Mitosis And Meiosis Flashcards
What is mitosis
Production of genetically identical cells for growyh, repair, sexual reproduction
Mitosis stages
Mitosis contains three main stages:
Interphase which contains of two growth stages G1+G2
Dna synthesis phase ( S1)
Mitosisis the nuclear division
Cytokinesis- splitting of the cell into two identical daughter cells
Mitosis description
Prophase - DNA condenses and coils, centrioles move to opposite poles
Metaphase - spindle fibres attach to centromeres and chronosomes line up at the equator
Anaphase- centromeres divide, chromatids line up at opposite poles
Telophase- chromosomes uncoil, nuclear envelope forms
Checkpoint locations
Between G1 and S= want to decide wether the Cell moves onto S phase
End of g1- checks cell is ready for S phase
Between g2 and mitosis- checks and repairs cell for all dna before cell enters mitosis
Ensures that the cell doesnt divide unecessarily
Middle of mitosis- ensures tha the cell is ready for mitosis and doesnt proceed to the next cell before its ready
Meosis
Meoisis 1 :cell dividies randomly , homologous pairs seperate from each other randomly, each cell has a maternal or paternal copy
Meiosis 2: each cell divides again creating 4 haploid cells
This creates genetic diversity due to the random pairing, creating different combinations
What is a stem cell
Undifferentiated cell that can divide indefinitely and turn into other types of cells
4 types of stem cells
Totipotent- can develop into any type of cell
Pluripotent - can develop into any cell BUT placenta and embryo
Multipotent- can develop into many cells
Unipotent- can only develop into one cell
Uses for stem cells
Can be used to repair tissues for patients
Can be used for drug testing
Can be used for research
Describe a specialised cell
A cell that can onlt perform a specific function
Describe function and structure of pallisade cells + guard cells in plants
Pallisade cells- specialised to absorb light energyfor photosynthesis , contains many chloroplasts ,packed closely together
Guard cells- when turgid, stroma opens , when flaccid stroma closes
Structure and function of root hair cells
Specialised to absorb water at low concentration
High surface area due to hairs
Meristem
Totipotent undiffeeentiated stem cells that can develop into any type of plant cell
