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Microbiology Lecture Exam #1
Terms in this set (140)
Bacteria, Archaea, Eukarya
4. Peptidoglycan cell walls
5. Divide via binary fission
6. Derive nutrition from organic or inorganic chemicals or photosynthesis
2. Look similar to bacteria, but are VERY different
3. Lack peptidoglycan cell walls
4. Often live in extreme environments
5. Include: Methanogens, Extreme halophiles (salt), Extreme thermophiles (heat)
2. Distinct nucleus
3. Chitin cell walls
4. Absorb organic chemicals for energy
5. Yeasts - unicellular
6. Molds/mushrooms are multicellular
2. Absorb or ingest organic chemicals
3. May be motile via pseudopods, cilia, or flagella
4. Free-living or parasitic (derive nutrients from a living host)
2. Cellulose cell walls
3. Found in freshwater, saltwater, and soil
4. Use photosynthesis for energy
5. Produce oxygen and carbohydrates
2. Consist of DNA or RNA core
3. Core is surrounded by a protein coat
4. Coat may be enclosed in a lipid envelope
5. Are replicated only when they are in a living host cell
6. Inert outside living hosts
Multicellular Animal Parasites?
2. Multicellular animals
3. Not strictly microorganisms
4. Parasitic flatworms and roundworms are called helminths
5. Some microscopic stages in their life cycles
Importance of Hooke's Observations?
Reported that living things are composed of little boxes, or "cells"
- Marked the beginning of cell theory: All living things are composed of cells
Importance of van Leeuwenhoek Observations?
Observed the first microbes (animalcules)
The hypothesis that life arises from nonliving matter; a "vital force" is necessary for life
The hypothesis that living cells arise only from preexisting living cells
Louis Pasteur's Importance?
1. Demonstrated that microorganisms are present in the air
2. Used S-shaped flasks
Golden Age of Microbiology?
Beginning with Pasteur's work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs
The microbial conversion of sugar to alcohol in the absence of air
What is glycocalyx in prokaryotes?
It is external to the cell wall, it is super thick and gooey. It is made of polysaccharides/polypeptides. There are two types: capsule (neat and firmly attached) or slime layer (loose/a mess).
- IMPORTANTLY: it contributes to virulence because it prevents phagocytosis or breakdown
What is flagella in prokaryotes?
They are filamentous appendages external of the cell that propel bacteria.
What are the three parts of flagella in prokaryotes?
1. Filament - outermost region
2. Hook - attaches to the filament
3. Basal body - consists of rods and pairs/ anchors flagellum to the cell wall/membrane
How do flagella move bacteria in prokaryotes?
They rotate to "run" or "tumble," basically taxi bacteria to move towards or away from stimuli
What are axial filaments in prokaryotes?
They are anchored at one end of cell and the rotation causes the cell to move like a corkscrew. Also known as endoflagella
What are fimbriae in prokaryotes?
They are hairlike appendages that allow for attachment
What are pili in prokaryotes?
They are protein structures involved in motility. They glide/twitch. And conjugation pili are involved in DNA transfer from one cell to another!
What is the cell wall in a prokaryote?
It is made of peptidoglycan (bacteria) and it prevents osmotic lysis (excess water diffuses into cell) and it protects cell membrane
What is peptidoglycan and how is it formed?
It is a polymer of repeating disaccharide in rows: N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). They repeat back to back and then rows are attached by polypeptides
What is a gram-positive cell known for?
Thick peptidoglycan and teichoic acids
What is a gram-negative cell known for?
Thin peptidoglycan, an outer membrane and periplasmic space
What are teichoic acids and what do they do?
They are lipoteichoic acids that link the cell wall to the plasma membrane aka the peptidoglycan. They provide antigenic specificity (how cells recognize a foreign/toxic substance)
What is the outer membrane of a gram-negative cell wall made up of?
Polysaccharides, lipoproteins, and phospholipids
What are gram-negative cell walls made up of?
The walls are made up of lipopolysaccharides!
What do gram-positive cell walls produce?
Produce exotoxins! Also high susceptibility to penicillin
What do gram-negative cell walls produce?
They produce endotoxins! Also low susceptibility to penicillin
What is a protoplast?
A wall-less gram-positive cell
What is a spheroplast?
A wall-less gram-negative cell
What are L forms?
Wall-less cells that swell into irregular shapes
What is the plasma membrane in a prokaryote?
It has a phospholipid bilayer that encloses the cytoplasm with proteins on the membrane surface.
What is the fluid mosaic model?
Membrane is stick/thick, but proteins move freely and phospholipids rotate/move laterally. It self seals!
What is simple diffusion?
Movement of a solute from an area of high concentration to an area of low concentration
What is facillitated diffusion?
The solute combines with a transporter protein in the membrane, ions move across with a concentration gradient
What is osmosis?
The movement of water across a permeable membrane from an area of high water to an area of low water concentration
What is osmotic pressure?
