Goal 4 - Viruses, Bacteria, Protists and Fungi Notes
Viruses – Pages 475-483
Viruses
Virus Structure
Structure = Made up of
(1) protein coat- capsid (located on the outside)
(2) small amount of nucleic acid - DNA or RNA (located on the inside).
Shape of Viruses
Viruses have three distinct shapes
1. Spherical
2. Rod
3. Phage
How are viruses named?
Examples of Viruses
Viruses
- Not living
- Don’t grow or develop
- No respiration
- Only reproduce within a host (can’t do it alone MUST have a host)
- Virus multiply through the lytic cycle where the virus attacks the host, injects it nucleic acid into the host, and then spreads or bursts from the host.
Virus Structure
Structure = Made up of
(1) protein coat- capsid (located on the outside)
(2) small amount of nucleic acid - DNA or RNA (located on the inside).
Shape of Viruses
Viruses have three distinct shapes
1. Spherical
2. Rod
3. Phage
How are viruses named?
- Named after the disease it causes. For example, rabies viruses or polio viruses
- Named after the tissues they infect. For example, Adenoviruses cause common cold found in the adenoids tissues between the back of the throat and the nasal cavity.
- Today viruses are given a genus name ending in the word virus and a species name.
- If a virus affects bacteria it is called a bacteriophage or phage.
Examples of Viruses
- HIV - RNA virus called retrovirus. HIV in a human host affects white blood cells. People with HIV eventually will get AIDS because more white blood cells become infected and produce new viruses. Remember white blood cells are used to fight diseases leaving the body unable to protect itself.
- Cancer - Some viruses are linked to cancer. Hepatitis B is a virus that can cause liver cancer and disrupts the normal growth and division of cells.
- Plant viruses - Plant viruses require wounds or bites to enter the host. ex. Tobacco mosaic virus – disease in tobacco plants which stunts plant growth.
Bacteria
Kingdom Monera (Bacteria) – Pages 485-495
Two types
Bacterial Shapes
Archaebacteria
Prokaryotic bacteria
Classified according to the environment in which they live
1. Methanogens – produce methane gas and live in places such as soil and intestines of herbivores
2. Halophiles – live in extremely salty environments – like the Dead Sea
3. Thermoacidophiles – live in acid sulfur springs of Yellowstone National Park and Undersea Vents
Reproduce asexually by Binary fission (asexual à copy chromosomes, attach and divide).
Binary Fission - How does this work?
First the bacterium copies its chromosomes. The original chromosome and copy become attached to the cells plasma membrane for a while. The cell grows larger and larger, and eventually the two chromosomes separate and move to opposite ends of the cell. Then a partition forms between the chromosomes. The partition separates cell into two smaller cells. Because each new cell has either the original or copy of the chromosome the resulting cells are identical. This process is rapid!
Also reproduce asexually by budding
Eubacteria
Eu- means true - True bacteria
Are they Helpful?
MOST are HELPFUL!!!
Are they harmful?
YES - Examples
How do we destroy bacteria?
Two types
- Archaebacteria - Extreme environment
- Eubacteria (page 487) - Common, majority
Bacterial Shapes
- Spherical
- Rod-like
- Spiral
- Thread-like
Archaebacteria
Prokaryotic bacteria
- Thrive in harsh environments previously through inhabitable
- Archa – means ancient
- Thought to be similar to the first organisms on earth
- Single celled or clustered together to form filaments
- Cell wall lacks peptidoglycan (a protein-carbohydrate molecule found in all other bacteria),
- cell membrane and ribosomal RNA
- Anaerobic (can not tolerate oxygen)
- Producers, Consumers or Decomposers
Classified according to the environment in which they live
1. Methanogens – produce methane gas and live in places such as soil and intestines of herbivores
2. Halophiles – live in extremely salty environments – like the Dead Sea
3. Thermoacidophiles – live in acid sulfur springs of Yellowstone National Park and Undersea Vents
Reproduce asexually by Binary fission (asexual à copy chromosomes, attach and divide).
Binary Fission - How does this work?
First the bacterium copies its chromosomes. The original chromosome and copy become attached to the cells plasma membrane for a while. The cell grows larger and larger, and eventually the two chromosomes separate and move to opposite ends of the cell. Then a partition forms between the chromosomes. The partition separates cell into two smaller cells. Because each new cell has either the original or copy of the chromosome the resulting cells are identical. This process is rapid!
