1 Biology Pg 3 Flashcards
(15 cards)
What addition did Virchow make to the cell theory in 1858?
Virchow stated that all cells arise from pre-existing cells.
What are the three major points of the Cell Theory?
- The cell is the smallest unit of structure of all living things.
- The cell is the unit of function of all living things.
- All cells arise from pre-existing cells.
What does the Cell Theory imply about a mango tree and a frog?
Both the mango tree and the frog are composed of cells that perform structural and functional roles.
What is the structural unit in living organisms?
Any part of the body of a frog or a mango tree shows a cellular structure when examined under a microscope.
What is the functional unit in living organisms?
Functions in the body of the frog or the mango tree are due to the activity of its cells.
How do cells die and get replaced?
Cells continuously die and are replaced by new ones formed by the division of younger cells.
What is the starting point of life for frogs and mango trees?
Life starts as a single cell: a fertilized egg for frogs and a seed for mango trees.
How does the number of cells relate to the size of an organism?
The bigger an organism, the greater the number of cells in its body.
What are examples of single-celled organisms?
Bacteria, yeast, and amoeba.
What are examples of few-celled organisms?
Spirogyra and Volvox.
What are examples of multi-celled organisms?
Human beings and mango trees.
How many cells does an average-sized adult human have?
Approximately 37-2 trillion cells.
What is the size of the smallest cells?
Bacteria (0.3-5.0 micrometre) and red blood cells (about 7 micrometre).
What is the size of the largest cells?
The ostrich egg is the largest single cell of the living world.
Why do cells generally remain small in size?
- Different regions of a cell can communicate rapidly.
- Cells have a large surface area/volume ratio.
