Eucaryotic Cell Structure and Function Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 4 Eucaryotic Cell Structure and Function

An Overview of Eucaryotic Cell Structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. An Overview of Eucaryotic Cell Structure membrane-delimited nuclei membrane-bound organelles that perform specific functions more structurally complex than procaryotic cell generally larger than procaryotic cell

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Table 4.1

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. AV= autophagic vacuole; C=centriole; Ch=chloroplast; CI=cilium; CR=chromatin; DV=digestion vacuole; F=microfilaments; G=glycogen; GA=Golgi apparatus; GE=GERL; LD=lipid droplet; M=mitochondrion; MT=microtubules; N=nucleus; NU=nucleolus; P=peroxisome; PL=primary lysosome; PM=plasma membrane; PV=pinocytotic vesicle; R=ribosomes and polysomes; RB=residual body; RER=rough endoplasmic reticulum; SER=smooth endoplasmic reticulum; SV=secretion vacuole Figure 4.1

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. AV= autophagic vacuole; C=centriole; Ch=chloroplast; CI=cilium; CR=chromatin; DV=digestion vacuole; F=microfilaments; G=glycogen; GA=Golgi apparatus; GE=GERL; LD=lipid droplet; M=mitochondrion; MT=microtubules; N=nucleus; NU=nucleolus; P=peroxisome; PL=primary lysosome; PM=plasma membrane; PV=pinocytotic vesicle; R=ribosomes and polysomes; RB=residual body; RER=rough endoplasmic reticulum; SER=smooth endoplasmic reticulum; SV=secretion vacuole Figure 4.2

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. AV= autophagic vacuole; C=centriole; Ch=chloroplast; CI=cilium; CR=chromatin; DV=digestion vacuole; F=microfilaments; G=glycogen; GA=Golgi apparatus; GE=GERL; LD=lipid droplet; M=mitochondrion; MT=microtubules; N=nucleus; NU=nucleolus; P=peroxisome; PL=primary lysosome; PM=plasma membrane; PV=pinocytotic vesicle; R=ribosomes and polysomes; RB=residual body; RER=rough endoplasmic reticulum; SER=smooth endoplasmic reticulum; SV=secretion vacuole Figure 4.3

The Plasma Membrane and Membrane Structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Plasma Membrane and Membrane Structure the fluid mosaic model is based on eucaryotic membranes major membrane lipids include phosphoglycerides, sphingolipids and cholesterol

The Plasma Membrane and Membrane Structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Plasma Membrane and Membrane Structure eucaryotic membranes contain microdomains called lipid rafts They are enriched for certain lipids and proteins They participate in a variety of cell processes such as cell movement and transduction

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.4

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Cytoplasmic Matrix, Microfilaments, Intermediate Filaments, and Microtubules The many organelles of eucaryotic cells lie in the cytoplasmic matrix Cytoskeleton vast network of interconnected filaments within the cytoplasmic matrix Filaments that form the cytoskeleton: microfilaments, microtubules, and intermediate filaments plays role in both cell shape and cell movement

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.5

Microfilaments minute protein filaments, 4 to 7 nm in diameter Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Microfilaments minute protein filaments, 4 to 7 nm in diameter scattered within cytoplasmic matrix or organized into networks and parallel arrays composed of actin protein involved in cell motion and shape changes

Microtubules shaped like thin cylinders ~ 25 nm in diameter Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Microtubules shaped like thin cylinders ~ 25 nm in diameter help maintain cell shape involved with microfilaments in cell movements participate in intracellular transport processes

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.6

Intermediate Filaments Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Intermediate Filaments heterogeneous elements of the cytoskeleton ~10 nm in diameter role in cell is unclear Some shown to form nuclear lamina Others help link cells together to form tissues

The Endoplasmic Reticulum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Endoplasmic Reticulum irregular network of branching and fusing membranous tubules and flattened sacs (cisternae – s., cisterna) Figure 4.7

