Morphology

1. Morphology Unit 1 Microbes, Protists, and Fungi

2. Ch 23 Bacteria • Prokaryotes - single cell organisms without a membrane bound nucleus and organelles. • All bacteria are prokaryotic and are the earliest known group of living organisms. • There are 2 branches of bacteria • Eubacteria - What we think of when we hear the word bacteria • Archaebacteria - (archaea) bacteria that lives in extreme conditions.

3. Archaea • Structure • Cells walls do not contain peptidoglycan (a protein carbohydrate compound that makes up most cell walls). • Have different amino acids and lipids than other bacteria.

4. Archaea • 3 major archaeal groups - • Methanogens - convert hydrogen gas and carbon dioxide into methane. Oxygen is poisonous to them, so they live in anaerobic (oxygen free) environments • Swamps, bottom of water, cow intestines • Halophiles - salt loving archaea • Great salt lake, dead sea • Thermoacidophiles - acidic environments with high temperatures • Hot springs, ocean floor vents

5. Bacteria • Structure • Three basic shapes • Rod shaped - bacilli • Sphere shaped - cocci, in chains - streptococci (strept throat), clusters - staphylococci (staph infection) • Spiral shaped - spirilla

6. Bacteria • Types • Proteobacteria - Nitrogen Fixing bacteria • Gram-positive - use to make antibiotics and other medicines, can kill people, makes milk sour. • Cyanobacterias - use photosynthesis, give off oxygen, offer food to freshwater ecosystems • Spirochetes - Gram negative, spiral shaped, causes diseases • Chlamidia - Gram negative coccid pathogen, depend and live on animal cell for survival.

7. Bacteria Structure and Function • Cell wall - for shape and protection • Cell membrane - lipid bilayers (selectively permeable), many metabolic functions occur here • NO membrane bound organelles • DNA - single closed loop attached to one point in the cell membrane • Has plasmids - small circular self replicating DNA loops • Endospore - thick coated resistant structure contains DNA to help survival • Capsules - polysaccharides (sugars) to bind to cell wall and protect against chemicals and drying out • Pili - hair-like proteins on surface to help to connect to other objects • Move by: flagella, slime or corkscrew rotations

8. Bacteria cont. • Bacteria gets its food

9. Ch 24 Viruses • Virus - a nonliving particle made up of a nucleic acid and protein/lipid-protein coat. • Causes many disease in living organisms • Useful tools for genetic research which started in the late 1800s • Appeared after living cells.

10. Viral Characteristics • Lack all organelles and a cytoplasm • Cannot carry out cellular functions (metabolism and homeostasis) • Do not grow by dividing • Cannot reproduce outside of host cell (do have DNA or RNA) • Use host cell’s ribosomes, ATP and enzymes to reproduce • Usually contains a protein coat and a nucleic acid core.

11. Viral Structure/Size • Some of the smallest particles able to cause diseases • Capsid: (protein coat) is the only covering of most viruses, acts as protection • Helix - rabies, measles • Icosahedrons - 20 triangular faces and 12 corners (adenovirus) • Spherical - influenza virus • Envelope: bilipid membrane that surrounds the capsid (AIDS, chicken pox, HIV)

12. Classification and Replication • Viruses are classified by • DNA or RNA • single stranded or double stranded DNA/RNA • linear or circular DNA/RNA • Membrane bound envelope or not. • Replication • Spread by air, water, food, or body fluids • Lifeless with no control over its movement without a host • Envelopes act as lock and key with hosts • Attaches and then takes over cell • Provirus - insertion of viral DNA to create viral proteins • Insertion of viral RNA infects cells RNA (retroviruses) • Bacteriophages - viruses that infect bacteria

13. Lytic and Lysogenic Cycles • Lytic Cycle - a virus invades a host cell, produces new viruses and ruptures the host cell when releasing newly formed viruses. • Lysogenic cycle - an infection that allows viruses to hide in their host for days, months or years. • Viruses that only reproduce by the lysogenic cycle are called Temperate viruses.

15. Viroids and Prions • Viroids - smallest known particle able to replicate, infect plants, and do not have a capsid. Only contains RNA • Prions - infectious protein particles that don’t have a genome, convert normal brain proteins into prion particles. (only contains a protein.) • Causes a number of degenerative brain diseases • Creutzfeldt-Jakob, mad cow disease

16. Ch 25 Protista • Protists – single celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom. • Some of the oldest eukaryotic cells are protists.

17. Protist Characteristics • Unicellular or multicellular • Most protists are unicellular (amoeba) with few being multicellular (brown algae). • Nutrition • Most protists are autotrophs (can make their own food) the same way plants are, but some are heterotrophs (eating other organisms or their byproducts and remains). • Motility/Movement • Flagella (dinoflagellates use flagella), cilia, pseudopodia, extending structures amoebas use to move.

