MICROBIOLOGY QUIZ 2 *General characteristics of bacteria and animal cells

The definition of Endospores/spore

Are thick protective covering around certain bacteria as fungi, making it highly resistant to dangerous environments.

How bacteria are reproduce: sexually or asexually?

Asexually

The device used in medical facilities for sterilization, for the killing of bacteria and spores

Autoclave

What structure maintains the shape of a bacterial cell?

Cell wall

The universal units the life

Cells

Internal structures of Prokaryotes

Cytoplasm, Ribosomes, and Endospores

The condition that induce the spore's formation

Depletion of nutrients, temperature, extreme desiccation and lack of nutrients unfavorable conditions.

Bacterial attachment structures

Flagella -movement Fimbriae - attachment, SMALL hair-like structure that allows attachment on solid tissues on the host sexual pili - LONG hair-like structure , transfer genetic material & adherence *capsule

Virulence

Increased" ability for an organism to produce an infection Degree of pathogenicity *the severity or harmfulness of a disease or poison.

Bactericidal

Inhibits the cell wall

Location of that organelle

Inside Eukaryotic cells.

Summary of bacterial cell's virulent structure

Fimbriae, capsule & toxins

The function of Ribosomes

Proteins synthesis - cell structure that makes protein. Protein is needed for many cell functions such as repairing damage or directing chemical processes

Passive movement / transport

is a movement of ions and other atomic or molecular substances across cell membranes without need of energy input

What kind of antibiotics will be used to treat the mycoplasma pneumonia

erythromycin, it inhibits protein synthesis, inside cell. Tetracycline and erythromycin compounds are very effective. The second-generation tetracyclines (doxycycline) and macrolides are the drugs of choice.

Bacteria cell wall

resists osmotic pressure

The definition of Eukaryotes

multi-cellular organism with a well developed nucleus, with organelles and surrounded by lipid membrane/nuclear envelope.

Definition of organelle

"Tiny little organs" organized or specialized structures within a living cell.

Why the peptidoglycan are important?

"it gives strength to the outer structure of the organism" peptidoglycan is the primary determinant of the characterisation of bacteria as gram-positive.

Definition of bacteriostatic agents

"suppresses" Bacteriostatic agent is a biological or chemical agent that stops bacteria from reproducing, while not necessarily killing them otherwise

The factors of bacterial virulence

1- Capsule 2-Attachment 3- toxins , SPORES, RESISTANCE, NO TEICHOIC ACIDS ON WALL *Attachment(adhesins) , Colonization, Invasiveness, Toxins & enzymes, inhibition of phagocytosis

Location of bacteria capsule

Above the cell wall

The function of cell membrane

Barrier between the cell and the outside world, it has a selective permeability.

The name of bacterial reproduction

Binary fission

How penicillin kills bacteria?

Breaks Down the cell wall

The instrument used to isolate the ribosomes

Centrifuge

Gram negative bacteria has

Double plasma membrane of polysaccharides, outer and inner

The difference between bacterial and human ribosomes and why is it useful?

Eukaryotic ribosomes are larger. They consist of a 60S large subunit and a 40S small subunit, which come together to form an 80S particle having a mass of 4200 kd, compared with 2700 kd for the prokaryotic 70S ribosome. -Size, composition EUKARYOTES 80S PROKARYOTES 70S

Eukaryotes membranes

Have sterols which makes it rigid, bacteria lack sterols

What is the function of Flagellum

Helps the bacteria move, rotate to propel the cell *whip-like structure that allows a cell to move

The function of cytoplasm

Holds organelles from colliding with other organelles, transports genetic material and the products of cellular respiration,It's Semifluid substance that has proteins enzymes, carbohydrates, lipids, inorganic ions -It is made up of mostly water and salt. Cytoplasm is present within the cell membrane of all cell types and contains all organelles and cell parts.

