Lecture Exam 1 Study Guide Flashcards
What is a microorganism? What are some examples?
- A microorganism is an organism that is too small to be seen with the unaided eye
- A germ, E. coli, S. aureus
The term used to describe a disease-causing microorganism is ____________________.
Pathogen
Who developed the formal system for classifying and naming organisms?
Carolus Linnaeus
Each organism has two names. The first name is the ________________ and the second name is the _______________________.
- Genus
- Species
How are the names of organisms written (i.e. what part of the name is capitalized, etc)?
First letter of Genus is capitalized and species is lower case
- Escherichia coli (E. coli italics or underlined separately)
List the main characteristics that define bacteria
-prokaryotic
-peptidoglycan cell wall
-hetero or autotroph
-unicellular
-asexual
List the main characteristics that define archaea (5)
-prokaryotic
-pseudomurin cell wall
-heterotroph
-unicellular
-asexual
List the main characteristics that define fungi (5)
-eukaryotic
-chitin cell wall
-heterotroph
-unicellular (yeast) or multicellular (mold/mushrooms)
-asexual or sexual
List the main characteristics that define protozoans (5)
-eukaryotic
-lacks cell wall
-usually heterotroph
-unicellular
-asexual or sexual
List the main characteristics that define algae
-eukaryotic
-cellulose cell wall
-autotroph
-unicellular or multicellular
-asexual or sexual
Why are viruses considered to be non-living?
- Acellular
- RNA only
- Obligated intracellular parasites
What are helminths?
- Flat and round worms
- No cell wall
- Heterotrophic
- Asexual and sexual reproduction
Carl Woese proposed that organisms may be classified into one of three different domains by analysis of their _____________________________________________.
rRNA
What are the three domains proposed by Carl Woese?
Bacteria
Archaea
Eukarya
Who was the first to report that living things were composed of little boxes or “cells” from looking at cork?
Robert Hooke
Who was the first to look at living microorganisms with a microscope?
Anton Van Leeuwenhoek
Compare spontaneous generation and biogenesis.
Spontaneous Generation:
Living organisms arise from non living components. “Vital force”. because there is water fish will appear
Biogenesis:
Living organisms arise from preexisting life
Describe the experiments performed by Redi, Needham, Spallanzani, and Pasteur.
Redi
- Compared meat decay in closed versus open jar. No maggots appeared
Needham
- Breifly boiled broth and sealed flask. Broth grew bacteria due to air contamination
Spallanzani
- Boiled covered broth. No growth.
Pasteur
- Boiled broth in goose neck flask. No bacterial growth
What is pasteurization?
- The application of gentle heat for a short time
- Results in reduced bacteria and longer shelf life
What are Koch’s postulates used for? What are the steps for Koch’s postulates?
- Used for etiology (causes) of diseases
1 - Pathogen must be present in Every case
2 - A pure culture of pathogens must be grown
3 - Infect healthy suceptible animal
4 - The pathogen must be reisolated
How did Jenner produce the 1st vaccine?
- Saw milk maids did not get small pox as a result of cows getting cowpox
- Exposed individual to material from cowpox lesion
- When individual exposed to small pox no infection occured as a result of immunity
What is the term for anything that has matter and takes up space?
Matter
Know the parts of the atom (i.e. the protons, neutrons, and electrons). Name which parts are positively charged, negatively charged, and neutral.
Protons +
Neutrons N
Electrons -
What are elements? What defines an element?
- Elements are when atoms have a specific number of protons, neutrons, and electrons which gives them properties
- An element is identified by the mass number (P + N), Atomic Number (P), and symbol
Fluorine has 9 protons, 9 neutrons, and 9 electrons. What is fluorine’s atomic number? What is fluorine’s mass number?
AN: 9
MN: 18
What are isotopes? What is it about carbon-12, carbon-13, and carbon-14 that makes them all carbon? What is different between carbon-14 and carbon-12?
- Isotopes are when atoms have a different number of neutrons
- All carbon due to number of protons
- The difference is C14 has two more neutrons than C12
How many electrons are in the first electron shell? How many electrons are in the second electron shell? How many in the third? When is an atom stable?
