810 likes | 1.05k Views
Transport. Absorption and circulation of materials. Aim: How do materials enter and exit the cell?. Transport: Absorption and circulation of materials. Nutrients enter cells through diffusion Structure of the Cell Membrane: “Phospholipid Bi-layer” Made of proteins and lipids.
E N D
Transport • Absorption and circulation of materials
Aim: How do materials enter and exit the cell? • Transport: • Absorption and circulation of materials. • Nutrients enter cells through diffusion • Structure of the Cell Membrane: • “Phospholipid Bi-layer” • Made of proteins and lipids
Cell Membrane: Semi/selectively permeable Small molecules diffuse through membrane Regulates movement of materials into and out of the cell based on size Fluid Mosaic Model:
Methods of Transport • Passive Transport a.k.a Diffusion: • No energy needed • Movement from High to Low concentration until equilibrium
Movement of materials from highlow concentration. Continues until equilibrium is reached Diffusion
Small Molecules that diffuse through cell membranes • Oxygen • Carbon dioxide • Water • Nutrients (simple sugars, amino acids)
Osmosis • Diffusion of H2O • High low concentration
Active Transport (Needs ATP) • Energy is needed to move materials • Low high concentration • Against concentration gradient • No equilibrium reached
Active Transport • Phagocytosis • Cell engulfs undissolved molecules • Pinocytosis • Cell membrane pinches in and absorbs dissolved molecules.
Transport of Water in Cells 1. Place a cell in salt water - water moves out of the cell – cell shrinks - less water outside the cell – water moves out
2. Place cell in distilled (pure) water -water moves into the cell ` -cell swells (could burst) • less water in the cell • - water moves in
What would occur if a solution of salt H2O or distilled (pure) water was added to a cell? • Adding a salt solution: • Since the concentration of H2O is higher inside the cell, the water flows outward to the area of low concentration. The water rushes out, the cell shrinks. • Adding distilled (pure) water • Since the concentration of H2O is higher outside of the cell, the water flows inward to the area of low concentration. The water rushes in, the cell could eventually burst.
Animal Cells shrivel like slugs in a salt solution because water leaves the cell!
Transport in Lower Organisms -ex. Ameba, paramecium 1. Diffusion 2. Osmosis 3. Cyclosis 4. Endoplasmic Reticulum
Transport in Plants vascular tissue: (veins) -xylem – transports water upwards - phloem – transports food in both directions
Roots: • Located under the ground. Provide support, anchorage, and absorb water. • Root hairs: • Increase surface area for water absorption. • Capillary Action: • Pulls H2O up in the xylem tubes. • This is because of adhesion and cohesion. • Adhesion- attraction between different molecules. • Cohesion- Attraction between like molecules. • H2O holds on to another H2O molecule.
Chapter 12- Human Transport • Blood • Liquid tissue • Transport medium • Contains: • Plasma • Red Blood cells (RBC) • White Blood cells (WBC) • Platelets
Plasma • Liquid portion of the blood, mostly water. • Contains nutrients, wastes, proteins • Proteins enzymes, hormones, and antibodies.
Red Blood Cells (RBC- Erythrocytes) • Most numerous blood cell • Lack a nucleus when mature • Disc-shaped • Carries oxygen (O2) & carbon dioxide(CO2) • Contains hemoglobin-pigment that allows RBC to carry O2 & CO2. • Live for 120 days-broken down in the liver and spleen. • Produced in the bone marrow.
White Blood Cells (WBC- Leukocytes) • Least numerous blood cell • Contains a nucleus • Large, round cell • Protects against infection • Phagocytes • Engulf and destroy bacteria (phagocytosis) • Lymphocytes • Produce antibodies which attack foreign materials called antigens.