Two types of Endoplasmic Reticulum (ER) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Two types of Endoplasmic Reticulum (ER) rough ER ribosomes attached synthesis of secreted proteins by ER-associated ribosomes smooth ER devoid of ribosomes synthesis of lipids by ER-associated enzymes

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Functions of ER transports proteins, lipids, and other materials within cell major site of cell membrane synthesis synthesis of lysosomes

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Golgi Apparatus membranous organelle made of cisternae stacked on each other dictyosomes stacks of cisternae involved in modification, packaging, and secretion of materials Figure 4.8 (a)

cis face associated with ER Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. movement of materials Figure 4.8 (b) cis face associated with ER

Lysosomes membrane-bound vesicles found in most eucaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lysosomes membrane-bound vesicles found in most eucaryotes involved in intracellular digestion contain hydrolases, enzymes which hydrolyze molecules and function best under slightly acidic conditions maintain an acidic environment by pumping protons into their interior

The Biosynthetic-Secretory Pathway Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Biosynthetic-Secretory Pathway used to move materials to lysosomes as well as from the inside of the cell to either the cell membrane or cell exterior proteins synthesized by ribosomes on rough ER released in small vesicles  cis face of Golgi apparatus trans face of Golgi apparatus transport vesicles released from trans face of Golgi

The Biosynthetic-Secretory Pathway (continued) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Biosynthetic-Secretory Pathway (continued) after release some vesicles deliver their contents to lysosomes while others deliver to cell membrane quality assurance mechanism Unfolded or misfolded proteins are secreted into cytosol, targeted for destruction by ubiquitin polypeptides. proteasomes destroy targeted proteins

Proteasome Degradation of Proteins Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Proteasome Degradation of Proteins Figure 4.9 (a)

Proteasome Degradation of Proteins Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Proteasome Degradation of Proteins Figure 4.9 (b)

The Endocytic Pathway endocytosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Endocytic Pathway endocytosis used to bring materials into the cell solutes or particles taken up and enclosed in vesicles pinched from plasma membrane in most cases materials are then delivered to lysosome and destroyed

Types of Endocytosis phagocytosis clathrin-dependent endocytosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Types of Endocytosis phagocytosis Use of cell surface protrusions to surround and engulf particles Resulting vesicles called phagosomes clathrin-dependent endocytosis involves membrane regions coated on cytoplasmic side with the protein clathrin (coated pits) coated pits have external receptors that specifically bind macromolecules pinching off of coated pits forms coated vesicles called receptor-mediated endocytosis

More Types of Endocytosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. More Types of Endocytosis caveolae–dependent endocytosis enriched in cholesterol and the membrane protein caveolin When caveolae pinch off membrane are called caveolar vesicles do not deliver their contents to lysosomes may play role in signal transduction, transport of small as well as macromolecules

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Autophagy Delivery of materials to be digested by route that does not involve endocytosis Involves digestion and recycling of cytoplasmic components Double membrane (may be from endoplasmic reticulum) surrounds cell component forming an autophagosome Autophagosome fuses with late endosome which ultimately becomes a lysosome

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.10

Once Lysosome is formed… Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Once Lysosome is formed… digestion occurs without release of lysosome enzymes into cytoplasmic matrix as contents are digested, products leave lysosome and can be used as nutrients resulting lysosome called a residual body which can release contents to cell exterior by process called lysosome secretion

Eucaryotic Ribosomes 80S in size Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Eucaryotic Ribosomes 80S in size 60S + 40S subunits may be attached to ER or free in cytoplasmic matrix Figure 4.3

Eucaryotic ribosomes… Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Eucaryotic ribosomes… Proteins made on ribosomes of RER are often secreted or inserted into ER membrane as integral membrane proteins Free ribosomes synthesize nonsecretory and nonmembrane proteins Some proteins are inserted into organelles

Mitochondria site of tricarboxylic acid cycle activity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitochondria site of tricarboxylic acid cycle activity site where ATP is generated by electron transport and oxidative phosphorylation Figure 4.3

Mitochondrial structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitochondrial structure outer membrane contains porins similar to the outer membrane of gram negative bacteria inner membrane highly folded to form cristae (s., crista) location of enzymes and electron carriers for electron transport and oxidative phosphorylation