18. Reproduction • Most reproduce asexually • Binary fission –a single cell divides into two • Multiple fission – produces more than two offspring • Some reproduce sexually • Conjugation – two individuals join and exchange genetic material stored in a small second nucleus.

19. Animal-like Protists • Animal-like protists are sometimes called protozoa; they move about capturing and consuming prey. • Pseodopodia – a large, rounded cytoplasmic extension that function both in movement and feeding. • Hundreds of species in freshwater, marine environments, soil, and inside humans.

20. Animal-like Protists cont. • Others are called Paramecium, found in ponds and streams feeding on decaying organic matter, bacteria, algae, and other small organisms. • Mouth pore –sucks in food into the gullet (stomach) • Undigested material exits through the anal pore, excess water gets released from the contactile vacuoles. • Macronucleus contains the DNA • Micronucleus participates in the exchange of genetic material during conjugation.

21. Plantlike Protists • Many plantlike protists are called algae and are autotrophic. • Reproduction-have single-celled gamete chambers (gametangia) instead of multicellular. • Have chlorophyll and undergo photosynthesis • Unicellular aglae- one single cell that are free-living aquatic organisms (phytoplankton) • Colonial Algae – groups of cells working in a coordinated manner. Some cells become specialized. • Filamentous algae – Multicellular, slender, rod-shaped with celled joined end to end. • Multicellular algae (kelp and seaweeds)- unusually large and complex, look most like plants.

22. Algae • The most well known plantlike protist • Algae are autotrophic protists. (make their own food) • Can be found in salt water • Can be found in fresh water. • Can have specialized structures for reproduction, movement and anchoring itself.

23. Plantlike Protists cont. Other organelles that help perform life’s functions: • Cell walls made of cellulose • shells • Chlorophyll and other pigments to help with photosynthesis • Some have high resistant cysts allowing them to live in extreme environments • Some are plantlike and animal like • Euglena - have chlorophyll but no cell wall, have a vacuole, have a cell membrane. In light they have chloroplasts (autotrophic) but in the dark they don’t and are heterotrophic.

24. Fungus-like Protists • Slime molds • Is a mass of cytoplasm that oozes around obstacles. • Move as independent organisms (move like amoebas) • The feeding stage of slime molds have multiple nuclei and is known as a multinucleate. • Some look like slugs and leave slime behind them. • Water molds • Parasitic • Undergo sexual as well as asexual reproduction • Cell walls • Similar enzymes and biological pathways

25. Examples of Protists Kelp forest Seaweed Kelp amoeba

26. Ch. 26 Fungi • Fungi - eukaryotic, nonphotosynthetic organisms. Most are multicellular and heterotrophs. • Main types • Molds - can grow on bread and are tangled masses of filaments of cells (known as Zygomycota) • Yeasts -unicellular fungi whose colonies resemble bacteria (make bread rise) • Important in industry • Used to make bread (yeast), produce antibiotics (molds), to manufacture gasohol.

27. Fungi Obtaining Nutrients • Fungi get their nutrients by absorbing organic molecules (usually from dead organisms) from their environment through their cells walls. (outside to inside) • They store nutrients in the form of glycogen. • Known as the recyclers of organic material in nature.

28. Structure of Fungi • Hyphae –individual filaments of fungi that make up a mycelium. • Cell walls that contain chitin (same thing that makes up exoskeleton of insects). • Most fungi have the ability to exist in two different forms. (dimorphism) • They do not have chloroplasts • The do not produce their own food (heterotrophic).

29. Fungi Reproduction • Asexual – reproduce thousands of genetically identical haploid cells. • Can reproduce with protective sacs (sporangiophores) This is where the spores form. (plural = sporangia) • Can reproduce from spores without sacs (conidia). • Can also reproduce by hypha drying and shattering to spread and release spores (fragmentation) • Budding- part of a yeast cell pinches itself off to produce a small offspring cell

30. Fungi Reproduction cont. • Sexual reproduction • Many fungi can reproduce both asexually and sexually. • Sexually- when two different mating types of the same breed come in contact, fungi will reproduce sexually for genetic variation, and increased survival ability. • Being able to reproduce both ways is extremely advantageous. Whatever the environment conditions are, the fungi can reproduce.

31. Fungi Evolution • Fungi were first thought to be unicellular and clung together after mitosis. • Scientists believe Fungi evolved from prokaryotes. • Fungi are probably as old as plants. 640mya.

32. Examples of Fungi Molds Yeasts