Week 3-4 Bacterial Structure and Function

D

A patient presents with a persistent cough, fatigue, and a cloudy region on their chest x-ray. After gram staining and TEM examination, the lab work shows that the infectious agent lacks a cell wall. Select which of following organisms is the possible cause of the disease? A. Streptococcus pneumonia B. E. coli C. Staphylococcus aureus D. Mycoplasma species

A

All of the following are true about the prokaryotic outer membrane EXCEPT A. It is composed of a phospholipid bilayer. B. It is found only in Gram-negative bacteria. C. It contains porins. D. It contains a toxic component. E. It contains a lipopolysaccharide layer.

E

All of the following statements about prokaryotic flagella are correct EXCEPT A. They are driven by the proton motive force. B. They are found in both Gram-positive and Gram- negative bacteria. C. Their motor is embedded in the cell envelope. D. They are used for chemotaxis. E. They move with a whiplike motion

D

Archaea and Bacteria are most similar in terms of their.. A. genetics (DNA) B. cell wall structure C. cell membrane structure D. unicellular structure

A

Archaea and Eukarya are most similar in terms of their.. A. genetics (DNA) B. cell wall structure C. cell membrane structure D. unicellular structure

A

Archaea and Eukarya are most similar in terms of their... A. genetics (DNA) --> are somewhat similar in B. cell wall structure --> very different in both C. cell membrane structure --> very different in both D. unicellular structure --> very different in both

D. unicellular structure

Archaea and bacteria are most similar in terms of their.. A. genetics (DNA) --> why they are in different domains B. cell wall structure --> archaea has different type C. cell membrane structure --> archaea has monolayer D. unicellular structure

phospholipid bilayer; ester linkage; LPS

Bacteria have a cell membrane made of _______ where the head and tail is linked by _____ linkage. The outer membrane is made of _______

Cytoplasm; Cell membrane; Cell wall; Nucleoid; Flagellum

Bacterial Cell consists mainly; _____ = consists of a gel-like network _____ = encloses the cytoplasm _____ = covers the cell membrane _____ = non-membrane-bound area of the cytoplasm that contains the chromosome _____ = external helical filament whose rotary motor propels the cell

peptidoglycan

Bacterial specific macromolecule that holds the cell shape and protects the delicate cytoplasmic membrane

proteins; glycan/carbohydrate

Cell Wall in Prokaryotes (Bacteria): Made of peptidoglycan which is made of _____(amino acids) and ___________(sugar)

A.

If a bacterial species lacks a cell wall, a reasonable prediction about the environment where this species lives is that it A. experiences a constant solute concentration. B. undergoes extreme temperature fluctuations. C. is rich in nutrients. Since the microbe can divide D. rapidly, a cell wall would get in the way. D. experiences a constant temperature.

thickness; nutrients and antibiotics.

In a mycobacterial cell wall, the arabinogalactan layer adds _____ to the cell wall. The mycolate outer membrane and phenolic glycolipids limit uptake of ____ and _____

ether

In archaean cell membranes, ______ links betweenglycerol and fatty acids; allows archaea to survive extreme temperatures

cell membrane

In bacteria, the _______________ creates energy for the cell

D

In bacterial cells, A. transcription, translation, and DNA replication are all spatially separate. B. transcription and DNA replication can occur together, but translation is spatially separate from transcription and replication. C. transcription and translation occur together but not while DNA replication is occurring. D. transcription, translation, and DNA replication can all occur at the same time in the same cell compartment.

periplasm

In gram negative bacteria, the space filled with water bw inner and outer membrane is called the ____

capsules

In gram positive cells.. not all bacteria have a capsule

negative

In gram________ bacteria, cell membrane is another word for inner membrane

gram-negative

Is E. coli gram negative or gram positive?

DAD; LYS

Know diff in interbridge b/w gram-positive and gram-negative. Amino acid #3 is different. ____ replaced by ____. The interbridge is made of tetrapeptides(4 amino acids) linkage.

S-layer, LPS, outer membrane (Lipoprotein&phospholipid bilayer), periplasm, cellwall, inner cell membrane

List the layers from top to bottom of Gram-negative

S-layer, peptidoglycan wall w/ teichoic acid, cell membrane

List the layers from top to bottom of Gram-positive

proteins;

Membrane ________ are receptors of signals. They also offer structural support., and help with ion transport and energy storage.

Tuberculosis (TB)

Mycobacterial cell envelopes : Ex:___________ is hard to kill bc of multiple layers. -antibiotics cannot kill it. -hard to stain bc of lipids and mainly mycolic acids on surface preventing stain to get to cell wall

acid fast stain; heat

Mycobacteriums are hard to stain, must be stained by ________ which needs _____ to melt lipids to get into cell wall

mild pneumonia

Mycoplasms without a cell wall cause ____________ bc of lacking the cell wall

A and B Peptidoglycan consists of a repeating disaccharides (or sugar units), NAG and NAM, which are connected by polypeptides, or proteins.

Peptidoglycan is made up of? Click all that apply. A. sugar units B. proteins C. nucleic acids D. lipids

Passive transport; active transport

Polar molecules and charged molecules require transport through specific protein transporters. - -______ transport =molecules move along their concentration gradient -_______ transport = molecules move against their concentration gradient -Requires energy -Usually in the form of ATP hydrolysis (FYI, ATP = energy)

diffusion

Small uncharged molecules, such as oxygen, can penetrate the cell membrane by _______.

False; thats the inner membrane; The outer membrane is made of LPS

T or F: the outer membrane is made of phospholipid bilayer.

between the inner and outer membrane in the periplasm

The cell wall is located where in a gram negative bacteria?

turgor pressure

The cell wall maintains _________ . The cell wall is porous but covalent bonds create _____ that protects the cell from osmotic shock

5

The interbridge consists of ___ glycineamino acids (pentaglycine interbridge)

O-polysaccharide; Lipid A

The neck of the LPS is called; The legs of the LPS is _____ and is an endotoxiin

LPS

The outer membrane is made of ___

amino acids; philic

The phospholipid bilayer in bacteria is made of _________ which are hydro______ and make up inner part of membrane.

B

The terms "peritrichous," "lophotrichous," and "monotrichous" describe the A. distribution of the nucleoid within a bacterium. B. distribution of flagella around a bacterium. C. shape of bacterial cells. D. means by which a bacterium obtains energy.

D Functions of bacterial cell membrane Energy generating functions, involving respiratory and photosynthetic electron transport systems, establishment of proton motive force, and transmembranous, ATP-synthesizing ATPase

What is the structure in prokaryotes that performs the same function as mitochondria in eukaryotes? A. Chloroplast B. Outer membrane C. Cell wall D. Cell membrane

.C. Mycolic acid is a waxy lipid in the genera Mycobacterium and Nocardia which increases their pathogenicity and provides protection

Which of following lipids are deposited in the bacterial cell wall of Mycobacterium tuberculosis and act as a protective cell barrier as well as increasing the bacterial pathogenicity? A. lipopolysaccharides B. cholesterol C. mycolic acid D. steroids

B

Which of the following cellular components is considered an endotoxin that is harmless as long as the pathogen remains intact but when released by a lysed cell overstimulates host defenses, which may result in a lethal endotoxic shock? A. Periplasmic proteins B. Lipopolysaccharides C. The cell wall D. Inner membrane phospholipids

C.

Which of the following is NOT a component of peptidoglycan? A. N-acetylmuramic acid B. N-acetylglucosamine C. Lipopolysaccharide D. Amino acids E. Peptide cross-links

hydrophilic

______ sugars cannot pass through hydrophobic part of membrane bilayer.

proteins

________ act as pump in transport: passive transport-does not require energy active transport-requires energy in form of ATP hydrolysis

Mycoplasm; if inside another cell it can survive in isotonic environment

_________ lack a cell wall How do they survive?

cell envelope

cell membrane, capsule, and cell wall are part of ___ which covers everything

cell wall

largest structure of bacterial cell

hydrophilic; hydrophobic

phospholipids have _____ heads and _____ tails

positive

teichoic acids are only found in gram-____ bacteria

phospholipids; proteins

what makes up the bacterial cell membrane?

