Chapter 3 - Cells: The living units (part a). Just as bricks and timbers are the structural units of a house, cells are the structural units of all living things, from one-celled “generalists” like amoebas to complex multicellular organisms such as humans, dogs, and trees. The human body has 50 to 100 trillion of these tiny building blocks. This chapter focuses on structures and functions shared by all cells. | Cells: The Living Units The cell is the smallest structural and functional living unit Organismal functions depend on individual and collective cell functions Biochemical activities of cells are dictated by their specific sub cellular structures called organelles Over 200 different types of human cells Types differ in size, shape, subcellular components, and functions Fibroblasts Erythrocytes Epithelial cells (d) Cell that fights disease Nerve cell Fat cell Sperm (a) Cells that connect body parts, form linings, or transport gases (c) Cell that stores nutrients (b) Cells that move organs and body parts (e) Cell that gathers information and control body functions (f) Cell of reproduction Skeletal Muscle cell Smooth muscle cells Macrophage Figure All cells have some common structures and functions Human cells have four basic parts: Plasma membrane - flexible outer boundary Cytoplasm - intracellular fluid Organelles - multiple functions Nucleus - control center Figure Secretion being released from cell by exocytosis Peroxisome Ribosomes Rough endoplasmic reticulum Nucleus Nuclear envelope Chromatin Golgi apparatus Nucleolus Smooth endoplasmic reticulum Cytosol Lysosome Mitochondrion Centrioles Centrosome matrix Cytoskeletal elements • Microtubule • Intermediate filaments Plasma membrane Bimolecular layer of lipids and proteins in a constantly changing fluid mosaic Plays a dynamic role in cellular activity Separates intracellular fluid (ICF) from extracellular fluid (ECF) Interstitial fluid (IF) = ECF that surrounds cells Figure Integral proteins Extracellular fluid (watery environment) Cytoplasm (watery environment) Polar head of phospholipid molecule Glycolipid Cholesterol Peripheral proteins Bimolecular lipid layer containing proteins Inward-facing layer of phospholipids Outward- facing layer of phospholipids Carbohydrate of glycocalyx Glycoprotein Filament of cytoskeleton Nonpolar tail of phospholipid molecule Phospholipids (lipid bilayer) Phosphate . | Cells: The Living Units The cell is the smallest structural and functional living unit Organismal functions depend on individual and collective cell functions Biochemical activities of cells are dictated by their specific sub cellular structures called organelles Over 200 different types of human cells Types differ in size, shape, subcellular components, and functions Fibroblasts Erythrocytes Epithelial cells (d) Cell that fights disease Nerve cell Fat cell Sperm (a) Cells that connect body parts, form linings, or transport gases (c) Cell that stores nutrients (b) Cells that move organs and body parts (e) Cell that gathers information and control body functions (f) Cell of reproduction Skeletal Muscle cell Smooth muscle cells Macrophage Figure All cells have some common structures and functions Human cells have four basic parts: Plasma membrane - flexible outer boundary Cytoplasm - intracellular fluid Organelles - multiple functions Nucleus - control center Figure Secretion .
