Chapter 4 microbio

exam 1

eukaryotic cell has what and how does it compare to bacteria?

eukaryotic cell has nuclei which makes it more complex than bacteria. it also has membrane bound organelles.

how did complex multicellular organisms evolve?

over time cells aggregated—> cells within colonies became specialized—> complex multicellular organisms evolved which is how we got here

eukaryotic flagella:

• external structure for movement

• diff from bacteria flagellum= around 10 times thicker

• structurally more complex as it has microtubules—> makes it look diff from prokaryotic (bacterial and archaea) flagella

eukaryotic cilia:

external structure for movement

• not as common

• similar to flagellum structure but smaller and exist in a greater amount

• found only in a single group of protozoa and some animal cells

microtubules

inside flagella= extend along length of flagellum

• 9 pairs of microtubules surround a pair of flagellum

• 9+2 arrangement (in picture, notice the two flagellum in center)

• also exist in cilia

Protozoa and helminth cell wall:

neither possess a true cell wall. Instead…

Protozoa= pellicle (not the same one in biofilms)

helminth= cuticle or integument

both structures do exactly what a cell wall would do

fungi cell wall:

made up of…

• chitin= polymer of glucose

• glycoprotein

• mixed glycans= capsules

humans don’t make these structures for their cell wall

• fungi also have sterols (specifically ergosterol) like humans which makes it hard to distinguish during treatments like chemotherapy; basically means it’s hard to harm the fungi without harming host

cell membrane has different…

sterols

sterols provide stability, think of cholesterol

important in cells that don’t have cell wall

nucleus:

where transcription happens

• nuclear envelope= nuclear membrane= double layer membrane made of 2 phospholipid bilayers.

• endoplasmic reticulum= extensions of nuclear envelope; where proteins get made

• nuclear pore= big, protein-based channel that is the primary gateway for transport

• nucleolus= nonmembrane bound structure inside the nucleus—> produces and assembles rRNA and proteins

rough endoplasmic reticulum (rough ER)

where protein translation happens

• as transcription being made, it’s already being translated= translation and transcription happen at the same time

Golgi apparatus:

Golgi body gets modified in here

Golgi apparatus modifies, sorts, and packages proteins and lipids from ER into vesicles for final transport

transport process:

condensing vesicles fuse with cytoplasmic membrane to release contents

what is natures assembly line made up of and what is the sequence? (cell’s protein production and processing pathway)

nucleus, ER, and Golgi Apparatus

• DNA—> RNA—> ribosomes/RER (through nuclear pores)

  • transcription happens when you copy DNA to RNA, DNA is copied into mRNA which then exits via the nuclear pore)

  • Ribosomes (often attached to the RER) read the mRNA and translate it into a protein

Lysosomes in phagocytosis

lysosome= small organelle w/vesicles and oxygen radical species (oxygen radical species= super toxic, only to be used as tool to kill bacteria)

1) engulfment of food by cytoplasmic membrane (could also be pathogen instead of food)

2) food vacuole/phagosome formed= lysosome inside food vacuole is called a phagolysosome

3) lysosome and vacuole merge/join—> if it’s breaking down food or pathogen, there’s extra steps

4) digestion

mitochondria:

why we believe 2 cells fused at some point—> mitochondria and chloroplasts are evidence for the endosymbiotic theory

• has its own DNA—> “could almost be another organism”

• provides energy

  • prokaryotes use cytoplasmic membrane to make energy/ATP

• cristae= inner membrane folds

• matrix= inside the cristae

• has 70s ribosome

eukaryotic ribosomes:

• large subunit is 60s, small is 40s—> 60s+40s= 80s

• present throughout cell

  • cytoplasm and cytoskeleton

• Attached to the rough endoplasmic reticulum

• Appear inside mitochondria and chloroplasts

eukaryotic cytoskeleton:

more complex than bacteria one

cytoskeleton ability to remodel is really important

• white blood cells remodel for important immune functions

Bacterial/Archaeal cell characteristics

Genetics:

