Transcript Cells teacher powerpoint

Chapter 3
Cells
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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