Also reproduce asexually by budding
Eubacteria
Eu- means true - True bacteria
- Single celled or cluster together to form colonies
- Prokaryotic
- Cell wall, cell membrane and circular DNA called a plasmid
- Heterotrophic, autotrophic, chemotropic
- Found everywhere and most are harmless
- Some are decomposers
- Reproduce asexually through budding or binary fission
Are they Helpful?
MOST are HELPFUL!!!
- Fertilize fields (nitrogen fixation)
- Recycle nutrients (decomposers à breakdown dead organism and waster into nutrients.
- Produce Food and medicine (food such as cheese, pickles, yogurt, vinegar, sauerkraut, and antibiotics such as streptomycin, erythromycin, bacitracin)
Are they harmful?
YES - Examples
- Strep throat
- Tuberculosis
- Tetanus
- Lyme Disease
- Dental Cavities
- Cholera
How do we destroy bacteria?
- In diseases… - Antibiotics
- In Food….- Heat Pasteurisation or Canning
Protists
Kingdom Protista – Page 503-521
Large, mixed up group!!!
Three Subgroups
1. Animal – like
Ciliates (page 507)
Flagellates
Sporozoa
2. Plant – like
Euglenas (page 511)
Golden Algae or Diatoms
Dinoflagellates
Brown Algae
Red Algae
Green Algae
3.Fungi-like - Absorb nutrients from the environment.
Synthesis
Transport
Excretion
Respiration
Nutrition
Growth and Development
Regulation
Reproduction
Large, mixed up group!!!
- eukaryotes
- Can be unicellular, multicellular, or colonial
- Need a watery environment
- Fresh or marine, snow, or damp soil
- Aerobic and have mitochondria for cellular respiration
- Some have chloroplasts for photosynthesis
- Grow or reproduce by mitosis, some by meiosis and fertilization.
Three Subgroups
1. Animal – like
- One-celled known as Protozoa
- Many protozoa are parasites living in water, on soil and on living and dead organisms
- Hetertrophs
- Animal like in mode of Nutrition - ingest food by phagocytosis like endocytosis); some have a mouth-like structure into which prey is put. Prey includes bacteria and small one celled organisms
- Four phylum of protozoan divided according to their method of movement
Ciliates (page 507)
- Have hair like structures called cilia which help them move freely
- Paramecium
- Live in fresh and salt water
- Have oral grooves to take in food – making them heterotrophic
- Reproduce by fission and conjugation
Flagellates
- Live in fresh and salt water
- Move by one or more flagella (look like a long whip)
- Some may be parasites and may cause disease
- Trypanosome, a flagellate, causes African sleeping sickness in humans and animals when it is transmitted by a bite of the tsetse fly
- Move by pseudopods (false feet)
- Amoeba – change shape as they move around their food. Some have hard shells. When dead on the ocean floor they become chalk or limestone
Sporozoa
- Contains only parasites that feed on the blood of humans and other animals
- Malaria is a disease that attacks humans when sporozoa are transmitted to the human bloodstream in the bite of the mosquito.
- Sporozoa have no way of moving on their own
2. Plant – like
- Algae (page 514)
- Unicellular or multicellular
- Chlorophyll-containing chloroplasts – can make their own food (producers)
- Nutrition is plant-like by photosynthesis. Most have chlorophyll.
- Classified into six phylum based upon pigments and how they store food
Euglenas (page 511)
- Characteristics of both plants and animals.
- Autotrophic and heterotrophic
- Live in fresh water
- Move around with a flagellum
- Have no cell wall
- Have an eyespot that responds to light
Golden Algae or Diatoms
- Single celled algae
- Chloroplasts filled with chlorophyll
- Store food in the form of oil
- Have a golden brown pigment that cover the green color of the chlorophyll
- Found in salt water
- Source of food for marine animals
- Have a cell wall
- When they are dead, form diatomaceous earth used in detergent, paint removers, and scouring powders
- Diatom shells contain silica – main element in glass and it is used in road paint to make the yellow lines visible at night
Dinoflagellates
- Found in both fresh and salt water
- Red pigment
- Move by using two flagella
- Glow in the dark
- Source of food for marine animals
- Have occasional “blooms” and over-populate in the water producing a “red tide” which creates massive fish kills
Brown Algae
- Multicellular and vary in size
- Kelp – type of brown algae important food source
- Carry on photosynthesis and play a role as producers in environment, producing about ¾ of world oxygen
Red Algae
- Multicellular
- Produce a type of starch on which they live
- Irish moss is a type of algae used to give tooth paste and pudding its smoothness
- Commonly called seaweed
- Food source in Asia and Europe
- Found in marine habitats with only 200 of the estimated species found in freshwater environments.