• has nucleic acids

• has chromosomes

Reproduction

• may or may not produce sex cells

• binary fission

Biosynthesis (converts simple precursor molecules (amino acids, sugars, nucleotides) into complex macromolecules (proteins, DNA, lipids) to sustain life)

• independent

• has ribosomes

Respiration- none

Photosynthesis

• may or may not have pigments

Motility/locomotor structures

• may or may not have flagella

Shape/protection

• membrane

• cell wall

• may or may not have glycocalyx (protective, barrier-forming, and signaling layer)

Complexity of function= yes

size= .5to 3 micrometers

eukaryotic cells characteristics:

Genetics:

• has nucleic acids

• has chromosomes

• has true nucleus

• has nuclear envelope

Reproduction

• mitosis

• produces sex cells

• binary fission

Biosynthesis (converts simple precursor molecules (amino acids, sugars, nucleotides) into complex macromolecules (proteins, DNA, lipids) to sustain life)

• independent

• Golgi apparatus

• endoplasmic reticulum

• has ribosomes

Respiration

• mitochondria

Photosynthesis

• may or may not have pigments

• may or may not have chloroplasts

Motility/locomotor structures

• may or may not have flagella

• may or not have cilia

Shape/protection

• membrane

• may or may not have cell wall

• may or may not have glycocalyx (protective, barrier-forming, and signaling layer)

Complexity of function= yes

size= 2- 300 micrometers

viruses characteristics:

Genetics:

• has nucleic acids

Shape/protection

• may have membrane (called an envelope if present)

• no cell wall (have capsids instead)

Complexity of function= may or may not be

size= .2micrometers

endosymbiosis:

symbiotic relationship where one organism lives inside body/cell if another—> explains origin of eukaryotic cell in which ancestral prokaryotes were engulfed by larger cells

• led to mitochondria and chloroplast formation

• bacteria engulfed by other descendants of last common ancestor (LCA) and become mitochondria/chloroplasts in eventual eukaryotic cells

Which of the following characteristics is evidence that

mitochondria evolved from bacterial cells?

A. Circular chromosome

B. Bacteria-like ribosomes

C. Capable of independent division

D. All of the choices are correct

D. All of the choices are correct

• mitochondria= DNA arranged in circular chromosome and replicate on their own (w/o host cell)

Which of the following organelles is responsible for protein

modification and distribution in the cell?

A. Nucleus

B. Golgi apparatus

C. Endoplasmic reticulum

D. Mitochondrion

E. Ribosome

B. Golgi apparatus

fungal cells:

can pose lot of damage to aquatic environments

2 basic cell forms:

• yeast= single cell, microscopic; oval/spherical in shape

  • pseudohyphae= chains of elongated, budding yeast cells that don’t detach after division; can’t see with the naked eye, you need a microscope

• hyphae= branching, thread-like tubular filaments

  • some types of hyphae fungi can be deadly

hyphae of molds:

long, single cell chains that can be tightly/loosley woven

hyphae of mold=haploid

• septate hyphae= cross walls called septa that divide hyphae into individual cells

• nonseptate hyphae= 1 tube that shares nuclei= no septa to create divisions

  • humans don’t have this because it causes catastrophic events for us

dimorphic fungus:

switch between 2 growth forms based on temperature

• mold in environment/soil is at cooler temps

• yeast in host cell is at warmer temps

3 types of fungal disease: community acquired infection

infection from day to day life, not hospital setting

• EX. covid, flu, pneumonia

3 types of fungal disease: hospital associated infection

infections patient get while they’re in the hospital for other conditions

• diff from opportunistic because this happens regardless of immune status of patient

3 types of fungal disease: opportunistic infection

patient has predisposing infections that have weakened the immune system and made them an easy target (think getting kicked while you’re already down)

• EX. vaginal yeast infection= everyone has candida fungi but if lactobacillus bacteria (good bacteria) is disturbed by something such as antibiotics, the candida can take advantage and grow

