9/8/2010. Chapter 4. Structures Internal to the Cell Wall. The Plasma Membrane. Functional Anatomy of Prokaryotic and Eukaryotic Cells

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Chapter 4 Functional Anatomy of Prokaryotic and Eukaryotic Cells Johana Meléndez Part II slides 39-87 Lectures prepared by Christine L.

4-9 Define simple diffusion, facilitated diffusion, osmosis, active transport, and group translocation. 4-10 Identify the functions of the nucleoid and ribosomes.

1 Chapter 4 Functional Anatomy of Prokaryotic and Eukaryotic Cells Johana Meléndez Part II slides Lectures prepared by Christine L. Case Structures Internal to the Cell Wall Learning Objectives 4-8 Describe the structure, chemistry, and functions of the prokaryotic plasma membrane. 4-9 Define simple diffusion, facilitated diffusion, osmosis, active transport, and group translocation Identify the functions of the nucleoid and ribosomes Identify the functions of four inclusions Describe the functions of endospores, sporulation, and endospore germination. The Plasma Membrane located inside cell wall and enclosing the cytoplasm Figure 4.14a 1

2 The Plasma Membrane Structure: Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane Proteins Figure 4.14b Fluid Mosaic Model- dynamic arrangement of phospholipids and proteins (they are not static) Membrane is as viscous as olive oil Proteins move to function Phospholipids rotate and move laterally Because they lack sterols they are less rigid than eukaryotic membranes Figure 4.14b The Plasma Membrane Function: Selective permeability allows passage of some molecules, but others are prevented from enetering. Enzymes for ATP production (energy) Photosynthetic pigments on infoldings of the membrane called chromatophores or thylakoids 2

cell contents ANIMATION Membrane Structure ** ANIMATION Membrane Permeability Movement of material across the membrane Passive From higher

3 Chromatophores Rhodospirillum rubrum Figure 4.15 The Plasma Membrane Damage to the membrane by alcohols, quaternary ammonium (detergents), and polymyxin antibiotics causes leakage of cell contents ANIMATION Membrane Structure ** ANIMATION Membrane Permeability Movement of material across the membrane Passive From higher to lower concentration Does not require energy Examples: simple diffusion, facilitated diffusion and osmosis Active From lower to higher concentration Requires energy from ATP Examples: active transport ATP driven, group translocation 47 3

Movement of Materials across Membranes Simple diffusion: Movement of a solute from an

Transport: Special Types of Diffusion ** ANIMATION Passive Transport: Principles of

17a Movement of Materials across Membranes Facilitated diffusion: Solute combines

17b-c Movement of Materials across Membranes Osmosis: The movement of water across a

4 Movement of Materials across Membranes Simple diffusion: Movement of a solute from an area of high concentration to an area of low concentration ANIMATION Passive Transport: Special Types of Diffusion ** ANIMATION Passive Transport: Principles of Diffusion ** Figure 4.17a Movement of Materials across Membranes Facilitated diffusion: Solute combines with a transporter protein in the membrane Figure 4.17b-c Movement of Materials across Membranes Osmosis: The movement of water across a selectively permeable membrane from an area of high water to an area of lower water concentration Osmotic pressure: The pressure needed to stop the movement of water across the membrane Figure 4.18a 4

side where there is a higher concentration of solutes,

outside higher than solutes inside Solutes outside less

18c e Movement of Materials across Membranes Active

translocation: Requires a transporter protein and PEP

5 The Principle of Osmosis Figure 4.18a b The Principle of Osmosis Water moves towards the side where there is a higher concentration of solutes, and less water Solutes outside= solutes inside Solutes outside higher than solutes inside Solutes outside less than solutes inside Figure 4.18c e Movement of Materials across Membranes Active transport: Requires a transporter protein and ATP Group translocation: Requires a transporter protein and PEP (phosphoenolpyruvic acid high energy P compound) ANIMATION Active Transport: Types ANIMATION Active Transport: Overview 5

