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Word Parts– NEW
• Mito – thread-like• Inter - between• Meta - middle• Ana - away• Telo - end• Phase – change• Kinesis – to split• Gameto – sex cell• Soma - body
– OLD
• Cyto - cell• Pro – before• Di – two• Hap - half• Homo – same• A – not• Osis - process
Cell Cycle
IPMAT+C
Two Types of Reproduction
• Sexual Reproduction (meiosis): requires two parents of the opposite sex and gametes: sperm and egg
• Asexual Reproduction: when one parent produces one or more identical offspring
3 Examples of Asexual Reproduction
1. Clone: creation of a genetically identical organism from one that already exists
2. Budding: group of cells that can be pinched off from the parent to form a new individual
3. Regeneration: re-growth of a missing part
4. Binary Fission: one cell divides into 2 separate genetically identical cells.
The Cell Cycle
Includes all other phases the cell goes through as it grows and replicates (divides)
It can be divided many different ways
• IPMAT+C
• Interphase + Mitosis + Cytokinesis
• Interphase + M Phase
M-Phase
Events of the Cell Cycle
3 Phases of Interphase
1. G1 - when the cell grows
2. S - when DNA (Chromosomes)replicates
3. G2 - the cell prepares for Mitosis
Chromosomes
Genetic information is passed from one generation to the next on chromosomes
– Each chromosome consists of 2identical “sister” chromatids.
– Each pair of chromatids is attached at an area called the centromere.
The M Phase
Also known as Cell Division
Divided into Mitosis and Cytokinesis:
– Mitosis – (PMAT)
– Cytokinesis – when the cell splits into 2 identical cells
Mitosis
Mitosis - the asexual reproduction of a somatic (body) cell
Mitosis is divided into 4 phases:1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Interphase•The phase of the cell cycle in which the cell increases in size and duplicates chromosomes
Prophase
• The phase of mitosis in which the chromatin coils into visible chromosomes, centrioles separate, and spindle fibers appear
Spindle forming
CentromereChromosomes(paired chromatids)
MetaphaseCentriole
Spindle Fibers
The phase of mitosis in which the chromosomes line up at the equator of the spindle and chromatids are attached by the centromeres to a separate spindle fiber
AnaphaseSister Chromatids
The phase of mitosis when the centromeres split and the chromatid pairs of each chromosome are pulled apart by microtubules
Telophase
The last phase of mitosis, when the chromosomes migrate to opposite ends of the cell, two new nuclear envelopes form, and the chromosomes uncoil to prepare for their own independent existence
Cytokinesis
The last phase of the cell cycle when the cell’s cytoplasm divides and separates into 2 new cells
Cytokinesis of Plants
A structure called the cell plate forms midway between the divided nucleus
Cell wallCell plate
Cyclin
• The protein cyclin regulates and controls the cell cycle.
• When cyclin is defective the cell loses control of the cell cycle and the cells grow uncontrollably.
Contact Inhibition• When cells have contact with each
other they know to stop growing
• Normal Growth
CUT
CancerCancer is when cells have lost their ability
to control their growth rate/cell cycle
A mass of cancer cells are called a tumor
Cancer cells may break loose from tumors and spread throughout the body, disrupting normal activities and causing serious medical problems or even death.
- Draw
Meiosis
“The Making of Me”
Chromosome Number
All organisms have a different number of chromosomes
Humans have 46 total:• 23 from dad• 23 from mom
Fruit Flies have 8 total: • 4 from dad• 4 from mom
Fruit Fly’s Chromosomes
• Each chromosomes that comes from the male parent has a matching chromosome from the female parent and is called Homologous
• A cell that contains both sets of homologous chromosomes is said to be diploid (2N)
– For Humans, the diploid number is 46 (2N=46)
– For Fruit Flies, the diploid number is 8 (2N=8)
• The gametes (sperm and egg) have a single set of chromosomes
• These cells are called haploid & written as (N)
– For Humans, the haploid number is 23 (N=23)
– For Fruit Flies, the haploid number is 4 (N=4)
Meiosis has 2 Cycles: Meiosis I
Prophase I Metaphase I Anaphase I Telophase I and
Cytokinesis
Interphase I
Meiosis I
Meiosis II
Telophase II and
CytokinesisProphase II
Metaphase II Anaphase IITelophase I and Cytokinesis I
Meiosis II
Gamete Formation
In male animals, meiosis results in four equal-sized gametes called sperm.
In female animals, only 1 egg is formed. The other 3 cells, called polar bodies, are not involved in reproduction.
Comparing Mitosis and Meiosis
Mitosis:
• Results in the production of two genetically identical diploid cells
• Each daughter cell receives an EXACT copy of chromosomes
Meiosis:
• Produces four genetically different haploid cells
• Each daughter cell receives HALF the number of chromosomes
• How sexually reproducing organisms produce gametes (sperm & egg)
Questions:
1. How many chromosomes do you have?
2. If a cell with 8 chromosomes goes through mitosis, how many chromosomes will the daughter cells have?
3. If a cell with 24 chromosomes goes through meiosis, how many chromosomes will the daughter cells have?