Microbiology: A Systems Approach PowerPoint to accompany Microbiology: A Systems Approach Cowan/Talaro Chapter 5 Eucaryotic Cells and Microorganisms Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 5 Topics Eucaryotes External structures Internal structures Fungi Protists Helminths

Eucaryotes External and internal structures are more complex than procaryotes Examples of eucaryotes Yeast Protozoa Algae Helminths Animal cells

The structure of algae, yeast and protozoa. Fig. 5.2 The structure of three representative eucaryotic cells

External Structures Appendages Glycocalyx Cell wall Cell membrane Flagella Cilia Glycocalyx Cell wall Cell membrane

A flagellum enables locomotion, and is composed of microtubules, arranged in a 9 + 2 fashion. Fig. 5.3 The structure of microtubules

Paramecium have cilia, which are similar to flagella but are smaller and more numerous. Fig. 5.4 Structure and locomotion in ciliates

Glycocalyx Complex outer layer Protection Adherence polysaccharides and network fibers Protection Adherence Reception of signals from other cells and the environment

Cell wall Chitin Glycoprotein Mixed glycans

Cell membrane Various sterols within the membrane will increase rigidity and stability Some cells will only possess a membrane Embedded transport proteins

A representation of the glycocalyx, cell wall, and membrane. Fig. 5.5 Boundary structure

Internal Structures Nucleus Endoplasmic reticulum Golgi apparatus Mitochondria Chloroplast (photosynthetic cells only) Ribosomes Cytoskeleton

Nucleus Membrane bound organelle Chromatin- chromosomal DNA Nucleolus- site for RNA synthesis Histones-proteins that associate with DNA during mitosis

An electron micrograph section of the nucleus showing its contents. Fig. 5.6 The nucleus

Eucaryotic cell division involves mitosis, in which the cell and nucleus undergo several stages of change. Fig. 5.7 changes in the cell and nucleus

Endoplasmic reticulum (ER) Two types Rough endoplasmic reticulum (RER) Smooth endoplasmic reticulum (SER) Nuclear envelope form membrane for the ER

RER Coated with ribosomes Site of proteins synthesis Transport material from the nucleus to the cytoplasm and cell membrane Transitional vesicles

The rough endoplasmic reticulum (RER) is the site of protein synthesis and transport into the cistern. Fig. 5.8 The origin and detailed structure of the RER

Golgi apparatus Closely associated with the ER Site for protein modification Cisternae – noncontinuous membrane network Condensing vesicles

Transitional vesicles leave the ER and enter the Golgi apparatus,and condensing vesicles leave the Golgi apparatus. Fig. 5.9 Detail of the Golgi apparatus

Organelles cooperate in protein synthesis and transport. Fig.5.10 The transport process

Lysosomes are transitional vesicles that contain enzymes for digestion of food particles. Fig. 5.11 The origin and action of lysosomes in phagocytosis

Mitochondria Site of energy generation Cristae-folds of the inner membrane Matrix-consist of ribosomes, DNA, and enzymes

The structure of the mitochondria and its contents. Fig. 5.12 General structure of a mitochondrion

Chloroplast Site of photosynthesis Thylakoids- folded membrane containing the green pigment chlorophyll Stroma- surrounds the thylakoids

The thylakoid is the site for the transformation of solar energy to chemical energy, which is then used to synthesize carbohydrates in the stroma. Fig. 5.13 Detail of an algal chloroplast

Ribosomes Associated with proteins synthesis Present in the cytoplasm and the surface of the ER

Cytoskeleton Anchor organelles Cellular structural support Enable cell shape changes Two types Microfilaments Microtubules

Microfilaments allow movement of molecules in the cytoplasm, and microtubules maintain shape of the cell and enable movement of molecules within the cell. Fig. 5.14 A model of the cytoskeleton

Fungi Present in nature (ex. mushrooms) Medically important (ex. athlete’s foot) Industrially important (ex. fermentation)

Fungi Classification Morphology Reproduction (asexual and sexual)

Morphology and Reproduction Hyphae cell Septate nonseptate Yeast cells Single cells Pseudohypha Reproduction Asexual and sexual process

A scanning electron micrograph of the hyphae cells. Fig. 5.15 Diplodia maydis, a pathogenic fungus

A scanning electron micrograph of yeast cells, and the budding reproductive process . Fig. 5.16 Microscopic morphology of yeasts

An example of the mold Rhizopus, and its stages of hyphae reproduction. Fig. 5.18 Functional types of hyphae using the mold as an example.

Asexual spore formation involves the mitotic division of a single parental cell. Fig. 5.19 Types of asexual mold spores

Sexual spore formation involves the fusion of two parental nuclei followed by meiosis. Fig. 5.20 Formation of zygospores

Mushrooms undergo sexual spore formation. Fig. 5.22 Formation of basidiospores in a mushroom

Subkingdoms of Fungi Amastigomycota Perfect Imperfect Mastigomycota

Black bread mold is classified as a Amastigomycota (Perfect). Fig. 5.23 A representative Zygomycota

Penicillium is another example Amastigomycota (Perfect). Fig. 5.24 A common Ascomycota

Mycelium is classified as an Amastigomycota (Imperfect). Fig. 5.25 Mycelium and spores of a representative of Deuteromycota

Fungi are capable of causing superficial and systemic infections. Table 5.2 Major fungal infections of humans

Protista Algae Protozoa

Algae Photosynthetic Inhabitants of fresh and marine waters Most are not considered human pathogens Pathogens produce toxins (ex. red tide) Unique morphology enables identification

Algae contain green chlorophyll as well as other pigments which include yellow, red and brown. Fig. 5.26 Representative microscopic algae

Protozoa Complex structure and function Ectoplasm and endoplasm Pseudopods, flagella, cilia Inhabitants of fresh water and soil Heterotrophs Reproduction (asexual) Trophozoite Encystment

An example of the complex structure associated with the protozoa Trichomonas vaginalis. Fig. 5. 28 The structure of a typical mastigophoran

Typical life cycle associated with most protozoa. Fig. 5.27 The general life cycle exhibited by many protozoa.

Medically important protozoa Amoeboid protozoa Brain infections Flagellated protozoa Giardiasis Apicomplexan protozoa Malaria

Representation of pathogenic amoebas, and nonpathogenic shelled amoebas. Fig. 5.29 Examples of sarcodinians

Representation of a ciliated protozoa, which are generally free-living and harmless. Fig. 5.30 Selected ciliate representatives

Representation of an apicomplexa, which are considered an intracellular parasite. Fig. 5.31 Sporozoan protozoan

The cycle of transmission involves the protozoa, host and vectors. Fig. 5.32 Cycle of transmission in Chagas disease

The stages of development and transmission of amoebic dysentery in the human host. Fig. 5.33 Stages in the infection and transmission of Amoebic dysentery

Helminths Tapeworms Flukes Roundworms Unique structural morphology enables identification

Helminths are multicellular animals with organ-like systems. Fig. 5.34 Parasitic flatworms

The pinworm life cycle in the human host. Fig. 5.35 The life cycle of the pinworm, a roundworm

Humans serve as a host for the life cycle of many different parasitic helminths. Table 5.4 Major helminths of humans and their modes of transmission.