VI' "Spending" Energy II: DNA REPLICATION AND MITOSIS

1
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase)
2
LE 12-5
INTERPHASE
S (DNA synthesis)
G1
Mitosis
Cytokinesis
G2
MITOTIC (M) PHASE
3
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase)     1.  Interphase        
4
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase)     1.  Interphase         -G1 high
metabolic activity (protein synthesis)
chromosomes diffuse one DNA double helix per
chromosome                
5
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase)     1.  Interphase         -G1 high
metabolic activity (protein synthesis)
chromosomes diffuse one DNA double helix per
chromosome                 Some cell types are
"stuck" in this stage when they mature... it is
only "stem cells" that keep dividing.  In some
tissues, all stem cells                
eventually mature, so the tissue can't regenerate
(neurons)
6
LE 12-15
G0
G1 checkpoint
G1
G1
If a cell receives a go-ahead signal at the G1
checkpoint, the cell continues on in the cell
cycle.
If a cell does not receive a go-ahead signal at
the G1 checkpoint, the cell exits the cell cycle
and goes into G0, a nondividing state.
7
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase)     1.  Interphase         -G1 high
metabolic activity (protein synthesis)
chromosomes diffuse one DNA double helix per
chromosome                 Some cell types are
"stuck" in this stage when they mature... it is
only "stem cells" that keep dividing.  In some
tissues, all stem cells                
eventually mature, so the tissue can't regenerate
(neurons)         -S replication phase DNA is
replicated - 2 helices per chromosome
8
LE 12-4
0.5 µm
Chromosome duplication (including DNA synthesis)
Centromere
Sister chromatids
9
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase)     1.  Interphase         -G1 high
metabolic activity (protein synthesis)
chromosomes diffuse one DNA double helix per
chromosome                 Some cell types are
"stuck" in this stage when they mature... it is
only "stem cells" that keep dividing.  In some
tissues, all stem cells                
eventually mature, so the tissue can't regenerate
(neurons)         -S replication phase DNA is
replicated - 2 helices per chromosome
10
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase)     1.  Interphase         -G1 high
metabolic activity (protein synthesis)
chromosomes diffuse one DNA double helix per
chromosome                 Some cell types are
"stuck" in this stage when they mature... it is
only "stem cells" that keep dividing.  In some
tissues, all stem cells                
eventually mature, so the tissue can't regenerate
(neurons)         -S replication phase DNA is
replicated - 2 helices per chromosome        
-G2 preparatory stage for Mitosis
11
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase) B. Mitosis
12
LE 12-5
INTERPHASE
S (DNA synthesis)
G1
Mitosis
Cytokinesis
G2
MITOTIC (M) PHASE
13
LE 12-6aa
INTERPHASE
PROPHASE
PROMETAPHASE
Centrosomes (with centriole pairs
Chromatin (duplicated)
Early mitotic spindle
Aster
Kinetochore
Fragments of nuclear envelope
Nonkinetochore microtubules
Centromere
Nucleus
Plasma membrane
Nuclear envelope
Chromosome, consisting of two sister chromatids
Kinetochore microtubule
14
LE 12-6ba
METAPHASE
ANAPHASE
TELOPHASE
Metaphase plate
Cleavage furrow
Nucleolus forming
Nuclear envelope forming
Centrosome at one spindle pole
Daughter chromosomes
Spindle
15
VI. "Spending" Energy II DNA REPLICATION AND
MITOSIS A. Cell Cycle (Interphase and Divisional
Phase) B. DNA Replication C. Mitosis    
-Prophase nuclear membrane breaks down spindle
apparatus forms from cytoskeletal actin strands.
Attach to kinetochores at centromeres Chromosomes
condense (supercoil)
G2 OF INTERPHASE
PROPHASE
PROMETAPHASE
16
LE 12-6da
C. Mitosis     -Prophase nuclear membrane breaks
down spindle apparatus forms from cytoskeletal
actin strands. Attach to kinetochores at
centromeres Chromosomes condense (supercoil)    
-Metaphase chromosome condensed and aligned on
metaphase plate attached to both poles by spindle
fibers  
TELOPHASE AND CYTOKINESIS
METAPHASE
ANAPHASE
17
LE 12-6da
C. Mitosis     -Prophase nuclear membrane breaks
down spindle apparatus forms from cytoskeletal
actin strands. Attach to kinetochores at
centromeres Chromosomes condense (supercoil)    
-Metaphase chromosome condensed and aligned on
metaphase plate attached to both poles by spindle
fibers     -Anaphase replicate helices are
separated spindle fibers moves them to opposite
poles of the cell.
10 µm
TELOPHASE AND CYTOKINESIS
METAPHASE
ANAPHASE
18
LE 12-6da
C. Mitosis     -Prophase nuclear membrane breaks
down spindle apparatus forms from cytoskeletal
actin strands. Attach to kinetochores at
centromeres Chromosomes condense (supercoil)    
-Metaphase chromosome condensed and aligned on
metaphase plate attached to both poles by spindle
fibers     -Anaphase replicate helices are
separated spindle fibers moves them to opposite
poles of the cell. -Telophase nuclear membrane
reforms at each pole.  Cytoplasm is divided.
