Key area 2.1 - Producing New Cells Flashcards
What is Mitosis ?
It’s the process of a cell making two exact copies of itself
During mitosis the parent cell will divide to produce two identical daughter cells
What’s the purpose of mitosis ?
It provides new cells for growth and repair of damaged cells
Describe chromosomes
Chromosomes are found within the nucleus of the cells, they carry the genetic information of the organism
Each chromosome is made up of two chromatids
Human cells have 46 chromosomes in the nucleus of each cell
Describe stages 1 + 2 of Mitosis
Stage 1: Chromosomes are replicating and doubling in number in preparation for mitosis
Individual chromosomes are not visible
Stage 2 : The chromosomes become coiled up and visible
Chromosomes are now made of pairs of identical chromatids
Describe stages 3 + 4 of Mitosis
Stage 3 : Pairs of chromosomes line up at the equator of the cell
Spindle fibres form and attach to the pairs of chromatids
Stage 4 : Spindle fibres contract and shorten
Pairs of chromatids are pulled apart
Chromosomes move to the opposite poles of the cell
Describe stages 5 + 6 of Mitosis
Stage 5 : Nuclear membranes form to produce 2 new nuclei
Stage 6 : The cytoplasm divides creating to identical daughter cells
What are stem cells ?
What is their purpose ?
Stem cells are found in animals and are unspecialised cells
They can divide to produce more stem cells or can develop into specialised cells
They have the potential to become different types of cell and are involved in growth and repair of body tissues
Name and describe the two types of stem cells
Tissue stem cells :
They can be found in the body throughout life ( bone marrow )
Embryonic stem cells :
Stem cells can be obtained from the embryo at a very early stage
What’s is the hierarchy of cells , tissues and organs ?
Cells ➡️ Tissues ➡️ Organs ➡️ Organ Systems
