Chromosomes and Cell Division 2/2 - First Lecture Flashcards
What are the stages of the cell cycle?
Interphase and mitosis
What are the different stages of interphase?
G1, S and G2
What happens during the G1 stage of interphase?
Protein and RNA synthesis Growth and maturation of the cell occurs DNA checking and subsequent repair occurs during the pause between G1 and S
What happens during the S phase of interphase?
DNA synthesis
What happens during the G2 phase of interphase?
Further synthesis of RNA and proteins Further growth Organelles such as mitochondria grow and divide Followed by proof reading and subsequent repair of newly synthesised DNA
What are the stages of Mitosis?
Prophase Metaphase Anaphase Telophase Cytokinesis
What happens during Prophase?
Chromosomes condense Nuclear membrane disappears Spindle fibres form from the centriole
What happens during metaphase?
Chromosomes allign t the equator of the cell Attached by fibre to each centriole Maximum condensation of chromosome
What happens during anaphase?
Sister chromatids separate at the centromere Move to opposite ends of the cell
What happens during telophase?
Nuclear membranes form
What happens during cytokinesis?
Cytoplasm separates
What is the structure of the centromere?
Repetitive DNA sequences (satellite DNA) Site of the kinetochore which is a protein complex that binds to microtubules
What is the difference between Heterochromatin and Euchromatin?
Heterochromatin is condensed structure Silenced genes Euchromatin Open structure Active genes
Where can you find satellite DNA and what is it?
Tandemly repeated DNA sequences at the Centromeres and telomeres of chromosomes
How is chromatin formed?
DNA packed within histone proteins