Transcript Chapter 7 Body Systems

Chapter 3
Anatomy of Cells
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Slide 1
Anatomy of Cells
• Cell Structure
• Cellular Components

Structure

Function
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Slide 2
Table 3-2
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Slide 3
Functional Anatomy of Cells
• The typical cell (Figure 3-1) – generic cell

Varies in size; all are microscopic (Table 3-1)

Varies in structure and function (Table 3-2)
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Slide 4
Typical Cell – Fig. 3-1
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Slide 5
Typical or Composite Cell – Fig. 3-1
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Slide 6
Cell Structures
• Plasma membrane—separates the cell from
its surrounding environment
• Cytoplasm—thick gel-like substance inside of
the cell composed of numerous organelles
suspended in watery cytosol; each type of
organelle (“little organ”) is suited to perform
particular functions (Figure 3-2)
• Nucleus—large membranous structure near
the center of the cell
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Slide 7
Cell Membranes
• Plasma membrane
(Figure 3-3)
• Membranous
organelles – sacs
and canals made of
the same material
as the plasma
membrane
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Slide 8
Cell Membranes
• Structure – is a double layer of phospholipid molecule

Phospholipid
• Heads are hydrophilic (water-loving)
• Tails are hydrophobic (water-fearing)

Cholesterol molecules are scattered among the phospholipids to
allow the membrane to function properly at body temperature

Membrane Proteins
• Controls what moves through the membrane
• Act as i.d. markers
• Act as receptors
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Slide 9
Cell Membrane
• Membrane Function

To keep cellular components inside the cell and
extracellular material outside the cell

Controls what moves into and out of the cell
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Slide 10
Cytoplasm and Organelles
• Cytoplasm – gel-like internal substance of
cells that includes many organelles
suspended in watery intracellular fluid called
cytosol

Cytosol – the watery intracellular fluid

Organelles – “little organs” each have a particular
structure and function
• Know the function of each organelle and be able to
identify it in a generalized figure of the cell
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Slide 11
Endoplasmic
Reticulum (Figure 3-5)
• Function: Synthesis
of proteins that will be
excreted from the cell
(rough ER) and
synthesize lipids for
the cell membrane,
steroid hormones,
and certain
carbohydrates,
removes and stores
Ca2+ from the cell’s
interior
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Slide 12
Endoplasmic Reticulum
• Two types of ER:

Smooth ER – do not have ribosomes attached
• Synthesizes certain lipids and carbohydrates and creates
membranes for use throughout cell
• Removes and stores Ca++ from cell’s interior.

Rough ER – have ribosomes attached to the outer
surface
• Ribosomes synthesize proteins, which move toward the Golgi
apparatus and then eventually leave the cell
• Function in protein synthesis and intracellular transportation
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Slide 13
Ribosomes
• Function: the site of protein synthesis

Attached to rough ER or scattered in the
cytoplasm
• Structure: made of two pieces, a large
subunit and a small subunit
• Ribosomes in the endoplasmic reticulum
make proteins for “export” or to be
embedded in the plasma membrane; free
ribosomes make proteins for the cell’s
domestic use
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Slide 14
Golgi Apparatus
• Function: Synthesizes
carbohydrates, processes
proteins from the ER; the
cell’s “post office”
• Structure: cisternae
stacked on one another
and located near the
nucleus
• Processes protein
molecules from the
endoplasmic reticulum
(Figure 3-8)
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Slide 15
Figure 3-8. The Cell’s Protein Export System
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Slide 16
Lysosomes
• Function: Bags of
digestive enzymes break
down defective cell parts
and ingested particles; a
cell’s “digestive system”
• Structure: Made of
microscopic membranous
sacs that have “pinched
off” from Golgi apparatus
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Slide 17
Proteasomes
• Function: Hollow protein cylinders that break down abnormal/misfolded
proteins and normal proteins no longer needed by the cell
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Slide 18
Peroxisomes
• Function: contain enzymes that detoxify
harmful substances

Often seen in kidney and liver cells
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Slide 19
Mitochondria
• Function: A cell’s “power plant”; the site of ATP synthesis
• Mitochondrial DNA: Each mitochondrion has a DNA molecule,
allowing it to produce its own enzymes and replicate copies of
itself
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Slide 20
Nucleus
• Definition—spherical body in center of cell;
enclosed by an envelope with many pores
• Function: Contains DNA (genetic code) – the
“brain” of the cell, dictates protein synthesis
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Slide 21
Nuclear Structure
• Nuclear Envelope – nuclear membrane, has nuclear
pores (controls entrance in and out of the cell)
• Nucleoplasm – nuclear substance
• Chromatin – the DNA in non-dividing cells
• Nucleolous – found in the nucleus, synthesizes rRNA
and combines it with protein to form ribosomes
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Slide 22
Nucleus
• Contains DNA (heredity molecules), which
appear as the following:

Chromatin threads or granules in nondividing cells

Chromosomes in early stages of cell division

Functions of nucleus are functions of DNA
molecules; DNA determines both structure and
function of cells and heredity
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Slide 23
Cytoskeleton
• Function: acts as a
framework to support
the cell and its
organelles; involved in
cell movement; forms
cell extensions
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Slide 24
Cytoskeleton
• Cell fibers – 3 types

Microfilaments

Intermediate Filaments

Microtubules
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Slide 25
Microfilaments
• Smallest cell fibers

“Cellular muscles”

Made of thin, twisted
strands of protein
molecules that lie
parallel to the long axis
of the cell

Microfilaments can
slide past each other,
causing shortening of
the cell
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Slide 26
Intermediate Filaments
• Twisted protein strands slightly thicker than
microfilaments; form much of the supporting
framework in many types of cells
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Slide 27
Microtubules
• Tiny, hollow tubes that are the thickest of the
cell fibers
• Function: move things around in the cell
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Slide 28
Centrosome
• Also called the microtubule-organizing center
(MTOC)
• Plays an important role during cell division
• The general location of the centrosome is
identified by the centrioles
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Slide 29
Cell Extensions
• Cytoskeleton that forms projections that
extend the plasma membrane outward to
form tiny, fingerlike processes
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Slide 30
Three Types of Cell Extensions
• Microvilli – founds in epithelial cells that line
intestines, increase surface area for absoption
• Cilia – short and numerous, move substances
along the surface of a cell
• Flagella – involved in total cell movement;
found on human sperm cells
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Slide 31
The Big Picture
• Review
• Conclusions
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Slide 32