MODULE 4
M4 CELL DIVISION AND REPRODUCTION 1.) G1 Phase (First Gap) – little change is visible however the
cell is quite active at the biochemical level.
6.1 THE GENOME - The cell is accumulating the building blocks of
chromosomal DNA and the associated proteins.
Genome- cell’s complete complement of DNA - Accumulate sufficient energy reserve to complete the
task of replicating each chromosome in the nucleus.
In prokaryotes, genome is composed of single=double stranded DNA 2.) S Phase (Synthesis of DNA) – nuclear DNA remains in a
molecule that forms a loop or circle. Nucleoid is the region in the cell semi-condensed chromatin configuration,
composing the genetic material of the cell. Plasmids are smaller are - The centrosome is duplicated. The two centrosome
smaller loops of DNA but is not essential for normal growth. will give rise to the mitotic spindle, the apparatus that
orchestrates the movement of chromosome during
In eukaryotes, genome is composed of several double-stranded,
mitosis.
linear DNA molecules bounde with proteins to form complexes
3.) G2 Phase (Second Gap) – the cell replenishes its energy
called chromosomes. Human cells have 46 chromosomes.
stores and synthesizes proteins necessary for chromosome
Diploid- when a somatic cell contains two matched sets of manipulation.
chromosomes (2n) -some organelle are duplicated and the cytoskeleton is
dismantled to provide resources for the mitotic phase.
Haploid- one set of 23 chromosomes (n). ex. is gametes or sex cells Mitotic Phase – a multistep process during which the duplicated
chromosome are aligned, separated and move to opposite poles of
Human somatic cells have 46 chromosomes consisting of two sets of the cell, and then are divided into two new identical daughter cells.
22 homologous chromosomes and a pair of nonhomologous sex First portion of mitotic phase – karyokinesis – nuclear division
chromosomes Second portion of mitotic phase – cytokinesis – physical separation
of the cytoplasmic components into the two daughter cells.
Homologous chromosomes- matched pairs of chromosomes in a
diploid organism. They have the same length and has specific
nucleotide segments called genes in the same location called locus
Genes- the functional units of chromosomes that determine specific
characteristics by coding for specific proteins.
Traits- the different forms of a characteristic (free or attached
earlobes)
Each copy of the homologous pair of chromosomes came from a
different parent. The copies of each of the genes may not be
identical. The variation within species is caused by the specific
combination of the genes inherited from both parents. Minor PROPHASE – chromosomes condense and become visible.
variations in traits such as those for blood type, eye color and height - Spindle fibers emerge from the centrosomes.
contribute to the natural variation found within a species. X and Y - Nuclear envelope breaks down
sex chromosomes are exempted to the rule of homologous - Nucleolus disappers.
chromosomes as the genes found in these cromosomes are not the Prometaphase – chromosomes continue to condense.
same - Kinetochores appear at the centromeres.
- Mitotic spindle microtubules attach to kinetochores.
- Centrosomes move toward opposite poles.
METAPHASE – mitotic spindle is fully developed, centrosomes are at
6.2 THE CELL CYCLE opposite poles of the cell.
- Chromosomes are lined up at the metaphase plate.
Cell cycle- is an ordered series of event involving cell growth and - Each sister chromatid is attached to a spindle fiber
cell division that produces two new daughter cells. originating from opposite poles.
Cells on the path to cell division proceed through a series of ANAPHASE – cohesion proteins binding the sister chromatids
precisely timely and carefully regulated stages of growth, DNA together break down.
replication and division that produces two identical (clone cells). - Sister chromatids (now chromosomes) are pulled
Two major phases of cell cycle: toward opposite poles.
1.) Interphase – the cell grows and DNA is replicated. - Non-kinetochore spindle fibers lengthen, elongating
2.) Mitotic Phase – the replicated DNA and cytoplasmic the cell.
contents are separated and the cell divides. TELOPHASE – chromosomes arrive at opposite poles and begin to
Interphase – the cell undergoes normal growth processor while also decondense.
preparing for cell division. - Nuclear envelope material surrounds each set of
chromosomes.
- The mitotic spindle breaks down.
CYTOKINESIS – animal cells: a cleavage furrow (fissure or crack)
separates the daughter cells.
- Plant cells: a cell plates separates the daughter cells.