10 µm
TELOPHASE AND CYTOKINESIS
METAPHASE
ANAPHASE
19
LE 12-10
Chromatin condensing
Nucleus
10 µm
Chromosomes
Cell plate
Nucleolus
Prometaphase. We now see discrete chromosomes
each consists of two identical sister
chromatids. Later in prometaphase, the nuclear
envelope will fragment.
Prophase. The chromatin is condensing. The
nucleolus is beginning to disappear. Although not
yet visible in the micrograph, the mitotic
spindle is starting to form.
Metaphase. The spindle is complete, and the
chromosomes, attached to microtubules at their
kinetochores, are all at the metaphase plate.
Telophase. Daughter nuclei are forming.
Meanwhile, cytokinesis has started The cell
plate, which will divide the cytoplasm in two, is
growing toward the perimeter of the parent cell.
Anaphase. The chromatids of each chromosome have
separated, and the daughter chromosomes are
moving to the ends of the cell as their
kinetochore micro- tubules shorten.
20
LE 12-9a
100 µm
Cleavage furrow
Daughter cells
Contractile ring of microfilaments
Cleavage of an animal cell (SEM)
21
LE 12-9b
Vesicles forming cell plate
Wall of parent cell
1 µm
New cell wall
Cell plate
Daughter cells
Cell plate formation in a plant cell (TEM)
22
UNIT 3 DARWIN AND MENDEL
23
I. Darwins Contributions
24
I. Darwins Contributions A. Life - Born
Feb 12, 1809
25
I. Darwins Contributions A. Life - Born
Feb 12, 1809 - Graduated Cambridge,
intending to join the clergy
26
I. Darwins Contributions A. Life - Born
Feb 12, 1809 - Graduated Cambridge,
intending to join the clergy - 1831-36,
Naturalist on H.M.S. Beagle
27
I. Darwins Contributions A. Life - Born
Feb 12, 1809 - Graduated Cambridge,
intending to join the clergy - 1831-36,
Naturalist on H.M.S. Beagle - 1859
Origin of Species
28
I. Darwins Contributions A. Life - Born
Feb 12, 1809 - Graduated Cambridge,
intending to join the clergy - 1831-36,
Naturalist on H.M.S. Beagle - 1859
Origin of Species - Died April 19, 1882,
interred in Westminster Abbey
29
B. The Origin of Species
30
B. The Origin of Species 1. One Long
Argument - observations leading to the
conclusions that - life changes through time
31
B. The Origin of Species 1. One Long
Argument - observations leading to the
conclusions that - life changes through time
- species descend from shared ancestors
A B C
32
B. The Origin of Species 1. One Long Argument
evidence of ancestry 2. Proposed Hypothesis
for HOW change occurs - Natural Selection
33
B. The Origin of Species 1. One Long Argument
evidence of ancestry 2. Proposed Hypothesis
for HOW change occurs - Natural
Selection 3. Dilemmas things that didnt fit
34
C. Observations 1. Geology - The Earth is
OLD - James Hutton (1726-1797) Scottish
Geologist
35
Hadrians Wall, but by the Roman Emperor Hadrian
in 122 A.D. 2000 years old, but no sign of
erosion. How much older must highly worn and
eroded granite outcrops be?
36
And how long must it have taken for the layers of
sediment comprising the White cliffs of Dover to
accumulate?
If rates of erosion and mountain building have
been uniform, governed by the processes we see
operating in nature today, then "(in
geology) we find no vestige of a beginning,no
prospect of an end." . (The Earth is
immeasureably old.)
37
C. Observations 1. Geology - The Earth is
OLD - Charles Lyell (1797-1875) British
Geologist Principles of Geology Promoted the
concept of UNIFORMITARIANISM
(slow, steady change, accumulating over long
periods of time, can result in major effects)
38
C. Observations 2. Paleontology a. Major
groups appear at different times - additive
recent
Mammals
Birds
Reptiles
Amphibians
Jawed fishes
Jawless fishes
past
39
C. Observations 2. Paleontology b. Within a
lineage, there are patterns of gradual change
40
C. Observations 2. Paleontology b. Within a
lineage, there are patterns of gradual
change c. Within a lineage, there are patterns
of radiation (many descendants from few
ancestors).
41
C. Observations 3. Comparative Anatomy -
Homologous Structures
42
C. Observations 3. Comparative Anatomy -
Homologous Structures
Same structure, but different uses in different
environments (correlated pattern)
43
C. Observations 3. Comparative Anatomy -
Analogous Structures
44
C. Observations 3. Comparative Anatomy -
Analogous Structures
Different structures, but same uses in the same
environment . (again, a correlation between
anatomy and environment)
45
C. Observations 3. Comparative Anatomy -
Analogous Structures
Different structures, but same uses in the same
environment . (again, a correlation between
anatomy and environment) Could the relationship
be causal?
46
C. Observations 3. Comparative Anatomy -
Vestigial Structures Whale hip bones
47
C. Observations 3. Comparative Anatomy-
Vestigial Structures Human structures
48
Argentina
Australia
C. Observations 4. Biogeography - Community
Convergence In similar environments, there are
organisms that fill similar ecological roles
and they are morphologically similar.
Correlated patterns