- 2
- 8
- 8
- An atom is stable when its valence shell is filled
What are ions? How do you know if an atom is an ion (i.e. what is different in the atom)?
Ions are when an atom gives one of its electrons or is donated an electron resulting in a net charge
- Na+Cl- Sodium is donating its electron to Cl to become stable
List and describe the three types of chemical bonds.
Ionic - When an electron is transfered from one atom to another resulting in net charges which causes attraction in oppositely charged ions
Covalent - When two or more atoms share one or more pairs of electrons
Hydrogen - Weak attractions between slightly positively and negatively charged atoms (H2O)
What is a compound and what is a molecule?
Molecule - A group of two or more atoms held together by chemical bonds
Compound - A substance formed by chemically combining two or more different elements
Is a NH3 molecule polar or non-polar? How do you know? How about a CH4 molecule?
- NH3 is Polar
- Because the electrons are not equally distributed
- CH4 is nonpolar
Why does sodium and chloride form a bond?
Because Na+ has a positive charge and Cl- has a negative charge
Why is water considered to be polar? In hydrogen bonding, what will the hydrogen of one water molecule bond with?
- The oxygen draws electrons toward itself and gains a small negative charge while the hydrogens gain a small positive charge
- H will bond to the oxygen of a different water molecule
What atoms do organic molecules always contain? What atom do inorganic molecules usually lack?
- Organic molecules contain carbon and hydrogen
- Typically lack carbon
What is a solution, a solute, and a solvent? When you add salt to water and the salt dissolves, what is the salt called?
- Solution is made of solute and solvent. Solute is solid component, solvent is liquid component
- Electrolyte
What makes a compound hydrophobic or hydrophilic?
Hydrophobic - Non-polar molecules that cannot interact with water
Hydrophilic - Polar molecules that can interact with water
What is an acid and what is a base? What is an example of each?
Acid: Substance that releases H+ in solution (HCl)
Base: Substance that releases OH- in solution (NaOH)
If an acid is added to water, will the pH of the solution increase or decrease? Why?
The pH will decrease as the concentration of H+ in the water increases
If a base is added to water, will the pH of the solution increase or decrease? Also, what happens to the hydroxide ion concentration as a result of a base being added?
The pH will increase as the H+ concentration decreases when it encounter OH- to make water
What is a buffer? How does it work (i.e. what happens when H+ is depleted or in excess)?
- A buffer is a solution that resists pH change
- It works by having a weak acid/base and its conjugate so neutralization occurs when a small amount of acid/base is added
- Once the buffer is broken/surpassed it will not hold off a pH change
Why is carbon central to life (i.e. what is it about its structure that makes it important)?
It can form 4 stable covalent bonds which are critical for making macromolecules
What are functional groups and why are they important?
Functional groups are groups of atoms that influence how a molecule interacts with its environment. They allow for protein folding, hydrophobic/philic interactions, disulfied bonds, and much more.
What are the four classes of macromolecules? List the necessary atoms that must be present within each of them.
Carbohydrates:
- C,H,O
Lipids:
- C,H,O
Proteins:
- C,H,O,N,S
Nucleic Acids:
- C,H,O,N,P
What type of reaction takes place when monomers are linked together to form polymers? What type of reaction takes place when polymers are broken down? What happens in each reaction?
Monomer linking:
- Condensation Reaction (dehydration synthesis)
Polymer breakdown:
- Hydrolysis Reaction
Fill in the following chart:
- Glucose, Cellulose
- Protein, Polypeptide
- DNA/RNA, Nucleotides
What are the four complex carbohydrates that are important for life? What is the function for each?
- starch- nutrient storage in plants
- glycogen- nutrient storage in animals
- cellulose- major source of fiber
- chitin- structure and strength
What is the structure of a fat? Is a fatty acid polar or non-polar? Why?
- Long carbon chain with many H
- Fatty Acids have hydrophobic tails and hydrophilic heads
- The tails are nonpolar, the phosphate head is polar
What is the difference between saturated and unsaturated fats? Which is more likely to be solid at room temperature? Why?
