BIOLOGY                       CONCEPTS & CONNECTIONS                                        Fourth EditionNeil A. Campbell...
MEMBRANE STRUCTURE AND FUNCTION5.10 Membranes organize the chemical activities of     cells • Membranes organize the chemi...
• Membranes are selectively permeable        – They control the flow of substances into and out          of a cell• Membra...
5.11 Membrane phospholipids form a bilayer• Phospholipids are                                                             ...
• In water, phospholipids form a stable bilayer         – The heads face outward and the tails face           inward      ...
5.12 The membrane is a fluid mosaic of     phospholipids and proteins• Phospholipid molecules form a flexible bilayer     ...
• The plasma membrane of an animal cell                       Glycoprotein                 Carbohydrate                   ...
5.13 Proteins make the membrane a mosaic of     function• Some membrane proteins form cell junctions• Others transport sub...
• Many membrane proteins are enzymes • Some proteins function as receptors for   chemical messages from other cells       ...
5.14 Passive transport is diffusion across a     membrane• In passive transport,                                          ...
5.15 Osmosis is the passive transport of water                                                                            ...
5.16 Water balance between cells and their     surroundings is crucial to organisms• Osmosis causes cells to shrink in a h...
5.17 Transport proteins facilitate diffusion across     membranes• Small nonpolar molecules diffuse freely through  the ph...
5.18 Cells expend energy for active transport• Transport proteins can move solutes across a  membrane against a concentrat...
FLUID                                                    Phosphorylated • Active                                          ...
5.19 Exocytosis and endocytosis transport large     molecules• To move large molecules or particles through a  membrane   ...
– or the membrane may fold inward, trapping           material from the outside (endocytosis)                    Figure 5....
• Three kinds of endocytosisPseudopod of            Food being                                          Plasma       Mater...
5.20 Connection: Faulty membranes can overload     the blood with cholesterol• Harmful levels of cholesterol can accumulat...
5.21 Chloroplasts and mitochondria make energy     available for cellular work• Enzymes and membranes are central to the  ...
Sunlight energy • Nearly all the chemical   energy that organisms   use comes ultimately                                  ...
Upcoming SlideShare
Loading in …5
×

Cell Transport

776 views
572 views

Published on

To study biology.

Published in: Education
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
776
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
16
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Cell Transport