At neutral pH, amino acids each have both a positively charged amine and a negatively charged carboxylate; that is, they can act as either a weak acid or a weak base.Charged ions, no matter what their size, will not freely pass through a plasma membrane. In an amino acid, if either charged group becomes neutralized by acid or base, the other group remains charged, so the molecule as a whole will never cross the membrane.

Amino acids have acidic and basic groups that can dissociate. Why are they not membrane-permeant weak acids or weak bases? Why do they fail to cross the phospholipid bilayer?

positive; negative

Antibiotics only kill gram _____ bacteria bc peptidoglycan is bigger and harder to miss and also penicillin cannot penetrate lipid layer of gram _____ bc the lipid layer is not soluble

Ether links; high ; terpenoids

Archaea have the most extreme variations in phospholipid side-chain structures. -____ between glycerol and fatty acids -Help to grow at ____ temperature -Hydrocarbon chains are branched __________

ether; temperature; acidity; diglycerol tetraethers

Archaeal membranes have ____-linked terpenoids which confer increased stability at high ______ and extreme _____. Some archaea have _________, which form a monolayer

terpenoids; monolayer

Archaeal membranes have ether-linked ________ which confer increased stability at high temperature and extreme acidity. Some archaea have diglycerol tetraethers, which form a _____

negative

Bacterial cells are protected by a thick cell envelope. The envelope includes a cell membrane and a peptidoglycan cell wall. A Gram-____ cell includes an outer membrane, and the cell membrane is called the inner membrane.

negative

By killing gram _____ cells, you may release alot of endotoxins

fractionation; lysis and ultracentrifugation.

Cell ______ isolates cell parts for structural and biochemical analysis. The compartments of a Gram-negative cell can be separated by cell ______ and ______

phospholipid bilayer; ester linked

Cell membrane. It is made of ________. Phospholipids are ______.

bidirectionally; replisome;

DNA is replicated ________ by the ______. During bacterial DNA replication, genes continue transcription and translation.

mutants

Genetic analysis of _____ reveals functions of cell parts. Genetic analysis complements cell fractionation.

positive; negative

Gram -______ cells only have one membrane unlike gram-______

one or two; outer membrane; -Lipoprotein -Phospholipid; Lipopolysaccharides (LPS); Porins

Gram negative: Consists of ___ or ___ sheets of peptidoglycan Covered by an ______ -Inward-facing leaflet includes -________ -________ Outward-facing leaflet contains: -________ -_______: serve as channel for ions and small molecules ^^^^ gram negative

teichoic acids; NAM(N-acetylmuramic acid); D-alanine; tetrapeptide

Gram positive bacteria (thick cell wall) -Multiple PG layers threaded by ________. -teichoic acid attaches to ______ or the ______ of the ___peptide ^^^Gram-positive

gram negative

Gram positive or gram negative?

B

Gram-positive and Gram-negative cells will have different color when Gram stained properly. For each step of the Gram-stain procedure, predict the colors of a Gram-positive or Gram-negative cell if decolorizer (alcohol)​ step were omitted during staining. A> Gram-positive cells would be purple. The Gram-negative cells would be colorless. B. Gram-positive and Gram-negative would both be purple. C. Gram-positive and Gram-negative would both be pink. D. Gram-positive cells would be purple. The Gram-negative cells would be pink.

C

Gram-positive and Gram-negative cells will have different color when Gram stained properly. For each step of the Gram-stain procedure, predict the colors of a Gram-positive or Gram-negative cell if mordant (iodine) step were omitted during staining. A. Gram-positive cells would be purple. The Gram-negative cells would be colorless. B. Gram-positive and Gram-negative would both be purple. C. Gram-positive and Gram-negative would both be pink. D. Gram-positive cells would be colorless. The Gram-negative cells would be pink.

