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VIRUS Viruses are nonliving particles that can only reproduce within a HOST CELL (living cell). Can NOT carry out life-sustaining functions. Viral Structure: 1. Nucleic Acid – DNA or RNA encodes for the synthesis of proteins – making new viruses 2. Capsid – protein coat surrounding nucleic acid; arrangement determines shape protects the nucleic acid from digestive enzymes contains special sites on its protein surface that allow the virus to attach and penetrate the host cell membrane 3. Envelope – membrane surrounding capsid; NOT found in all viruses Viral Replication – Capsid proteins on virus must match proteins on host cell. Lytic cycle: 1. virus attaches to host cell and injects viral DNA 2. viral DNA uses host cell to create new viruses 3. new viruses assemble –destroying host VIRAL DISEASES Mumps Rabies Influenza Herpes Lysogenic cycle: Smallpox Chickenpox Measles AIDS Polio Hepatitis 1. virus attaches to host cell and injects viral DNA 2. viral DNA integrates with host DNA creates provirus 3. provirus is replicated along with host cell’s DNA 4. virus may become active, switching to the lytic cycle, destroying host TREATMENT: Antiviral drugs – treat symptoms or suppress the virus o your immune system has to kill the virus Vaccine – preparation of weakened or killed virus/viral particle stimulates immune system to prevent infection by “teaching” it to recognize virus Edward Jenner created smallpox vaccine Jonas Salk created polio vaccine Extras-- Oncogenic viruses – cause cancer; genes disrupt cell cycle Retrovirus – contains RNA; produces a DNA copy of the viral RNA and inserts viral DNA into host cell Prion – protein particle with no nucleic acid; accumulation of proteins in an area kills cells Viroid - small naked single-stranded RNA molecules that cause plant diseases Domain Archae Domain Bacteria Kingdom Archaebacteria prokaryotes cells walls lack peptidoglycan May be ancestors of eukaryotes - DNA sequences of key genes are more like eukaryotes live in extremely harsh environments Classification based on environment: 1. Methanogens – all anaerobes and produce methane; live in marsh mud, etc. 2. Halophiles – live in extreme salt environments; Great Salt Lake 3. Thermoacidophies – live in acidic/hot places; volcanic vents, hot springs Bacterial Structure o o o o Kingdom Eubacteria prokaryotes cell walls contain peptidoglycan (sugar & amino acid molecule) live almost everywhere cause diseases Classification based on: 1. shape and cell arrangement arrangement: staphylo(clusters) or strepto(chains) or diplo (pairs) shape: coccus(round) or bacillus(rod) or spirillum(spiral) 2. movement - flagella, cilia or use vectors 3. Heterotrophic (use endocytosis/exocytosis) OR Autotrophic (photosynthesis – use light energy or chemosynthesis – use inorganic compounds) 4. O2 requirements – obligate anaerobe (can’t survive in O2) OR obligate aerobes (must have O2 to survive)OR facultative anaerobe (live with or without O2) 5. Gram Stain lab test: Gram positive (+) turns purple, more peptidoglycan; Gram negative (–) turns pink, less peptidoglycan Gram– are more resistant to antibiotics Capsule – sticky protective layer that helps evade immune system and adhere to substances Plasmids - accessory rings of DNA; can be used as vectors to carry foreign DNA into bacteria during genetic engineering procedures; can carry resistant genes Endospore – thick internal wall that encloses the DNA; formed so bacteria can remain dormant during harsh environmental conditions. Pili – allow bacteria to stick to surfaces BACTERIAL Reproduction 1. Binary fission – grows, replicates DNA, and divides; (asexual) – identical daughter cells 2. Conjugation – pili form bridge, exchange DNA then split; (sexual) – diversifies population 3. Transformation – bacteria taking up free pieces of DNA secreted by live bacteria or released by dead bacteria (sexual BACTERIA – Good or Bad?? HELPFUL decomposers – break down dead matter and recycle nutrients nitrogen fixation – convert atmospheric nitrogen into soil nitrogen form denitrification – convert excess soil nitrogen form into atmospheric nitrogen photosynthesis – produces oxygen human uses – food, digest petroleum, remove waste from H2O, synthesize drugs, bacterial enzymes used in genetic engineering mutualistic relationships – both organisms benefit; ex. bacteria in human colon HARMFUL pathogens – cause disease by breaking down tissue or release toxins BACTERIAL DISEASES Strep throat Syphilis Tuberculosis Lyme disease Typhoid fever Pneumonia Tetanus Gonorrhea Treatment – Antibiotics – destroy bacterial cells by inhibiting cell wall growth or protein synthesis Alexander Fleming created first antibiotic – penicillin Vaccine (prevention) – stimulates immune response Controlling Bacteria – 1. Sterilization – kill bacteria by heat or chemical action Joseph Lister created the first antiseptic to disinfect instruments before surgery (1860). 