Chapter 5 - Cell Membrane Structure and Function Flashcards
Cell Membrane Functions
9 of them: Barrier between inside and outside; regulate diffusion/active transport; sense environmental changes (acidity), maintain structure, cell-to-cell communication; protection, movement, secretion, and some transport
Cell Membrane Structure
Phospholipid Bilayer: hydrophilic (polar) head hydrophobic (nonpolar) tail tail head
Types of Membrane Proteins
RATER
Receptor, Attachment, Transport, Enzymes, Recognition
Receptor Proteins
Stimulate cell response
Recognition Proteins
Separates self from not self
Enzymes
Break down or put together
Attachment Proteins
Holds cytoskeleton to membrane, attaches cells
Transport Proteins
Channel (Passive): diffusion
Carrier (Active)
Types of Diffusion (Passive Transport)
Simple, Facilitated, Osmosis
Diffusion
From high concentration area to low concentration (down a gradient)
Increase concentration or temp or pressure = increase diffusion speed
Continue until equalization
Requires no energy (ATP)
Facilitated Diffusion
Polar ions go through membrane via carrier proteins
Simple Diffusion
Nonpolar molecules go straight through membrane
Osmosis
Water specific, hypertonic (higher concentration) to hypotonic (lower concentration) until isontonic (equally concentrated)
Hypertonic
Higher concentration for water
Hypotonic
Lower concentration for water
Isotonic
Equal concentration between waters
Active Transport
Small ions moving up a gradient (low to high) Requires energy (ATP)
Endocytosis
Moving into cell
Requires ATP
Pinocytosis and Phagocytosis and Receptor-Mediated
Exocytosis
Moving out of cell
Particles or large molecules
Vesicles carry to membrane where they are released
Pinocytosis (Endo)
Cell drinking - enfolds “food” and gives to vesicles
Phagocytosis (Endo)
Cell eating - membrane extends and engulf (white blood cells)
Receptor-Mediated (Endo)
Protein-coated membrane lined with receptors combine then infold (steroids, iron)
