cell division Flashcards
What does the cell cycle consist of?
Interphase (G1, S, and G2) mitosis and cytokinesis
What does the cell cycle lead to?
Genetically identical cells
How is the cell cycle regulated?
Checkpoints which control the cycle.
Where are the checkpoints in the cell cycle located?
After G1, after G2 and during metaphase
What does the G1 checkpoint check for?
The chemicals needed for replication are present, any damage to DNA and growth
What does the G2 checkpoint check for?
If all of the DNA has been replicated properly, if there is any damage, and if it is big enough.
What does the metaphase checkpoint check for?
The cell checks chromosomes are attached to the spindle before mitosis can continue
What are the main stages of mitosis?
Prophase, metaphase, anaphase, telophase
Why is mitosis important for life cycles?
It’s important for growth, tissue repair and asexual reproduction in plants animals and fungi
Why is meiosis significant in life cycles?
It produces haploid cells and genetic variation by independent assortment and crossing over
What happens in G1?
The cell grows and new organelles and proteins are made.
What happens during S phase?
S phase strands for synthesis, the cell replicates its DNA and gets ready to divide by mitosis
What happens in G2?
The cell continues to grow and proteins needed for cell division are made
What happens in M phase?
Mitosis and cytokinesis
What happens in interphase?
The cell prepares to divide, is DNA is unraveled and replicated to double its genetic content. The organelles are also replicated and ATP content is increased
What happens during prophase?
The chromosomes condense, and tiny bundles of protein called centrioles move to opposite ends of the cell. This forms a network of protein fibres called the spindle. The nuclear membrane breaks down and chromosomes lie free in the cytoplasm
What happens in metaphase?
The chromosomes each with two chromatids line up along the middle of the cell. They become attached to the spindle by their centromere. The metaphase checkpoint also occurs where the cell checks that the chromosomes are attached to the spindle.
What are chromosomes made from?
Two chromatids joined by a centromere