What describes tissues?
Which observations support the cell theory?
I- Mature red blood cells do not contain a nucleus.
II- Cells from a multicellular organism can be cultured in isolation.
III- Muscle fibres contain many nuclei.
IV- All cells develop from pre-existing cells
What is the ratio of the relative size of a eukaryotic cell, a virus and a prokaryotic cell?
What is the correct order of increasing size for the following biological structures?
I- The diameter of a virus
II- The diameter of a bacterium
III- The diameter of a cell surface membrane
IV- The diameter of a eukaryotic cell
What happens as a cell grows larger?
The diameter of living cells varies considerably. Typical diameters are:-
a prokaryote, such as Streptococcus- 750nm
a eukaryotic cell, such as white blood cell- 15 m
Given these measurements, the diameter of the white blood cell is how many times greater than the prokaryote?
Which scientist first used the term cell?
Differentiation results in cells:
Stem cells can form many kinds of cells.In contrast, most body cells cannot form different types of cells. For example, skin cells can only make skin cells, and nerve cells only make nerve cells. Which statement best explains why skin cells will never become nerve cells?
Cells are limited in size by the
One early piece of evidence supporting the cell theory was the observation that
What is the order of size of cell components?
(from left to right, from largest to smallest)
In an electron micrograph, a DNA molecules appear 1 mm wide. The magnification of micrograph is 500,000. What is the width of DNA molecule?