  • this is the system of opportunistic infection

fungi and human disease:

Nearly 300 species of fungi can cause human disease

Reactions – allergies and toxins

• all fungi are degraders and can grow on basically anything

• fungi make toxins that can make ppl really sick

• as long as they have something to break down, they’ll thrive

Asexual mold spores and the 2 major types

mold make spores for reproduction not survival like bacterial endospores

1) Sporangiospores= develop inside sac-like structure called sporangium

2) Conidiospores= exposed, naked spores produced in chains on conidiophores (specialized fungal stalks)

**major diff= enclosed vs. naked

From which sources can fungi derive nutrients?

A. Dead plants and animals

B. Living tissues

C. Rubber

D. Petroleum products

E. All of the choices are correct

E. All of the choices are correct

• dead plants/animals= decomposed by fungi

• living tissue= parasitic fungi

Protozoa:

unicellular eukaryotes

• single celled

• “primitive animals”

• Most are harmless, living in water and soil

• A few species are pathogens responsible for many infections

• single cell organism

  • can enter humans easier than multicellular organisms

  • easy to gauge their temp

    • below room temp= will be in a community

    • above room temp= will be in a person

• many protozoa do sexual reproduction

protozoa life cycle:

2 stages:

1) trophozoite= mature

• form that does the reproduction= form that actively causes infection

• some trophozoites turn into cyst while others only have the trophozoite form

• transmitted by direct contact or some type of vector

• active, motile, and feeding stage

2) cyst= infectious stage—> out in the environment and present in contaminated food or water= spreads disease

• Dormant, resting stage

• Resistant

  • cyst is survival structure and is meant to endure deprivation

• Can be dispersed

**apicomplexans= don’t have their own locomotion so they depend on other vectors

• apical complex= Used to attach to and penetrate host cells

life cycle of protozoa:

1) trophozoite= active, reproducing, feeding stage (flexible membrane)

2) cell rounds up and loses motility

3) mature cyst= dormant, resting stage

4) cyst wall breaks open

5) trophozoite is reactivated

**trophozoite vs. cyst= 2 very diff life forms even though they are the same organism

protozoa transmission:

Some protozoan groups exist only in the trophozoite phase

• Many alternate between the trophozoite and cyst stage, depending on the habitat

• protozoan parasites

  • Trichomonas vaginalis

  • Entamoeba histolytica and Giardia lamblia

• some protozoans don’t go in wild, they are passed person to person

protozoa reproduction

all reproduce via simple, asexual mitotic cell division or multiple fission

most protozoa also do sexual reproduction

major pathogenic protozoa: amoeboid protozoa (move and feed by changing shape, specifically through the extension of temporary, flowing cytoplasmic projections known as pseudopods)

**grouped based on how they move

Entamoeba histolytica

• disease: Amoebiasis (intestinal and other symptoms)

• reservoir/source (where do we find them when they’re not infecting people): humans, water, food

Naegleria, Acanthamoeba

• disease: brain infection

• reservoir/source: water

major pathogenic protozoa: Ciliated protozoa

Balantidium coli= only ciliated protozoa pathogenic of people

• disease: Balantidiasis (intestinal and other

  symptoms)

• reservoir/source: pigs, cattles, primates

major pathogenic protozoa: Flagellated protozoa

Giardia lamblia

• disease: Giardiasis (intestinal distress)

• reservoir/source: Animals, water, and food

Trichomonas vaginalis

• disease: Trichomoniasis (vaginal symptoms)

• reservoir/source: Human

Trypanosoma brucei, T.cruzi

• disease: Trypanosomiasis (intestinal distress and widespread organ damage)

• reservoir/source: animals, vector-borne (diseases transmitted to humans or animals by living organisms)

Leishmania donovani, L.tropica, L. brasiliensis

• disease: Leishmaniasis (either skin lesions or widespread involvement of internal organs)

