 2 lenses

o Objective Lens: the lens right above the object, can have a  series of lenses (4x, 10x, 40x, and 100x)  

▪ Low Power: 10x10=100

▪ High Power: 10x40=400

▪ Oil Immersion: 10x100=1000 used to reduce light  

refraction

o Ocular Lens: lens closest to the eye (can be monocular or  binocular) – is 10 or 12.5 power (this is the 10 being  

multiplied by the objective lens powers above)  

• Light needs to be focused on specimen for best resolution Types of Microscopy

• Bright Field Microscopy

o Used in medical labs

o Image made w/light through the object

o Image absorbs light, darker than the background

o Used for live & fixed material

▪ Stain to improve contrast but kills microorganisms

• Dark Field Microscopy

o Illuminates objects from side

o Object white against dark background

o No stain used

o Living objects can be seen  

• Fluorescence Microscopy

o UV light used w/filters to protect eyes

o Use dyes that fluoresce when exposed to UV light

▪ Have specificity to certain cell structures

▪ Can be coupled to antibodies to specifically target an  

object  

▪ Used to target specific bacteria or look for specific viral  antigens  

• Transmission Electron Microscopy (TEM)

o Uses a wavelength of an electron beam of ~0.5nm and  creates a resolution of ~0.3nm = greatest magnifying  

resolution

o Use very thin sections (20-100nm) for the beam to go  

through specimen

o Use heavy metal salts to stain image & make contrast

o Nuclei diffract electrons

o Max magnification is 120,000x = can see what is inside things • Scanning Electron Microscope (SEM)

o Makes 3D image

o Sample is plated w/thin layer of a metal w/large nuclei (ex.  gold)

o Electrons scanned across surface of sample & detector detects  reflected electrons  

o Image shown on TV screen

o Magnification not as good as TEM, ~10nm

Contrast: difference in intensity between two objects or between the object  & the background

• Enhance Contrast by Staining  

o Thick cell walls retain blue/purple stain (The Principle stain) o Thin cell walls lose principle/1st stain and allow to see the  Secondary Stain = cells are pink  

o Staining also deals with charges

▪ Positive Staining: Stains the organism

▪ Negative Staining: Stains the background, acidic dyes  

used are repulsed by the negative charges on the cells  

and don’t stain them (the capsules of bacteria are  

negatively charged) –AKA Capsule Stain

o Simple Staining: made of single basic dye, soak the smear in  dye for 30-60 seconds and rinse

o Differential Staining: Use more than one dye to see different  cells & structures

Taxonomy

Taxonomy: organizing, classifying, and naming living things, was created by  Carl Von Linne (Linneaus)

Classification: The orderly arrangement of organisms into Groups Nomenclature: Assigning names

Identification: determining and recording traits of organisms for placement  into taxonomic schemes

Old Whittaker System

• Set up with Binomial (Scientific) Nomenclature, everything had two  names – 1st name = Genus & 2nd name = Species  

o Ex: Homo Sapiens

• Thought originally only 2 Kingdoms: Plantae and Animalia o Noticed certain organisms didn’t fit and created kingdoms  Protista, Bacteria (Monera), and Myceteae for fungi

7 Main Taxa

• Species: the most specific, organisms that can successfully  interbreed

• Genera: Similar species

• Families: Similar genera

• Orders: Similar families

• Classes: Similar orders

• Phyla: Similar classes

• Kingdoms: similar phylas

• The classification is determined by genetic/cellular level, use  rRNA to compare things, Woes and Fox were the first to do  this

There are 3 Domains which cover all organisms and then they are  categorized by the 7 main taxa starting with kingdoms and getting more  specific from there

• Archaea: Odd bacteria that live in extreme conditions

• Bacteria: True bacteria (*Prokaryotes fall under Bacteria and  Archaea)

• Eukarya: have nucleus and organelles

How to Assign Names

• Binomial (Specific) Nomenclature

o 2 Names  

▪ Genus – capitalized

▪ species – lowercase

o Both italicized or underlined

o Sometimes shorten first name with first letter and period.  o Inspiration for names varied & imaginative  

o Names usually mean something

▪ Ex: Staphylococcus aureus (S. aureus)

???? Staphyl = bunch of grapes (tells plane of division)