6 Which agents can cause injury to the bacterial plasma membrane? 4-8 How are simple diffusion and facilitated diffusion similar? How are they different? 4-9 Cytoplasm The substance inside the plasma membrane Gelatinous solution containing water, nutrients, proteins, and genetic material. Site for cell metabolism Site for many biochemical and synthetic activities 70%-80% water Figure 4.6 The Nucleoid Bacterial chromosome genetic material Plasmids: extra-chromosomal DNA, can be advantageous but not necessary Figure 4.6 6

Ribosomes A ribosome is a combination of RNA and protein, and is involved in

6 The Prokaryotic Ribosome Protein synthesis 70S 50S + 30S subunits Figure 4.

inclusions Sulfur granules Carboxysomes Gas vacuoles Magnetosomes Phosphate

1,5-diphosphate carboxylase for CO 2 fixation Protein-covered cylinders Iron

7 Ribosomes A ribosome is a combination of RNA and protein, and is involved in protein synthesis. Figure 4.6 The Prokaryotic Ribosome Protein synthesis 70S 50S + 30S subunits Figure 4.19 Inclusions Metachromatic granules (volutin) Polysaccharide granules Lipid inclusions Sulfur granules Carboxysomes Gas vacuoles Magnetosomes Phosphate reserves Energy reserves Energy reserves Energy reserves Ribulose 1,5-diphosphate carboxylase for CO 2 fixation Protein-covered cylinders Iron oxide (destroys H 2 O 2 ) Inclusion bodies enable a cell to store nutrients, and to survive nutrient depleted environments or store gases to provide buoyancy. 7

8 Endospores Resting cells Resistant to desiccation, heat, chemicals, radiation... Bacillus, Clostridium Sporulation: Endospore formation Germination: Return to vegetative state Formation of Endospores by Sporulation 9&alaid=ala_ &showSelfStudyTree =true Figure 4.21a Where is the DNA located in a prokaryotic cell? 4-10 What is the general function of inclusions? 4-11 Under what conditions do endospores form?

Flagella and Cilia Flagella are few and long in relation to cell size; cilia are numerous and short.

9 The Eukaryotic Cell Figure 4.22a Flagella and Cilia Learning Objective 4-13 Differentiate prokaryotic and eukaryotic flagella. Flagella and Cilia Flagella are few and long in relation to cell size; cilia are numerous and short. Flagella and cilia are used for motility, and cilia also move substances along the surface of the cells. Both flagella and cilia consist of an arrangement of nine pairs and two single microtubules. Figure 4.23a-b 9

Flagella and Cilia Microtubules Tubulin 9 pairs + 2 array Figure 4.23c The Cell Wall and Glycocalyx Learning Objective 4-14 Compare and contrast prokaryotic and eukaryotic cell walls and glycocalyxes.

10 Flagella and Cilia Microtubules Tubulin 9 pairs + 2 array Figure 4.23c The Cell Wall and Glycocalyx Learning Objective 4-14 Compare and contrast prokaryotic and eukaryotic cell walls and glycocalyxes. The Cell Wall and Glycocalyx Cell wall Plants, algae, fungi Carbohydrates Cell walls are made out of: Cellulose, (algae and some fungi) chitin, (fungi) glucan, mannan (yeast cells) Glycocalyx Consist of sticky carbohydrates that covers plasma membrane These carbohydrates can be bonded to proteins (glycoproteins) and lipids (glycolipids) in membrane Provides means for attachment, cell- cell recognition and strengthens cells surface 10

11 Q&A Penicillin was called a miracle drug because it doesn t harm human cells. Why doesn t it? The Plasma Membrane Learning Objective 4-15 Compare and contrast prokaryotic and eukaryotic plasma membranes. The Plasma Membrane Phospholipid bilayer Peripheral proteins Integral proteins Transmembrane proteins Sterols (not found on prokaryotes, except Mycoplasma bacteria) Glycocalyx carbohydrates Similar in function and structure to prokaryotes Different types of proteins and carbohydrates associated 11

The Plasma Membrane Selective permeability allows passage of some molecules Simple diffusion Facilitative diffusion Osmosis Active transport

fluid and dissolved substances Cytoplasm Learning Objective 4-16 Compare and contrast prokaryotic and eukaryotic cytoplasms.