• reservoir/source: animals, vector-borne

major pathogenic protozoa: Apicomplexan protozoa= uses gliding motility, lets them invade host cells without cilia, flagella, or pseudopodia

Plasmodium vivax, P. falciparum, P. malariae

• disease: Malaria (cardiovascular and other symptoms)

• reservoir/source: human, vector-borne

Toxoplasma gondii

• disease: Toxoplasmosis (flulike illness or silent infection)

• reservoir/source: animals, vector-borne

Cryptosporidium

• disease: Cryptosporidiosis (intestinal and other symptoms)

• reservoir/source: water, food

Cyclospora cayetanensis

• disease: Cyclosporiasis (intestinal and other symptoms)

• reservoir/source: water, fresh produce

The active, feeding, and motile stage of the protozoan life

cycle is the blank stage.

A. cyst

B. endospore

C. trophozoite

D. merozoite

E. All of the choices are correct

C. trophozoite

helminths:

microscopic

2 categories based on section through the worm being flat or circular:

1) flatworms (phylum Platyhelminthes)

• divided into cestodes (tapeworms) and trematodes (flukes)

2) roundworms (phylum Nematoda)

• aka Aschelminthes (ex. earthworm)

pathogenic flatworms

Tapeworm:

• very well developed reproductive system

• they are hermaphrodites

• tapeworm= absorbs

• scolex has suckers that will hook onto tissue lining of intestinal wall

• not motile, can’t move by themselves

• not much of a nervous system

• sectioning has eggs, will be able to see fertile mature eggs on cuticle

• cuticle matures as you move from the scolex

• mature eggs break off and end up in our soil or water and that’s how they infect people

  • person consumes the tapeworm and the eggs hatch in the intestinal lining

  • becuz they living in intestine, they dont have their own digestive system, they just mooching off host

Flukes:

• very small

• very thin

• have pharynx, esophagus, and intestine

• oral sucker will attach to tissue

• mostly full of testes and ovary

pathogenic roundworm:

• mostly full of testis and ovaries because they mostly just reproduce

• has mouth and digestive tract

• male is smaller than female

In pathogenic helminths, the most developed organ is the

________ tract

reproductive

helminth Reproduction comparison

• fertilized egg, larval, and adult stages—> worm

• Roundworms: sexes are separate and different in appearance

• Flukes: sexes can be separate or hermaphroditic (have both male and female sex organs)

• Tapeworms: generally hermaphroditi= self fertilizing

Helminth life cycle:

• transmit= 1st step= transmission via fecal matter or orally

• intermediate (secondary) host= 2nd step= sometimes is humans

• definitive (final) host= host where reproduction takes place; not always humans

• Transport host= intermediate that experiences no parasitic development

Sources for human infection= contaminated food, soil,

water, or infected animal

Examples of Helminths and How They Are Transmitted: intestinal roundworms (nematodes)

Infective in egg (embryo) stage:

• Ascaris lumbricoides

  • disease or worm: Ascariasis

  • host requirement: Humans

  • spread to humans via: Fecal pollution of soil with eggs

• Enterobius vermicularis

  • disease or worm: Pinworm

  • host requirement: Humans

  • spread to humans via: Close contact

Infective in larval stage:

• Trichinella spiralis= wiped out after standardizing food given to pigs (stopped feeding pigs straight trash and started an actual diet)

  • disease or worm: Trichina worm

  • required host: Pigs, wild mammals

  • spread to humans via: Consumption of meat containing larvae

Examples of Helminths and How They Are Transmitted: tissue roundworms (nematodes)

note they are not spread fecally or orally

Onchocerca volvulus

• disease or worm: River blindness

• required host: Humans, black flies

• spread to humans via: Fly bite

Dracunculus medinensis

• disease or worm: Guinea worm

• required host: Humans and Cyclops (an aquatic

  invertebrate)

