Chapter 10
Q. How many times can a cell go through mitosis?
The concept of the Hayflick limit was advanced by American anatomist Leonard Hayflick in 1961, at the Wistar Institute in Philadelphia, Pennsylvania, United States. Hayflick demonstrated that a normal human fetal cell population will divide between 40 and 60 times in cell culture before entering a senescence phase.
Table of Contents
- Q. How many times can a cell go through mitosis?
- Q. Do all types of cells undergo mitosis?
- Q. How often do cells divide?
- Q. Why do cells divide instead of growing larger?
- Q. Can a cell get too big?
- Q. What determines the cell shape?
- Q. How many shapes of cells are there?
- Q. What are the main shapes of cells?
Q. Do all types of cells undergo mitosis?
Mitosis happens in all eukaryotic cells (plants, animals, and fungi). It is the process of cell renewal and growth in a plant, animal or fungus.
Q. How often do cells divide?
Organisms grow because cells are dividing to produce more and more cells. In human bodies, nearly two trillion cells divide every day.
Q. Why do cells divide instead of growing larger?
Cells are limited in size because the outside (the cell membrane) must transport the food and oxygen to the parts inside. As a cell gets bigger, the outside is unable to keep up with the inside, because the inside grows a faster rate than the outside.
| Question | Answer |
|---|---|
| What are two reasons why cells divide rather than continue to grow indefinitely? | The larger a cell becomes… 1the more demans the cell places on its DNA 2the more trouble the cell has moving enough nutrients and wastes across the cell membrane |
Q. Can a cell get too big?
Can a cell get too big? If a cell gets too big it’s volume increases faster than its surface area. If the cell gets too big the there is not enough surface area for the cell to transport nutrients and waste. nuclear membrane starts to form again.
Q. What determines the cell shape?
Three general factors determine cell shape: the state of the cytoskeleton, the amount of water that is pumped into a cell, and the state of the cell wall. Each of these three factors is highly dynamic, meaning they are constantly in flux or can be suddenly changed. This dynamism is how cells can vary in shape.
Q. How many shapes of cells are there?
There are over 200 different cell types in the human body. Each type of cells is specialised to carry out a particular function, either solely, but usually by forming a particular tissue.
Q. What are the main shapes of cells?
The most common cell morphologies are cocci (spherical) and bacilli (rods). Coccibacillus are a mix of both, while vibrio are shaped like a comma, spirilla are shaped like a helix (a spiral, sort of like a stretched-out Slinky), and spirochetes are twisted like a screw.