- Saturated fats have all bonding spaces filled with know double bonds
- Unsaturated fats have at least one double bond between two carbons, this usually cause kinks in the long hydrocarbons
- Saturated fats are solid at room temperature while unsaturated fats are not because the kinks mean the fats cannot stick together as closely as the linear saturated fats
What class of macromolecules do steroids belong to? What class of macromolecules do phospholipids belong to?
- Lipids
- Lipids
Describe how phospholipids orient themselves to form cell membranes (i.e. what part of the phospholipid interacts with the inside of the cell, etc.).
The hydrophobic tails turn into eachother while the polar hydrophilic heads face out. This allows the polar heads to touch water while the nonpolar tails do not interact with water
What is different between one amino acid and another? In other words, which part of the amino acid is variable?
- Sidegroups
Describe the four levels of structure of proteins.
Primary: AA sequence (Peptide bonds)
Secondary: Beta pleated sheets or helix interacting with itself (H bonds)
Tertiary: Irregular folding due to disulfied, H, and ionic bonds with itself
Quaternary: Multiple tertiary units interacting with eachother
Why is a fever so bad for our body?
- Because the increased temperature can interupt the bonding interactions of our proteins
Which monomer is composed of a sugar, phosphate group, and a nitrogenous base?
- Nucleotide
Compare and contrast DNA and RNA (i.e. what is the same and what is different).
DNA:
- Deoxyribose
- AT,CG
- Double stranded
RNA:
- Ribose
- AU,CG
- Single stranded
What structures are found in ALL cells?
Plasma membrane, ribosomes, cytosol, and DNA
What are some examples of eukaryotic cells? What are some examples of prokaryotic cells?
Eukaryotic:
- Human cells, plant cells, yeast, amoeba
Prokaryotic:
- E.coli, P.aeruginosa, T.pallidum
What are the differences between prokaryotic and eukaryotic cells?
Prokaryote:
- No nucleus
- No membrane bound organelle
- 70s Ribosome
- Cell membrane
- Cell wall
- Generally small
Eukaryote:
- Nucleus
- Membrane bound organelle
- 80s ribosome
- Cell membrane
- Cell wall
- Generally larger
What is the approximate size of a bacteria?
1-10 micrometers x .2-1 micrometers
Are most bacteria monomorphic or pleomorphic? What do those two terms mean?
Monomorphic - Only have one morphological shape
Pleomorphic - Can have variation is size color and shape
- Most bacteria are monomorphic
Describe each of the following shapes of bacteria (morphology): bacillus, coccus, vibrio, spirillum, and spirochete.
Bacillus: Rod shaped
Coccus: Spherical
Vibrio: Boomerang
Spirillum: Spiral
Spirochete: Long spiral
What is the difference between bacillus and Bacillus?
bacillus is the shape while Bacillus iss the scientific name for a bacteria
Describe each of the following bacterial arrangements: diplo-, strepto-, and staphylo-.
Diplo - pairs
Strepto - chain
Staphylo - cluster
What is the glycocalyx in prokaryotic cells and what is it made of? What are the two types of glycocalyx and how do they differ?
- A gelatinous external layer made of polysacc or polypeptides
- Slime Layer and Capsule
- Slime layer is loosely organized and attached
- Capsule is highly organized and tightly attached
Explain what a capsule is, what it’s made of, and the advantages it confers to bacteria.
- Type of glycolax made of polysacc. or polypep. organized and tightly attached preventing dehydration, phagocytosis, and providing adherance
When growing in an animal, Bacillus anthracis produces a capsule that is resistant to phagocytosis. The capsule is composed of the amino acid D-glutamic acid. Why is this capsule resistant to digestion by the host’s phagocytes?
Most proteins are made of L-aa and our enzymes are unable to recognize D-aa and target them
What are biofilms?
Complex inter-microbial communities forming slime or hydrogels
What advantage do the pillar-like structures give bacteria in a biofilm?
Increased surface area for nutrients
What are common sites that biofilms are found?