Pathogenicity

Is the ability/capability to produce disease *harm the host

How does Erythromycin kills bacteria

It interferes/Inhibit protein synthesis Erythromycin, an antibiotic that inhibits the synthesis of vital proteins in susceptible bacteria, may be either bacteriostatic (i.e., inhibiting bacterial reproduction but not killing bacterial cells) or bactericidal (i.e., killing bacteria by direct action), depending on its concentration and the type of microorganism against which it is used It works by preventing bacteria from producing proteins that are essential to them. Without these proteins the bacteria cannot grow, replicate and increase in numbers. Erythromycin doesn't directly kill the bacteria, but leaves them unable to increase in numbers. The remaining bacteria eventually die or are destroyed by the immune system. This treats the infection.

What is surgical asepsis

Killing microbes, bacteria and spores

Broad -spectrum penicillin

Kills Gram negative bacteria by entering their channels called Porins

The bacterial wall,

LOCATION: Lies outside the cell membrane FUNCTION OF CELL WALL: maintains the characteristic shape of the cell, and it prevents OSMOSIS

External Structures of Prokaryotes

Membranes, Walls, and Capsules

Why overuse of antibiotics harms you?

One common cause of opportunistic infection is clostridium difficile (klos-TRID-e-uhm dif-uh-SEEL). Like many opportunistic bacteria, C. difficile live in the environment and do not normally harm healthy people. However, certain groups of people, like older adults who have been on antibiotics for a long time, are vulnerable. When antibiotics kill too many friendly bacteria in the intestine, C. difficile multiplies and produces toxins that make the person sick with symptoms like fever, nausea, diarrhea, and inflammation.

An Isotonic solution

Overall concentration of solutes are equal, water leaves and enters the cell at the same rate.

The chemical composition of bacterial cell wall

PEPTIDOGLYCAN -a substance forming the cell walls of many bacteria, consisting of glycosaminoglycan chains interlinked with short peptides. "The backbone of the cell wall"

What is the function of the Golgi complex

Packaging and transportation of material

The difference between passive and active transport

Passive does not require ATP, Active transport requires ATP Active Transport moves ions from low concentration to high, using metabolic energy in the form of ATP. Passive Transport (or Diffusion) moves ions from high concentration to low, using no metabolic energy.

The difference between pathogenicity and virulence:

Pathogenicity is The ability to produce a disease Virulence is the degree of that microbe to cause disease

The antibiotics that inhibit the bacterial wall synthesis

Penicillin G -is natural and Penicillin V semisynthetic "Methicillin kills penicillin resistant bacteria" Semisynthetic penicillins -nafcillin, oxacillin, ampicillin, amoxicillin, carbenicillin, ilicarcillin Both natural and semisynthetic penicillins. B-lactamase penicillin,

What shape do wall-deficient bacteria have

Polymorphic L-form bacteria are pleomorphic, that is, they can change size and shape L-form bacteria lack flagella, long slender appendages that allow some forms of bacteria to propel themselves forward by using a whip-like motion.

The mechanisms of penicillin resistance. How bacteria inactivate penicillin?

Produces enzymes that make penicillin ineffective, Breaking penicillin chemical structure by making b-lactamase enzyme β-lactamase that destroys the active component (the β-lactam ring) of penicillins, extremely important antibiotics for treating human infections.

Ribosomes size on both cells

Prokaryotes 70s Eukaryotes 80s

What is superbug?

a strain of bacteria that has become resistant to antibiotic drugs.

