Chapter 12: Cellular
Reproduction
Objectives:
1.
You will understand the
terminology associated with
chromosomes
2.
You will understand the
individual parts of the cell cycle
3.
You will understand the phases
of mitosis
4.
You will understand how cells
regulate their reproduction
5.
You will understand the basics
of how malfunctions of cellular
regulation can cause cancer.
DNA Packaging Terminology
Chromatin – Mix of nucleic acid and
proteins
Chromosomes – Packaged DNA
– Nucleic acid packaged around proteins
-Human Somatic (46) - Diploid
-Human Gametes (23) – Haploid
-Sister Chromatids – Identical
chromosomes that are attached at a
centromere - Have already duplicated
-Mitosis – is the splitting of the
nucleus followed cytokinesis
Cell Cycle
Interphase
-G1 or Gap phase:
cell grows by multiplying organelles
and proteins
-S Phase or Synthesis:
Cell continues to grow as DNA
duplicates or makes an exact copy
(sister chromatid)
-G2 or Gap phase:
Cell continues to grow and gets
ready to divide. (SA to Volume)
Mitosis: Nuclear division
Cytokinesis:
final division of
organelles and cells into identical
daughter cells
Mitosis Part I
-Chromosomes have
duplicated
-Chromatin has been condensed into
visible chromosomes
-Microtubules extend and
some bond to kinetochore
-Centrosomes have
duplicated each having two
centrioles
-Chromosomes appears with sister
chromatid
-Nuclear envelope is
breaking up
-Mitotic spindles are growing and
centrosomes are moving towards
opposite poles
Mitosis Part II
-Chromosomes align on the
metaphase plate
-Anaphase begins when the sister
chromosomes begin to be pulled
towards opposite poles
-Nuclear envelope now forms
-Cohesion proteins are cleaved
-Chromosomes become less dense
-Kinetochore microtubules jerk the
sister chromatids back and forth
until they all align in the middle
-Kinetochore microtubules shorten
-Cytokinesis begins
-Sister chromatids are now
daughter chromosomes
Cytokinesis
Animal Cells
Plant Cells
-Cleavage is driven by cytoskeleton
-microfiliments
-Vesicles carrying cell wall
components collect forming the cell
plate
Binary Fission
-Reproduction in Bacteria
-Asexual
Produces indentical copies of parent
Evolution of Mitosis
p. 237 figure 12.12
Molecular Regulation
Internal and External Regulation
1.
2.
3.
4.
Growth factors p. 241
Kinetochores
Density Dependent
Anchorage Dependent
Cell Signaling Malfunctions
-Cancer is the uncontrolled dividing of cells – Cells don’t heed the stop signals
-Cells are transformed (mutated into a cancerous cells)
-Benign tumors stay in one place
-Malignant tumors spread (metastasis)
-Cancer Cells
-Can have different number of chromosomes
-Have different metabolic pathways
-Changes in cell surface – Can change anchorage of cancer cells to other cells
-Grow in clumps and may have attract blood vessels to grow towards the tumor