Micro. - Exam 1 Study Guide

Microbes are ubiquitous - What does that mean? (Ch.1)

Ubiquitous = Found everywhere

An object that is free of all life forms = Sterile

The three domains of all life: Bacteria, Archaea, and Eukarya. Where did these cell types originate from? and how long ago?

• The Bacteria & Archaea = Prokaryotes

• Then Fungi, Helminths, Protozoans, Animals, Plants, Eukarya = Eukaryotes

Three domains originate from the last common ancestor (LCA)

How long ago? 3.8 billion

What makes the Prokaryotes different from the Eukaryotes? (Ch.1)

Prokaryotes = No nucleus, No organelles, cell wall - Peptidoglycan

Eukaryotes = Nucleus, organelles, ~ (sometimes) cell wall - Fungus

What is classification in phylogeny? What about nomenclature? (Ch. 1)

Phylogeny = “Tree of life”

Classification in phylogeny: The orderly arrangement of organisms into a hierarchy, placing them on the “branching tree of life” (Phylogeny)

Nomenclature: The assignment of scientific names for Genus and species, giving a proper name in 2 parts

Ex: “Tree of Life” - Phylogeny

• 3 Domains (Most general category): Bacteria, Archaea, Eukarya

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• species (Most specific)

(For Genus & Species: Need to know nomenclature)

What rules do we have to follow in nomenclature? (Ch.1)

Rules:

• 2 parts: Genus & species

• Underlined (Both parts)

• Genus is capitalized, species is lowercase

Ex: (Proper name in 2 parts)

• “Genus species” - Handwritten

• “Genus species” - Typed (Has to be italicized if typed)

What did the following scientists do or how did they contribute to the field of Microbiology? (Ch.1)

• Joseph Lister

• Ignaz Semmelweis

• Robert Koch

• Antonie van Leeuwenhoek

• Louis Pasteur (he is mentioned in multiple chapters)

Joseph Lister:

• Introduced hand-washing with disinfectants (Aseptic techniques)

• The surgeon who advocated using disinfectants on hands and in the air prior to surgery (HW)

Ignaz Semmelweis: Handwashing (rinse hands in between patients)

Robert Koch:

• “Koch’s Postulates” = a series of steps to identify a microbe in a disease (Postulates = Steps)

• Famous for discovering the microbe that was causing Anthrax, he figured that out with his steps

• Scientist that showed that anthrax was caused by the bacterium, Bacillus anthracis (HW)

Antonie van Leeuwenhoek:

• Invented the microscope

• The Dutch merchant who made and used quality magnifying lenses to see and record microorganisms (HW)

Louis Pasteur:

• First to provide Germ Theory

• Disproved “Spontaneous generation” with the swan-neck flask experiment

• He came up with the Anthrax vaccine

• Discovered viruses (Gave us the name virus)

• The concept of abiogenesis was finally disproven by: Pasteur’s use of swan-neck flasks (HW)

What is genetic engineering? (Ch.1)

Manipulating DNA of an organism to create something in the industrial setting

“When humans manipulate the genes of microorganisms, the process is called?: genetic engineering” (HW)

4 main types of macromolecules that make up life?

• Carbohydrates

• Lipids

• Proteins

• Nucleic acids

• Peptidoglycan, ATP, agar, enzymes, antibodies, DNA/ RNA

• [Have a general idea of where these are / what their purpose is] (Ch.1)

Peptidoglycan: Component of bacterial cell wall (The Structure that’s inside bacterial cell walls) specific to just bacteria in the cell wall

ATP: Energy for the cell

Agar: An Important component of culture media; a substance that solidifies our media

Enzymes: Catalysts for all chemical reactions in cells. Speeds up reactions. (Proper description: “Biological catalyst”; speeds up reaction)

Antibodies: Products of our immune cells; glycoproteins with specific regions of attachment for bacteria, viruses, and other microorganisms

DNA: Cell instructions

RNA: Copy of cell instructions

Prokaryotes

Bacterial structures – know where they are found and their purpose: (Ch.3)

Which ones listed are found in ALL bacteria?

• Flagella

• Pili

• Fimbriae

• Glycocalyx (slime layer, capsule)

• Outer membrane & LPS layer (gram -)

• Cell wall

• Cytoplasmic membrane

• Cytoplasm

• Ribosomes

• Cytoskeleton

• Chromosome

• Plasmid

• Endospores

Flagella = Structure for movement

Pili = Conjugation (swapping DNA between bacteria)

Fimbriae = Attachment

Glycocalyx (slime layer or capsule) = Outer layer for protection

• It can look like a slime layer or capsule

• Capsule protects bacteria from phagocytosis (white blood cells eating bacteria)

Outer membrane & LPS layer (gram -): Extra layer in the cell wall for gram -’s

• Only found in gram - bacteria

Cell wall = Structure & Support

Cytoplasmic membrane = Metabolism (Found in ALL bacteria)

Cytoplasm = Water (Found in ALL bacteria)

