Post on 15-Dec-2015
2 sister chromatids
Chromosomes OR Chromatids
ReplicationAnaphase
1 Chromosome
Interphase
2 identical Chromosome2 identical chromatids
One in each daughter cell.
Prophase
Interphase Prophase Metaphase
Parent cell Visible but not organized
Chromosomes lining up
Anaphase Telophase Interphase
Pulling apart Cell dividing Two identical cells
X marks the spot
Reproduction and Cell Division
The modern cell theory states that• All living things are made of one or more cells• The cell is the functional unit of life• All cells come from preexisting cells
There are 2 types of organism reproductionAsexual and Sexual
• Differentiate among the various methods of asexual reproduction
• Identify the different types of asexual reproduction
KEY WORDS
Asexual ReproductionBinary FissionBudding SporulationRegenerate Vegetative propagation
Asexual Reproduction
• Cell duplication using mitosis* and cytokinesis • Produces genetically identical cells.
1.Cells are “clones” - exact copy of original. 2. Rapid and effective method of reproduction. 3. No cellular diversity.
Various Types of Asexual Reproduction
Bacteria:
• Single-cell organisms (Unicellular).• Do not have a true nucleus. • Asexual reproduction called binary fission.• Example - E. coli (Escherichia Coli)
- organism splits into two equal sized cells each with chromosome of complete DNA.
Protists
• Unicellular organisms (with a nucleus). • Reproduce using standard mitosis. • Example - Ameoba
Fungi (1)
• Cell duplicates nucleus, forms outgrowth.• Asexual reproduction called Budding.• New cell is not the same size as original cell.
Unequal division of cytoplasm • Example – yeast
Standard mitosis Budding
Fungi (2)
• Large number of small spores formed by mitosis*• Spores released.• Form new organism when conditions are good.• Asexual reproduction called Sporulation.• Example – mould
Plants
• New organism created from roots, stems, leaves.• Asexual reproduction called Propagation • Example – strawberry plants (runners)
Animals
• Split into two big groups:Vertebrates (with backbones) Invertebrates (without backbones)
• Invertebrates will usually reproduce asexually.• Fragmentation – ability of an animal to
regenerate (regrow) parts of the body.
The simpler the animal, the greater the ability to regenerate.
Asexual reproduction - advantages.
• Easy to reproduce – even if you can’t move (stationary).• No need to find a partner.• Each cell will look and function the same – no variation.
Asexual reproduction - disadvantages.
• Can lead to overcrowding (and competition).• One disease can wipe out a whole species – no variation.• No possibility for adaptation and evolution.