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Chapter 3
Cells
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Fig. 3A pg. 46
Fig. 3A pg. 46 top
Fig. 3A pg. 47 left
Fig. 3A pg. 47 left top
Fig. 3A pg. 47 right
Fig. 3A pg. 47 right top
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