Ch.10-1 Growth & Reproduction

POINT > Consider limits to cell size POINT > Define cell division POINT > Describe asexual reproduction POINT > Describe sexual reproduction

What difficulties might a cell face as it increases in size? POINT > Consider limits to cell size

1 cm2 cm3 cm How does surface area compare to volume? Side Length Surface Area VolumeRatio 1 cm 2 cm 3 cm Highest Ratio - Most Surface Area to Volume

Two problems if the surface to volume ratio gets too low: 1. Too much demand placed on DNA to produce proteins (only have one nucleus/one set of DNA) 2. Diffusion of nutrient and waste materials through the cell would take too long in a large cell Cells need lots of cell surface area for diffusion to be effective

Cells have to be small so that a) many cells can fit in a small area b) cell surface to volume ratio is small c) diffusion can be effective getting things in and out of the cell d) The DNA is not too far away from the cell membrane

Cell division: Process by which a cell divides into two daughter cells by replicating its DNA to provide each new daughter cell with one complete copy of genetic information

Asexual reproduction: Production of genetically identical offspring from a single parent Bacteria, yeast (most of the time), some plants & animals

Sexual Reproduction: Production of genetically unique offspring by inheriting genetic information from two separate parent organisms  Most animals & plants, yeast (sometimes)

AsexualSexual Form new cells Usually Faster Good when environmental conditions are favorable Good when environmental conditions vary Diversity may help survival if environment changes

Read pages Assess page 278 #1-3