???? Coccus = “berry,” spherical shaped cell

???? Aureus = “golden,” yellow color  

Evolution of Microorganisms

• Phylogeny: the natural relatedness between groups  

• Evolution

o All new species come from an existing

o Close relatives have similar features, evolved from a common  ancestor  

o Usually progress towards a greater complexity  

Characteristics of Cells

• Eukaryotic Cells: (Animals, Plants, Fungi, & Protists)

o Membrane-bound organelles (perform specific functions and  compartmentalize cytoplasm)

o Has double-membrane bound nucleus with DNA in  

chromosomes

• Prokaryotic Cells: (Bacteria & Archaea)

o No nucleus or other membrane bound organelles

o How to classify Prokaryotes:  

▪ Microscopic Morphology: individual cocci or bacilli  

appearance  

▪ Macroscopic Morphology: Colony appearance

▪ Bacterial Physiology

▪ Serological Analysis: use liquid portion of blood after  

clotting factors removed to determine the  

microorganisms

▪ Genetic and Molecular Analysis

▪ If something causes a similar disease they are  

often named something similar

Bacterial Taxonomy based on Bergey’s Manual of Systematic Bacteriology • Classification based on genetic information = phylogenic • Not all organisms have the same amount of G+C content (chemical  content), affects DNA H-bonding

• (Remember that bacteria are Prokaryotic) There are 2 main  Domains

o Archaea  

o Bacteria

• 5 Major Subgroups w/25 different phyla in each one

*Within the 3 Domains (Eukarya, Archaea, and Bacteria) there are  Organelles in the Bacteria Category because of Endosymbiosis (The idea that  eukaryotic life evolved from prokaryotic life, will have some of the same  characteristics)

Species and Subspecies

• Species: bacterial cells w/overall similar pattern of traits • Strain/Variety: A culture from one parent that differs from the  others of that species (different structure or metabolism)

o Ex: Biovars and morphovars

• Type: subspecies w/differences in antigenic  

makeup/immunoresponse (serotype or serovar), susceptibility to  viruses (phage type) & pathogenicity (pathotype)

Diagnostic Scheme for Medical Use

• Phenotypic qualities to identify

• Limited to bacterial disease agents

• Categorizes bacteria based on shape, arrangement, physiological  traits, cell wall structure

Dimensions of Bacteria (Prokaryotic)

Morphology: shape of organism

• Cocci: roughly spherical  

o Staphylo: clusters of cocci, form when planes of cell divide  randomly

o Strepto: Long chains of cocci, form when cocci cell divides  down the center plane & the resulting cells stay connected  ▪ Diplococcus: cocci that divide down the center plane &  

stay connected in pairs

o Tetrad: the cocci divide in two planes and the four resulting  cells stay connected

o Sarcina: Cocci that divide in 3 planes, stay connected to make  a 3D tetrad  

• Bacillus: non-spore forming rods

o Gram Positive (Thick peptidoglycan = retains purple dye) o Obligate Intracellular Parasite are Bacilli

▪ Can’t grow outside the host

▪ Very small

▪ Pleomorphic (shape varies) or Coccobacilli  

▪ Ex: Rickettsia and Chlamydia

• Endospore Producing Bacilli

o Soil organisms

o Gram Positive (Thick peptidoglycan = retains purple dye) o Ex: Bacillus & Clostridium

• Helical Bacteria

o Spirochetes: Flexible twisting bacteria, rod-shaped, have  flagella at both ends that tightly spiral around cell

▪ Move by creeping motion

▪ Has 70 turns (wound less tight)  

o Spirilla: rigid twisting rod shaped structure

▪ Flagella helps move with swimming motion (like  

corkscrew)

▪ Have 20 turns (wound tightly)

Size of microorganism: measured in micrometers

• Largest bacteria 0.75mm, could see w/naked eye

• Smallest bacteria 140 nm

Prokaryotic Structures: cell membrane, cytoplasm, ribosomes, one or a  few chromosomes

• External Structures: Appendages and Glycocalyx

o Appendages (2 groups)

▪ Motility  

???? Flagella: long structures, extend beyond the  surface of the cell and glycocalyx, used to propel  through the environment,  

• 3 parts

o Filament: long, thin, hollow, helical  

structure made of protein called  

Flagellin

o Hook: curved structure that connects  

the filament to the basal body, made  

of different proteins

o Basal Body: Stack of 2 and 4 rings of  

protein firmly anchored into cell wall,  

varies between gram (-) and gram  

(+) cells, it doesn’t extend into the  

cytoplasm  

• Rotates 360 degrees to move prokaryotic  cells like a boat propeller

• Number and arrangement of flagella varies o Monotrichous: one flagella at one end  