3 stages of interphase:
M4 CELL DIVISION AND REPRODUCTION 1.) G1 Phase (First Gap) – little change is visible however the
cell is quite active at the biochemical level.
6.1 THE GENOME - The cell is accumulating the building blocks of
chromosomal DNA and the associated proteins.
Genome- cell’s complete complement of DNA - Accumulate sufficient energy reserve to complete the
task of replicating each chromosome in the nucleus.
In prokaryotes, genome is composed of single=double stranded DNA 2.) S Phase (Synthesis of DNA) – nuclear DNA remains in a
molecule that forms a loop or circle. Nucleoid is the region in the cell semi-condensed chromatin configuration,
composing the genetic material of the cell. Plasmids are smaller are - The centrosome is duplicated. The two centrosome
smaller loops of DNA but is not essential for normal growth. will give rise to the mitotic spindle, the apparatus that
orchestrates the movement of chromosome during
In eukaryotes, genome is composed of several double-stranded,
mitosis.
linear DNA molecules bounde with proteins to form complexes
3.) G2 Phase (Second Gap) – the cell replenishes its energy
called chromosomes. Human cells have 46 chromosomes.
stores and synthesizes proteins necessary for chromosome
Diploid- when a somatic cell contains two matched sets of manipulation.
chromosomes (2n) -some organelle are duplicated and the cytoskeleton is
dismantled to provide resources for the mitotic phase.
Haploid- one set of 23 chromosomes (n). ex. is gametes or sex cells Mitotic Phase – a multistep process during which the duplicated
chromosome are aligned, separated and move to opposite poles of
Human somatic cells have 46 chromosomes consisting of two sets of the cell, and then are divided into two new identical daughter cells.
22 homologous chromosomes and a pair of nonhomologous sex First portion of mitotic phase – karyokinesis – nuclear division
chromosomes Second portion of mitotic phase – cytokinesis – physical separation
of the cytoplasmic components into the two daughter cells.
Homologous chromosomes- matched pairs of chromosomes in a
diploid organism. They have the same length and has specific
nucleotide segments called genes in the same location called locus
Genes- the functional units of chromosomes that determine specific
characteristics by coding for specific proteins.
Traits- the different forms of a characteristic (free or attached
earlobes)
Each copy of the homologous pair of chromosomes came from a
different parent. The copies of each of the genes may not be
identical. The variation within species is caused by the specific
combination of the genes inherited from both parents. Minor PROPHASE – chromosomes condense and become visible.
variations in traits such as those for blood type, eye color and height - Spindle fibers emerge from the centrosomes.
contribute to the natural variation found within a species. X and Y - Nuclear envelope breaks down
sex chromosomes are exempted to the rule of homologous - Nucleolus disappers.
chromosomes as the genes found in these cromosomes are not the Prometaphase – chromosomes continue to condense.
same - Kinetochores appear at the centromeres.
- Mitotic spindle microtubules attach to kinetochores.
- Centrosomes move toward opposite poles.
METAPHASE – mitotic spindle is fully developed, centrosomes are at
6.2 THE CELL CYCLE opposite poles of the cell.
- Chromosomes are lined up at the metaphase plate.
Cell cycle- is an ordered series of event involving cell growth and - Each sister chromatid is attached to a spindle fiber
cell division that produces two new daughter cells. originating from opposite poles.
Cells on the path to cell division proceed through a series of ANAPHASE – cohesion proteins binding the sister chromatids
precisely timely and carefully regulated stages of growth, DNA together break down.
replication and division that produces two identical (clone cells). - Sister chromatids (now chromosomes) are pulled
Two major phases of cell cycle: toward opposite poles.
1.) Interphase – the cell grows and DNA is replicated. - Non-kinetochore spindle fibers lengthen, elongating
2.) Mitotic Phase – the replicated DNA and cytoplasmic the cell.
contents are separated and the cell divides. TELOPHASE – chromosomes arrive at opposite poles and begin to
Interphase – the cell undergoes normal growth processor while also decondense.
preparing for cell division. - Nuclear envelope material surrounds each set of
chromosomes.
- The mitotic spindle breaks down.
CYTOKINESIS – animal cells: a cleavage furrow (fissure or crack)
separates the daughter cells.
- Plant cells: a cell plates separates the daughter cells.
3 stages of interphase:
