Definitions Parasites feed on living hosts Saprophytes feed on dead matter Decomposers breakdown dead matter and recycle the nutrients Pathogens are disease causing organisms (most parasites are also pathogens) Extra cellular digestion is the process by which bacteria and fungi feed Binary fission is the process by which bacteria reproduce

Viruses

Char. Of LifeVirus MovementNo ReproductionYes SensitivityNo GrowthNo RespirationNo ExcretionNo NutritionNo 3

Viruses Viruses are simple but effective pathogens Viruses can infect all living things Range from 20 to 20millionth of a millimetre. Can only be seen with an electron microscope.

Viral structure Viruses come in a variety of shapes Consists of a core of genetic material surrounded by a protein coat=capsid Some viruses also have a membrane. This membrane can have proteins embedded in it

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Viral reproduction Essentially all a virus is is a set of instructions for making new viruses. MRS GREN is not followed by viruses and the only ‘living’ characteristic that they have is reproduction They lie on the border between the living and no living worlds

Viral reproduction Essentially all a virus is is a set of instructions for making new viruses. MRS GREN is not followed by viruses and the only ‘living’ characteristic that they have is reproduction They lie on the border between the living and no living worlds

Viral replication A virus cannot reproduce itself independently, it needs another cells parts to replicate itself. When a virus lands on the surface of a cell it inserts its genes into the host cell. The viral genes take over the cells processes to produce new viruses. These build up in the cell until it eventually bursts releasing the new viruses into the host where they can infect new cells.

Smallpox, Mumps, Measles - Virus

POXVIRUSES 14 BACK

Bacteria

Bacteria are unicellular organisms with no nucleus Sphere, rod, or spiral shaped Usually 0.01mm in length and only visible under the higher powers of the microscope Over 3000 known kinds They are found almost everywhere including in living things Colonies growing on agar look like shiny spots of various colours

Spherical (coccus)Staphylococcus Rod shaped E.coli (bacillus) Spiral (spirillum)Vibrio cholerae Shape Example

Bacteria structure

Structure functions Cell wall: Maintains cell shape Cell membrane: Controls entry and exit of materials Chromosome: Carries genetic information Cytoplasm: fills cell and provides medium for chemical reactions to occur Flagellum: Assists the bacterium to move Capsule: Provides protection from external environment

MRS GREN Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition

Movement Many bacteria move by hair-like threads called flagella. These are made up of long stands of protein Non-flagellum bacteria float in water or on the wind. Or are carried/spread by their hosts

Respiration Not breathing! The process of releasing energy from food molecules Bacteria carry out: - Aerobic respiration (requires oxygen) - Anaerobic respiration (without the presence of oxygen)

Sensitivity Bacteria display sensitivity to their environment. They can move along concentration gradients until they reach their optimum environment. i.e. Temperature/ acidity/ Oxygen/ Magnetic

Growth In optimum conditions bacteria do grow, but their goal is reproduction so they grow up to a certain point where they have enough resources to reproduce.

Reproduction Reproduce asexually by a process called Binary fission The bacterium’s chromosome is duplicated and the cell then pinches in half and two identical daughter cells are produced

Excretion Bacteria excrete by allowing waste to diffuse out of the cell membrane into the environment i.e. CO 2 from aerobic respiration

Nutrition Bacteria ‘feed’ by secreting enzymes which break down their food source into smaller molecules that can be absorbed by the bacteria. This is called extra-cellular digestion.

Parasites – Live on or in larger organisms and feed off them. If they cause disease they are called pathogens. Saprophytes – Consume dead matter. These bacteria are scavengers and decomposers. Autotrophs – Self-feeders. They can make food from non-living materials i.e. chemicals/ sunlight. - Green and purple sulfur bacteria.

Factors that inhibit bacteria growth Light Temperature Chemicals Acidity Food supply

Bacterial Growth Competition for food and space means bacteria die Death or Decline Stationary Log or Exponential Lag Optimal conditions Rapid growth Toxin production causes human sickness Time Number of bacteria Copy

Fungi

A group of immobile organisms that feed on dead or living organisms and exposed food 70,000 known kinds 50 fungi among NZ’s most threatened species Can be unicellular and multi-cellular Most common cause of plant disease

Structure Hyphae: Fine feeding threads Sporagium: Spore capsule that produces spores Spores: reproductive cell, germinates and spreads out hyphae

Mass of Hyphae

MRS GREN Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition

Movement Immobile But can spread by producing networks of hyphae.

Reproduction Asexual and sexual production of spores Spores germinate when they land on tissue and put out hyphae.

Yeasts

Sensitivity Show active responses to their surroundings

Growth Grow by spread of hyphae

Respiration Carry out aerobic and anaerobic respiration to create energy from food

Excretion Allow waste to diffuse out of cells and into the surrounding envrionment

Nutrition Secrete enzymes that break down food, the absorb digested food Extra-cellular digestion in fungi Copy

Respiration Carry out aerobic and anaerobic respiration to create energy from food

Micro-organisms are helpful Food production Bread Alcohol Cheese Yoghurt Nutrient recycling Composting Medicine production Antibiotics Insulin

Sewage treatment by microbes

Microbes clean our water 1.Stores rainwater 2.Metal grids keep out weeds and debris 3.Chemicals make particles stick together 4.Stands for 3hr to let large particles sink (digested by microbes) 5.Gravel and sand removes most particles 6.Kills microbes 1. Reservoir 4. sedimentation3. Coagulation 6. Chlorination 5. Filtration 2. Screening