of the cell

o Lophotrichous: group of flagella at  

one end of the cell

o Amphitrichous: one flagella at both  

ends of the cell

o Peritrichous: Flagella all around the  

perimeter of the cell  

• Flagellar Responses: Guide bacteria in  

certain direction in response to outside  

stimulus

o Chemotaxis: guided by chemical  

stimuli (either positive or negative)

o Phototaxis: guided by light stimuli

o Signal sets flagella in rotary motion in  

either clockwise or counterclockwise  

direction, moving towards nutrients

▪ Counterclockwise: smooth,  

linear direction = Run, if  

bacteria in high concentration  

will run more

▪ Clockwise: Tumbles, if bacteria  

in low concentration will tumble  

more

▪ Attachments or Channels

???? Fimbriae: fine proteinaceous, hair-like bristles on  

cell surface

• Function: Adhesion to other cells and  

surfaces

???? Pili: Rigid tubular structure

• Function: join bacterial cell for partial DNA  

transfer = Conjugation (an exchange of  

genetic material in mating types)

• 1-3 present per cell

• Found only in Gram Negative (-) cells (thin  

peptidoglycan layer and outer membrane,  

doesn’t hold purple stain = pink cell)

o Glycocalyx: surface coating of cell wall

▪ Capsule: tight grouping

???? Chemicals in these are similar to the host so the  

white blood cells don’t recognize them and cant  

perform phagocytosis on them

▪ Slime Layer: loose grouping

▪ Functions of both are similar (both made of glycoprotein  and polysaccharide)

???? Keep cell from drying out (desiccation)

???? Help bacteria stick together to form Biofilms

(aggregates of cells stuck together in a film)

???? Prevent WBC from phagocytosis

• The Cell Envelope: External covering outside of the cytoplasm, 2  layers, helps maintain cell integrity

o Cell Wall: provides structure, protects from osmotic forces,  helps attach to other cells, resists antimicrobial drugs

o Cell Membrane: Selectively permeable, nutrients flow in and  wastes flow out

o 2 Groups of Cell Envelopes

▪ Gram Positive (+) Bacteria: Thick cell wall made of  peptidoglycan around the cell membrane.  

???? Contains Teichoic Acid: in part of peptidoglycan  layer, does not extend all the way through

???? Contains Lipoteichoic Acid: extend through the  whole peptidoglycan layer & attached to cell  

membrane

???? 1 Periplasmic Space

???? Peptidoglycan layer 20-80nm thick  

???? Ex: Staphylococcus aureus

▪ Gram Negative (-) Bacteria: Outer cell membrane, thin  peptidoglycan layer and then the cell membrane inside ???? Has Porins on the outside

???? 2 Periplasmic spaces  

???? Peptidoglycan layer 8-10nm thick  

???? Ex: Escherichia coli (E. coli)

o Peptidoglycan Structure:  

▪ Polymer of NAM/NAG chains  

???? NAM: N-acetylmuramic acid

???? NAG: N-acetylglucosamine  

▪ Cross links between adjacent NAMs give strength, these  differ between Gram(+) and Gram(-)

???? Gram(+) Cross Linkage

• There is an Interbridge of repeating Glycine  

units between the Lysine of one NAM & the  

Alanine of the NAM next to it

???? Gram(-) Cross Linkage

• There is a direct bond between the DAP of  

one NAM & the Alanine of the NAM next to it

▪ Penicillin affects the direct bonds between adjacent  chains, but the outer membrane of Gram(-) make it  hard for penicillin to penetrate  

▪ Lysozyme also breaks down NAM-NAG chains

o Non-typical Cell Walls 

▪ Bacteria that don’t have typical cell wall structure  

(Mycobacterium & Nocardia)  

???? Gram(+) cell wall with Mycolic Acid give cell wall  

waxy nature because it’s a lipid = this wall called  

an Acid-Fast Cell Wall

• Gives it pathogenicity & high resistance to  

chemicals & dyes

• Must use Acid-Fast Stain to diagnose  

infections caused by these microorg.  

▪ Bacteria w/No Cell Wall (Mycoplasma)

???? Cell membrane stabilized w/sterols (ex:  

cholesterol)  

???? Pleomorphic (less structured, more flexible)  

• Internal Structures of Bacteria (Reminder: Prokaryotic) o Cytoplasm: gelatinous solution of sugars, amino acids & salts,  70-80% water (solvent used in all cell functions)

o Chromosomes: Single, circular, double-stranded DNA, has all  the genetic material, in prokaryotes. not packaged around  histones but packaged into Nucleoid

o Plasmids: small circular, double-stranded DNA, not essential  for bacteria to growth or metabolism