12 The Plasma Membrane Selective permeability allows passage of some molecules Simple diffusion Facilitative diffusion Osmosis Active transport Endocytosis (no group translocation) Phagocytosis: Pseudopods extend and engulf particles Pinocytosis: Membrane folds inward, bringing in fluid and dissolved substances Cytoplasm Learning Objective 4-16 Compare and contrast prokaryotic and eukaryotic cytoplasms. Cytoplasm Eukaryotes have complex internal structures and cytoskeleton (structures that consist of small rods that provide support and shape to cells). Table

13 Cytoplasm Cytoplasm membrane: Substance inside plasma and outside nucleus Cytosol: Fluid portion of cytoplasm Cytoskeleton: Microfilaments, intermediate filaments, microtubules Cytoplasmic streaming: Movement of cytoplasm throughout cells to help distribute nutrients Important enzymes found in the cytoplasmic fluid of prokaryotes are found in the organelles of eukaryotes Ribosomes Learning Objective 4-17 Compare the structure and function of eukaryotic and prokaryotic ribosomes. Ribosomes Protein synthesis 80S (subunits are 60S and 40S) Membrane-bound: Attached to ER Free: In cytoplasm 70S In chloroplasts and mitochondria (endosymbiotic theory) 13

14 Identify at least one significant difference between eukaryotic and prokaryotic flagella and cilia, cell walls, plasma membranes, and cytoplasm The antibiotic erythromycin binds with the 50S portion of a ribosome. What effect does this have on a prokaryotic cell? On a eukaryotic cell? 4-17 Organelles 4-18 Define organelle Describe the functions of the nucleus, endoplasmic reticulum, Golgi complex, lysosomes, vacuoles, mitochondria, chloroplasts, peroxisomes, and centrosomes. Organelles Nucleus: Contains chromosomes ER: Transport network Rough: protein synthesis Smooth : lipid synthesis, inactivate and detoxify drugs Golgi complex: Membrane formation and secretion. Modification of proteins to form glycoproteins, glycolipids and lipoproteins. Lysosome: Storage of digestive enzymes Ex. Phagocytosis contain enzymes that destroy bacteria Vacuole: Brings food into cells and provides support 14

Contain their own 70s ribosomes and DNA Peroxisome: Oxidation of fatty acids; destroys H 2 O 2 Centrosome:

15 Organelles Mitochondrion: Cellular respiration, main site for energy production (ATP). Contain their own 70s ribosomes and DNA Can replicate on their own Chloroplast: Photosynthesis. Contain their own 70s ribosomes and DNA Peroxisome: Oxidation of fatty acids; destroys H 2 O 2 Centrosome: Consists of protein fibers and centrioles. Role on cell division. The Eukaryotic cell Figure 4.24 Lysosomes and Vacuoles Figure 4.22b 15

Compare the structure of the nucleus of a eukaryote and the nucleoid of a prokaryote. 4-18 How do rough and smooth ER compare structurally and functionally?

16 Compare the structure of the nucleus of a eukaryote and the nucleoid of a prokaryote How do rough and smooth ER compare structurally and functionally? 4-19 The Evolution of Eukaryotes Learning Objective 4-20 Discuss evidence that supports the endosymbiotic theory of eukaryotic evolution. Endosymbiotic Theory Explains the origin of eukaryotes from prokaryotes One organism lives within another Figure

17 Which three organelles are not associated with the Golgi complex? What does this suggest about their origin?

Biology: Life on Earth

Teresa Audesirk Gerald Audesirk Bruce E. Byers Biology: Life on Earth Eighth Edition Lecture for Chapter 4 Cell Structure and Function Copyright 2008 Pearson Prentice Hall, Inc. Chapter 4 Outline 4.1 What