MCB 2610: Eukaryotic Comparison and Antibacterials

is the glycocalyx an internal or external structure in a eukaryotic cell?

external structures

what is the glycocalyx in a eukaryotic cell?

Sticky carbohydrates extending from animal plasma membrane

- Bonded to proteins and

lipids in membrane→ glycoproteins

- Strengthens the cell surface

- Helps attach cells together

- Cell-cell recognition

how do eukaryotic cells move

flagella and cilia: make it move or "beat"

- microtubules

what are pseudopodia or pseudopods

- contain cytoplasm

- used for cellular locomotion

do have bacterial flagella have a different structure than eukaryotic flagella

YES: completely different structure

what do flagella help with

propel the cell through water

flagella in eukaryotic cells are

few and long: whip-like

cilia in eukaryotic cells are

short and many: vibration-like

what are microtubules

long hollow tubes made up of a protein called tubulin

how many parallel pairs of microtubules surround the central pair of microtubules

nine parallel pairs: 9 (outside) + 2 (inside) array

what causes the flagellum to bend

sliding of the microtubules relative to each other

- up and down sliding

EXAM Q: bacteria is powered by proton motor force, but eukaryotic cells are powered by...

ATP!

what are features of the cell wall in eukaryotic cells

- simpler than bacterial

- consists of polysaccharides

- if they lack cell walls, they will have some kind of protective layer on them

what is the flexible outer protein covering protozoa

pellicle

what polysaccharides consist in plants

cellulose

what polysaccharides consist in fungus

chitin - N-acetylglucosamine (NAG) units

what polysaccharides consist in yeast

glucan and mannan

what are differences in the eukaryotic plasma membrane

eukaryotic: contains carbohydrates to attach on sites for bacteria

- contain sterols and increase resistance to osmotic lysis

- eukaryotic and prokaryotic are very similar: in function and basic structure

EXAM Q: what is the biggest difference between eukaryotic and bacterial plasma membranes

ENDOCYTOSIS

- Phagocytosis: pseudopods extend and engulf particles (eating)

- Pinocytosis: membrane folds inward, bringing in fluid and dissolved substances (smaller molecules, opposite of phagocytosis)

- Receptor-mediated endocytosis: binding to a receptor then membrane folds in (turning on receptor)

what is phagocytosis

pseudopods extend and engulf particles: eating

what is pinocytosis

membrane folds inward, bringing in fluid and dissolved substances: smaller molecules (opposite of phagocytosis)

what is receptor-mediated endocytosis

binding to a receptor than membrane folds in: turning on receptor

what is the major difference in eukaryotic cytoplasm compared to bacteria

Eukaryotic has complex internal structure, consisting of small rods

(microfilaments, intermediate filaments, microtubules) = cytoskeleton

where do most metabolic reactions occur

cytoplasm

what are cytoplasm traits

- a semifluid, gelatinous, nutrient matrix

- provides support, shape and assists in transport of substances

- contains storage granules and a variety of organelles: each organelle has a specific function and organelle means little organ

what are the subunits of ribosomes in eukaryotic cells

60S: large subunit

40S: small subunit

= 80S

what are the two locations for 80S

- Free ribosomes: suspended in the cytosol, makes proteins that function in the cytosol

- Bound ribosome: attached to the outside of the endoplasmic reticulum, make proteins for insertion into membranes

what are free ribosomes

suspended in the cytosol,

makes proteins that function in the cytosol

what are bound ribosomes

attached to the outside of

the endoplasmic reticulum, make proteins

for insertion into membranes

what is the role of the nucleus in eukaryotic cells?

contains chromosomes

what is the role of the ER in eukaryotic cells?

transport network

what is the role of the Golgi complex in eukaryotic cells?

membrane formation and

secretion

what is the role of the lysosome in eukaryotic cells?

digestive enzymes

what is the role of the vacuole in eukaryotic cells?

brings food into cells and

provides support

what is the role of the mitochondrion in eukaryotic cells?

cellular respiration

what is the role of the chloroplast in eukaryotic cells?

photosynthesis

what is the role of the peroxisome in eukaryotic cells?

oxidation of fatty acids;

destroys H2O2

what is the role of the centrosome in eukaryotic cells?

consists of protein fibers and centrioles, important for cell division

what is contained in the nucleus of eukaryotic cells

- DNA

- Nuclear envelope: encloses the nucleus, covered in pores

- Pore complex: regulates entry and exit of proteins and RNAs, as well as large complexes of macromolecules

what is inside the nucleus of eukaryotic cells

- DNA is organized into discrete units: chromosomes

- Structures that carry genetic information

– Each chromosome contains one long linear DNA molecule associated

with many proteins (histones)

– These proteins and the DNA together are called chromatin.