▪ There are variations in Segregation of these, some  linear some circle

▪ Sometimes harbor in antimicrobial resistance genes o Ribosomes: Made of 2 subunits of protein & rRNA

▪ 60% made of rRNA (the biggest portion and most  

important component, makes peptide bonds, can be  

enzymatic making enzymes included the one that  

translates)

▪ Function: synthesis of proteins

▪ Different than Eukaryotic Ribosomes because smaller & sediment faster when centrifuged  

▪ Two Types:  

???? 30S + 50S = 70S Bacterial Ribosomes, found  

inside organelles

???? 40S + 60S = 80S Eukaryotic Ribosomes, found  outside organelles

• Prokaryotes have BOTH types of  

ribosomes

o Inclusions & Granules 

▪ Intracellular storage bodies

▪ Size, number & their content varies

▪ When environmental sources are depleted the bacterial  cell can use these

▪ Ex: glycogen, poly-β-hydroxybutyrate, gas vesicles for  floating, sulfur & phosphate granules (metachromatic  granules), particles of iron oxide

o Cytoskeleton: Internal network of proteins associated w/cell  wall

o Endospores: formed by microbes, toughest & longest living  form of life

▪ High resistance due to high levels of Calcium &  Dipicolinic Acid

▪ Longevity = ~250 million yrs.

▪ Resistant to ordinary cleaning & boiling

▪ Destroyed by pressurized steam @ 120°C for 20-30  min.

▪ When dehydrated = metabolically inactive – is how they  live for so long  

▪ Sporulation: Formation of an Endospore, depends on  the species vegetative cell can form endospore  

centrally, subterminally, or terminally

???? Step 1) In a Vegetative Cell (single cell develops  into an endospore when one or more nutrients are  limited, this endospore reactivates to transform  

into a vegetative cell) DNA is replicated

???? Step 2) DNA aligns along cell’s long axis

???? Step 3) The cytoplasmic membrane invaginates to  form the Forespore

???? Step 4) the cytoplasmic membrane grows and  

engulfs the forespore in a 2nd membrane,  

vegetative cell’s DNA disintegrates

???? Step 5) A Cortex of Calcium and dipicolinic acid is  

deposited between the two membranes

• the cell holding the Endospore at this point  

is called the Sporangium

???? Step 6) Spore coat forms around the endospore

???? Step 7) Endospore matures, spore coat  

completed, resistance increases

???? Step 8) Endospore released, divides again under  

right conditions

Eukaryotic Structures (Major difference from Prokaryotic is contains a  membrane-bound nucleus & has membrane-bound organelles, can also be  unicellular or multicellular)

• Organisms Studied

o Protozoa: Always Unicellular

o Fungi & Algae: Unicellular or Multicellular

o Helminths: animals w/unicellular egg or larval forms, animals  themselves are multicellular

• External Structures

o Glycocalyx: outermost layer of cell, comes in direct contact  w/environment

▪ Made of polysaccharides, is a network of fibers  

▪ Can be Slime Layer or Capsule

▪ Eukaryotes not as structurally organized as prokaryotes ▪ Function: adhere cells to one another, strengthen cell  

surface, protect against dehydration, cell to cell  

recognition & communication

o Under Glycocalyx, some Eukaryotes have Cell Wall some don’t ▪ Fungi & Algae – thick rigid cell wall

???? Cell Wall: Provide support & shape

???? Fungi: thick layer of polysaccharide fibers made of  

chitin or cellulose + thin layer of mixed glycans

???? Algae: Variation of chemical composition, some  

common ones: cellulose, pectin, mannans, silicon  

dioxide, calcium carbonate

???? Some cells that have cell walls can also have  

things like Sterols  

▪ Protozoa, some algae, all animal cells – no cell wall,  only Cell Membrane  

o Cytoplasmic/Cell Membrane:  

▪ Bilayer of phospholipids & proteins

▪ Function: selectively permeable barrier for transporting  material into & out of the cell, proteins are like  

recognition molecules, receptors, carriers, enzymes, or  channels.

