7th Grade Virus & Fungi

Standard 3.3.7.B

• B Viruses – extremely small non-living particles

1. simple structure, vary in shape a. protein coat, surrounds the

b. core of nucleic acid (RNA or DNA) 2. reproduce only in host cell

a. attaches itself to cell membrane of host

b. injects DNA/RNA into host cell c. viral DNA directs host to

reproduce new viruses d. host cell bursts releasing new

viruses

3. classified according to host a. bacterial b. plant – tobacco mosaic c. animal d. human – smallpox, hepatitis, Ebola, common cold

4. Because it is parasitic, duplication of the virus is rapid, usually causing illness or disease in the host.

https://www.youtube.com/watch?v=PHp6iYDi9ko

C. Protists 1. cells with nuclei and organelles 2. mostly single-celled, may live in colonies 3. may eat or make food 4. reproduce asexually or sexually 5. found in fresh and salt water; moist places

• 6. Protozoans – animal-like protist a. can move, respond to environment b. no cell wall c. reproduce by fission d. classified by structures of movement

1) sarcodinis – move by extending cytoplasm in a pseudopod, ex. Amoeba 2) ciliates – tiny hairs which cover body move

back and forth, ex. Paramecium 3) flagellates – whiplike structure propels it 4) sporozoans – no movement structures; reproduce by spores; parasitic

• https://www.youtube.com/watch?v=Ttl1iAVVSjQ

• E. Fungi - Fungi are a group of living organisms which are classified in their own kingdom. This means they are not animals, plants, or bacteria. Unlike bacteria, which have simple prokaryotic cells, fungi have complex eukaryotic cells like animals and plants.1. cells have cell walls, nuclei, organelles 2. many-celled 3. lack chlorophyll, can’t photosynthesize 4. digest food by releasing enzymes into surrounding organic surroundings, breaking it down, absorbing it

• 5. reproduce – asexually by budding or sexually by spore formation

• 6. form specialized structures, but no true roots, stems, or leaves

• 7. classified by spore-producing structures a. thread-like – spore cases at tip of hyphae; ex. mold b. sac fungi – spores produced in sac-like

structures; ex. mildew, morels, truffles; yeasts reproduce by budding

c. club fungi – club-shaped structure holds spores; ex. common mushroom d. imperfect fungi – no known sexual reproduction; ex. penicillin

https://www.youtube.com/watch?v=ruBAHiij4EA

8. helpful a. source of food b. flavor cheeses c. yeast used to make bread, alcohol d. produce certain drugs, ex. penicillin e. decomposers in food webs