BIOL-N251 Exam 1

What microorganisms are

-Range in size (smallest virus to the largest parasites and fungi)

What are different type of microorganisms

Prokaryotes and Eukaryotes

difference between prokaryotic and Eukaryotic cells

Prokaryotic: "pre-nucleus" No membrane bound organelles, example: bacteria

Eukaryotic: "true-nucleus", possess membrane bound organelles; parasites, amoeba, paramecium, man

Microorganism also include the viruses

only consist of proteins and nucleic acid.

viroids and prions

smaller and less complex infectious particles than viruses

-Viroids are only genetic material they have no protein

-Prion don't have a genetic material

Prokaryotic cell

-Plasma membrane: genetic material, pass genetic

-Fimbriae: let them stay in place

Eukaryotic cell

Structure of bacterial cell

Flagellum, Fimbria, Pillus, Cell envelope. Glycocalyx, Coating.

Flagellum

provide motility, allow prokaryotic to move around

Fimbria

-small blister like fibers on surface

-helps bacteria stick to each other and surfaces

Pillus (pilli)

-Elongated, rigid tubular structure

-sexual reproduction: conjugation

- Transfer DNA from one cell to another

-Bacteria become resistant to drugs

genetic material is pilus

is responsible for bacteria being antibiotic resistant

Cell Envelope

-Composed of the glycocalyx (outter one), Cell wall (Middle), and cell membrane.

-Protects the cell

Cell membrane

-closest to the cell

-Flexible thin skin that encloses the cells interior

-controls in/out transport of substances (via proteins in membrane)

Cell wall

-Middle Part

-Provide rigidity, strength, and protection

-Different Structure from Gram+ and Gram- bacteria

-Cell wall-deficient. bacteria:cause chronic diseases (ex: lyme)

Glycocalyx

-External Layer

-Slime Layer: loose, soluble polysaccharide; not bound to the cell; aids bacteria in colonizing surfaces slide along solid surfaces

Glycocalyx function

coating of macromolecules: protect the cell, helps cell adhere to its environment

Coating :Capsule

-Bound to the cell

-Thick gummy consistency

-gives colonies a sticky, mucoid characteristics

-Makes bacteria more virulent: protect bacteria from some phagocytosis by the cells of the host

-prevents drying out of bacteria

-Aids in attachment to surfaces for colonization

Phagocytosis

Engulf and destroy microorganisms

Chemitaxis

Chemical attraction of phagocyte to bacterium. Chemical attractants are microbial products, components of damaged tissue, and products of complement system

Adherence

Attachment of phagocyte plasma membrane to microorganisms

Ingestion

-Plasma membrane of phagocyte extends out projections called pseudopods that surround the microbe.

-Forms a sac called phagosome

Digestion

-Phagosome comes into contact and fuses with lysosomes that contain digestive enzyme and bactericidal substances

-Forms a larger vacuole called the phagolysosome

-Phagolysosome moves to cell membrane

Excretion/Exocytosis

elimination of digested contents (waste)

Cell Wall Importance

Made up of subunits found nowhere else in nature

In many species causes symptoms of disease

Site of action of some of the most effective antibiotics

Differences in chemical composition determines the gram

staining properties of the cell

Cell wall function

Protects the cell and gives it shape

Outer membrane function

Protect the cell against some antibiotics (only present in gram -)

cell membrane function

regulates the movement of substances in and out of the cell; contains enzymes important to cellular respiration

Plasmid

circular piece of DNA that contains some genes obtained through genetic recombination

Capsule & Slime layer

protect the cell and assist in attaching the cell to other surfaces

cell wall strong structural support

prevents the cell from bursting or collapsing due to changes in the environment

Bacterial Environment

usually consist of some water with small amounts of salts and other molecule

Bacterial cytoplasm

Is concentrated solution of salts and molecules

Water will tend to flow into the cell to

equalize the concentration of molecules

cell wall resist the force

preventing the cell from bursting

Cell wall chemical structure

Composed of peptidoglycan

Only found in bacteria

Similar to chitin found on lobster, insects, and cutin of plants

cell membrane

1-regulate entry and departure of the cell

2-typical structure: phospholipids with proteins

3- some areas of the membrane fold inward forming mesosomes

-increases the internal surface area for membrane function

-Most enzymes needed for biochemical reactions are located on the membrane

Protoplasm

site of biochemical and synthetic activity

contains 70-80% water, sugars, amino acids, salts, enzymes, chromatin body, ribosomes, mesosomes, granules