A

Gram-positive and Gram-negative cells will have different color when Gram stained properly. For each step of the Gram-stain procedure, predict the colors of a Gram-positive or Gram-negative cell if primary stain (crystal violet) step were omitted during staining. A. Gram-positive and Gram-negative would both be pink. B. Gram-positive and Gram-negative would both be purple. C. Gram-positive cells would be purple. The Gram-negative cells would be colorless. D. Gram-positive cells would be colorless. The Gram-negative cells would be pink

A

Gram-positive and Gram-negative cells will have different color when Gram stained properly. For each step of the Gram-stain procedure, predict the colors of a Gram-positive or Gram-negative cell if secondary stain (safranin)​ step were omitted during staining. A. Gram-positive cells would be purple. The Gram-negative cells would be colorless. B. Gram-positive and Gram-negative would both be purple. C. Gram-positive and Gram-negative would both be pink. D. Gram-positive cells would be colorless. The Gram-negative cells would be purple

phagocytosis; shape; osmotic stress

Gram-positive: The capsule (c) -Made of polysaccharide and glycoprotein -Protects cells from ________ -Also found in some Gram negative bacteria S-layer (s) -Found in both free-living bacteria and archaea -Consisting of protein or glycoprotein -Helps with cell _____ and protect cell from _______

-Cell wall -Few prokaryotes, such as the mycoplasmas, have no cell wall -They can cause pneumonia -

How do prokaryotes protect their cell membrane?

Arabinan forms ester links to mycolic acids

In a bacterial cell envelope what does the ester linkage form between?

both free-living bacteria and archaea; protein and glycoprotein

In what are S-layers found? What makes up S-layers?

A. N-terminal cysteine triglyceride; m-diaminopimelic; C-terminal lysine; B. Lipopolysaccharide (LPS); phosphoglucosamine; O antigen

Lipoprotein and lipopolysaccharide. A. Murein lipoprotein has an ________________ inserted in the inward-facing leaflet of the outer membrane. The _______ forms a peptide bond with the ______________ acid of the peptidoglycan (murein) cell wall. B. ___________ consists of branched and unbranched short-chain fatty acids linked to a dimer of ____________. One glucosamine is linked to a core polysaccharide extending out from the cell, which is attached to about 40 repeating units of a polysaccharide known as _______. C. Lack of murein lipoprotein in mutant Salmonella bacteria causes the outer membrane to balloon out (arrow), when the cell tries to divide (TEM).

Structural support, Detect environmental signals, Ion transport and energy storage

Membrane proteins serve numerous functions: - - -

Polar; charged

Membrane: _______ molecules and ______ molecules require transport through specific protein transporters... active transport and passive transport.

outer envelope; genome; cell functions

Most bacteria share fundamental traits: -Thick, complex ____________ -Compact _________ -Tightly coordinated __________ Archaea, like bacteria, are prokaryotes - Have unique membrane and envelope structures

peptidoglycan (PG); N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).; 4 to 6 amino acids.

Most bacterial cell walls are made up of ________.. The PG molecule consists of: - ______ and ______ -PG layers are bound to each other by a peptide of __ to __ _______________.

mycolic acids

Mycobacteria of the phylum Actinomycetes have a complex multilayered envelope that includes defensive structures such as ______. Examples include Mycobacterium tuberculosis, the cause of tuberculosis, and M. leprae, the cause of leprosy.

galactose polymer (galactan); arabinose polymer (arabinan); phospholipids and phenolic glycolipids

Mycobacterial envelope structure. A complex cell wall includes a peptidoglycan layer linked to a chain of ____________(___) and __________(___). Arabinan forms ester links to mycolic acids, which form an outer bilayer with phenolic glycolipids. Outside the outer bilayer is a capsule of loosely associated _________ and ______.

