Eukaryotes

What are the basic differences again?

Characteristic Prokaryotes Eukaryotes

# of cells Unicellular Uni or multi

DNA shape DNA is circular, no histones

DNA in chromosomes w/histones

DNA location Free in cell In PM-bound nucleus

True organelles? No Yes

Ribosomes 70S 80S

First amino acid in protein

Formylmethionine Methionine

Cell wall? Yes-peptidoglycan No (animalia); Yes (plantae—cellulose); Fungi (chitin)

Reproduction Binary fission three ways to reproduce

Mitosis

Do they have flagella?• Some do!• Some also have cilia • Both made of 9+2 pattern of microtubules

Do they have cell walls?• Most do…

– Plantae (cellulose), fungi (chitin), protists (called the pellicle)– Cell wall is chemically simpler– Since no PPG, antibiotics do not harm eukaryotes

• Some have a glycocalyx– Animalia

How about a PM?

• Yes—all have– Very similar to

prokaryotes– Phospholipid bilayer

w/• Proteins• Cholesterol

• Fluid mosaic theory• Semi-permeable

membrane – For small items

• Endocytosis and exocytosis– For bigger items

What’s different about the cytoplasm?

• Contains– Cytosol– Organelles– Cytoskeleton

• Cytoplasmic streaming

What about the organelles?

• True organelle– membrane-

bound– Performs

specific function

• Eukaryotes have organelles

What is the nucleus?• DNA storage site• Director of _______

synthesis• Nuclear envelope• Nuclear pores• Nucleoli• Chromatin

What about eukaryotic DNA?

• DNA wrapped around histones

• Chromatin vs chromosomes

• Mitosis and meiosis– Neither in

prokaryotes

What are some of the organelles?• Endoplasmic reticulum

– Smooth– Rough

• Ribosomes– 80S (40S + 60S)– What is it in prokaryotes?– Chloroplasts and mitochondria have 80S

ribosomes• More on why this is later

What are some of the organelles?

What are some of the organelles?

• Golgi complex– Transport vesicle– Transfer vesicle—between cisterns– Secretory vesicles– Storage vesicles

• Lysosomes– Single

membrane

– Digestive enzymes

What are some of the organelles?

What are some of the organelles?

• Vacuoles– Space or cavity– Sometimes used

for endocytosis– Storage– Water retention

• Mitochondria (mitochondrion)– Inner membrane

= cristae– Filled with matrx– Have some DNA

and 70S ribosomes• More about why

later!

What are some of the organelles?

What are some of the organelles?

• Chloroplasts– Stacked

thylakoids– 70S

Ribosomes and DNA

– More on why later!

What is the cytoskeleton?

• Microfilaments• microtubules

Why is there DNA in mitochondria and

chloroplasts?

• Endosymbiotic theory

Types of Eukaryotes

A survey by kingdoms

Why should I care about microbial eukaryotes?

• Over half the world is infected with them!

• Some examples:– Malaria– Hookworm – Tapeworms– African

trypanosomiasis

What is the Kingdom Fungi?

• Macroscopic fungi• Microscopic fungi

Mycology: The Study of Fungi

What are the characteristics of fungi?

• Chitin• Hyphae

– pseudohyphae

• Heterotrophic– saprobes

• Yeasts vs. Hyphae• Dimorphic

What are the characteristics of fungi?

Yeasts

• Unicellular fungi• Fission yeasts divide

symmetrically• Budding yeasts divide

asymmetrically

Figure 12.3

Dimorphism

• Pathogenic dimorphic fungi are yeastlike at 37°C and moldlike at 25°C

Figure 12.4

How do fungi reproduce?

• Asexual spore– Formation

• Sporangiosphore• Conidiospore

– Arthrospore– Blastoconidium

• Chlamydospore

• Sexual spore formation

• Plasmogamy: Haploid donor cell nucleus (+) penetrates cytoplasm of recipient cell (–).

• Karyogamy: + and – nuclei fuse.

• Meiosis:Diploid nucleus produces haploid nuclei (sexual spores).

How do fungi reproduce?

Sexual Spores

• Zygospore: Fusion of haploid cells produces one zygospore.

Figure 12.6

Sexual Spores

• Ascospore: Formed in a sac (ascus).

Figure 12.7

Sexual Spores

• Basidiospore: Formed externally on a pedestal (basidium).

Figure 12.8

Fungal Diseases (Mycoses)

• Systemic mycoses: Deep within body• Subcutaneous mycoses: Beneath the skin• Cutaneous mycoses: Affect hair, skin, and

nails• Superficial mycoses: Localized, e.g., hair

shafts• Opportunistic mycoses: Caused by normal

microbiota or environmental fungi

Zygomycota

• Conjugation fungi• Coenocytic• Produce

sporangiospores and zygospores– Rhizopus, Mucor

(opportunistic, systemic mycoses)

Ascomycota

• Sac fungi• Septate• Produce ascospores and

frequently conidiospores.– Aspergillus

(opportunistic, systemic mycosis)

– Blastomyces dermatitidis, Histoplasma capsulatum (systemic mycoses)

– Microsporum, Trichophyton (cutaneous mycoses)

Basidiomycota

• Club fungi• Septate• Produce basidiospores

and sometimes conidiospores.– Cryptococcus

neoformans (systematic mycosis)

Fungi Positive Effects Negative Effects

Saccharomyces Bread, wine, beer Food spoilage

Trichoderma Cellulose used for juices and fabric

Cryphonectria parasitica (chestnut blight)

Taxomyces Taxol production Ceratocystis ulm (Dutch elm disease)

Entomorphaga Gypsy moth control

Economic Effects of Fungi

What is the kingdom Protista?

• Subkingdoms– Algae – Protozoa

What are the algae?

• Autotrophs– Photosynthetic

• Plankton • Red tide: diatoms

What are the protozoa?

• Unicellular• Heterotrop

hs• Encystment• Reproduce

– Asexually– Conjugatio

n

What are the protozoa?

• Classified on locomotion

Phylum Motility ExampleSarcodina Pseudopods

video

Amoeba

Mastigophora

Flagella rush hour

Euglena

Cilophora Cilia a relative Paramecium

Apicomplexa Non-mobile Plasmodium (pic above)

Can you give some pathogenic examples?

What are helminths?• Multicellular• Heterotrophs• Pathogenic groups

include:– Flatworms

• Tapeworms• Trematodes

– Roundworms

Humans as Intermediate Host

Figure 12.28

Remember!