Mitochondrial structure… Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitochondrial structure… matrix contains ribosomes, mitochondrial DNA, and large calcium phosphate granules contains enzymes of the tricarboxylic acid cycle and enzymes involved in catabolism of fatty acids

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.11

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.12

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.13

Chloroplasts type of plastid site of photosynthetic reactions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chloroplasts type of plastid pigment-containing organelles observed in plants and algae site of photosynthetic reactions surrounded by double membrane Figure 4.3

Chloroplast structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chloroplast structure the stroma (a matrix) is within inner membrane contains DNA, ribosomes, lipid droplets, starch granules, and thylakoids thylakoids flattened, membrane-delimited sacs grana (s., granum) – stacks of thylakoids site of light reactions (trapping of light energy to generate ATP, NADPH, and oxygen)

Chloroplast structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chloroplast structure stroma is site of dark reactions of photosynthesis (formation of carbohydrates from water and carbon dioxide) algal chloroplasts many contain a pyrenoid participates in polysaccharide synthesis

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.14

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.15

The Nucleus and Cell Division Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Nucleus and Cell Division nucleus membrane-bound structure that houses genetic material of eucaryotic cell Figure 4.3

Nuclear structure chromatin dense fibrous material within nucleus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nuclear structure chromatin dense fibrous material within nucleus contains DNA condenses to form chromosomes during cell division

Nuclear structure… nuclear envelope Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nuclear structure… nuclear envelope double membrane structure that delimits nucleus penetrated by nuclear pores pores allow materials to be transported into or out of nucleus

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. freeze-etch preparation of the conidium of the fungus Geotrichous candidum; note large convex nuclear surface with nuclear pores scattered over it Figure 4.15

The Nucleolus  1 nucleolus/nucleus not membrane enclosed Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Nucleolus  1 nucleolus/nucleus not membrane enclosed important in ribosome synthesis directs synthesis and processing of rRNA directs assembly of rRNA and ribosomal proteins to form ribosomes

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.16

Mitosis and Meiosis mitosis one component of cell cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitosis and Meiosis mitosis one component of cell cycle distributes DNA to 2 new nuclei ploidy (number of chromosomes) of progeny cells is the same as the parent thus, after mitosis, a diploid organism remains diploid

preparation for mitosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. period of cell growth preparation for mitosis synthesis of RNA, ribosomes, and cytoplasmic constituents Figure 4.17

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.18

Mitosis and Meiosis… meiosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitosis and Meiosis… meiosis complex, two-stage process of nuclear division number of chromosomes in the resulting progeny cells is reduced by ½ diploid  haploid

Figure 4.19 generalized eucaryotic life cycle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. generalized eucaryotic life cycle Figure 4.19

External Cell Covering Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. External Cell Covering cell wall rigid variable make-up algae – cellulose and pectin diatoms – silica fungi – chitin, cellulose, and glucan

External Cell Covering Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. External Cell Covering pellicle relatively rigid layer of components just beneath plasma membrane common in protozoa not as strong or rigid as cell wall provides characteristic shape to cell

Cilia and Flagella cilia (s., cilium) flagella (s., flagellum) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cilia and Flagella cilia (s., cilium) 5-20 μm long beat with two phases, working like oars flagella (s., flagellum) 100-200 μm long move in undulating fashion

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.20

Structure of flagella and cilia Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structure of flagella and cilia membrane-bound cylinders ~ 2 μm in diameter axoneme set of microtubules in a 9 + 2 arrangement basal body at base of flagellum or cilium directs synthesis of flagella and cilia

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.21

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 4.23

Comparison of Procaryotic and Eucaryotic Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Comparison of Procaryotic and Eucaryotic Cells Figure 4.24

Comparison of Procaryotic and Eucaryotic Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Comparison of Procaryotic and Eucaryotic Cells Table 4.2

The molecular unity of procaryotes and eucaryotes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The molecular unity of procaryotes and eucaryotes same basic chemical composition same genetic code same basic metabolic processes