ester; phenolic glycolipids; capsule

Mycobacterial envelope structure. A complex cell wall includes a peptidoglycan layer linked to a chain of galactose polymer (galactan) and arabinose polymer (arabinan). Arabinan forms ______ links to mycolic acids, which form an outer bilayer with ________. Outside the outer bilayer is a ______ of loosely associated phospholipids and phenolic glycolipids.

bacteria; antibiotics; transpeptidase; D-Ala-D-Ala dipeptide; -MRSA (methicillin-resistant S. aureus) -VRSA (vancomycin-resistant S. aureus)

Peptidoglycan (PG) is unique to ______ -Excellent targets for _______ -Penicillin inhibits the ______ that cross-links the peptides -Vancomycin prevents cross-bridge formation by binding to the terminal ____________ -Antibiotics resistant strains - -

vancomycin; penicillin

Peptidoglycan cross-bridge formation. . A disaccharide unit of glycan has an attached peptide of four to six amino acids. The amino terminus of the peptide forms an amide bond with the lactate group of muramic acid. On the peptide, the extra amino group of m-diaminopimelic acid can cross-link to the carboxyl terminus of a neighboring peptide. The connection of D-alanine to the peptide is blocked by ______, which binds D-Ala-D-Ala. The cross-bridge formation by transpeptidase is blocked by _______.

E. coli= gram-negative S. aureus= gram-positive

Peptidoglycan in Escherichia coli and Staphylococcus aureus.

glycerol; ethanolamine

Phosphatidylethanolamine contains a _______ linked to two fatty acids, and a phosphoryl group with a terminal _________which carries a positive charge.

ether; methyl ; fused; tetraethers; monolayer

Terpene-derived lipids of archaea. In archaea, the hydrocarbon chains are ____ linked to glycerol, and every fourth carbon has a _______ branch. In some archaea, the tails of the two facing lipids of the bilayer are________ , forming ______; thus, the entire membrane consists of a single layer of molecules (a ________).

positive; negative ;

The Gram stain distinguishes between Gram-_______ cells, with thick cell walls, which retain the crystal violet stain, and Gram- _____ cells, with thinner cell walls, which lose the crystal violet stain but are counterstained by safranin.

outer membrane; positive; negative; negative

The Gram-______ cell has a thick cell wall with multiple layers of peptidoglycan, threaded by teichoic acids. The cell wall may be covered by an S-layer and a capsule (not shown). The Gram-_____ cell has a single layer of peptidoglycan covered by an ______ _____. Some Gram-negative species include an S-layer or a capsule (not shown). The cell membrane of Gram-_______ species is called the inner membrane.

nucleoid; nucleoid

The Nucleoid, RNA and Protein: -Eukaryotic cells have a nucleus -Prokaryotic cells have a ______ -region in cytoplasm that contain chromosomes -The _______ forms about 50 loops or domains.

phagocytosis; archaea

The S-layer of proteins is highly porous but can prevent _________ and protect cells in extreme environments. In _________, the S-layer serves the structural function of a cell.

S-layer; S-layer

The _______ of proteins is highly porous but can prevent phagocytosisand protect cells in extreme environments. In archaea, the ________ serves the structural function of a cell.

mycobacterial ; arabinogalactan; mycolate outer membrane; phenolic glycolipids

The __________ cell wall includes features of both gram positive and gram negative cells. The _______ layer adds thickness to the cell wall. The _________ and __________ limit uptake of nutrients and antibiotics.

hydrophobic fatty acid; hopanoids; cholesterol; proteins.

The bacterial cell membrane consists of a phospholipid bilayer, with ________ ______ _____ chains directed inward, away from water. The bilayer contains stiffening agents such as ________, which serve the same function as ________ in eukaryotic membranes. Half the volume of the membrane consists of ________.

nutrient ; toxins; LPS; porins

The gram negative outer membrane regulates _______ uptake and excludes ______. The outer membrane contains_______and protein ______ of varying selectivity.