???? Endocytosis: Active Transport, membrane  

distends to form pseudopods around a substance  

and bring it into the cell

• Phagocytosis: Bringing in a solid substance

• Pinocytosis: Bringing in a liquid substance  

• Stuff brought in contained in a Food Vesicle  

• Amoeboid Action: some use this for  

locomotion by extending pseudopod &  

streaming into it

???? Exocytosis: how things exported from the cell,  

vesicles w/stuff inside fuse to cytoplasmic  

membrane & dump it out

▪ Sterols help with stability

▪ Eukaryotic Cells contain membrane-bound organelles,  these are 60-80% of cell volume

• In Cytoplasm/Internal Structures

o In TEM microscopic image, the varying darkness in the  cytoplasm is varying density

▪ Euchromatin = light, less dense

▪ Heterochromatin = dark, more dense

▪ The more tightly packed DNA (more dense) is being  silenced

???? DNA is packaged around Histones ???? beads on a  string (Nucleosomes) ???? chromatin fiber ???? form  

loops ???? compress to form Chromatid

o Rough Endoplasmic Reticulum: 

▪ Ribosomes adhere to it

▪ assemble proteins into their secondary, tertiary, and  quaternary structure

▪ transport proteins throughout the cell

▪ modifies protein w/glycoprotein (sugar wrapped around  the protein)

o Smooth Endoplasmic Reticulum: 

▪ Make Lipids

▪ Release Calcium ions

▪ Detoxify organic chemicals

▪ Produce steroid hormones

o Golgi Complex: 

▪ Structure: flattened hollow sacs in a phospholipid  bilayer

???? Cisternae: Flattened membrane disk, Golgi

contain 3-20 most contain 6

???? Transitional Vesicles: a sac with molecules that  comes from the ER

???? Condensing Vesicles (Secretory Vesicles):

packages secretions into these sacs that fuse to  

the cytoplasmic membrane & dump contents  

outside cell w/exocytosis

▪ Function: modifies proteins to be sent other places,  receives & packages large molecules to export from the  cell  

o Lysosomes: vesicles with enzymes that come from the Golgi ▪ Involved w/intracellular digestion & protects against  microbes

o Vacuoles: membrane bound sacs with particles to be  digested, excreted, stored

o Phagosome: A food vesicle (vacuole) that is taken into the  cell by endocytosis, when it fuses with a lysosome from the  Golgi called a phagolysosome

o Mitochondrion: 

▪ Shape: Spherical to elongated, has 2 membranes ▪ Structure:  

???? Cristae: Inner bilayer that has many folds to  

increase the surface area, where most of ATP  

produced in eukaryotic cells produced

???? Matrix: contains (prokaryotic) 70S ribosomes &  circular DNA (has genes for some RNA & few  

mitochondrial polypeptides made by mitochondrial  ribosomes)

▪ Function: Makes ATP, part of the Krebs Cycle (Citric  acid cycle), works w/electron transport

o Chloroplast: light harvesting organelle, found in  photosynthetic eukaryotes

▪ Structure: two phospholipid bilayer membranes & DNA,  make a few polypeptides w/own 70S ribosomes.

???? Thylakoids: membranous sacs that provide a lot  of surface area for chloroplasts to  

photosynthesize. Chlorophyll found here.  

???? Grana: Stacks of Thylakoids

???? Stroma: Space enclosed by the inner membrane,  contains mix of metabolic products, enzymes &  

ions

o Cytoskeleton 

▪ Function: Anchor organelles, help cytoplasmic  streaming, move organelles within the cytosol, move  cytoplasmic membrane for endocytosis & amoeboid  action

▪ Structures:  

???? Microtubules made of tubulin, are spindle fibers  and are also part of the Eukaryotic Flagella, also  

transport things

???? Microfilaments made of actin, used for amoeboid  

movement, cytokinesis, cell movement  

???? Intermediate filaments made of various proteins

Kingdom Fungi:  

• Majority unicellular/colonial, few have cellular specialization • Been around for 650 million yrs.

• Species number difficult because mating forms look different than  non-mating forms, could look different & be the same thing • 100,000 species divided into 2 groups  

o Macroscopic Fungi (Mushrooms, puffballs, gill fungi)

o Microscopic Fungi (molds, yeast)

▪ Two Morphologies = Dimorphic (Transitions between  

two forms to become pathogenic)

???? Yeast: round ovoid shape, reproduce asexually,  

the form that is pathogenic

???? Hyphae: long filamentous fungi or molds, the  

form that is benign

• When in individuals called “hyphae,” when  

make a mat of them called, “Mycelium”

(filamentous fungal growth)

• Fungal Organization

o Grow in loose colonies

o Yeast: soft, uniform in texture & appearance

o Filamentous Fungi: mass of hyphae = Mycelium (cottony,  hairy, velvety texture)

▪ Septate: when hyphae is divided with cross walls, each  separate part has its own nucleus

???? Aseptate Hyphae: no cross walls dividing

???? Septate Hyphae: cross walls dividing

▪ Vegetative Hyphae: digests & absorbs nutrients

▪ Reproductive Hyphae: makes spores for reproduction

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