Presentation is loading. Please wait.

Presentation is loading. Please wait.

1 Eukaryotic Cells The History of Eukaryotes They first appeared approximately 2 billion years ago. Evidence suggests evolution from prokaryotic organisms.

Similar presentations


Presentation on theme: "1 Eukaryotic Cells The History of Eukaryotes They first appeared approximately 2 billion years ago. Evidence suggests evolution from prokaryotic organisms."— Presentation transcript:

1 1 Eukaryotic Cells The History of Eukaryotes They first appeared approximately 2 billion years ago. Evidence suggests evolution from prokaryotic organisms by symbiosis. Organelles originated from procaryotic cells trapped inside them. -> Endosymbiosis

2 2 Endosymbiosis Algae

3 3 Eukaryotic Cells Eukaryotic Organisms in Microbiology

4 4 Eukaryotic Cells Form and Function of the Eukaryotic Cell

5 5 Eukaryotic Cells Form and Function of the Eukaryotic Cell

6 6 Eukaryotic Cells External Structures Locomotor appendages Flagella -> long, sheathed cylinder containing microtubules in a 9+2 arrangement -> covered by an extension of the cell membrane -> 10X thicker than prokaryotic flagella -> function in motility Cross section -> arrangement of proteins Longitudinal section Locomotor pattern

7 7 Eukaryotic Cells External Structures Locomotor appendages Cilia -> similar in overall structure to flagella, but shorter and more numerous -> found only on a single group of protozoa and certain animal cells -> function in motility, feeding and filtering Structure Locomotion

8 8 Eukaryotic Cells External Structures Glycocalyx - an outermost boundary that comes into direct contact with environment environment - usually composed of polysaccharides - appears as a network of fibers, a slime layer or a capsule - functions in adherence, protection, and signal reception - beneath the glycocalyx -> Fungi and most algae have a thick, rigid cell wall. -> Protozoa, a few algae, and all animal cells lack a cell wall and have only a membrane. have only a membrane.

9 9 Eukaryotic Cells External Boundary Structures Cell wall - rigid, provides structural support and shape -> Fungi have thick inner layer of polysaccharide fibers composed of chitin or cellulose and a thin layer of mixed glycans. -> algae – varies in chemical composition; substances commonly found include cellulose, pectin, mannans, silicon dioxide, and calcium carbonate

10 10 Eukaryotic Cells External Boundary Structures Cytoplasmic (cell) membrane - typical bilayer of phospholipids and proteins - sterols confer stability - serves as selectively permeable barrier in transport - Eucaryotic cells also contain membrane-bound organelles that account for 60-80% of their volume.

11 11 Eukaryotic Cells Internal Structures

12 12 Eukaryotic Cells Internal Structures - compact sphere, most prominent organelle of eukaryotic cell cell - nuclear envelope composed of two parallel membranes separated by a narrow space and is perforated with pores separated by a narrow space and is perforated with pores - contains chromosomes - nucleolus – dark area for rRNA synthesis and ribosome assembly assembly Nucleus

13 13 Eukaryotic Cells Internal Structures Nucleus Cell division -> Mitosis 1.Replication of Chromosomes 2.Separation of replicated Chromosomes into 2 cells

14 14 Eukaryotic Cells Internal Structures Endoplasmic reticulum – two types: Rough endoplasmic reticulum (RER)– Rough endoplasmic reticulum (RER)– originates from the outer membrane of the nuclear envelop and extends in a continuous network through cytoplasm; rough due to ribosomes; proteins synthesized and shunted into the ER for packaging and transport; first step in secretory pathway Smooth endoplasmic reticulum (SER)– Smooth endoplasmic reticulum (SER)– closed tubular network without ribosomes; functions in nutrient processing, synthesis and storage of lipids, etc. Rough Endoplasmic reticulum

15 15 Eukaryotic Cells Internal Structures Golgi apparatus - consists of a stack of flattened sacs called cisternae - closely associated with ER - Transitional vesicles from the ER containing proteins go to the Golgi apparatus for modification and maturation. Golgi apparatus for modification and maturation. - Condensing vesicles transport proteins to organelles or secretory proteins to the outside. -> The secretary pathway