- The number and composition of chromosomes and the number of genes

on each chromosome are characteristic of the particular species of

organism. (Human diploid cells have 46 chromosomes (23 pairs), Elephants have 56 chromosomes, Nematodes have 11 chromosomes)

DNA is organized into discrete units called

chromosomes

what does each chromosome of eukaryotic cells contain

one long linear DNA molecule associated

with many proteins (histones)

proteins (histones) and DNA together make...

chromatin

what are lysosomes

digestive compartments:

- Is membranous sac with acid environment

- Have hydrolytic enzymes (work well in an acid environment)

- cells use to digest various molecules without harming the cytoplasmic

components of the cell.

- Can digest bacteria

what are organelles for energy in eukaryotic cells

mitochondria

characteristics of mitochondria in eukaryotic cells

- “Power plants,” “powerhouses,” or “energy factories”

- Found in all eukaryotic cells- the power of the cell!

- ATP molecules are produced within mitochondria by cellular respiration

- Number of mitochondria varies depending on the activities of the cell.

- Can grow and divide

- Have own ribosome (70s)

- Circular DNA

what is the endosymbiont theory

- Double membranes

- Contain Ribosomes: produce own proteins

- Circular DNA

- Grow independent within the cell

what is endosymbiosis in modern cells

Examples of bacteria living inside a host, losing genes that are important for it's survival outside the host.

- Tsetse flies: blood meal from mammalian blood

how does Paramecium use endosymbiosis in modern cells

Paramecium ingests algae and uses them for photosynthesis

how can eukaryotes microorganisms be harmful

- depends on time of parasite (ex. protozoa: can cause significant human diseases)

- small amount needed to cause disease

- can be intracellular (inside cell) or extracellular (do not need cell)

- unable to withstand dying: cannot be free in the environment

- arthropod vectors

what are Protozoa

- Nonphotosynthetic, eukaryotic organisms

- Most protozoa are unicellular, free-living, and found in soil and water.

- Protozoans cells are

more animal-like than

plant-like

what characteristics do Protozoa have?

MOTILITY:

- Protozoa are sometimes divided into groups, based on their method of locomotion:

- Amebae move by means of pseudopodia

- Ciliates move by means of hairlike cilia,

- Flagellates move by means of whiplike flagella

what causes many human diseases

parasitic protozoa cause many human diseases

what is Chagas disease

the kissing bug

- usually confined to Tropics but weather gets warmer and migrates to the states

- "kisses" you on face and leaves parasite and people itch and then put it inside their bodies

- fever: some people will have no symptoms

- the bugs usually enter at night

what are Helminth

- another type of parasite

- part of life cycle is microscopic

- usually spread in microscopic form: roundworms and flatworms

what is Taeniasis?

tape worm that is found in cattle and pigs if not cooked properly

what is the study of fungi

mycology

scientists who study fungi are called

mycologists

where are fungi found

virtually everywhere: >600,000 different species

are fungi harmful or beneficial

some fungi are harmful, some are beneficial

what do fungi include

yeasts, molds, and fleshy fungi (mushrooms)

are fungi plants

NO, fungi are not plants; they are not photosynthetic

what are characteristics of fungi

- Cell walls contain a polysaccharide called chitin.

- Cell membranes contain ergosterols (antifungal drugs)

- Some fungi are unicellular (yeast), while others grow as Multicellular filaments called hyphae.

what are fungal spores

- Help classify fungi

- Spores are either asexual or

sexual

- Not like bacterial spores

- Can be harmful to breath in (Blastomycosis: Blastomyces

dermatitidis)

what are yeasts

type of fungi

where are yeasts found

- in soil and water

- on the skins of many fruits and vegetables

- on humans

what are yeasts used to make

Yeasts have been used for centuries to make wine and beer (Saccharomyces cerevisiae is a yeast used in baking)

what is Candida albicans

yeast most frequently isolated from human clinical specimens: can be a apart of micro biofilm and is only okay in small amounts

what is a fungal disease infection called

mycosis

what is it called when fungal pathogens cycle between hyphae and yeasr-like?

dimorphic

fungal disease characteristics

- chronic: long lasting

- fungi grow slow

- hard to treat

how are people at risk of fungal infections

- Strong antibiotics for a long period of time.