Ribosomes = Protein synthesis; making proteins (Found in ALL bacteria)

Cytoskeleton = Extra Support (Found in ALL bacteria)

Chromosome = DNA (Found in ALL bacteria)

Plasmid = Extra DNA for extra traits

Endospores = for survival

• To protect the genetic material (Protect DNA); during harsh or unfavorable conditions

Know the shapes and arrangements: (Ch.3)

Coccus, bacillus, vibrio, spirillum & spirochete

• Diplococcus

• Staphylococcus

• Streptococcus

• Streptobacillus

• Palisades

Coccus: Round-shaped

Bacillus: Rod-shaped

Vibrio: Curved rod-shaped

spirillum & spirochete: Spiral-shaped

Diplococcus: Pair of round cells

Staphylococcus: Irregular cluster (Clump)

Streptococcus Chain of round cells

Streptobacillus: Chain of rod-shaped cells

Palisades: Random arrangement of bacilli

What does pleomorphic mean?

Variations in cell wall shape

Know the names for different arrangements of flagella

Polar: flagella at one or both ends

Monotrichous (One): Single flagellum

Lophotrichous: small bunches of flagella emerging from the same site

Amphitrichous: Flagella at both ends of the cell

Peritrichous: Flagella are dispersed randomly all over the cell

Cell wall differences: Gram + vs. Gram - (Ch.3)

• Why do they stain different? What’s different in their cell walls?

• What are the Basic steps of gram stain?

Why do they stain different?

• Because of their cell wall differences

What’s different in their cell walls?

• Gram + : Thick peptidoglycan layer; Purple (“Positively purple”)

• Gram - : Thin peptidoglycan layer, outer membrane (Pink / Red)

  • Decolorize w/ alcohol (Decolorize on 3rd step)

Basic steps of gram stain:

1) Primary stain = Crystal violet

2) Mordant = Iodine

3) Decolorizer = Alcohol

4) Counter stain = Safranin

What makes the ‘special’ groups different [Mycobacteria & Mycoplasma]? (Ch.3)

Mycobacteria: Thick Cell layer wall of Mycolic acid *Very Resistant* (Has a cell wall)

Mycoplasma: They have No cell wall

How do flagella move?

What is chemotaxis? (Ch.3)

How do flagella move? - They move by Chemotaxis

Chemotaxis: movement of bacteria in response to chemical signals

• Positive chemotaxis: movement toward favorable chemical stimulus

• Negative chemotaxis: movement away from a repellent

What makes the bacterial ribosomes different than those in eukaryotic cells? (Ch.3)

Size difference & units

Prokaryotes: (Bacterial Ribosomes) “Odd #’s” or “Bacteria are odd little organisms”

• 50S (Large subunit)

• 30S (Small subunit)

• 70S (Large and small subunits together = One ribosome)

Eukaryotes: (Eukaryotic cells) “Even #’s Eukaryotes”

• 60S

• 40S

• 80S (Eukaryotic ribosome)

What is an endospore? (Ch.3)

Why do some bacteria make one? What is the purpose?

What is an Endospore? = Survival little shell for DNA

Why do some bacteria make one? = So that they survive during really bad conditions, so one cell survives, single cell surviving

Dinstiction of endospores:

• Fungalspores: Fungal spores are meant for reproduction (1 spore can make multiple fungal spores)

• Endospores for bacteria: Not multiplying (no reproduction), just a single cell surviving

What is the purpose?

Eukaryotes: (Ch.4)

• Name structures Eukaryotes have that Prokaryotes don’t

• What is the function of each organelle listed above?

Mitochondria: Energy or metabolism for the cell

• The mitochondria is not just metabolism (Metabolism is just the summary of the process)

• (TQ!) The proper term is aerobic respiration = process of extracting energy (happening in mitochondria) from chemical compounds

Golgi apparatus: Modifying proteins

Nucleus: Holds DNA

Endoplasmic Reticulum (Rough): Protein synthesis (Where proteins are made)

Differences in DNA / Chromosomes: Chromatin & histone proteins (Ch.4)

DNA:

Eukaryotes: Have Chromatin & Histone proteins

Prokaryotes: Do not have Chromatin & Histone proteins

Chromosomes:

Eukaryotes: DNA has histone proteins, helps it squish down and condense down into chromatin

Prokarytes: Don’t have that

Which groups of Eukaryotes have cell walls? Which groups have cilia? (Ch.4)

Which groups of Eukaryotes have cell walls?

• Fungal group (Fungus): cell walls made of chitin

Which group have Cilla?

