The origin of cells Flashcards
1
Q
What are the three claims of the cell theory?
A
- All living organisms are made up of cells
- All cells come from the division of pre-existing cells
- The cell is the basic unit of all living organisms, it is the structural and functional unit of them
2
Q
What did Louis Pasteur disprove and hence prove?
A
- He disproved the theory of spontaneous generation and pence supported the theory that cells come from pre-existing cells
3
Q
What is the theory of spontaneous generation?
A
- Life things could emerge from non-living matter such as dust and air
4
Q
Explain the experiment that disproved the spontaneous generation.
A
- He made three separate experiments, each flask had a swan-neck
- The first one was kept the same, NO microbes grown
- The second the neck was broken off, microbes grown
- The third, neck remained but flask tilted, microbes grown
- Each initial flask was heated
5
Q
Explain why no microbes grew in the first flask and bacteria grew in the second and third flask.
A
- Any microbes from the air were trapped in the curve of the swan-neck
- The broth turned cloudy, since the microbes from the air multiplied
- The tilted flask exposed the broth to microbes in the curve of the swan-neck
6
Q
Where did the first cells originate from? What are the conditions required for the emergence of life?
A
- First cell most likely came from non-living material
- Conditions: simple organic molecules (amino acids, fatty acids, carbohydrates), large organic molecules (phospholipids, RNA, DNA), replication of nucleic acids, set pH, membranes
7
Q
What is the endosymbiotic theory?
A
Check book for explanation
8
Q
What are 5 examples of evidence to support the endosymbiotic theory? (Characteristics of prokaryotes)
A
- Both have double membranes, which is expected for cells that were taken in by endocytosis
- Have circular naked DNA, (prokaryotic characteristic)
- DNA formed as single chromosomes
- Divide by binary fission
- Likely influenced by some antibiotics