2. Refrigeration – bacteria grows at a slow rate in cold temperatures Kingdom Protista Eukaryotes Mostly Uni- or Some Multicellular First Eukaryotic organism on Earth – appeared about 1.5 billion years ago Most live in watery habitats CLASSIFIED according to the way they obtain nutrients: 1. Animal-like protist - heterotroph 2. Plant-like protist - autotroph 3. Fungi-like protist – heterotroph ANIMAL-LIKE PROTIST (AKA: PROTOZOANS) 1. 2. 3. 4. Zooflagellates – use flagella Ciliates – use cilia Sarcodines – use pseudopods Sporozoans - parasitic Amoeba Protozoans Unicellular Contractile vacuole – regulate water level Some live symbiotically within organisms – termite and zooflagellate Paramecium Disease Malaria Giardiasis African Sleeping Sickness Amebic Dysentery Protozoan Plasmodium species – carrier Anopheles mosquito Giardia species – carrier beavers; contaminated H2O Trypanosoma species – carrier Tsetse fly Entamoeba species – contaminated H2O PLANT-LIKE PROTIST (AKA: ALGAE) Unicellular Algae 1. Euglena 2. Dinoflagellates – algal blooms produce red tide 3. Diatoms – cell walls rich in silicon Multicellular Algae (aka: seaweed) – red, brown, green algae Pigments vary to efficiently harvest light energy for photosynthesis Phytoplankton – population of photosynthetic organism Cell walls composed of cellulose when waste is excessive, algae grows into masses called algal blooms; depletes nutrient in H2O which kills aquatic organisms Human uses of Algae – much of Earth’s O2 is produced by algae – uses photosynthesis to produce oxygen chemicals in algae – medicines(treat ulcers, arthritis), make plastics, deodorants, paints etc. food --nori wraps in sushi, ice cream, candy bars, syrups, etc. FUNGI-LIKE PROTIST Multicellular, decomposers, produce spores, cell walls made of cellulose Includes slime molds & water molds Can be parasitic to plants - cause diseases such as blight, mildews Kingdom Fungi Fruiting body Eukaryotes Heterotrophs – Decomposers All fungi are multicellular, except for yeast STRUCTURE – Cell walls – contain chitin (carb) Hyphae – thin filament Mycelium – thick mass of hyphae Fruiting bodies – reproductive structure How do fungi spread? fungi need proper temperature, moisture & food or they remain dormant in soil spores are scattered by wind, water or animal REPRODUCTION – 1. Budding (asexual) – cells break off and grow new fungus 2. Spores (asexual) – reproductive cell germinates into new fungus 3. Sexual reproduction – Two mating types (+ & -) fuse nuclei then divide to produce haploid spores germinate into new fungus – produce genetically diverse spores ECOLOGICAL ROLES – 1. Saprophytes (decomposer) - absorb nutrients from dead organic matter. 2. Parasites - absorb nutrients from body fluids of host organism causing plant and human diseases. (wheat rust, corn smuts, ringworm, yeast infection, thrush, etc) 3. Used to produce medicines - penicillin, cortisone, antibiotics, vitamins 4. Fermentation process to produce food – cheese, bread, etc. 5. Mutualistic symbionts - both reciprocate with some beneficial function. Mycorrhiza – special roots and fungi association (fungi increase absorption of water/minerals and fungi release enzymes to free nutrients in the soil & plant provides product from photosynthesis) Lichen – fungus and green algae association (algae carries out photosynthesis, providing the fungus with a source of energy & fungus provides water, minerals and protect the algae) KINGDOM PLANTAE Characteristics of Plants – cell walls – composed of cellulose eukaryotes autotroph multicellular Green algae are believed to be the ancestors of plants. Survival NEEDS: invasion of plants – sunlight occurred about 430 gas exchange million years ago water & minerals movement of water and nutrients Adaptations – Evolutionary trend was to move from water to land, plants had to adapt…… Adaptations for attainment of resources Land plants evolved methods to gain vital minerals from the soil. Green algae absorb nutrients they need directly from the water they live in. Land plants have to live without being suspended in water. o Roots developed as a structure that allowed plants to obtain minerals and water from the soil. o Some plants developed vascular tissue (xylem & phloem) that act as a transport system to bring water and other substances such as minerals up the plant body, allowing for increased plant size. o All plants contain lignin which binds to cellulose fibers to harden and strengthen the cell walls of plants to support growth. o Stems developed to store and transport water & nutrients. o Leaves are modified to maximize photosynthesis. Adaptations to reduce water loss Strategies to catch and retain water were vital for the survival of land plants. Once removed from moist, swampy areas, plants risk desiccation, or drying out. o To prevent desiccation, many plants developed a cuticle (a thick, waxy, watertight barrier) that covers the plant and prevents loss of moisture to the air. o The stomata are openings in the cuticle that allow for gas exchange and transpiration of water as the plant photosynthesis. Adaptations for reproduction The reproductive processes of the earliest plants to