chromatin body

Bacterial chromosome; DNA aggregates in dense area called the nucleoid

Plasmid

circular piece of DNA: extrachromosomal strand

Protective function: provides resistance to drugs

Advantage to man: use this in genetic engineering techniques

Ribosomes

used in protein synthesis, inside prokaryotic cells

inclusion granules

concentrate nutrients inside the cell, storage & are not permanent

Gram positive cell wall

-thick layer of peptidoglycan associated with teichoic acid

-Retain Crystal violet stain

Mordant joins with crystal violet forming large molecules

gram negative cell wall

thin layer of peptidoglycan

Outer membrane and periplasmic space

Crystal violet-mordant molecule can escape when decolorized

gram stain reagents

Crystal violet - primary stain

Gram's iodine - mordent

Acetone alcohol - decolorizer

Safranin - counter stain

Gran staining procedure

-apply primary stain ( stains all the the bacteria)

- Apply mordant, binds with the stain inside the cell wall making a larger molecule

-decolorize with acetone/alcohol: this causes the stain to escape some bacterial cell walls rendering them unstained.

-add a counterstain: this adds color to the cells that were decolorized

Differences between gram positive and gram negative

Gram positive: one layer, thick, no outermembrane, periplasmic space present in some, chemical composition: petidoglycan, Teichoic Acid and lipotechoic acid. Porin protein absent. Less lipid. More Peptidoglycan. More penetrable. Less resistance to molecules.

Gram negative: two layers, thin, outermembrane is present. periplasmic space present in all. Chemical composition: lipopolysaccharide, lipoporteins and peptodoglycan. Porins protein present. Lipid More. Peptidoglycan Less. Less penetrable of molecules. More resistance to molecules.

Bacterial shapes

coccus, streptococcus, staphylococcus, diplococcus, tetrad, Sacrina, Bacillus, Diplobacillus, streptobacillus, coryneform bacillus, spirillum, vibrio and spirochete

Effect of penicillin on the cell wall

-effectiveness depend on the composition of the cell wall.

-toxic to bacteria because it inhibits the synthesis of peptidoglycan layer

-more effective against gram positive cells than gram negative bc outer membrane for gram negative prevents penicillin from reaching peptidoglycan layer

transmissible

An infectious disease agent that is transmitted from either a reservoir or a portal of exit to

another host's portal of entry. The disease is transmitted in one of three modes: 1-contact transmission 2- vehicle transmission 3-vector transmission

contact transmission

Direct: person to person (kissing, touching, sexual)

Indirect: one host to another by fomites, needles, toothbrushes, drinking glasses

Droplet: droplets of mucus that exit mouth/nares during exhaling, coughing, and sneezing

vehicle transmission

spread of pathogens via air, drinking water, and food, as well as bodily fluids being handled outside the body. Airborne, waterborne, foodborne, blood and body fluid

vector transmission

animals that transmit diseases from one host to another

Biological: vectors affecting humans are bitting arthropods mosquitoes, ticks, lice, fleas, mites

Mechanical: vectors passively carry pathogens to new hosts on their feet or other body parts. Houseflies , cockroaches

epidemic

Appearance of infectious disease or condition which attacks many people at the same time in same geographical location flu, food poison

Pandemic

Epidemic that occurs simultaneously on more than one continent Aids, Covid, flu

endemic

A disease peculiar to and recurring continuously in a particular locality or population. (Ex: histoplasmosis- Ohio Valley)

contagious

A communicable disease that is easily transmitted from a reservoir or person. ( ex:common cold, legionnaires disease)

Epidemiology

The study of the occurrence, distribution, and spread of disease in humans. (Ex: tracking SARS, Bird Flu, seasonal flu)

Incidence: the number of new cases of a disease in a given area or population during a given period of time

Prevalence: the total number of cases, new and existing in a given area or population during a given period of time

Microorganisms as our Foe: 750 million infectious diseases a year worldwide

>200,000 deaths annually in the US

Tens of billions of dollars in health care

Leading cause of illness and death: respiratory, diarrheal disease

food borne outbreak common ones

Salmonella, shigella, E. Coli, Staph, Bacillus Cereus, clostridium, listeria, noro virus

Ways Microorganisms help us ( how are microorganisms our friends?)

