Transcript Cell Reproduction

Cell Reproduction
Chromosomes
Mitosis
Meiosis
Chromosomes
Cell Division
• Cell Division is the process by which
cells reproduce.
• information in the cell is contained in
genes → genes code for proteins →
proteins carry out cellular functions
• Each body cell that results from cell
division must have an exact copy of
the DNA in the original cell.
Chromosome Structure
Chromosome
Structure
Chromosome Structure
Chromosome
Structure
Chromosome Number
Karyotype
Diploid vs. Haploid
• Diploid (2n): a cell that
contains both chromosomes
of a homologous pair
• Humans = 46 (somatic cells:
body cells)
• Haploid (n): a cell that has
only one chromosome of
each homologous pair
• Humans = 23 (gametes:
egg and sperm)
Mitosis
Mitosis
• Mitosis: the division of the cell
nucleus in which the chromosomes
in the parent cell divide into two
identical sets
• In somatic cells (body cells), the
number of cells is increased
without changing the information
contained in the DNA or the
amount of DNA in those cells.
Binary Fission
• Binary Fission: cellular division of
unicellular organisms that produces
identical offspring
Cell Cycle
Overview
Important Structures
Equator
Polar
Fibers
Asters
Kinetechore
Centrioles
Kinetechore
Fibers
Mitosis in Animals
Cell
Membrane
Nucleolus
Nucleus
G1
• Normal
growing cell
• DNA =
chromatin
• Organelles
are doubling
(not shown)
S
• DNA
Replication
G2
• Final
Preparation
for Mitosis
Prophase
• Chromosome
formation
• Nucleus and
nucleolus
disappear
• Centrioles
begin forming
spindle fibers
Telophase
• Nucleus and
nucleolus
reappear
• Chromatids
uncoil back to
chromatin
• Beginning of
cell division
Anaphase
Metaphase
• Chromosomes • Chromosomes
split into
line up along
chromatids
the equator
• Chromatids
move to
opposite
poles
Cytokinesis
• Complete cell division results in daughter cells
that are exactly the same as the original
Mitosis in Plants
Cleavage Furrow & Cell Plate
Control of Cell Size
• Cell Size
(SA/V)
• Regulatory
Checkpoints
- Enzymes
Meiosis
Overview
Meiosis
Genetic Recombination
• Genetic Recombination: the process
that results in chromosomes being
arranged in many different ways
• crossing-over between homologues or
chromatids
• homologous pairs separate
independently in meiosis I
• sister chromatids separate
independently in meiosis II
CROSSING
V
E
R
CROSSING
V
E
R
Independent
Assortment