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The Working Cell Figures 5.14 – 5.19

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Presentation on theme: "The Working Cell Figures 5.14 – 5.19"— Presentation transcript:

1 The Working Cell Figures 5.14 – 5.19
CHAPTER 5 The Working Cell Figures 5.14 – 5.19

2 Water Balance in Plant Cells
Water balance in plant cells is different They have rigid cell walls They are at the mercy of the environment Figure 5.14

3 Active Transport: the Pumping of Molecules Across Membranes
Active transport requires energy to move molecules across a membrane Lower solute concentration Solute Higher solute concentration Figure 5.15

4 Exocytosis and Endocytosis: Traffic of Large Molecules
Secretes substances outside of the cell Outside cell Plasma membrane Cytoplasm (a) Exocytosis Figure 5.16a

5 Endocytosis Takes material into the cell (b) Endocytosis Figure 5.16b

6 In phagocytosis (“cellular eating”) a cell engulfs a particle and packages it within a food vacuole
In pinocytosis (“cellular drinking”) a cell “gulps” droplets of fluid by forming tiny vesicles Pseudopod of amoeba Food being ingested Figure 5.17

7 Receptor-mediated endocytosis
Is triggered by the binding of external molecules to membrane proteins

8 The Role of Membranes in Cell Signaling
LDL particle Phospholipid coat Protein Receptor protein Cholesterol Plasma membrane Cholesterol processed Liver cell Figure 5.18

9 Cellular communication
Begins with the reception of an extracellular signal The signal transduction pathway Consists of proteins and other molecules that relay the signal

10 Reception Transduction Response
Outside cell Inside cell Reception Transduction Response Receptor protein Hydrolysis of glycogen releases glucose for energy Signal transduction pathway Epinephrine (adrenaline) from adrenal glands Plasma membrane Figure 5.19

Organisms use many different enzymes Scientists compare enzymes from different organisms Comparisons show similarities between organisms

12 The processes of natural selection and directed evolution
Both result in the production of new enzymes with new functions

ATP and Cellular Work Energy for cellular work Adenosine Adenosine (Phosphate transferred to other molecules) Adenosine triphosphate Adenosine diphosphate Energy from organic fuel Visual Summary 5.1

14 Higher water concentration (hypotonic)
Passive Transport, Osmosis, and Active Transport Requires no energy Requires energy Passive transport Osmosis Active transport Higher solute concentration Higher water concentration (hypotonic) Higher solute concentration Solute Water Solute Solute Lower water concentration (hypertonic) Lower solute concentration Lower solute concentration Visual Summary 5.2

15 Exocytosis and Endocytosis: Traffic of Large Molecules
Visual Summary 5.3

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