Life science
Grade: 11
Characteristics of viruses:
All viruses are parasites living in plants, animals or bacteria.
Viruses are very specific with regard to their host.
Viruses cause many diseases in plants and animals e.g., AIDS, rabies, mumps,
measles.
Viruses reproduce by transforming the hosts nucleic acids into virus nucleic acids
when they multiply.
Characteristics of bacteria:
Some bacteria are auto-trophic (manufacture their own food)
Others are heterotrophic (unable to make their own food)
Two types of autotrophic bacteria:
Photosynthetic bacteria manufacture their own food using light energy.
Chemosynthetic bacteria manufacture their own food using energy released from
chemical processes.
Three types of heterotrophic bacteria:
Parasitic bacteria obtain their food from other living organisms on which they live,
if these parasitic bacteria cause diseases we say they are pathogenic bacteria or
pathogens. If they do not cause diseases, we say they are non-pathogenic or non-
pathogens.
Saprotrophic bacteria obtain their food from dead plants and animals.
Mutualistic bacteria which live in or on plants and animals for the benefit of both
organisms
Fungi characteristics:
Fungi have cell walls.
Do not have chlorophyll, they are all heterotrophic.
Fungi reproduce by means of spores.
Fungi are not all the same in terms of where spores are produced, examples:
mold produces its spores in special spore cases called sporangia.
Mushrooms produce spores in club-shaped structures usually found within cap-like
fruiting bodies.
Produce spores in sac-like structures.
There are methods that differ in nutrition. For example:
some fungi depend on living organisms for their food, they are parasites.
Some obtain their food from dead remains of plants and animals, they are
saprotrophic.
, Role of micro-organisms in maintaining balance in the environment and web of life:
page 17
some micro-organisms are auto-trophic.
These auto trophic micro-organisms are produced.
Whales
Plankton small crustaceans sardines humans
Sharks
Symbiotic relationship page: 17-18
Symbiotic refers to an interaction in which two organisms of different species.
It includes the following type of interactions:
Mutualism – where both organisms in the relationship benefit
Parasitism – in which the one benefits and the other is harmed.
Commensalism – where one benefits by using others for support.
Chloroplast diagram: page 125
Bryophytes: page 55
Grade: 11
Characteristics of viruses:
All viruses are parasites living in plants, animals or bacteria.
Viruses are very specific with regard to their host.
Viruses cause many diseases in plants and animals e.g., AIDS, rabies, mumps,
measles.
Viruses reproduce by transforming the hosts nucleic acids into virus nucleic acids
when they multiply.
Characteristics of bacteria:
Some bacteria are auto-trophic (manufacture their own food)
Others are heterotrophic (unable to make their own food)
Two types of autotrophic bacteria:
Photosynthetic bacteria manufacture their own food using light energy.
Chemosynthetic bacteria manufacture their own food using energy released from
chemical processes.
Three types of heterotrophic bacteria:
Parasitic bacteria obtain their food from other living organisms on which they live,
if these parasitic bacteria cause diseases we say they are pathogenic bacteria or
pathogens. If they do not cause diseases, we say they are non-pathogenic or non-
pathogens.
Saprotrophic bacteria obtain their food from dead plants and animals.
Mutualistic bacteria which live in or on plants and animals for the benefit of both
organisms
Fungi characteristics:
Fungi have cell walls.
Do not have chlorophyll, they are all heterotrophic.
Fungi reproduce by means of spores.
Fungi are not all the same in terms of where spores are produced, examples:
mold produces its spores in special spore cases called sporangia.
Mushrooms produce spores in club-shaped structures usually found within cap-like
fruiting bodies.
Produce spores in sac-like structures.
There are methods that differ in nutrition. For example:
some fungi depend on living organisms for their food, they are parasites.
Some obtain their food from dead remains of plants and animals, they are
saprotrophic.
, Role of micro-organisms in maintaining balance in the environment and web of life:
page 17
some micro-organisms are auto-trophic.
These auto trophic micro-organisms are produced.
Whales
Plankton small crustaceans sardines humans
Sharks
Symbiotic relationship page: 17-18
Symbiotic refers to an interaction in which two organisms of different species.
It includes the following type of interactions:
Mutualism – where both organisms in the relationship benefit
Parasitism – in which the one benefits and the other is harmed.
Commensalism – where one benefits by using others for support.
Chloroplast diagram: page 125
Bryophytes: page 55
