Chapter 3 Flashcards
Who Discovered Cells?
-Robert Hooke in 1665 -Observed cork slices -Coined the term “cells”
Schleiden and Schwann Cell Theory
Schleiden- concluded that all plant parts are made of cells Schwann- stated that all animal tissues are composed of cells
Cell Theory
-All life forms are made of one or more cells -Cells only arise from pre-existing cells -The cell is the smalled form of life
Cell Types
-Cells that connect body parts, form linings or transport gases -Cells that move organs and body parts -Cells that store nutrients -Cells that fight disease -Cells that gather info and controls body functions -Cells of reproduction
Cells that connect body parts, form linings, or transport linings
-Fibroblasts -Erythrocytes -Epithelial cells
Cells that move organs and body parts
-Skeletal muscle cell -Smooth muscle cells
Cell that stores nutrients
-Fat cell
Cell that fights disease
-Macrophage
Cell that gathers info and controls body function
-Nerve cell
Cell of reproduction
-Sperm
Plasma Membrane functions
-Boundary-separates intracellular fluid from extracellular fluid -Regulates transport of molecules into and out of the cell -Recognition molecules that identify a cell to other cells
Membrane Lipids
-75% phospholipids Lipid bilayer -5% glycolipids Lipids with polar sugar groups on outer membrane surface -20% cholesterol Increases membrane stability
Membrane Proteins
-Integral Proteins -Peripheral Proteins -Filament of Cytoskeleton
Integral Proteins
-Firmly inserted into the membrane -Often transmembrane -Usually transport proteins -Often contains pores -Can mediate attachment to cytoskeleton and extracellular matrix
Peripheral Proteins
-Loosely attached to integral proteins -Usually enzymes
Filament of Cytoskeleton
-Cytosolic -Supports membrane -Gives cells their shape
Glycocalyx
-Carbohydrate coat of cell surface Glycolipids Glycoproteins -Important in cell recognition Immune cells MHC proteins ABO blood groups
Plasma Membrane Special Features
-Microvilli -Gap Junctions -Tight Junctions
Microvilli
-Finger like projections of the cell membrane -Increase surface area of cell -Aid in absorption -Found in small intestine, kidney
Gap Junctions
-Transmembrane proteins that form pores that allow small molecules to pass from cell to cell -Found in cardiac myocytes and smooth muscle cells
Tight Junctions
-Prevent molecules from passing through layers of cells -Found in the intestines
How do molecules pass through cell membranes?
-Passive transport -Active transport
Passive Transport
-Does not require energy (ATP) -Molecules move down a concentration gradient
Active Transport
-Requires ATP -Molecules move against a concentration gradient
Simple Diffusion
-Molescules diffuse directly through phospholipid bilayer -Molecules must be small, non-polar, and lipid soluble (O2, CO2, Ureae, Alcohol) -Requires concentration gradient
Facilitated Diffusion Channel Mediated
-Molecules diffuse directly through channels down concentration down concentration gradient -Usually small polar charged molecules (Na+, K+)