• spread to humans via: Ingestion of water containing Cyclops

Examples of Helminths and How They Are Transmitted: flatworms—flukes

Schistosoma japonicum

• disease or worm: Blood fluke

• required host: Humans and snails

• spread to humans via: Skin penetration of larval stage

Examples of Helminths and How They Are Transmitted: flatworms—tapeworms

Taenia solium

• disease or worm: Pork tapeworm

• required host: Humans, swine

• spread to humans via: Consumption of undercooked or raw pork

Diphyllobothrium latum

• disease or worm: Fish tapeworm

• required host: Humans, fish

• spread to humans via: Consumption of undercooked or raw fish

life cycle of the pinworm (intestinal roundworms)

• most common helminth but it is benign

• common where small kids congregate—> day care

• hatch in the small intestine but mainly live, mature, and mate in the large intestine (colon) and rectum

• sexual reproduction

eggs are super sticky so kid can re-infect themselves or infect other kids via contact or leaving eggs on toys/surfaces

eggs emerge from anus—> scratching but contaminates hands—> eggs stuck on hands now—> swallowed= self infection, contact with another kid= cross infection

itching due to female worms laying eggs around the anus at night

Distribution and Importance of Parasitic Worms

• ~ 50 species of helminths cause human diseases

• Distributed in all areas of the world, not just developing areas

• more common in tropical areas

Differentiate among the flagellar structures of bacteria,

eukaryotes, and archaea

bacteria= motion is rotating, not membrane bound, structure is helical filament

eukaryotes= motion is whip-like bending, membrane bound, 9+2 microtubule

archaea= motion is rotating, not membrane bound, structure grows from base

List similarities and differences between eukaryotic and

bacterial cytoplasmic membranes

Similarities

• Phospholipid bilayer

• Selective permeability

• Embedded proteins

Bacterial Membrane

• No sterols

• Single membrane

• Simpler organization

Eukaryotic Membrane

• Sterols present (cholesterol)

• More complex signaling

Key difference:
Sterols + energy production site.

how do the nucleus, endoplasmic reticulum, and

Golgi apparatus act together with vesicles during the

transport process

• Nucleus → makes mRNA with instructions for proteins.

• Rough ER → ribosomes build and fold proteins.

• Vesicles → carry proteins from ER to Golgi.

• Golgi apparatus → modifies, sorts, and repackages proteins.

• Vesicles → deliver proteins to the cell membrane, lysosomes, or outside the cell.

List two detrimental and two beneficial activities of fungi

(from the viewpoint of humans)

Beneficial activities of fungi:

1. Food production – used in making bread, cheese, and beer.

2. Medicine – source of antibiotics like penicillin.

Detrimental activities of fungi:

1. Cause diseases – e.g., athlete’s foot, ringworm.

2. Spoil food – mold

List three general features of fungal anatomy.

• chitin

• mixed glycans

• glycocalyx

Differentiate among the terms heterotroph, saprobe, and

parasite.

heterotroph = can’t make its own food and relies on other organisms= general consumer

saprobe = type of heterotroph that eats dead matter

parasite = type of heterotroph that eats living host.

Explain the relationship between fungal hyphae and the

production of a mycelium

Fungal hyphae= thread-like filaments that grow and branch. When many hyphae intertwine and form a network, they create a mycelium, which is the main body of the fungus.

hyphae → network = mycelium.

Describe the protozoan characteristics that illustrate why

protozoa are informally placed into a single group

• Unicellular eukaryotes

• Heterotrophic

• Motile – move using cilia, flagella, or pseudopodia.

• Lack cell wall – unlike plants and fungi.

• Mostly aquatic

three means of locomotion exhibited by protozoa.

cilia, flagella, pseudopodia= temporary extensions of the cell body for crawling or engulfing food

Explain why a cyst stage might be useful to a protozoan.

cyst allows protozoan to survive harsh conditions and then re-emerge as a trophozoite when conditions are safe

Adulthood and mating of helminths occurs in the blank.

A. larvae

B. intermediate host

C. cyst

D. definitive host

E. egg

D. definitive host