Flashcards in The Nature And Variety Of Iiving Organisms (T1) Deck (63):
The study of
Life and living things
Generally, what two categories can things be split into?
What are the seven characteristics of life?
What is sometimes added as an 8th characteristic of life?
Control - the ability to control internal conditions
Briefly describe the characteristic 'movement'...
Both animals and plants move. Animals through their muscles and plants through growth and reacting to stimuli such as sunlight.
Briefly describe the characteristic 'reproduction'...
All animals and plants reproduce.
Plants produce seeds which give rise to more of their species.
Broadly speaking there are two main types of reproduction..
- sexual reproduction, when two parents come together along with the union of two gametes
- asexual reproduction, when one parent reproduces itself
Briefly describe the characteristic 'sensitivity'...
- both animals and plants have an awareness of internal conditions and external environments.
- animals in general react quickly to external stimuli like heat and touch
- plants react slowly to stimuli such as sunlight
Give an example of a plant that reacts quickly to touch...
The Venus flytrap
Describe the characteristic 'growth'...
The increase in size and mass of plants and animals as they age / mature / feed
Briefly describe the characteristic 'respiration'...
- the process of unlocking or transferring energy from food
- it is the breakdown of glucose using oxygen to produce energy
- the energy is then used to drive further chemical reactions
Briefly describe the characteristic 'excretion'...
The process of getting rid of metabolic waste produced by the body (eg: urine and carbon dioxide)
Getting rid of faeces is NOT excretion. What is is?
Briefly describe the characteristic 'nutrition'...
- animals and plants need food for energy
- plants feed by process of photosynthesis
- animals rely on eating other plants or animals
Plants also have organs - give four examples...
Name the seven main organ systems in the human body...
- digestive system
- respiratory system
- circulatory system
- excretory system
- nervous system
- endocrine system
- reproductive system
What are the 5 kingdoms of living organisms?
Why are viruses not categorised as 'living'?
- until they invade a host they cannot be classified as living
- they are described as being on the threshold of life
Are plants unicellular or multicellular?
All plants are multicellular
Due to plant's method of photosynthesis, they are described as what kind of feeders?
What are the two main types of plants?
- flowering plants, like cereals, herbaceous legumes and conifers
- green plants such as algae, ferns and mosses
As animals feed in other organisms, they are known as what kind of feeders?
How do animals usually achieve movement amongst and other such functions?
Through nervous communication - communications between neurons in the nervous system
In what form do animals store carbohydrates in their cells?
Animals store carbohydrates in the cells as the compound glycogen
Animals are unicellular or multicellular?
What are the six groups of animals?
Animals with no backbone, such as sponges, inspects, segmented worms etc...
They breathe using gills under water and have no limbs
Vertebrates (have a spine) and generally lay eggs in water
Cold blooded vertebrates, distinguished from amphibians by their scales and their ability to lay hard shelled amniotic eggs
Have feathers, bills and can usually fly
Distinguished from reptiles and birds by hair, three middle ear bones, mammary glands (in females) and the region of the brain called the Neo Cortex
Are fungi multicellular or unicellular?
Can be unicellular (yeasts) and multicellular (mushrooms and toadstools)
What substance is the cell wall of fungi made of?
A substance called chitin
How do fungi feed?
They secrete digestive enzymes onto food materials then absorb the organic product
What kind of feeders are fungi known as?
What are the enzymes that are secreted our of fungi cells for saprotrophic nutrition known as?
What is the hyphae?
A network of threadlike filaments under the soil, beneath and connected to mushrooms and toadstools
What is often the reproductive structure of mushrooms and toadstools?
Quite often the mushrooms or toadstools themselves
What is a whole network of hyphae called?
How can fungi store carbohydrates?
Fungi can store carbohydrates as glycogen
Where is the hyphae located on mould?
A mould is like a mushroom without its fruiting body and just consists of the network of hyphae
Instead of seeds, how do fungi reproduce?
What are protoctists?
- sometimes known as 'the Dustbin Kingdom'
- a mixed group of organisms with no distinct identity
- microscopic single-called organisms
- can exists either on their own or in cell colonies
Briefly describe and give examples of two different types of protoctists...
- some, like the amoeba, have features similar to animal cells. These are known as Protozoa.
- others, like chlorella, have chloroplasts and carry out photosynthesis. These are known as algae.
Give an example of a pathogenic protoctista...
Plasmodium, which causes malaria
Algae are usually unicellular, but give an example of when they can be multicellular
Some species of algae like seaweeds are multicellular and can grow to a great size
- small single-called organisms
- bacteria cells are much smaller than those of animals, plants or protoctists and have a much simpler structure
- all bacteria are surrounded by a cell wall composed of complex chemicals made of polysaccharides and proteins
- some species have another layer outside the cell wall called a capsule or slime layer
- have no nucleus, but instead DNA is in a single chromosome, loose in the cytoplasm, forming a circular loop
How do bacteria feed?
Some can photosynthesise, but most feed on living or dead organisms
What are flagella (singular - flagellum) ?
Structures that allow some bacteria cells to swim, by corkscrew type movements
Give an idea of how small bacteria are...
- a typical animal cell is approx 10um to 50um in diameter
- a typical bacteria is only 1 to 5um in length
What are the three shapes of bacteria?
3/4 of all known bacteria contain small circular rings of DNA. What are they called?
Give two examples of bacteria...
- lactobacillus bulgaricus is rod shaped and used in the production of yoghurt from milk
- pneumococcus is spherical and acts as a pathogen causing pneumonia
- parasitic and can only reproduce inside living cells
- have no cellular structure, but have a protein coat and contain one type of nucleic acid; DNA or RNA
- sometimes a membrane called an envelope may surround a virus particle but the virus steals this from the surface membrane of a host cell
How big are virus cells?
Around 0.01 and 0.1um in diameter
How does a virus reproduce?
- enters a host cell
- takes over the hosts genetic machinery to make more virus particles
- once enough particles have been made the host cell dies
- the virus particles are released to infect more cells
Usually the immune system destroys an invading virus and the person survives, but sometimes the virus destroys the immune system itself. Give example...
HIV (Human Immunodeficiency Virus) which eventually causes the disease AIDS (acquired immune deficiency syndrome)
Describe a virus which infects plant cells...
The tobacco mosaic virus, which interferes with the ability of the tobacco plant to make chloroplasts, causing mottled patches on the leaves
What are pathogens?
Microorganisms that cause disease
What type of cells can pathogens be?
They can be bacteria, viruses, protoctists and sometimes fungi
How does vaccination work?
Pathogens are passed into the body in a weakened form, just enough to create enough white blood cells to protect the body from the disease