- Teeth, Lungs, Heart valves, Catheters, bladder, All mucus membranes, Implants
What advantages do a biofilm give to a bacterium?
- Physical shielding
- Increased survival
- Chemical resistance
- Conjugation
- Nutrient sharing
What are the three parts to the prokaryotic flagellum and what does each part do?
- Filament: Contains globular protein flagellin that forms intertwining chain forming a hollow helix
- Hook: Moves to aid in flagella movement
- Basal body: Anchors flagellum to cell wall and plasma membrane
How does the basal body of flagellum vary for Gram (+) bacteria compared to Gram (-) bacteria?
Additional basal rings required for gram negative (4:2)
What are the different arrangements of bacteria flagellum?
Monotrichous - 1 at one end
Lophotricus - >1 at one end
Amphitrichous - Tuft at both ends
Peritrichous - Over entire cell
What is chemotaxis and what is phototaxis? What is the difference between positive chemotaxis and negative chemotaxis?
Chemotaxis: Chemical stimuli such as positive (glucose) or negative (motility inhibitor)
Phototaxis: Light stimuli
What are H-antigen and why are they useful?
- H antigens are flagella proteins used to determine strains of bacteria
ex. E.coli O157:H7- O polysaccharide
- H is the type of flagellum protein
What are axial filaments used for? How do they work? What type of organisms have axial filaments?
- Used for allowing spirochetes to rotate and corkscrew to move
- Also called endoflagella
- Anchored at one end of a cell
- Present in gram negative spirochetes
What are the fine, proteinaceous, hair-like bristles on the surface of a bacterial cell, that are used for adhesion to surfaces and other cells called?
- Fimbriae are a type of adhesin to stick to surfaces and other cells
What are pili and what cell types have them? What are they used for?
Rigid tubular structure made of pilin protein. Found in gram (-) cells. They are used for transfer of genetic material(conjugation), act like fimbriae and assist in attachment, act like flagella and make a bacterium motile
What types of genes can be transferred during conjugation? (5)
Genes for antibiotic resistance, capsule production, fimbriae production, pili production, toxin production
What is the function of the bacterial cell wall? What is it made primarily of in most bacteria?
prevents osmotic lysis and protects the cell membrane and is made of peptidoglycan
Describe the structure of peptidoglycan.
polymer of disaccharide contains a NAG and a NAM and rows of carbohydrates are linked by polypeptides
Draw and label gram (+) and gram (-) cell envelope structures.
What does the Gram negative outer membrane protect the bacteria from? (5)
phagocytes, complement, antibiotics, digestive enzyme, detergents, etc
What are the components for the lipopolysaccharides (LPS) in the outer cell membrane of Gram negative bacteria? What is each used for?
- O polysaccharide- an antigen
- core polysaccharide- provide stability
- lipid A- endotoxin embedded in top layer
Why is it important for a physician to know if an infection is caused by a Gram negative or a Gram positive bacterium? Be specific!
- The doctor would know the correct antibiotic to use because some antibiotics are only effective against one type of bacteria. for example, penicillin is only effective against gram positive
- If the patient has a gram negative infection, you would not want to prescribe a drug that would cause the bacteria to rupture and release lipid A. lipid A is an endotoxin and could cause the patient to go into shock
List the 4 steps of the Gram stain and explain how each step works during the staining process.
Explain why Mycobacterium is medically-important, how its cell wall is unique, and any advantages this bacterium has towards survival in the external environment and inside the human body.
- Atypicall cell wall (60% mycolic acid) is sticky and waxy
- It is antibiotic resistant, dehydration, phagocytic and chemical protection
Describe the cell wall (or lack of) for Mycoplasma pneumoniae. What does it use in the cell membrane to protect against lysis?
- Lacks cell wall and is pleomorphic
- Cholesterol from host in membrane to protect from lysis
- No reponse to typical antibodies because cell wall cannot be targetted
What are two types of chemicals that damage the cell wall? Do those chemicals affect Gram negative or Gram positive bacteria more?