The pressure needed to stop the movement of water across the membrane
What is isotonic solution?
Solute concentration is the same as that inside the cell
What is an hypotonic solution?
Solute concentration lower outside than inside the cell; aka water moves into cell
What is a hypertonic solution?
Solute concentration is higher outside the cell than inside; water moves out of cell
What is active transport?
It requires a transporter protein and ATP, you're going against the gradient
What is group translocation?
It requires a transporter protein and PEP, substance is altered as it crosses the membrane
What is the cytoplasm?
Substance inside plasma membrane, mostly water
What is a bacterial chromosome?
Circular thread of DNA that contains the cell's genetic information
What are plasmids?
Extra chromosomal DNA
What are ribosomes?
The site of protein synthesis = total is 70S
- 50S + 30S subunits
What are endospores?
They are resting cells that are produced when nutrients are depleted. Super strong, super resistant to heat/chemicals/radiation
What is sporulation?
What is germination?
Endospores return to vegetative state
What are flagella in eukaryotes?
Long projections that are few in number that help move substances along cell surface
What are cilia in eukaryotes?
Short projections, a lot of them and used for moving substances
What allows flagella to move in a wavelike manner?
Microtubules that are made up of protein
What is the cell wall in eukaryotes?
Made up of carbohydrates (plants, algae, fungi)
What is glycocalyx in eukaryotes?
They are carbohydrates bonded to proteins and lipids in plasma membrane (animal cells)
Compare plasma membrane in prokaryotes and eukaryotes?
Both have phospholipid bilayer, but eukaryotes is made up of carbohydrates. Both are involved in passive/active diffusions. But prokaryotes are involved in phagocytosis/endocytosis
Where are 80S membrane-bound ribosomes?
Attached to endoplasmic reticulum or free in the cytoplasm
Where are 70S ribosomes?
In chloroplasts and mitochondria
What is rough ER?
Lots of ribosomes and sites of protein synthesis
What is smooth ER?
No ribosomes, and synthesizes cell membranes, fats and hormones
Important function of Golgi complex?
They transports modified proteins via secretory vesicles to plasma membrane
What do lysosomes contain?
What do vacuoles do?
Bring food into cells; shape and storage!
What do peroxisomes do?
Oxidize fatty acids
What are centrosomes?
Protein fibers that form the mitotic spindle
What is the endosymbiotic theory?
Basically the larger bacterial cells ate the smaller bacterial cells, which became the first eukaryotes
What allows for the plasma membranes passage of some molecules, but not others?
What are photosynthetic pigments on membranes?
What are ionic bonds?
Attractions between ions of opposite charge (one loses an electron and one gains)
- Example: NaCl
What are covalent bonds?
They form when two atoms share one or more pairs of electrons
- Example: H20
What are hydrogen bonds?
Form hone a hydrogen atom that is already covalently bonded to an O or N is attracted to another N or O
What do organic compounds contain?
Carbon and hydrogen
Ionic bond and dissociate into one or more H+ and negative ions
Ionic bond and dissociate into one or more OH- ions
Dissociate into cations and anions
What do carbohydrates do?
They provide cell structure and cellular energy sources. AKA sugars and starches
Monomers of carbohydrates?
Monosaccharides - simple sugars
Di/polysaccharides - two monosaccharides joined by dehydration synthesis or broken down by hydrolysis
What is dehydration synthesis?
Dehydration synthesis is when you remove one H2O molecule to combine two molecules
What is hydrolysis?
Hydrolysis is the separation of two macromolecules by adding water.
What are lipids?
The main part of cell membranes, non polar and insoluble in water
What are simple lipids?
Fats or triglycerides; formed by dehydration synthesis
What are saturated fats?
No double bonds in the fatty acids
- Examples: Meat, dairy
What are unsaturated fats?
One or more double bonds in the fatty acids
- Examples: Oils, nuts
What makes up the cell membrane?
Complex lipids known as phospholipids (hydrophilic head and hydrophobic tail)
What do proteins do?
Essential in cell structure and function!
- Examples: enzymes, transporter proteins, flagella
Monomers of proteins?
Amino acids - contain a carboxyl group (-COOH), Amino group (-NH2) and a side group
Levels of protein structure?
1. Primary - polypeptide chain
2. Secondary - amino acid chain foils/coils
3. Tertiary - helix folds irregularly
4. Quaternary - two or more polypeptides
Monomers of Nucleic acids?
Nucelotides; which consist of a five-carbon sugar, phosphate group and nitrogen base
What is deoxyribonucleic acid?
AKA DNA; adenine hydrogen bonds with thymine and cytosine hydrogen bonds with guanine
What is RNA?
Ribonucleic acid; which plays a role in protein synthesis. Adenine hydrogen bonds with uracil and cytosine hydrogen bonds with guanine.
What is resolution?
The ability to distinguish two points
What is the refractive index?
The measure of light-bending ability
What is Brightfield illumination?