What cellular organelles are responsible for protein synthesis

Ribosomes and Rough endoplasmic Reticulum

Who is credited for discovery and naming "the cell"

Robert Hooke

What chemical maintains the shape of mycoplasma cell membrane

STEROLS - hard lipid. Resistant to lysis, Bacteria it's extremely small. Mycoplasma species do not have a cell wall, which makes them resistant to penicillin it's also an anaerobic bacteria

Passive processes include:

Simple diffusion, Facilitated diffusion , osmosis NO ENERGY

What is the function of Smooth ER

Synthesize lipids and transport material inside the cell

Describe Griffith experiment with the pneumococcal pneumonia on mice and his conclusion

The capsule protects bacteria from immune system

The cell organelle that regulates the entry and exit of materials in the bacteria and animal cells is

The cell membrane

Binary fission:

The process whereby a cell divides Asexually to produce two daughter cells. BUT are NOT IDENTICAL

Why the generation time is too short?

The shorter the generation time, the faster the number of bacteria increases within the host. bacteria has a generation time of 20 minutes Varies on PH, Availability of nutrients.

What is the conjugation or bacterial matting?

The transfer process where bacteria transfer DNA to another bacteria.

Definition of bactericidal antimicrobial agents

They kill bacteria

The purpose of conjugation?

To exchange/transfer genetic information

The function of sex pilli

Used to transfer DNA material from bacteria cell to another. LONG hair-like structure , transfer genetic material & adherence

A Hypotonic solution

Water enters the cell by osmosis -Concentration of solute is lower than that in the cell. -Cell swells and bursts and undergoes osmotic lysis for excessive water intake *Bacteria lives in hypotonic solution due to their rigid cell wall. penicillin inhibits bacterial cell wall, causing the cells to burst.

A Hypertonic solution

Water leaves the cell, by osmosis Concentration of solute is higher than that in the cell. Cells shrink and collapse greater concentration of solutes on the outside of a cell when compared with the inside of a cell.

Why penicillin is not harmful for the human cells?

We do not have a cell wall, penicillin only acts on cell wall *Human cells do not make or need peptidoglycan Penicillin, one of the first antibiotics to be used widely, prevents the final cross-linking step, or transpeptidation, in assembly of this macromolecule. The result is a very fragile cell wall that bursts, killing the bacterium. No harm comes to the human host because penicillin does not inhibit any biochemical process that goes on within us.

What is endotoxin and the medical problems it causes?

a toxin that is present inside a bacterial cell and is released when the cell disintegrates. It is sometimes responsible for the characteristic symptoms of a disease, e.g., in botulism. " Endotoxic shock "

The function of fimbriae

attachment, SMALL hair-like structure that allows attachment on solid tissues on the host, they enable bacteria to adhere to surfaces

What is the function of lysosomes

digestion and waste removal

The definition of prokaryotes

single-celled organism that lack a nucleus and organelles. Has cell wall. 1. Typically their DNA is not enclosed within a membrane and is usually a singular, circularly arranged chromosome. 2. No histones (special chromosomal proteins found in eukaryotes); 3. They generally lack organelles. 4. Their cell walls almost always contain the complex polysaccharide peptidoglycan. 5. They usually divide by binary fission, where DNA is copied, and the cell splits into two cells. This involves fewer structures and processes than eukaryotic cell division.

Osmosis

the net movement of "water" molecules across a selective permeability membrane from an area of of high concentrations of water molecules to an area of lower concentration of water molecules by simple diffusion or by water channels(aquaporins)

The principle of simple diffusion?

the overall movement of molecules or ions from an area oh high concentration to an area oh low concentration, continues until its evenly distributed NO ENERGY

The definition of the generation time?

the time it takes for the population to double", or doubling time, The time between divisions

Similarity and difference in prokaryotes and eukaryotes:

"Similarity" Flagella, cell division, cytoplasm, ribosomes, Chromosomes "Difference:" Prokaryotes: Binary fission, complex cell wall, small ribosomes, no cytoskeleton, circular DNA, simple appendages Eukaryotes: Mitosis, No cell wall, Big ribosomes, Cytoskeleton, linear DNA, complex appendages

External Structure of bacteria

Bacteria Capsule -above cell wall, it's "invencible"

The structure difference between Gram Positive and Gram-negative bacteria?

