Ch 12 Cell Cycle & Mitosis Exam 3 Flashcards
Cell Theory
-all living things are made of cells
-cells come from pre-existing cells
Mitosis
-cell replication
-separate the copies
S Phase
-copy the DNA
-process DNA replication
Cytokinesis
-divide the cytoplasm
Chromosomes and DNA
-DNA is packaged in chromosomes
Sister Chromatids
-contain identical DNA sequences
-are attached at the centromere
Unreplicated Chromosome
-consists of a single, long DNA double helix wrapped around proteins
Replicated Chromosome
-consists of two copies of the same DNA double helix
G1 Phase
-cell growth
-prepares for S phase
G2 Phase
-cell prepares for division(m-phase)
M Phase
-splits chromosomes & cytoplasm
-division of the nucleus and division of the cytoplasm
-contains prophase, prometaphase, metaphase, anaphase, & telophase
G1-S Checkpoint
-big enough?
-nutrients
-signal to divide
-DNA damage
G2-M Checkpoint
-DNA copied correctly?
-DNA damage
M-Phase Checkpoint
-did spindle attach to chromosome?
-did chromosomes separate?
Interphase
-chromosomes replicate
-cells are ready to enter m-phase
-each chromosome is composed of two sister chromatids
-centrosomes have replicated
-G1, S, G2 occur
Prophase
-1st step
-chromosomes condense
-spindle apparatus begins to form
Prometaphase
-2nd step
-nuclear envelope breaks down
-microtubules contact chromosomes at kinetochores
Metaphase
-middle phase(3rd step)
-chromosomes complete migration to middle of cell at an imaginary metaphase plate
-spindles are completely formed
Anaphase
-4th step(against phase)
-sister chromatids separate into daughter chromosomes
-daughter chromosomes are pulled to opposite poles in the cell
Telophase
-5th step(last)
-nuclear envelope re-forms around chromosomes
-chromosomes de-condense
Cytokinesis
-divides the cell into two daughters
-cytoplasm divides into each cell
-in plants the spindle apparatus is where the cells will separate
-in other eukaryotes cleavage furrow forms
M Phase Promoting Factor
-protein kinase that activates M-phase
Cyclin-CDK Regulation
-phosphorylation of one site inhibits kinase activity
-phosphorylation of a different site activates kinase activity
Cancer
-defects that activate proteins required for cell growth when they shouldn’t be
-defects that prevent tumor suppressor genes from putting the brakes on cell cycle
Cancer Properties
-cancer starts as a single mutated cell
-mutations allow the cell to acquire new characteristics
Uncontrolled Growth
-loss of social control
Invasive Growth
-cells from the tumor can detach & invade other parts of the body
