Chapter 4 - Cell Division Flashcards
What are induction and deduction?
Induction is when a conclusion is made from observations.
Deduction is when a conclusion is made from accepted facts.
What is a hypothesis?
An assumption based on limited evidence.
It must be falsefiable: meaning it can be tested.
What is a theory?
A proposed explanation based on evidence.
What are the three components of cell theory?
Cells are the basic unit of life, they are the smallest living thing.
All organisms are made up of one or more cells.
All cells come from pre-existing cells.
Describe Redi’s experiment that disprooved spontaneous generation.
Redi showed that maggots did not spontaneously generate from meat.
He did so by putting meat in a semi-closed container, showing that even if air could still pass, maggots did not generate from the meat.
Describe Pasteur’s experiment to disproove spontaneous generation.
Pasteur proved that if broth was sterilized, that is, the micro-organisms present in it were removed, then new micro-organisms would not generate.
This experiment involved boiling broth and putting it in two different swan-necked flasks.
The flask with a broken neck has its broth exposed to germ-filled air, and so micro-organisms are generated.
The flask with the intact neck is not exposed to the germs in the air, no micro-organisms generate.
What is the difference between the control treatment and the experimental treatment?
The experimental treatment or group receives the treatment that the scientists wish to study. In the case of Pasteur’s broth, it is the sterilized broth.
The control group does not receive the treatment, in this case, it is the un-sterilized broth.
What are the controlled variables?
Apart from the effect we want to isolate, nothing else is changed between the two experiments. This guarantees that no other outside factor could have affected the results.
What are the dependent and independent variables?
They are self explanatory. In the case of Pasteur’s experiment, the bacteria having or not having access to the broth is the independent variable, while the broth staying good or going bad is dependent on the independent variable.
What is repeatability?
The process is written down so that others can perform the experiment and see the results for themselves. This ensures transparency.
What are the steps of the scientific method?
- Make observations,
- Ask critical questions,
- Form hypothesis,
- Make a prediction to test the hypothesis,
- Experiment,
- Go back to step 2 if needed, adjust hypothesis,
- Record results,
- Form a conclusion,
- Convince peers.
How do we think the first cell came to be?
What were early forms of life based on?
Conditions on early earth are believed to have allowed the formation of amino acids and hydrocarbons.
The early forms of life were probably based on RNA, as it can self assemble, self replicate, transfer energy and catalyze reactions.
What are the 7 properties of life?
Cellular (3 components of cell theory)
Ordered complexity
Sensitivity
Growth and reproduction
Energy utilisation
Homeostasis
Evolution.
What is organized complexity?
Under a microscope, the live can be distinguished from the dead by observing ordered complexity.
What is energy utilisation?
Energy is required to power the chemical reactions necessary for life. Energy can be absorbed from food (heterotrophic), the sun (photoautotrophic), chemicals (chemoautotrophic).
