Viruses

Question 1

what are viruses?

Answer 1

viruses are a strand of genetic material (DNA or RNA), surrounded by a protein coat

Question 2

are viruses alive?

Answer 2

no, they do not respire or carry out any of the other normal processes taking place in living organisms

Question 3

how do viruses reproduce?

Answer 3

• by entering a host cell, they take over the ribosomes and enzymes in the cell to make new virus particles
• when many new viruses have been made, the cell dies and the viruses are released to infect new cells

Question 4

can viruses infect other organisms?

Answer 4

viruses can infect all other organisms (e.g. Tobacco Mosaic Virus causes brown patches on leaves by stopping chloroplast production, while Influenza infects humans)

Question 5

what are decomposers?

Answer 5

fungi and some bacteria

Question 6

how do decomposers feed?

Answer 6

by saprotrophic nutrition

Question 7

what is saprotrophic nutrition?

Answer 7

• when decomposers secrete digestive enzymes outside of their cells onto the dead organism
• the dead organism is broken down into small, soluble molecules, which are then absorbed by the decomposer for extracellular digestion