Unit 2: Producing New Cells Booklet Key Points Flashcards
How many chromosomes are in a human body cell?
Human body cells contain 46 chromosomes arranged in 23 pairs
What do all body cells contain?
All body cells contain 2 sets of matching chromosomes, one set from the mother and one set from the father
What do diploid cells have?
2 sets of matching chromosomes
What is the chromosome complement?
The number of chromosomes a cell contains is it’s chromosome complement. Each species has it’s own chromosome complement.
What is the chromosome complement of human cells?
The chromosome complement of human cells is 46.
What is a chromosome made of?
2 chromatids joined at the centromere
What happens during DNA replication?
DNA replication makes a copy of each chromosome and before mitosis and cell division, they are joined together. When they are still joined together, each copy is called a chromatid. The combination of 2 joined chromatids is still called one chromosome.
What happens when unicellular organisms divide?
When unicellular organisms divide, they form a complete copy of themselves.
Why do multicellular organisms divide?
Multicellular organisms divide to provide new cells for growth, repair of damaged tissues and replacement of dead or damaged cells.
What is the process of a diploid cell dividing called?
Mitosis
What happens during mitosis?
During mitosis, two identical daughter cells are produced which contain the same number of chromosomes as the parent cell. This is important as they maintain the diploid chromosome complement and so have exactly the same genetic information as the mother cell. The cells can carry out the same functions as the parent cell.
What are the stages of mitosis?
- Nucleus contains long, uncoiled chromosomes which are difficult to see.
- Chromosomes make copies of themselves and become visible as pairs of identical chromatids.
- Chromosomes line up at the equator of the cell.
- Spindle fibres attach to chromosomes and pairs of chromatids are pulled apart.
- Chromatids move to opposite poles
- Nuclear membrane forms and cytoplasm divides.
What are stem cells?
Stem cells are unspecialised cells involved in growth and repair. They are responsible for the production of specialised cells in animals. They have the ability to become any type of cell.
What are the two types of stem cells?
Embryonic stem cells and tissue stem cells.
What is an embryonic stem cell?
Embryonic stem cells are derived from embryos that develop from eggs that have been fertilised in a laboratory.