50; domains

The nucleoid forms about ___ loops or _______.

leaflets

The two layers of phospholipids are called ______

RNA polymerase; messenger RNA.; mRNA; polypeptide; transfer RNA (tRNA); prokaryotes

Transcription and Translation: RNA synthesis COUPLED to protein synthesis. As the DNA sequence is transcribed into a strand of messenger RNA, ribosomes already start translating the RNA to synthesize proteins. ________ transcribes DNA into a single strand of RNA-For most genes, it is _____. _______ immediately binds to a ribosome for translation into a _____. This is aided by _______, which brings the amino acids to the ribosome. In ________, translation is tightly coupled to transcription.

nucleus; cytoplasm

Transcription occurs in the ____ translation occurs in the ____

Having multiple layers of peptidoglycan increases the cell's resistance to osmotic shock, to desiccation stress, and to enzymes that cleave the cell wall. On the other hand, it requires more energy and biomass to build the layers of peptidoglycan. In addition, a thick cell wall could slow the uptake of nutrients. The mycobacteria, which have exceptionally thick cell walls, grow relatively slowly.

What do you think are the advantages and limitations of a cell's having one layer of peptidoglycan (Gram-negative) versus several layers (Gram-positive)?

made of polysaccharide and glycoprotein

What is the capsule made of?

Have hydrophilic and hydrophobic regions that lock the protein in the membrane.

What locks proteins into the membrane?

A common means of resistance to antibiotics is to pump them out of the cell. A protein pump that effluxes other molecules might mutate to capture vancomycin and export it from the cell. Another possibility is that an enzyme could modify the vancomycin by adding phosphoryl groups or acetyl groups, which would prevent the antibiotic from binding the alanine dipeptide. Still another possibility is that the bacteria might evolve a thicker cell wall that would exclude the vancomycin from the inner layers of peptidoglycan

What other ways can you imagine that bacteria might mutate to become resistant to vancomycin?

C and D Ebola virus can be readily viewed with both scanning and transmission electron microscopy. It is too slender to be viewed with any type of light microscopy.

What types of microscopy have provided the most information about the structure and morphology of Ebola virus? A. dark field microscopy B. bright field microscopy C. transmission electron microscopy D. scanning electron microscopy E. phase contrast microscopy

A

When properly Gram-stained, Gram-positive and Gram-negative will have ______ and ______ color respectively. A. Purple and Pink B. Pink and Purple C. Purple and colorless D. Pink and colorless

A. Remember that both Gram-positive and Gram-negative cells will have the combined crystal violet-iodine complex in the cell wall before the decolorizing agent is applied. Gram positive cells will be able to retain the purple colored complex whereas Gram negative cells will lose the complex after the application of a decolorizer acetone alcohol.

You are performing Gram staining on a heat-fixed smear of E. coli culture. You have already completed the steps of application of a primary stain crystal violet and a mordant iodine. If you observe the slide under the microscope at this step, what will be the color of the cells? A. purple B. pink C. colorless D. any of the above is possible

cell membrane; cell membrane ; mitochondria

_____ is the structure that defines the cell _______ is also used for energy production similar to _________ of eukaryotic cells

Fluorescence

_____ microscopy reveals the location and dynamics of individual components.

polar; charged; facilitated

_____ molecules and ______ molecules require membrane proteins to mediate transport. Such _____ transport can be active or passive

the capsule

_______ , composed of polysaccharide and glycoprotein filaments, protects cells from phagocytosis. Both gram positive and gram negative can have this.

mycoplasmas

_______ cause pnemonia and are prokaryotes without a cell wall.

Transmission electron

________ microscopy shows how cell parts fit within the cell as a whole.

Eukaryotic

_________ cells have a nucleus and extensive membranous organelles

Membrane proteins

_________ serve diverse functions, including transport, cell defense, and cell communication.

periplasm

cell wall is submerged in water filled space called...

weak acids and weak bases

membrane-permanent _____________ exist partly in an uncharged form that can diffuse across the membrane to either increase or decrease the H+ concentration within a cell.