evolve from green algae still required an aquatic environment. Consequently, these primitive land plants could live only in highly moist, swampy areas. Plants evolved the ability to reproduce without water and began to populate drier environments. o The seed allowed safe dispersal of plant embryos by supplying it with nutrition and protection against hostile conditions. Seeds can remain dormant during unfavorable conditions. o Pollen grains containing the male gamete could be dispersed without water. o Flowers developed to attract pollinators and allow for greater dispersal of the pollen. o Fruits developed to protect the embryo and allow for greater dispersal of the plant. Can plants DEFEND themselves? Mechanical defense -incorporated into the physical structure of the organism. -- thorns, spines and stiff hairs that repel a predator Chemical defense - occurs when the plant produces stinging sensations, paralysis, poisoning, or just a bad taste. Camouflage - the organism blends into its environment or appear to be something they are not Classification – Xylem – transports H2O Phloem – transports dissolved nutrients Nonvascular Plants: Bryophytes nonvascular – instead uses rhizoids for movement of minerals & water via diffusion produces spores (reproductive cells) – sperm require water for fertilization habitats and size of plant is limited due to lack of vascular tissue Vascular Plants: Tracheophytes 1. Seedless vascular – reproduce with spores 2. Gymnosperms – produces seeds in cones 3. Angiosperms – produces flowers and seeds in fruit TROPISMS ~plants adjust growth in response to environmental stimuli o Gravitropism or Geotropism– a growth response to gravitational forces o Phototropism— when stems/leaves adjust the direction of growth in response to light o Thigmotropism— plants shift a direction of growth as they contact objects How do plants control their growth in response to environmental stimuli? Most plants do this by way of chemical messengers known as hormones. A hormone is a chemical that is produced in one part of an organism and transferred to another part to affect the activities of that part of the plant. Auxins – hormone responsible for regulating phototropism in a plant by stimulating the elongation of cells & helps promote the growth of fruit…during fall auxin levels decrease causing ripened fruit to fall and plants will lose their leaves Abscisic Acid – inhibits plant growth during times of stress such as cold temperature or drought Gibberellins – growth hormones that cause plants to grow taller & increase the rate of seed germination and bud development KINGDOM ANIMALIA All animals are multicellular, eukaryotes and most have tissues, organs, and organ systems. They have no cell walls. Animals are aerobic heterotrophs that ingest other organisms or withdraw nutrients from them. Animals reproduce sexually; many also reproduce asexually. Their embryos usually develop through a series of stages. Most animals are motile; they actively move about during all or part of the life cycle. MAJOR ANIMAL GROUPS Phylum Porifera - sponges Phylum Cnidaria – hydras, jellyfish Phylum Platyhelminthes (flatworms) – flukes, tapeworms Phylum Nematoda (roundworms) – pinworms, hookworm Phylum Annelida (segmented worms) – leeches, earthworms Phylum Arthropoda – crustaceans, spiders, insects Phylum Mollusca – snails, slugs, clams, squids, octopi Phylum Echinoderms – starfish, sea urchins Phylum Chodata Invertebrate chordates – tunicates, lancelets Vertebrate chordates – fish, amphibians, reptiles, birds, mammals Animal Behaviors Behavior – anything an organism does in response to a stimulus in its environment. Behaviors develop through interactions between genes and environmental inputs. Behavior is ADAPTIVE – adapting allows animals TYPES of behaviors: to survive!!! 1. Innate Behavior – inherited behaviors (You are pre-wired to recognize stimuli before being born!) Reflexes circadian rhythm – occur in daily patterns Instincts migration – periodic movement from one place to territoriality another aggression hibernation – dormancy during winter submission estivation –dormancy during summer courtship behavioral cycles 2. Learned Behavior – these behaviors are acquired or learned over time. Organisms can alter their behaviors as a result of experience. Habituation – organism decreases or stops its response to a repetitive stimulus that neither rewards nor harms the animal Imprinting – when an organism forms an attachment to an object or other organism after birth and copies it. For example, sparrows have an innate ability to recognize their own species’ song. To sing the complete version, the young birds must first hear it sung by the adults. Adaptations for DEFENSE Mechanical defense occurs when an animal uses its physical structures such as claws, tusks, stingers and shells. Other examples of mechanical defense include camouflage, cryptic coloration, disruptive coloration, counter shading, etc… Chemical defense occurs when the animal produces stinging sensations, paralysis, poisoning, or just a bad taste.