Chapter 8 - The Developing Cell Flashcards
What happens during Growth 1 in interphase?
- cell increases in size and mass
- all metabolic processes remain active
- organelles replicated (except mitochondria and chloroplasts)
- increased protein synthesis occurs
What happens during the synthesis phase of interphase?
- DNA is replicated
- using SCR
What happens in Growth 2 in interphase?
- chloroplasts and mitochondria increase in size and divide
- energy stores are increased
- spindle fibers start to form
What are the 4 stages of mitosis?
- Prophase
- Metaphase
- Anaphase
- Telophase
What is cytokinesis?
Equal division of cytosine and organelles
Forms 2 genetically identical daughter cells
What is the importance of mitosis?
- growth of multicellular organisms
- repair of damaged tissues
- replacement of cells
- asexual reproduction
What happens in prophase?
- longest phase of mitosis
- chromosomes shorten and thicken
- centrioles move towards poles
- microtubules form
- nucleolus breaks down
- nuclear envelope breaks down
What happens in metaphase?
- chromosomes line up on the equator
- spindle fibres attach to the centromere
What happens in anaphase?
- spindle fibres contract
- pulling force on centromeres
- centromeres split
- daughter chromosomes pulled to opposite poles
What happens in telophase?
- daughter chromosomes reach poles
- chromosomes uncoil and lengthen
- spindle fibres disintegrate
- centrioles replicate
- nuclear envelope reforms around chromosomes at each pole
- nucleolus reforms
What happens in cytokinesis in animal cells?
- cell surface membrane invaginates
- cleavage furrow forms in the middle of the cell
- cell surface membrane pinches until 2 sides can meet
- cytoplasm divides equally
- organelles divide equally
What happens in cytokinesis in plant cells?
- vesicles from golgi apparatus assemble on the equator
- this is the cell plate
- vesicles fuse with each other and with the cell surface membrane
- new sections of cellulose cell wall form along the new sections of membrane (middle lamella)
- cytoplasm divides equally in 2
- organelles divide equally in 2
Why is it important that a cell wall is formed along the middle lamella before the 2 daughter cells are separated in plant cells?
to prevent osmotic lysis from the surrounding aqueous environment.
What is apoptosis?
- programmed cell death in multicellular organisms
- ordered and controlled process
What is necrosis?
- unregulated cell death after trauma
- cell surface membrane ruptures
- hydrolytic enzymes released
