2.6 Flashcards
Describe each stage of cell cycle
M phase - mitosis and cytokinesis
Gap phase 1 - cell grows and new organelles and proteins are made
Synthesis - cell replicates its DNA for mitosis
Gap phase 2 - cell keeps growing and proteins needed for cell division are made
What does each check point do?
Regulates the cycle to make sure it’s ok for the process to continue
What are the main stages of mitosis?
Prophase
Metaphase
Anaphase
Telophase
What happens during prophase?
The nuclear envelope starts to break down so chromosomes lie free in cytoplasm
Centrioles move to opposite ends of the cell forming a spindle
What happens during metaphase?
Chromitids line up in the middle of the cell attaching to the spindle by their centromere
What happens during anaphase?
The centromeres divide into sister chromatids which move to opposite ends of the cell
What happens during telophase?
The chromatids reach opposite poles and uncoil to become chromosomes again
A nuclear envelope forms around each group of chromosomes resulting in two nuclei
What is the importance of mitosis?
It is needed for growth of multicellular organisms and repairing tissues
What is the importance of meiosis?
It produces gametes for sexual reproduction
Allows for genetic variation and natural selection to take place
Explain cell specialisation
Stem cells are unspecialised cells which can divide and to become new specialised cells during differentiation
What does meiosis 1 do?
Introduce genetic diversity