16 16 Eukaryotic Cells Internal Structures Lysosomes -> vesicles containing enzymes that originate from Golgi apparatus used for breaking down material -> Trash bin of the cell !!! -> involved in intracellular digestion of food particles and in protection against invading microbes (Phagocytosis) and -> involved in intracellular digestion of food particles and in protection against invading microbes (Phagocytosis) and absorbing any material (molecules) from outside (Endocytosis)

17 17 Eukaryotic Cells Internal Structures Mitochondria - consists of an outer membrane and an inner membrane with folds called cristae cristae - Cristae hold the enzymes and electron carriers of aerobic respiration. - divide independently of cell - contain DNA and procaryotic ribosomes - function in energy production

18 18 Eukaryotic Cells Internal Structures Chloroplast - found in algae and plant cells - outer membrane covers inner membrane folded into sacs, thylakoids, stacked into grana - larger than mitochondria - contain photosynthetic pigments - convert the energy of sunlight into chemical energy through photosynthesis photosynthesis - primary producers of organic nutrients for other organisms

19 19 Eukaryotic Cells Internal Structures Ribosomes - composed of rRNA and proteins - 40S and 60S subunits form 80S ribosomes - larger than procaryotic ribosomes (70S) - function in protein synthesis 30S 50S70S

20 20 Eukaryotic Cells Internal Structures Cytoskeleton - flexible framework of proteins -> microfilaments and microtubules - form network throughout cytoplasm - involved in movement of cytoplasm, amoeboid movement (motility), transport, and structural support transport, and structural support

21 21 Eukaryotic Cells Eukaryotic Microbes -> Fungi -> Algae -> Protozoa -> Parasitic worms

22 22 Eukaryotic Cells Kingdom Fungi 100,000 species divided into 2 groups: -> macroscopic fungi (mushrooms, puffballs, gill fungi) -> microscopic fungi (molds, yeasts) Majority are unicellular or colonial; a few have cellular specialization

23 23 Microscopic fungi Slime mold Yeast

24 24 Macroscopic fungi

25 25 Eukaryotic Cells Microscopic fungi Exist in two morphologies: -> yeast – round ovoid shape, asexual reproduction, unicellular -> hyphae – long filamentous fungi or molds Some exist in either form – dimorphic: mold-like at low temperature, yeast like at 37 degrees C, characteristic of some pathogenic molds

26 26 Eukaryotic Cells Macroscopic and Microscopic view – Molds/fungi Mixed cultures of mold Hyphal structures Structural types of hyphae

27 27 Eukaryotic Cells Macroscopic and Microscopic view - Yeast Morphology of yeast

28 28 Eukaryotic Cells Fungal Nutrition -> All are heterotrophic (org. Carbon Source) -> Majority are harmless saprobes living off dead plants and animals dead plants and animals -> Some are parasites, living on the tissues of other organisms, mycoses – fungal infections other organisms, mycoses – fungal infections -> Growth temperature 20 o -40 o C -> Extremely widespread distribution in many habitats habitats Mycellium growing on raspberries Fungus growing on skin

29 29 Eukaryotic Cells Fungal Organization -> Most grow in loose associations or colonies -> Yeast – soft, uniform texture and appearance -> Filamentous fungi – mass of hyphae called mycelium; cottony, hairy, or velvety texture hairy, or velvety texture - hyphae may be divided by cross walls – septate - hyphae may be divided by cross walls – septate - vegetative hyphae – digest and absorb nutrients - vegetative hyphae – digest and absorb nutrients - reproductive hyphae – produce spores for reproduction - reproductive hyphae – produce spores for reproduction

30 30 Eukaryotic Cells Fungal Organization

31 31 Eukaryotic Cells Fungal Reproduction - Asexual -> All Fungi have asexual reproduction !!! -> Primarily through spores formed on reproductive hyphae -> Asexual reproduction – spores are formed through budding or mitosis; conidia or sporangiospores

32 32 Eukaryotic Cells Fungal Reproduction - Sexual -> Sexual reproduction – spores are formed following fusion of male and female strains and formation of sexual structure and female strains and formation of sexual structure -> Sexual spores and spore-forming structures are one basis for classification. classification.

