Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 3 Cells

Fig. 3A pg. 46

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Fig. 3.1

Fig. 3.2a

Fig. 3.p049 Cell Membrane

Eukaryotic cells, cont’d. Functions of the cell membrane –Functions as a barrier between the cell and its environment –Regulates what substances move into and out of the cell –Contains receptors that determine how a cell will respond to stimuli in the environment –Contains proteins that are important in immune responses –It is a very dynamic, fluid structure

Fig. 3.4a The Nucleus

Fig. 3.2b The Nucleus

Eukaryotic cells, cont’d. Nucleus –Contains the genetic material DNA –Chromatin-threadlike DNA which has a grainy appearance –Nucleolus-dark regions of chromatin which produce rRNA which composes ribosomes –Nuclear membrane- double layered, surrounds nucleus and has large pores

Fig. 3.5a Rough & Smooth Endoplasmic Reticulum

Fig. 3.5c Ribosomes

Eukaryotic cells, cont’d. Ribosomes- –site of protein assembly –Composed of rRNA –Exist either as free ribosomes or bound to endoplasmic reticulum

Fig. 3.5ab

Fig. 3.5b

Eukaryotic cells, cont’d. –Rough endoplasmic reticulum (rer) Complex system of sacs and channels Has attached ribosomes Serves as site of assembly of proteins for export Assembled proteins enter channels for processing –Addition of sugar chains to form glycoproteins Released in vesicles –Smooth endoplasmic reticulum (ser) Synthesizes lipid products such as phospholipids and steroids Released in vesicles

Fig. 3.6

Eukaryotic cells, cont’d. Golgi apparatus –packaging and processing center for cell products –Receives the vesicles from er –Vesicles fuse with Golgi and products are released inside –Further modification of glyoproteins occurs –Products are packaged into secretory vesicles and released to the cell membrane –Golgi also produces lysosomes-protein containing vesicles within cells

Fig. 3.7 Lysosomes

Eukaryotic cells, cont’d. Lysosomes –Contain hydrolytic enzymes –Fuse with vesicles from cell membrane containing macromolecules –Digestion occurs and nutrients released to cell –Also may be involved in programmed cell death- ”suicide sacs” Lysosomal membranes in old or damaged cells rupture and enzymes digest the cell

Fig. 3.9 Mitochondria

Eukaryotic cells, cont’d. Mitochondria –Site of cellular respiration-production of ATP –Outer double membrane surrounds fluid-filled matrix –Inner folded membrane-folds are called cristae –Cristae provide increased surface area for the production of ATP

Fig. 3.p056c