Section 1
 To get bigger or make more cells that is the question?
 Limit to cell growth
o DNA overload
 DNA’s function
 Protein synthesis, everything is made of proteins
o Transport of materials
 As cell gets larger, what would happen to rate of
diffusion of materials?
 Consider a plant cell
Cell Size
Surface Area
(length x width x 6)
Volume
(length x width x height)
Ratio of Surface Area
to Volume
 To get bigger or make more cells that is the question?
 Limit to cell growth
o DNA overload
 DNA’s function
 Protein synthesis, everything is made of proteins
o Transport of materials
 As cell gets larger, what would happen to rate of
diffusion of materials?
 Consider a plant cell
 Surface area L X W X # of sides
 Volume L X W X H
 Ratio
 Process of creating two new daughter cells from one
o Genetically identical
 Purpose
o Regulates the size of a cell
o Repair of damaged cells
o Replace old cells
o Asexual Reproduction
Section 2
 Prokaryotes
 Cell division is a two step process
o Copy DNA
o Divide cytoplasm
 Eukaryotes
 Much more complex
o Cell division includes two main processes
 Mitosis Cytokinesis
 Become visible in the
cell only prior to cell
division
 DNA becomes tightly
coiled
 Structure
 Become visible in the
cell only prior to cell
division
 DNA becomes tightly
coiled
 Structure
 Chromosome number
G1 phase
M phase
S phase
G2 phase
 Interphase
o Preparation for mitosis
o Normal cell activities
o 3 sub phases
 G1 Phase(first gap)
 Cell growth
 Raw materials created for DNA synthesis
 S Phase (synthesis)
 DNA is replicated
 G2 Phase
 New organelles are created
 Proteins needed for spindle fibers are created
 M phase
o Composed of two parts
o Mitosis
o Cytokinesis
 4 phases
 Prophase
o Chromosomes condense and become visible
o Spindle fibers are created
 Centriole
 From microtubules
o Nuclear envelope breaks down
o Spindle fibers attach to chromatids within
centromere
 4 phases
 Prophase
o Chromosomes condense and become visible
o Spindle fibers are created
 Centriole
 From microtubules
o Nuclear envelope breaks down
o Spindle fibers attach to chromatids within
centromere
 Metaphase
o Chromosomes line up across middle
 4 phases continued
 Anaphase
o Centromeres break down
o Sister chromatids separate
 Daughter chromosomes
o Pulled by spindle fibers
o At end, chromosomes are at opposite poles
 4 phases continued
 Anaphase
o Centromeres break down
o Sister chromatids separate
 Daughter chromosomes
o Pulled by spindle fibers
o At end, chromosomes are at opposite poles
 Telophase
o Chromosomes begin to uncoil
o Spindle fibers break down
o Nuclei reform
 Animal cell
o Cytoplasm is pinched inward by proteins
 Actin and myosin
 Animal cell
o Cytoplasm is pinched inward by proteins
 Actin and myosin
 Plant cells
o Create a cell plate
o Vacuoles are created by golgi apparatus
Section 3
 Cyclins
o Protein family that when produced regulate passage of cell
through cell cycle
 Two major types of regulation
o Internal
 Checkpoints
 G1, G2, and M
 Stop signals
o External
 Growth factors
 Proteins produced by cells that cause other cells to divide
 Ex. MPF (maturation promoting factor)
 Wound healing
 Speeds up process of cell division
 Density dependent
 Slows down
 Uncontrolled cell growth
 Divide to form masses of cells called tumors
 Uncontrolled cell growth
 Divide to form masses of cells called tumors
o Benign
o Malignant
 Uncontrolled cell growth
 Divide to form masses of cells called tumors
o Benign
o Malignant
 Environmental triggers
o Carcinogens
 Genetic influence
o p53 gene- oncogene
o Normally does not allow cell to divide until it has the
proper number of chromosomes