- Absorb blue waves and are found at great depth often devoid of other photosynthetic organisms
Green Algae
- Store food in the form of starch
- one-celled colonial or multinucleated organisms
- live in water or out of water
- chlorophyll
- thought to be ancestors to land plants
3.Fungi-like - Absorb nutrients from the environment.
- Features of both fungi and protists
- Slime molds (page 517), water molds, and labylathulomyetes
- Obtain energy from decomposing organic material – hetertrophs
- Slime molds – found in damp soil and on rotting food
- reproduce using sporagia (a structure found in fungi)
- decomposers
- Water molds, downy mildews and white rusts
- Feed on dead organisms and some parasites to plants or animals
- One of the water molds attacked the potato crop in Ireland in the 1840s causing famine that resulted in death of over a million people.
- Contractile Vacuoles = pump out excess water
Synthesis
- DNA Synthesis, protein synthesis (enzymes), organic compound synthesis, photosynthesis in some.
Transport
- Cytoplasmic streaming àmovement of cytoplasm all around the cell (organism’s body), moves material like a river
- Endocytosis, exocytosis (vacuoles)
Excretion
- Contractile vacuole - get rid of excess water (most live in watery environments – fresh and marine)
- Exocytosis to get rid of waste (food)
- Example: amoeba
Respiration
- Diffusion
Nutrition
- Autotrophs and Hetertrophs
- Absorb nutrition/food directly from outside through membrane (endocytosis, phagocytosis)
- Digest food inside of vacuoles, using enzymes found in lysosome
Growth and Development
- Asexual - one cell grows until it reaches limit. It divides to make 2 protists
Regulation
- Eye spots - pigments that help find sunlight
- Positive Phototaxis
Reproduction
- Unicellular = asexual reproduction
- Some sexual = fission, conjugation (connect and swap parts of DNA)
Fungi
Kingdom Fungi – Page 529-543
Mode of Nutrition
Fungi are Heterotrophic and secrete enzymes, allowing then to digest their food
Useful Fungi
- Eukaryotes
- Some are edible some are poisonous
- Live in aquatic environments, soil, mud and decaying plants
- Include black bread mold, yeast, mushrooms, and truffles
- Not motile - Don’t move around.
- Not dependant upon light - can occupy dark habitats
- Can grow in any direction
- Hyphae = thread-like filaments that build all multi-cellular fungi (basic unit of structure)
- Mycelium = network of hyphae (may contain different types of hyphae)
- Cell walls of fungi composed of Chitin = complex carbohydrate for strength and flexibility.
Mode of Nutrition
Fungi are Heterotrophic and secrete enzymes, allowing then to digest their food
- Fungi are also saprophytes – organisms that live in or on matter that they decompose as they use it for food.
- Food digested outside body and nutrients absorbed from the environment. They digest then ingest.
- Major decomposers, mutualists, and parasites
- Lichen is a fungus that grows together with algae creating a symbiotic relationship. Rocks and dead trees are broken down into soil by the lichen. The algae provide food through photosynthesis, and the fungi provide protection and structure. Some lichens cannot grow in areas with high pollution, so they are often used as an indicator or the level of pollution in an area
- Fungi along with bacteria are the great recyclers. Together they keep the earth from becoming buried under mountains of waste.
- Reproduce sexually and asexually with reproductive cells called spores.
- Spores are produced sexually by the fruiting body, the visible portion of a reproductive structure like a mushroom. The spore is released into the air and if conditions are right, it grown into an individual on its own. The fruiting body forms gametes that reproduce sexually.
- Fungi reproduce asexually through mitosis and budding. Budding occurs when a piece of the organism becomes detached and continues to live and grow on its own as a complete structure
- Human diseases - Nail fungus
- Diseases in plants and animals
- Some fungal species cause diseases by growing on and causing irritation to the skin, hair, nails or mucus membrane of animals
- Many are not harmful, but they are irritating and difficult to eliminate. Fungal spores can also be inhaled and cause infections in the lungs and other organs. These types of infections are not very common but can cause permanent damage.
- Causes rot and contamination of food.
- Can destroy manufactured goods except plastic and some pesticides.
Useful Fungi
- Yeast
- Antibiotics (penicillin and cephalosporin)
- Medicines (cyclosporine)
- Organic acids - citric acids in Coke is from Aspergilla
- Steroids and hormones - the pill
- “Stinky Cheese” - Fungus Pencillium is responsible for the flavors of Roquefort and Camembert