Purpose of the Cell Cycle
Why are Cells so Small? With your table, think about why cells need to grow and divide?
Cell Growth and Division Cell division occurs in all living organisms 2 Types of living organisms Prokayotes-unicellular organisms Bacteria Eukaryotes- multicellular organisms Plants and animal
Prokaryotes reproduce through cell division
Cell division in Eukaryotes Eukaryotes use cell division for specific function in an organism. Cell division is involved in Growth- how an organism gets larger Development- makes specialized cells like nerve cells Repair- heals wounds and injuries Reproduction- creates sex cells for sexual reproduction.
Main reasons for ALL cells dividing Gas and nutrient exchange- allows the organism to extract and produce energy to carry out the functions of life 2) DNA overload- allows for a lot of DNA to exist in the cell. -DNA a molecule found in all living organisms that contains the directions an organism needs to grow, maintain itself and reproduce.
Cells division limits cell size Why do we want cells to be small? Allows more surface area to volume ratio. EXAMPLE: What is the ratio of vowels to consonants in the alphabet? 5 vowels 21 consonants Answer: 5:21 or 5 to 21 or 5/21
Surface to volume ratio Amount of surface an object has to the amount of volume(space) it occupies. Formulas: Surface area=length x width x 6 (cube) Volume= length x width x height Surface area to volume = surface area/volume
Surface area to volume Solve for each cube ?
What do you observe? Limits to cell growth Increase cell size= more work for cell Harder to transfer materials through the cells DNA would fail to provide instructions
Cells grow, develop and repair Growth Large organisms has more cells Small organisms have less cells
Development Cells develop and become specialized to perform specific functions Skin Nerve Muscle Liver Can you think of more?
repair Cells help an organism body repair injury through cell division
Reproduce Cellular division in sex cells through meiosis for fertilization to occur