Download CH10-Cell-Reproduction

CH8 Cell Reproduction
Why Cells Reproduce
• Growth of the organism
• Replace old or damaged cells
• Maintain cell size
– Reduce size of cell as it grows
– Surface area – to – volume ratio
Chromosomes
• Made up of organized and packaged DNA
– Deoxyribonucleic Acid
– 2m of DNA in one cell (almost 2000 miles of DNA)
– genes are segments of DNA (code RNA & Proteins)
In Text Pg 151
Terms to know
• Chromatin
– DNA and proteins
• Histone
– Protein what DNA winds around
• Chromatid (s) (Sister – identical pair)
– Made up of one strand of DNA
• Centromere
– Holds chromatids together
A Comparison
Prokaryotic Cells
No true nucleus
Single Circular Loop of
DNA
Condense with twisting
and winding
Eukaryotic Cells
True Nucleus
23 prs (humans) of Linear
DNA molecules
Condense with help of
histones
Preparing for Cell Division
• DNA must be copied, sorted,
separated
• Organelles, in eukaryotes, must
be duplicated
• Prokaryotes go through binary
fission
Eukaryotic Cell Division
• Cell Cycle
– Repeating sequence of events that occur during
the life cycle of a cell
1. Growth
2. DNA replication
3. Division of the nucleus and cytoplasm
Cell Cycle
– Interphase consist of the 1st three
• G1 (Cell growth)
– organelles made
• S (Synthesis)
– DNA duplicated
• G2 (Growth and preparation)
– Microtubules form
– Mitosis (Nucleus Divides)
– Cytokinesis (Cytoplasm Divides)
Interphase
• Time in this phase varies
• Controlled by signals from proteins and
environment
• G1 and G2 check points
– Determine if cell healthy for division
– Checks for mistakes in DNA copies