• Spindle fiber (mitotic spindle)
- long microtubules used for cell division
• Kinetochores
- protein complex where spindle fibers attach
CELL REPRODUCTION
Chromatin vs. Chromatid vs. Chromosome
Reproduction During interphase, DNA is loose (Chromatin)
- duplicating; making copies Then it is tightly packed (Sister Chromatids)
- formation of organisms of the same kind And joined together by the centromere (Chromosome)
Importance of Cell Reproduction CELL CYCLE
a) For growth - consists of:
b) For maintenance & repair
- repair and replacement of worn out cells/tissues a) Interphase
c) Perpetuation of Species - cell growth and copying of chromosomes in
- the existence of living things preparation for cell division
b) Mitotic (M) Phase
Extinction - mitosis and cytokinesis
- opposite of reproduction
- complete disappearance of a certain species Eukaryotic Cell Cycle
- Series of events taking place in a cell leading to its division
Cell Division and duplication of its DNA to produce two daughter cells
- integral part of the cell cycle, the life of a cell from
formation to its own division
- process in which cells duplicate themselves into two
identical daughter cells
• In unicellular organisms the division of one cell
reproduces the entire organism
• For multicellular organisms:
a) Development from a fertilized cell
b) Growth
c) Repair
Genome
- the complete set of genes/DNA present in a cell or
organism
1) Cell Growth Checkpoint
Nucleosomes - occurs towards the end of Growth Phase 1 (G1)
- eight histone proteins wrapped by the DNA - checks whether the cell is big enough and has made
the proper proteins for the synthesis phase
• If not, the cell goes through a resting period (G0)
Chromosomes
- Greek : chroma (color) + soma (body) until it is ready to divide
- DNA molecules packaged (via histones) into thread-like
structures 2) DNA Synthesis Checkpoint
- ahuman being consists of 23 pairs of chromosomes - occurs in the Synthesis Phase (S)
- checks whether the DNA has been replicated correctly
Parts of the Chromosome
3) Mitosis Checkpoint
a) Sister Chromatids - occurs during the Mitosis Phase (M)
- two threadlike strands into which a chromosome - checks if mitosis is complete, and if so, the cell divides
divides longitudinally during cell division and the whole cycle repeats
- consists of a long arm (q) and a short arm (p)
b) Centromere
- region where the chromatids are attached together
- area where the spindle fibers are attached
- made out of cohesin proteins
, MITOSIS Bacterial Reproduction
- duplication and distribution of chromosomes during cell
division • Binary Fission
- type of cell division by prokaryotes (bacteria and
archaea)
- the chromosome replicates and two daughter
chromosomes actively move apart
CELL CYCLE CONTROL SYSTEM
Checkpoints
- control points where there are stop and go-ahead signals
1) G1 Phase Checkpoint
- checks for nutrients, growth factors and DNA damage
2) G2 Phase Checkpoint
- checks for cell size and DNA replication
3) M Phase Checkpoint
- checks for chromosome spindle attachment
Proteins
a) Kinases
a) G2 of Interphase
- enzymes that activate or inactivate other proteins
- centrosome divides into two distinct centrosomes through phosphorylation
- chromosomes cannot be seen
- must attach to a cyclin to be active (cyclin-dependent
kinases (Cdks))
b) Prophase b) Growth Factor
- chromatin fibers condenses into discrete - proteins produced by other cells that stimulate other
chromosomes
cells to divide
- the nucleolus disappears
- each chromosome appears as two identical sister • Density-dependent inhibition
chromatids - stops most cells from dividing when they’re
- the mitotic spindle forms and the centrosomes move overcrowded
towards opposite poles • Anchorage dependence
• Prometaphase - reliance of cells to be attached to a substratum
- nuclear envelope fragments
- the nuclear membrane gradually disintegrates Cancer Cells
- microtubule invades the nuclear area and
attaches to the kinetochore Transformation
- non-kinetochore microtubules interacts to the - process of genetic alteration
opposite pole, thus, lengthening the cell
a) Benign Tumor
c) Mitosis
- abnormal cells remain at the original site; normally do
- centrosomes align at center a.k.a. metaphase plate not cause serious damage
- push and pull of microtubular units b) Malignant Tumor
- abnormal cells that can spread to new tissues
d) Anaphase
- disjunction of sister chromatids upon the break of the
Metastasis
centromere
- spread of cancer cells to other parts of the body which can
- cohesin proteins are cleaved cause additional tumors
- chromosomes migrate toward the opposite poles
- shortest stage of mitosis
- disappearance of spindle fibers except asters
e) Telophase
- reappearance of nuclear membrane and nucleolus
- two daughter nuclei forms in the cell
Cytokinesis
- division of the cytoplasm
- cleavage furrow appears in animal cells