• Protozoans

Fungus: (Ch.4)

Know the diffrence between molds vs. yeast, or dimorphic

Molds: have Hyphae

Yeast: round-shaped cells, yeast are yeast

Dimorphic: can be both (Yeast & Hyphae), depending on the temperature

Fungus: (Ch.4)

Know the structures: hyphae (septate vs aseptate), mycelium, budding

Hyphae:

• If hyphae has a line going down the middle = Septate

  if hyphae doesn’t have line down the middle = Aseptate

Mycelium: buddle of hypahe, a mask of hyphae

Budding: process of the yeast reproducting, forming a new yeast cell

Fungus: (Ch.4)

Know the terms: heterotrophic, saprobic, and parasitic

Heterotrophic: Get nutrients from a wide variety of organic substrates

Saprobic: get nutrients from dead plants and animals -Decomposing fungi

Parasitic: grow on the bodies of living animals or plants

Fungus: (Ch.4)

What makes up fungal cell walls that is different than bacterial cell walls?

Chitin

Helminths: (Ch.4)

Know the name for the 3 main groups, both the proper and common name

The Helminths: 3 main groups, both proper & common names

• Tapeworms (Common name) - Cestodes (proper name)

• Flukes (Common name) - Trematodes (Proper name)

• Roundworms (Common name) - Nematodes (Proper name)

Parasitic = means that these organisms require what? (Ch.4)

Require a living host to survive

Basic life cycle: (Ch.4)

• What is the basic life cycle of helminths?

• Intermediate host vs definitive host, what is the difference between the two?

Basic life cycle of helminths:

• Fertilized egg → Larvae → adult worm

Intermediate vs. Definitive:

• Intermediate host: is where larvae develop

• Definitive host: is where the adult worm develops

Porozoans:

Kingdom Protista with algae

2 basic life stages:

1) Cyst - asleep, dormant

2) Trophozoite - active, moving & feeding

Viruses = Obligate intracellular parasites, what does that mean? (Ch.5)

Have to be inside of a living host to multiply

History of viruses - who first proposed term virus and then what is meant by filterable virus? (Ch.5)

Who first proposed the term “virus”? - Louis Pasteur

What is meant by a filterable virus? - The virus passes through the filter, virus is smaller than bacteria, it passes through the filter

What are the viral structures of these?: (Ch.5)

• Nucleic acids

• Capsid

• Envelope

• Glycoprotein spikes

• Naked vs Enveloped virus

Nucleic acids:

• DNA or RNA, double stranded or single stranded

Capsid:

Protein shell surrounding nucleic acid

different capsid types:

• Nucleocapsid: the capsid + nucleic acid

• Naked viruses: nucleocapsid only

Envelope:

• External covering of a capsid, usually a peice of the hosts cell membrane

Glycoprotein spikes:

• Can be found on naked or enveloped viruses

Naked vs Enveloped virus:

Naked virus: nucleocapsid only

Enveloped virus: Take some of the cell membrane when released from a host cell

• How do they get an envelope? - From stealing it from the host’s cell membrane

Know the order of the steps of viral replication (Ch. 5)

1. Adsorption

   What is ‘host range’ and ‘tropism’ (Adsorption)

   • Host range = the limited range of cells that a virus can infect

   • Tropism = specificities of viruses for certain tissues

2. Penetration

   What are the two ways viruses can get in? (Penetration)

   • A) Endocytosis - Cell eats virus

   • B) Fusion - Virus envelope fuses with host

3. Uncoating

4. Synthesis

5. Assembly

6. Release

   What are the two ways viruses can get out? (Release)

   • A) Cell Lysis/ Rupture

   • B) Budding

What are Bacteriophages? (Ch.5)

Viruses that infect bacteria (the weird looking ones)

Cytopathic effects (CPE) - what is this? what do they look like & why do we look for them? (Ch.5)

Cytopathic effects (CPE) what is this?

• Damage to a cell from a virus that we can see under a microscope

• CPE’s all have to be viewed under a microscope

Types of CPEs:

Syncytia: cells fused together as a clump or mass

Plaque: This is clear spot where the cells are destroyed

Inclusion body: Debris from dead cells

Why do we look for them?

• They tell us if a virus was present, evidence of a viral infection

Extras:

• Latent viruses

• Oncogenic viruses

• Satellite viruses

• Viroid?

• What is a prion? What do prions results in [general description of disease]

Antiviral treatments:

• Have to target step in replication cycle

• Ideally would harm virus and not host

• Easier to prevent with vaccine than treat after infected

Latent viruses = dormant/asleep

Oncogenic virus = Tumor-producing virus

Satellite viruses = Dependent on other viruses for replication

Viroid = incomplete virus or plant

What is a prion? = it is an infectious protein

What do prions result in? = is progessive fatal neurogeical disease

What is 1? (Name & Function)

Name: Flagellum

Function: Movement

What is 2? (Name & Function)

Name: Capsule

Function: Protection

What is 3? (Name & Function)

Name: Cell wall

Function: Structure & Support

What is 4? (Name & Function)

Name: Cytoplasmic membrane

Function: Metabolism

What is 5? (Name & Function)

Name: Cytoplasm

Function: Water

What is 6? (Name & Function)

Name: Ribosome

Function: Make proteins

What is 7? (Name & Function)

Name: Fimbriae

Function: Attachment

What is 8? (Name & Function)

Name: Plasmid

Function: Extra traits

What is 9? (Name & Function)

Name: DNA

Function: Cells instructions