th
7
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=P
Hp6iYDi9ko
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=Ttl1iAVV
SjQ
• 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