  1. 1. BIOLOGY CONCEPTS & CONNECTIONS Fourth EditionNeil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor CHAPTER 5 The Working Cell Modules 5.10 – 5.21 From PowerPoint® Lectures for Biology: Concepts & Connections Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  2. 2. MEMBRANE STRUCTURE AND FUNCTION5.10 Membranes organize the chemical activities of cells • Membranes organize the chemical reactions making up metabolism → → Cytoplasm Figure 5.10Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  3. 3. • Membranes are selectively permeable – They control the flow of substances into and out of a cell• Membranes can hold teams of enzymes that function in metabolismCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  4. 4. 5.11 Membrane phospholipids form a bilayer• Phospholipids are Head the main structural components of membranes• They each have a hydrophilic head Symbol and two hydrophobic tails Tails Figure 5.11ACopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  5. 5. • In water, phospholipids form a stable bilayer – The heads face outward and the tails face inward Water Hydrophilic heads Hydrophobic tails Water Figure 5.11BCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  6. 6. 5.12 The membrane is a fluid mosaic of phospholipids and proteins• Phospholipid molecules form a flexible bilayer – Cholesterol and protein molecules are embedded in it – Carbohydrates act as cell identification tagsCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  7. 7. • The plasma membrane of an animal cell Glycoprotein Carbohydrate (of glycoprotein) Fibers of the extracellular matrix Glycolipid Phospholipid Cholesterol Microfilaments Proteins of the cytoskeleton CYTOPLASM Figure 5.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  8. 8. 5.13 Proteins make the membrane a mosaic of function• Some membrane proteins form cell junctions• Others transport substances across the membrane Figure 5.13 TransportCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  9. 9. • Many membrane proteins are enzymes • Some proteins function as receptors for chemical messages from other cells – The binding of a messenger to a receptor may trigger signal transduction Messenger molecule Receptor Activated molecule Figure 5.13 Enzyme activity Signal transductionCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  10. 10. 5.14 Passive transport is diffusion across a membrane• In passive transport, Molecule substances diffuse of dye Membrane EQUILIBRIUM through membranes without work by the cell – They spread from areas of high EQUILIBRIUM concentration to areas of lower concentration Figure 5.14A & BCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  11. 11. 5.15 Osmosis is the passive transport of water Hypotonic Hypertonic• In osmosis, water solution solution travels from an area of lower solute concentration to Selectively permeable Solute molecule membrane an area of higher HYPOTONIC SOLUTION HYPERTONIC SOLUTION solute Water molecule concentration Selectively permeable Solute molecule with membrane cluster of water molecules NET FLOW OF WATER Figure 5.15Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  12. 12. 5.16 Water balance between cells and their surroundings is crucial to organisms• Osmosis causes cells to shrink in a hypertonic solution and swell in a hypotonic solution – The control of water balance (osmoregulation) is essential for organisms ISOTONIC HYPOTONIC HYPERTONIC SOLUTION SOLUTION SOLUTION ANIMAL CELL (1) Normal (2) Lysing (3) Shriveled Plasma membrane PLANT CELL Figure 5.16 (4) Flaccid (5) Turgid (6) ShriveledCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  13. 13. 5.17 Transport proteins facilitate diffusion across membranes• Small nonpolar molecules diffuse freely through the phospholipid bilayer• Many other kinds of molecules pass through selective protein pores by facilitated diffusion Solute molecule Transport protein Figure 5.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  14. 14. 5.18 Cells expend energy for active transport• Transport proteins can move solutes across a membrane against a concentration gradient – This is called active transport – Active transport requires ATPCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  15. 15. FLUID Phosphorylated • Active OUTSIDE CELL Transport protein transport protein transport in two solutes across a First membrane solute 1 First solute, 2 ATP transfers 3 Protein releases inside cell, phosphate to solute outside binds to protein protein cell Second solute 4 Second solute 5 Phosphate 6 Protein releases binds to protein detaches from second solute Figure 5.18 protein into cellCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  16. 16. 5.19 Exocytosis and endocytosis transport large molecules• To move large molecules or particles through a membrane – a vesicle may fuse with the membrane and expel its contents (exocytosis) FLUID OUTSIDE CELL CYTOPLASM Figure 5.19ACopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  17. 17. – or the membrane may fold inward, trapping material from the outside (endocytosis) Figure 5.19BCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  18. 18. • Three kinds of endocytosisPseudopod of Food being Plasma Material bound toamoeba ingested membrane receptor proteins PIT Cytoplasm Figure 5.19CCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  19. 19. 5.20 Connection: Faulty membranes can overload the blood with cholesterol• Harmful levels of cholesterol can accumulate in the blood if membranes lack cholesterol receptors Phospholipid LDL PARTICLE outer layer Receptor protein Protein Cholesterol Plasma membrane Vesicle CYTOPLASM Figure 5.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  20. 20. 5.21 Chloroplasts and mitochondria make energy available for cellular work• Enzymes and membranes are central to the processes that make energy available to the cell• Chloroplasts carry out photosynthesis, using solar energy to produce glucose and oxygen from carbon dioxide and water• Mitochondria consume oxygen in cellular respiration, using the energy stored in glucose to make ATPCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
  21. 21. Sunlight energy • Nearly all the chemical energy that organisms use comes ultimately Chloroplasts, site of photosynthesis from sunlight CO2 Glucose + + H2O Mitochondria O2 • Chemicals recycle sites of cellular respiration among living organisms and their environment (for cellular work) Figure 5.21 Heat energyCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

×