- cell plate appears in plants
- long microtubules used for cell division
• Kinetochores
- protein complex where spindle fibers attach
CELL REPRODUCTION
Chromatin vs. Chromatid vs. Chromosome
Reproduction During interphase, DNA is loose (Chromatin)
- duplicating; making copies Then it is tightly packed (Sister Chromatids)
- formation of organisms of the same kind And joined together by the centromere (Chromosome)
Importance of Cell Reproduction CELL CYCLE
a) For growth - consists of:
b) For maintenance & repair
- repair and replacement of worn out cells/tissues a) Interphase
c) Perpetuation of Species - cell growth and copying of chromosomes in
- the existence of living things preparation for cell division
b) Mitotic (M) Phase
Extinction - mitosis and cytokinesis
- opposite of reproduction
- complete disappearance of a certain species Eukaryotic Cell Cycle
- Series of events taking place in a cell leading to its division
Cell Division and duplication of its DNA to produce two daughter cells
- integral part of the cell cycle, the life of a cell from
formation to its own division
- process in which cells duplicate themselves into two
identical daughter cells
• In unicellular organisms the division of one cell
reproduces the entire organism
• For multicellular organisms:
a) Development from a fertilized cell
b) Growth
c) Repair
Genome
- the complete set of genes/DNA present in a cell or
organism
1) Cell Growth Checkpoint
Nucleosomes - occurs towards the end of Growth Phase 1 (G1)
- eight histone proteins wrapped by the DNA - checks whether the cell is big enough and has made
the proper proteins for the synthesis phase
• If not, the cell goes through a resting period (G0)
Chromosomes
- Greek : chroma (color) + soma (body) until it is ready to divide
- DNA molecules packaged (via histones) into thread-like
structures 2) DNA Synthesis Checkpoint
- ahuman being consists of 23 pairs of chromosomes - occurs in the Synthesis Phase (S)
- checks whether the DNA has been replicated correctly
Parts of the Chromosome
3) Mitosis Checkpoint
a) Sister Chromatids - occurs during the Mitosis Phase (M)
- two threadlike strands into which a chromosome - checks if mitosis is complete, and if so, the cell divides
divides longitudinally during cell division and the whole cycle repeats
- consists of a long arm (q) and a short arm (p)
b) Centromere
- region where the chromatids are attached together
- area where the spindle fibers are attached
- made out of cohesin proteins
, MITOSIS Bacterial Reproduction
- duplication and distribution of chromosomes during cell
division • Binary Fission
- type of cell division by prokaryotes (bacteria and
archaea)
- the chromosome replicates and two daughter
chromosomes actively move apart
CELL CYCLE CONTROL SYSTEM
Checkpoints
- control points where there are stop and go-ahead signals
1) G1 Phase Checkpoint
- checks for nutrients, growth factors and DNA damage
2) G2 Phase Checkpoint
- checks for cell size and DNA replication
3) M Phase Checkpoint
- checks for chromosome spindle attachment
Proteins
a) Kinases
a) G2 of Interphase
- enzymes that activate or inactivate other proteins
- centrosome divides into two distinct centrosomes through phosphorylation
- chromosomes cannot be seen
- must attach to a cyclin to be active (cyclin-dependent
kinases (Cdks))
b) Prophase b) Growth Factor
- chromatin fibers condenses into discrete - proteins produced by other cells that stimulate other
chromosomes
cells to divide
- the nucleolus disappears
- each chromosome appears as two identical sister • Density-dependent inhibition
chromatids - stops most cells from dividing when they’re
- the mitotic spindle forms and the centrosomes move overcrowded
towards opposite poles • Anchorage dependence
• Prometaphase - reliance of cells to be attached to a substratum
- nuclear envelope fragments
- the nuclear membrane gradually disintegrates Cancer Cells
- microtubule invades the nuclear area and
attaches to the kinetochore Transformation
- non-kinetochore microtubules interacts to the - process of genetic alteration
opposite pole, thus, lengthening the cell
a) Benign Tumor
c) Mitosis
- abnormal cells remain at the original site; normally do
- centrosomes align at center a.k.a. metaphase plate not cause serious damage
- push and pull of microtubular units b) Malignant Tumor
- abnormal cells that can spread to new tissues
d) Anaphase
- disjunction of sister chromatids upon the break of the
Metastasis
centromere
- spread of cancer cells to other parts of the body which can
- cohesin proteins are cleaved cause additional tumors
- chromosomes migrate toward the opposite poles
- shortest stage of mitosis
- disappearance of spindle fibers except asters
e) Telophase
- reappearance of nuclear membrane and nucleolus
- two daughter nuclei forms in the cell
Cytokinesis
- division of the cytoplasm
- cleavage furrow appears in animal cells
- cell plate appears in plants