Lysozyme:
- Found in sweat, tears, mucus, saliva
- Digest disacc in peptidoglycan
Penicillin:
- Inhibits peptide bridges in peptidoglycan
Describe the structure of the phospholipid bilayer. What causes it to orient in the way that it does?
The bilayer is composed of phospholipids which have hydrophilic heads pointing out and hydrophobic tails turned in towards eachother to avoid interacting with water. This composition is caused by hydrophobic/philic interactions
What are the functions of the cell membrane in bacteria?
- Regulates what enters and exits cell
- Energy production
- Cell to cell communication
What does the fluid mosaic model state? Is the membrane a fluid structure or a rigid one?
The fluid mosaic model states the membrane bilayer is fluid with many surface proteins and cholesterol to increase fluidity
Name the 4 components of the plasma membrane in Eukaryotic cells and list the function of each.
Phospholipid bilayer - Hydrophilic heads and hydrophobic tails make it fluid
Cholesterol molecules - Patchy substance, help maintain an optimal level of fluidity
Proteins - Makes it mosaic; integral - bound hydrophobic or peripheral proteins
Glycocalyx - Protein binding sites, when it attaches to proteins and phospholipids cell lubrication and adhesion molecules
What part of a phospholipid is hydrophobic? What part is hydrophilic?
Hydrophilic polar heads
Hydrophobic nonpolar tails
Compare and contrast the cell membrane in prokaryotic cells and in eukaryotic cells.
Prokaryotic:
- Fluid phospholipid bilayer
- No sterols besides Mycobacterium
Eukaryotic:
- Fluid phospholipid bilayer
- Sterols
- Carbohydrates on surface
What is the difference between a solution that is hypertonic, hypotonic, or isotonic? Know which direction water will move if a cell is placed into each solution.
Hypertonic: High salt concentration outside = H2O exits cell (plasmolysis)
Hypotonic: High salt concentration inside cell = H2O swells cell (osmotic lysis)
Isotonic: H2O enters and exits at same rate as salt concentrations are equal
If you see a cell in which water is moving into the cell, is the solute concentration outside the cell higher or lower than the solute concentration inside the cell?
- The solute concentration is higher inside the cell and it can swell leading to osmotic lysis
Describe the structure and function of ribosomes. How are prokaryotic ribosomes different from eukaryotic ribosomes?
structure- large and small subunits, rRNA and protein
function- protein synthesis
pro-70s
euk-80s
Explain what an endospore is, what it’s made of, and what it’s functions.
- An endospore is a metabolically inactive cell that forms within a vegatative mother cell when harsh conditions are encountered. It will then germinate when favorable conditions are met
- Made of keratin
- Allows for survival under extremely harsh conditions
Bacillus anthracis - causes anthrax - lives in aerobic conditions
Clostridum genus in anaerobic conditions
What organelles are found in animal cells, but not in plant cells? What organelles are found in plant cells, but not in animal cells?
Animal- centrosome, lysosome, cillia, flagellum
Plant- vacuole, cell wall, chloroplast
What is the source, oxygen requirements, and disease associated with Bacillus anthracis?
- Soil and infected animals
- Aerobic
- Anthrax
What is the source, oxygen requirements, and disease associated with Bacillus cereus?
- Soil and rice
- Aerobic
- Food poisoning
What is the source, oxygen requirements, and disease associated with Bacillus botulinum?
- Soil and canned food
- Anaerobic
- Botulism food poisoning (flacid muscle)
What is the source, oxygen requirements, and disease associated with Clostridium perfringens?
- Soil and wound trauma
- Anaerobic
- Gas Gangrene
What is the source, oxygen requirements, and disease associated with Clostridium tetani?
- Soil and deep wounds
- Anaerobic
- Tetanus (spastic paralysis)
What is the source, oxygen requirements, and disease associated with Clostridium difficile?
- Soil and diarrhea
- Anaerobic
- Pseudomembraneous colitis
Some
Killers
Have
Pretty
Nice
Capsules
Streptococcus pneumoniae
Klebsiella pneumoniae
Haemophilis influenzae
Pseudomonas aeroginosa
Neisseria menigitidis
Cryptococcus neoformans