33 33 Eukaryotic Cells Fungal Reproduction – sexual -> Zygospores– diploid spores (2n) are formed following fusion of male and female strains and female strains zygospore germinates -> meiosis occurs -> haploid vegetative cells are zygospore germinates -> meiosis occurs -> haploid vegetative cells are released. released. -> Ascospores – haploid spores (n), formed following fusion of male and female strains in fungal sac -> ascus and female strains in fungal sac -> ascus zygote (fused) cells undergo meiosis -> formation of haploid spores zygote (fused) cells undergo meiosis -> formation of haploid spores

34 34 Eukaryotic Cells Fungal Reproduction – sexual -> Ascospores in a fruit body Ascomycetes -> Penicillium

35 35 Eukaryotic Cells Fungal Reproduction – sexual -> Basidiospores – haploid sexual spores in a fruit body Basidiomycetes Fruit body

36 36 Eukaryotic Cells Fungal Classification Subkingdom Amastigomycota – terrestrial -> inhabitants including those of medical importance: Fungi perfecti (sexual + asexual spores): -> Zygomycota – zygospores; sporangiospores and some conidia -> Zygomycota – zygospores; sporangiospores and some conidia -> Ascomycota – ascospores; conidia -> Ascomycota – ascospores; conidia -> Basidiomycota – basidiospores; conidia -> Basidiomycota – basidiospores; conidia Fungi imperfecti (just asexual cycle know until now): -> Deuteromycota – majority are yeasts and molds; no sexual spores known; conidia -> Deuteromycota – majority are yeasts and molds; no sexual spores known; conidia

37 37 Eukaryotic Cells Roles of Fungi -> Adverse impact - mycoses, allergies, toxin production - destruction of crops and food storages -> Beneficial impact - decomposers of dead plants and animals - sources of antibiotics, alcohol, organic acids, vitamins - used in making foods and in genetic studies

38 38 Eukaryotic Cells Roles of Fungi

39 39 Eukaryotic Cells Kingdom Protista -> Algae Diatoms -> silica cell wall -> Protozoa Ameba

40 40 Eukaryotic Cells Kingdom Protista Algae -> Photosynthetic organisms -> Contain chloroplasts with chlorophyll and other pigments -> Produce large proportion of atmospheric O 2 -> Most are free-living in fresh and marine water – plankton. -> Provide basis of food web in most aquatic habitats -> Classified according to types of pigments and cell wall -> Kelps, seaweeds, euglenids, green algae, diatoms, dinoflagellates, brown algae, and red seaweeds brown algae, and red seaweeds -> Dinoflagellates can cause red tides and give off toxins that cause food poisoning with neurological symptoms. food poisoning with neurological symptoms. -> Used for cosmetics, food, and medical products

41 41 Eukaryotic Cells Kingdom Protista Protozoa -> 65,000 species -> Vary in shape, lack a cell wall -> Most are unicellular; colonies are rare -> Feed by engulfing other microbes and organic matter -> Most have locomotor structures – flagella, cilia. -> Many can enter into a resting stage when conditions are unfavorable for growth and feeding – cyst. unfavorable for growth and feeding – cyst. -> Most are harmless, some are animal parasites Pathogen Protozoa -> Malaria (Plasmodium ), Pathogen Protozoa -> Malaria (Plasmodium falciparum/vivax/ovale/malariae ), Toxoplasmosis (Toxoplasma gondii) Toxoplasmosis (Toxoplasma gondii)

42 42 Eukaryotic Cells Kingdom Protista Cycle of Infection - Protozoa

43 43 Eukaryotic Cells Parasitic Helminths (Worms) -> 50 species parasitize humans. -> Acquired though ingestion of larvae or eggs in food; from soil or water; some are carried by insect vectors water; some are carried by insect vectors -> Multicellular animals, organs for reproduction, digestion, movement, protection movement, protection Major Groups: 1. Flatworms 2. Roundworms 2. Roundworms

44 44 Eukaryotic Cells Parasitic Helminths (Worms) Life cycle of roundworms


Download ppt "1 Eukaryotic Cells The History of Eukaryotes They first appeared approximately 2 billion years ago. Evidence suggests evolution from prokaryotic organisms."

Similar presentations


Ads by Google