- Immunocompromised

what does it mean for a fungi to be a true pathogen

infect typically healthy hosts

(ex: respiratory infections, such as Histoplasmosis)

what are dermatophytes?

- True pathogens

- Infect skin, hair and nails

- Dermatophytic infections are "(Tinea or ring worm)"

RING WORM: caused NOT by a worm but fungus

- Some fungi can stimulate allergies or produce mycotoxins

what is the comparison of membrane structure in bacteria and eukarya

BOTH: have phospholipid bilayer

what is the comparison of lipid structure in bacteria and eukarya

BOTH: ester linkage and straight fatty acid chains

what is the comparison of sterols in bacteria and eukarya

bacteria have NO sterols

eukarya have sterols

what is the comparison of proteins in bacteria and eukarya

bacteria: HIGH abundance

eukarya: LOW abundance

what are the basic structural components of bacteria

- gram-positive: thick peptidoglycan layer (surface of peptidoglycan layer decorated by teichoic acid)

- gram-negative: thin peptidoglycan layer (outer membrane has phospholipid inner leaflet and lipopolysaccharide outer leaflet)

structure of flagella in bacteria vs. Eukarya

bacteria: non-flexible hollow helical filament and extends outside of cell membrane and cell wall

Eukarya: flexible and covered by cell membrane

assembly of flagella in bacteria vs. Eukarya

bacteria: Flagellin monomers are transported out inside of hollow flagella

Eukarya: Microtubule segments are transported out along the outside of the axoneme via an intraflagellar transport system

arrangement of flagella in bacteria vs. Eukarya

bacteria: Polar (one or multiple) and Peritrichous (multiple)

Eukarya: varies by cell type

motion of flagella in bacteria vs. Eukarya

bacteria: Motor in membrane turns flagella in a screw‐like motion and energy from a proton motive force

Eukarya: Slide microtubules gives a whip‐like motion to the flagella and energy from hydrolysis of ATP

what are bacteriostatic antimicrobial drugs

STATIC: slowed down or preventing further growth

- Prevent bacteria from growing

- tend to target bacterial protein synthesis and metabolic pathways

what are bactericidal antimicrobial drugs

- Kill bacteria

- Tend to target bacterial cell walls or cell membranes and nucleic acids

Bactericidal drugs might seem more

effective, but there are drawbacks like...

- Kills normal microbiota

- Can lead to a spike in bacterial toxin release that can be deadly (e.g., LPS)

what are antibacterial agents

used to treat bacterial diseases

what are antibiotics

a substance produced by a microorganism that kills or inhibits the growth of other microorganisms

what are semisynthetic antibiotics

Antibiotics that have been chemically modified to kill a wider variety of pathogens or reduce side effects are called (ex: ampicillin)

what is the narrow spectrum activity

a small or narrow range of different microbial types they affect (Example: Penicillin- works on Gram positive bacteria)

- if you know what infection you have, you have time to specifically pick out a antibacterial drug

what is the broad spectrum activity

affect a wider range of both Gram-negative and Gram-positive bacteria. ( save time, more destructive)

- not sure of infection or not enough time to find out

is penicillin bactericidal or bacteriostatic, what are some disadvantages?

(bactericidal) Natural

- Penicillin G (injected) and Penicillin V (Oral)

- Narrow spectrum of activity

- Very Susceptible to beta-lactamases: (on a plasmid)

what is a semisynthetic beta lactam

- Contain chemically added side chain

- Broad spectrum

- Side chains

- More stable in acidic environments

- More readily absorbed

- Less susceptible to deactivation

what do beta-lactams target

transpeptidases

what does a beta-lactam ring look like

what are non-beta-lactam antimicrobials that target bacterial peptidoglycan synthesis

- Glycopeptides: vancomycin

- Effective against Gram-positive organisms

- Preferred treatment for Clostridium difficile

what are the three ways bacteria can develop resistance

1. target alterations

2. drug inactivation

3. reducing drug concentrations

what are target alterations

altering the drug's target

what is drug inactivation?

Bacteria may produce enzymes that inactivate the drug

what is reducing drug concentrations

Limiting drug entry or pumping drugs out of cells

- naturally resistant: cell wall