Cells and animals Flashcards
What is movement?
A change in position of parts of an organism or the whole organism (locomotion)
What is a stimulus and what is a response?
Stimulus=change in the environment
Response=how you react to the stimulus
What are the different stimuli?
-touch
-chemicals
-heat
-light
-sound
What is sensitivity?
To be sensitive means to be able to detect a stimulus in the environment using receptors and be able to respond in some what to that stimulus
What is growth?
A permanent increase in size of an organism at some stage during their lifecycle
What is assimilation?
When substances are built up into structures of the body
What is respiration?
Respiration is the chemical reaction in which food is broken down to release energy. CO2 and H2O are also produced as waste products.
Where does respiration occur?
In every cell of every living organism
What gas does respiration require?
Oxygen
What is excretion
Excretion is the process by which organisms remove the waste products produced by metabolism from the body.
What is nutrition?
Nutrition is the process by which organisms obtain the essential substances that are needed for life.
What is heterotrophic nutrition?
Animals and non-green plants cannot make their own food so they depend on plants and other animals.
What does heterotrophic nutrition mean?
Hetero=others Trophic=feeding
What are animals that do heterotrophic nutrition called?
Heterotrophs
Types of heterotrophs, what do each of them feed on?
Carnivores - animals
Omnivores - plants and animals
Herbivores - plants
Parasites - living organisms
Saprotrophs - dead material (play important part in decomposition)
What is autotrophic nutrition?
Green plants make their own food by the process of photosynthesis
What does autotrophic nutrition mean?
Auto=self Trophic=feeding
Explain the process of photosynthesis
Plants take in CO2 (from the atmosphere) and water (from the soil) and build them up into complex food molecules using the energy from the sun (absorbed by chlorophyll in chloroplasts)
What is reproduction?
The production of new organisms either sexually or asexually
Differences between sexual and asexual reproduction
sexual:
2 parents required
involves union of male and female gamete
the offspring only resemble their parents and are not identical to them
few offspring are produced at one time
asexual:
1 paren required
no gametes involved
all offspring are identical to parent
asexual reproduction may take place very quickly and sometimes a very large number of offspring are produced
By who and when was the cell discovered?
Robert Hooke in 1665
What were the first cells observed?
Cork cells, more specifically dead cell walls
Who and when were the first living cells observed?
Antony Van Leeuwenhoek in 1674
What does The Cell Theory say?
- All living organisms are composed of cells, they may be unicellular or multicellular
- The cell is the most basic unit of life
- All cells arise from pre-existing, living cells
How much is a micrometer?
one thousandth of a millimeter
How do microscopes enhance our sight
They magnify things and at the same time resolve them
What is resolving power?
The ability to distinguish between2 objects
What is the maximum magnifying power of a light vs an electron microscope?
light = x400 (3 objective lenses= x4 x10 and x40, eyepiece = x10)
electron = x1,000,000
How much can the naked eye resolve?
one tenth of a mm
What do the electron and light microscopes use to magnify?
light = light and glass lenses
electron = beam of electrons and electromagnets
What do we use to see cells under light microscopes?
Cytoplasm is composed of mainly water, which is transparent to light, this makes it difficult to see the cell so we stain the cell using dyes e.g. methylene blue, iodine
Why can an electron microscope magnify more than a light microscope?
Electron wavelengths are thousands of times shorter than visible light so an electron microscope can resolve object thousands of times smaller
Why is the electron microscope so important?
Because it allowed scientists to see the internal structure of cell’s organelles and enabled them to understand their function
What type of images does the scanning electron microscope produce?
3D