Chapter 2- Cell division and stem cells Flashcards
Why are cells needed for growth?
We need more cells as we grow, and some cells become damaged or weakened over time, so we require new ones to replace those.
Why do we need cells for development?
We need new cell types as we develop new tissues within our body.
Why do we need cells for repairing?
We loose cells each day, and so we need new cells to replace the lost ones.
What is the cell cycle?
The series of steps that takes place as a cell grows and then divides.
What are the steps of the cell cycle?
- G1 phase, Cellular growth- The cell gets larger and produces more sub-cellular structures, such as mitochondria and ribosomes.
- S phase, Synthesis - DNA synthesis replicates chromosomes so that each consists of two arms ( copies)
- G2 phase, Growth 2- Metabolic changes assemble all the cell material necessary for mitosis and cytokinesis.
ALL THE PHASES SBOVE ARE KNOWN AS AN INTERPHASE. - Mitosis- Nucleus divides
- Cytokinesis- the cells cytoplasm and membrane divide, creating two genetically identical “daughter” cells.
How many pairs of chromosomes do human cells have?
23 pairs.
How many chromosomes do human cells have in total?
46
cells created by mitosis are what?
Genetically identical to eachother.
When a cell divides, how many cells are produced?
2
Describe the process of mitosis
- In mitosis, all the chromosomes in the nucleus of a cell are copied
- The chromosomes line up in the middle of the cell and the nucleus of the cell breaks down.
- The chromosomes separate and the cell divides into two daughter cells.
- The two new cells contain identical chromosomes as each other and as the parent cell.
What is mitosis?
the process by which a cell replicates its chromosomes and then segregates them, producing two identical nuclei in preparation for cell division.
Name two types of stem cells found in animals
Embryonic stem cells and adult stem cells.
What are two key features of stem cells?
They can divide by mitosis to form more cells.
The can differentiate into specialized cells.
What is the process of an embryonic stem cell?
- When a sperm cell fertilizes an egg cell they form a single cell called a zygote.
- This cell then divides by mitosis to form a ball of cells which we call an embryo.
3.The cells in this embryo are known as embryonic stem cells and can differentiate into any type of cell.
Can adult stem cells divide by mitosis?
Yes
Can adult stem cells differentiate into all types of specialized cell?
No
What are some examples of specialized cells that stem cells can differentiate into?
Skin cells, blood cells and nerve cells.