4.2 What is a Cell

cell

-the smallest unit that shows the properties of life
-it has the capacity for metabolism, homeostasis, growth and reproduction

eukaryotic cell

divided into various functional parts, has a nucleus

prokaryotic cell

smaller and simpler than eukaryotic cells, no nucleus

plasma membrane

the cell's outer membrane, it separates metabolic activities from events outside of the cell

nucleus

double membraned sac holding a eukaryotic cell's DNA

nucleoid

the region of cytoplasm in which the DNA inside prokaryotic cells is concentrated

cytoplasm

semifluid mixture of water, sugars, ions and proteins between the plasma membrane and the region of DNA

ribosomes

structures on which proteins are built

surface to volume ratio

a physical relationship that strongly influences cell size and shape

lipid bilayer

the structural foundation of all cell membranes
-consists of 2 layers of lipids whose hydrophopic tails are sandwiched b/w its hydrophilic heads

phospholipid

the main type of lipid in cell membranes