Dark objects are visible against a bright background; best with stained samples
What is Darkfield Microscopy?
Light objects are visible against a dark background; good for things that can't be stained
What is Phase-contrast microscopy?
Allows examination of living organisms/internal cell structures (works for unstained samples)
What is Fluorescence microscopy?
Uses a fluorescent dye that emits fluorescence when illuminated with UV light (aka absorb light)
What is Transmission electron microscopy?
A beam of electrons is shot through the specimen (up to 100x)
What is Scanning Electron Microscopy?
An electron gun scans the surface of specimen, produces a 3D image
What is Atomic Force Microscopy?
A metal and diamond probe is placed on specimen and creates a 3D image
What is pasteurization?
Application of a high heat for a short time
Importance of Lister's work?
Used a chemical antiseptic to prevent surgical wound infections
Importance of Koch's work?
Created postulates to link a specific microbe to a specific disease
Importance of Jenner's work?
Used cox pox to create a vaccination for small pox (aka immunity)
Who discovered penicillin by accident and how?
Alexander Fleming because he noticed how there was circle of no growth surrounding the bacteria
What is phycology?
Study of algae
What is normal microbiota?
The microbes that are normally present in and on the human body (aka on your hand or gut bacteria)
What are biofilms?
They are microbes that attach to solid surfaces and grow into masses (super sticky and gross); will grow on lots of things and can cause infections and are often resistant to antibiotics
What is catabolism?
The break down of complex molecules (macromolecules), which provides energy and building blocks for anabolism (exergonic)
What is anabolism?
Uses energy and building blocks from catabolism to build macromolecules (endergonic)
What are metabolic pathways?
Sequences of enzymatically catalyzed chemical reactions in a cell
- determined by enzymes
What is the collision theory?
Chemical reactions occur when atoms, ions and molecules collide
What is activation energy?
Collision energy required for a chemical reaction to occur
What is the reaction rate?
Frequency of collisions containing enough energy to bring about a reaction
What are catalysts? An example?
They speed up chemical reactions w/o being altered. Enzymes are catalysts! They act on a specific substrate and LOWER activation energy.
What is formed when the substrate contacts the enzyme's active site?
A enzyme-substrate complex
What is the turnover number?
The number of substrate molecules an enzyme converts to a product per second
What do enzymes usually end with?
Enzyme Components: Apoenzyme
Enzyme Components: Holoenzyme
Apoenzyme plus cofactor
Enzyme components: Cofactor
Nonprotein component aka coenzyme
What are competitive inhibitors?
They fill the active site of an enzyme and compete with the substrate
What are noncompetitive inhibitors?
They interact with another part of the enzyme (allosteric site) rather than the active site in a process called allosteric inhibition
What is oxidation-reduction?
Oxidation is the removal of electrons and reduction is the gain of elections, so a redox reaction is an oxidation paired with a reduction reaction
How is ATP generated?
By the phosphorylation of ADP w/ energy
What is oxidative phosphorylation?
When electrons are transferred from one electron carrier to another along an electron transport chain on a membrane that releases energy to generate ATP aka respiration
What is photophosphorylation?
Light energy is converted to ATP when the transfer of electrons from chlorophyll through a system
What is Glyclosis?
The oxidation of glucose to pyruvic acid produces (4) ATP and (2) NADH
- Overall net gain of two net gain molecules of ATP
Additional pathways to glycolysis?
Pentose phosphate pathway and Entner-Doudoroff pathway
What occurs in the Krebs cycle?
Pyruvic acid is oxidized and loss of CO2 occurs
- Results in Acetyl CoA and NADH
- Oxidation of acetyl CoA produces NADH, FADH2, ATP and disposes of CO2
What is the electron transport chain and where does it occur?
It is a series of carrier molecules that are reduced as electrons and are passed down the chain
- It occurs in the plasma membrane of prokaryotes and the mitochondria membrane of eukaryotes
What is chemiosmosis?
Electrons from NADH pass down the electron transport chain while protons are pumped across membrane
- Releases energy to synthesize ATP
What are light-dependent (light) reactions?
Conversion of light energy into chemical energy
What are light-independent (dark) reactions?
ATP and NADPH are used to reduce CO2 to sugar via Calvin-Benson cycle
Energy and carbon source of photoautotrophs?
Energy source is light. Carbon source is energy in Calvin-Benson cycle to fix CO2 to sugar
- Can be oxygenic or anoxygenic
- Ex: cyanobacteria
Energy and carbon source of photoheterotrophs?
Energy source is light and carbon source is organic compounds
- Ex: green bacteria
Energy and carbon source of chemoautotrophs?
Energy source is inorganic chemicals and carbon source is CO2.
- Ex: Iron-oxidizing bacteria
Energy and carbon source of chemoheterotrophs?
Energy source is chemical and carbon source is organic compounds.
- Ex: animals
What are amphibolic pathways?
Metabolic pathways that function in both anabolism and catabolism
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