smallest living unit
In human body:
~75 trillion cells
~200 different types
2μm-1m (average 50μm)

lets your body grow, change, and adapt to new conditions and activities Your body recycles and renews all of its chemical components at intervals ranging from minutes to years

1. shapes, 2. function, 3.plasma membrane, 4.cytoplasm, 5.cytosol, 6.organelles, 7.interstitial fluid

Different cells have different shapes

Unique morphology is related to function

All cells surrounded by plasma membrane:
–Separates cells from the environment

Plasma membrane “holds in” the cytoplasm

Cytoplasm consists of cytosol (fluid) and organelles (structures)

Body cells surrounded by interstitial fluid
– Interstitial fluid = fluid outside the membrane

Different cells have different shapes and their unique morphology is related to unique function

all body cells except sex cells

-Cells are the building blocks of all plants and animals
- All cells come from the division of preexisting cells
-Cells are the smallest units that perform all vital physiological functions
-Each cell maintains homeostasis at the cellular level

-Physical barrier to maintain homeostasis: separates intracellular fluid (cytosol) from extracellular fluid (iterstitial fluid)
-different conditions in each
-Regulates exchange with extracellular environment
-Provides sensitivity: cell communication and
signaling
-Provides structural support: attachment site
to hold tissues together

1.Phospholipids 2.Cholesterol 3.Carbohydrates

self assemble into bilayer

resist osmotic lysis

linked to other molecules as proteoglycans, glycoproteins, and glycolipids (carb part protrudes from extracellular side creating outer carb layer called glycocalyx)

-lubrication & protection
-anchoring & locomotion
-binding specificity (acts as
receptor)
-self recognition

1/2 mass of plasma membrane

span width of membrane

adhere to inner or outer surface

1.anchoring proteins 2.recognition proteins
3.enzymes 4.receptors 5.carrier proteins 5.channels

attachment

self identification by immune system

catalyze reactions in cytosol or extra cellular fluid

bind ligands for signaling, or import/export

transport solutes in/out

move ions & H2O in/out