Gram+ positive - Thick layer of peptidoglycan , lacks outer membrane, Gram- negative - Thinner layer of peptidoglycan, has an extra plasma membrane of lipopolysaccharides ,extra outer membrane, in which penicillin cannot go through to destroy cell wall. *Gram-negative bacteria are more resistant against antibodies because of their impenetrable cell wall due to peptidoglycan membrane. Gram-positive bacteria do not have an outer cell membrane

Why G- negative are more dangerous than G+ positive bacteria?

Gram-negative bacteria have an outer membrane of lipopolysaccharide, making penicillin ineffective. Lipopolysaccharide is an endotoxin which increases the severity of inflammation. This inflammation may be so severe that septic shock may occur.Release lipolychachorites endotoxins that kills tissues. Gram-negative bacteria are more dangerous as disease organisms, because their outer membrane is often hidden by a capsule or slime layer which hides the antigens of the cell and so acts as "camouflage" Often the presence of a capsule will increase the virulence of a pathogen.

Why Erythromycin doesn't kill the human and animal cells?

Humans do not have peptoglycan, 'Macrolides block only bacterial ribosomes and prevent them from building proteins. Since proteins do all the cell's work, a bacterium that cannot build proteins cannot survive. Erythromycin, which is commonly used to treat respiratory tract and skin infections, is a macrolide." human cells do not have cell walls, while many types of bacteria do. The antibiotic penicillin works by keeping a bacterium from building a cell wall. Without support from a cell wall, pressure inside the cell becomes too much and the membrane bursts

Facilitated diffusion

Integral membrane proteins function as channels or carriers that facilitates the the movement of ions or larger molecules across the plasma membrane. aka "transporters" or "permeases" NO ENERGY

Why the capsular chemicals make the pneumonia bacteria virulent?

It is covered by polysaccharides *Capsules are usually polymers of simple sugars (polysaccharides) Virulence is caused by the chemical composition of the capsule

What is MRSA

Methicillin Resistant Staphylococcus Aureus

What is the site of energy production

Mitochondria

The structural similarity and difference between Prokaryotes and Eukaryotes

Prokaryotes : are smaller,lack a nucleus, no membrane bound organelles, ribosomes are small,cell division by binary fission, have capsules, more peptidoglycan, have cell wall Eukaryotes : are bigger, have a nucleus, complex organelles, ribosomes are bigger, cell division by mitosis, less peptidoglycan, do not have cell wall

Prokaryotes and Eukaryotes

Prokaryotic Cell Characteristics No membrane bound nucleus Archbacteria and Eubacteria Kingdoms Naked DNA, no protein covering, circular in shape No membrane bound organelles Small and primitive Eukaryotic Cell Characteristics Organized nucleus Protist, Fungi, Plant Animal Kingdoms Histone protein covering, arranged in organized chromosome structure Membrane bound organelles Larger and more advanced

Key concepts of microbial cell structure

Prokaryotic cells lack nucleus and enclosed membrane organelles Bacteria have a lot of membranes around : the inner, cytoplasmic membrane , the wall , the capsule.

Function of bacteria capsule

Protects the bacteria from human defense called phagocytosis

Cell wall deficient bacteria

RESISTANT TO PENICILLIN Because it acts on cell wall, not on protein. Do not have cell wall,L-phase or L-form bacteria, are bacterial variants that lack a cell wall, -mycoplasma SMALL, DO NOT HAVE STEROLS IN CELL MEMBRANE ONLY KILLED BY antibiotics that inhibit protein synthesis such as Tetracycline,erythromycin they resist β-lactam drugs such as penicillin, and may be able to evade the innate immune response. Contains both RNA & DNA

What is the selective permeability?

is one that allows certain molecules or ions to pass through it by means of active or passive transport.

Active movement

the cell uses ENERGY in the form of ATP to move substances across the plasma membrane, such as actively transported ions such as Na+, K+, H+, amino acids and simple sugars