NATURE AND VARIETY OF LIVING ORGANISMS Flashcards
name the 5kingdoms classification of living organisms
- Bacteria
- Protoctista
- Fungi
- Plantae
- Animalia
why are viruses not part of the living organism classification?
They are not made of cells and are not able to carry out some of the functions that are characteristics of living organisms.
However, they can reproduce and by parasitising cells.
describe the features of a plant organism.
These are multicellular organisms.
Their cells contain chloroplasts (an organelle that contain chlorophyll, a green pigment that traps light energy) so they are able to carry out photosynthesis.
Their cells have cellulose cell walls.
They store carbohydrates as starch or sucrose.
(examples of these are; flowering plants like …. cereals (e.g. maize) or herbaceous legumes (e.g. peas or beans)
describe the features of an animal organism
These are multicelular organisms.
They do not contain chloroplasts and are not able to carry out photosynthesis.
They do not have cell walls.
They usually have nervous coordination (so can rapidly respond to the changes in the environment) and are able to move from one place to another.
They often store carbohydrate and glycogen (lots of glucose molecules joined together and is stored in liver and muscle cells)
(examples: mammals (humans) or insects (housefly and mosquito)
Describe the features of a fungi organism
Some of them are single celled, but some have a body called mycelium (which is made up of hyphae - thread like structures which contain many nuclei)
They have cell walls made of chitin
Most feed by extra cellular secretion of digestive enzymes. By secreting enzymes outside their body and on to food material and absorption of organic products so they can absorb their nutrients.
They store carbohydrate as glycogen
(examples: Mucor (a typical hyphal structure- multicellular and has mycelium and hyphae) or yeast (single celled fungus)
They cannot photosynthesise
describe the features of a bacteria organism
These are microscopic single celled organisms.
They have a simple cell structure. They have a cell wall, cell membrane, cytoplasm and plasmids- It does not have a nucleus but has a single circular chromosome of DNA.
Some can carry out photosynthesis but most feed of other living or dead organisms
(Examples: lactobacillus bulgaricus (a rod-shaped bacterium used in the production of yogurt from milk) or pneumococcus (a spherical bacterium that acts as the pathogen causing pneumonia)
describe the features of Protoctists
A microscopic single celled organism
Some have chloroplasts and are similar to plant cells whereas others are more like animal cells and some are even pathogens (e.g algae or seaweed)
examples: some like the amoeba (lives in pond water and more related to animal cell), chlorella (has chloroplasts and is more plant like) and a pathogenic example is plasmodium (which is responsible for causing malaria)
describe the key features of a viruses
These are small particles (smaller than bacteria)
They are parasitic and can reproduce only inside living cells, they can infect all living organisms.
They have a wide variety of shapes and sizes.
They do not have a cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA.
examples: tobacco mosaic virus (causes discolouration in leaves of the leaves of tobacco plants as it prevents the formation of chloroplasts), the influenza virus (causes flu and the HIV virus that causes AIDS)
what is an organelle?
they are tiny structures within cells e.g nucleus
name the parts of an animal cell
nucleus, cytoplasm, cell membrane
name the parts of a plant cell
nucleus, cytoplasm, vacuole, cell membrane, cell wall
what does a nucleus do
it is an organelle which comtains the genetic material that controls the cells activity. It is surrounded by its own membrane.
what does a cell membrane do?
this membrane forms the outer surface of the cell and controls the substances that go in and out.
what does a cyptoplasm do?
it is a gel-like substance where most of the cells chemical reactions happen. It contains enzymes which control these reactions.
what does the vacuole do?
it’s a larger organelle which contains cell sap (a weak solution of sugars and salts) and helps supports the cell