-breakdown food in the gut

- produce foods: yogurt, cheese, wine, bread

-used to make vitamins, insulin, drugs

- Decompose waste

- Recycle nutrients back into the earth

- used as a food source for other organisms

-make chemical products: acetone, glycerine, organic acids, enzymes, alcohols

-Agriculture

Broth

a liquid medium that contains various nutrients and is used to culture bacteria and other microorganisms in culture

Agar

A gelatinous material derived from algae, specifically used as a culture medium of bacteria and other cells for diagnostic or laboratory experiments purposes. Agar melts at 85 C, solidifies at 32-40 C. This property known as hysteresis

Deep

Used for a culture where you need a deep inoculation into a solid medium that is used especially for the growth of anaerobic bacteria

Slants

a culture made on the slanting surface of a solidified medium in a test tube that has been tilted to provide a greater area for growth. slanr, Butt-

Plates

A petri dish that contains a solid growth medium, typically agar plus nutrients used to culture small organisms such as microorganisms

incubation

Act of maintaining controlled environmental conditions for the purpose of favoring growth or development of microbial cultures

colony

A visible mass of microorganisms all originating from a single mother cell, therefore a colony constitutes a clone of bacteria all genetically alike

picking colonies

selecting a colony from a plate and transferring it to another media or a slide

Loop

A simple tool used mainly by microbiologist to retrieve an inoculum from a culture of microorganisms. The loop is used in the cultivation of microbes on plates by transferring inoculum for streaking

Needles

Used in the field of microbiology to transfer and inoculate living microorganisms. It is one of the most commonly implicated biological laboratory tools and can be disposable or re-usable

Cross contamination

the spreading of pathogens from one food to another

Anaerobic tests

No oxygen

Aerobic

Oxygen

Metabolism

General term used for all of the reaction occurring in cells

Types of reactions

catabolic and anabolic

catabolic reaction

The metabolic breakdown of complex molecules into simpler ones, often resulting in a release of energy

Anabolic reaction

The phase of metabolism in which simple substances are built into the complex materials of living tissue

anabolic pathways

Small molecules are assembled into large ones. Energy is required

Catabolic pathways

Large molecules are broken down into small ones. Energy is released.

catabolism

energy is released and stored in cells as ATP

breakdown of large molecules by catabolic process results in production of smaller molecules

Anabolism

-opposite of catabolism by synthesizing larger molecules into cellular structures.

-Building requires more energy which comes from ATP molecules produced during catabolism

Reactants

A starting material in a chemical reaction

products

The elements or compounds produced by a chemical reaction.

relationship between catabolism and anabolism

Catabolism provides energy for anabolism

Enzymes characteristics

-Protein molecules that act as catalyst: increase the rate of a reaction that would normally occur at a slow rate.

-An enzyme works on a specific type of substrate: substrate fits into the enzymes active site.

Lock and key fit: lock is enzyme, key is substrate

Active site

The part of an enzyme or antibody where the chemical reaction occurs.

An enzyme

not permanently changed nor becomes part of the product of the reaction

activation energy

the amount of energy needed to trigger a chemical reaction

Enzyme lowers activation energy

makes reaction go faster

catalyst

substance that speeds up the rate of a chemical reaction

substrate

A specific reactant acted upon by an enzyme

Naming enzymes

named after the substrate or the kind of reaction they catalyze.

End with the suffix "ase"

Some enzyme still go by their old name

Two main methods used for production energy from nutrient

1- Fermentation

2-Respiration

Fermentation (Reduction)

-The final acceptor in the pathway is an organic molecule, pyruvic acid

-Made in the pathway itself so no externally supplied acceptor is needed, thus oxygen not required

-The pyruvic acid is further reduced to lactic acid and ethanol, called end products, depending on the species of bacteria.

-Produces less energy from glucose

Respiration (Oxidation)

-Final acceptor is an inorganic molecule, usually CO2 and H2O

-O2 must be supplied by the environment

-Produces more energy from glucose

Describe three characteristics of enzymes

1-Protein molecules that act as catalyst: increase the rate of a reaction that would normally occur at a slow rate.

2-An enzyme works on a specific type of substrate

3-Enzyme lower activation energy

given a substrate, name the enzyme

Lipid-Lipase

Maltose-Maltase

Sucrose-Sucrase

Protein-Protease

Amylose-Amylase

Lactose-Lactase

Given a graph representing activation energy, identify the reaction curve with and without enzyme

Aerobic respiration and anaerobic respiration

2 types of cellular respiration