Transcript Chapter 1: Organization of the Body

for
the QUIZ
:
 Name the 4 MAJOR, most abundant elements in the




body. O H C N
What are ionic and covalent bonds
What is metabolism?
What is CATABOLISM? What is ANABOLISM?
What is HYDROLYSIS? What is DEHYDRATION
SYNTHESIS?
 Name the vital roles played by WATER in the
body .
 What is the ‘NORMAL’
pH of the blood?
Name the 4 Categories of Key
ORGANIC COMPOUNDS in the
body.
Name the distinguishing
characteristics between DNA and
RNA
Name the organelles of the cell
Prep for Quiz, cont.
 Describe the structure of the cell
membrane
 Name the cellular structure which is
the command /control center, the site
of genetic material for the cell.
 What cell. organelle is the Powerhouse of
the cell?
 Name the 4 phases of MITOSIS and how
they look
Chapter 3: Anatomy of Cells
The BASIC ,STRUCTURAL and
FUNCTIONAL building blocks
the BODY
are the CELLS
of
- Each individual cell is
capable of carrying out ALL
the basic functions of LIFE,
yet cells are SPECIALIZED,
and
DIFFERENTIATED
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BASIC CELL STRUCTURES:
PLASMA (cell) MEMBRANE,
CYTOPLASM;
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Nucleus , Nucleolus
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Mitochondria,
Endoplasmic reticulum, (smooth and rough)
Golgi Apparatus,
RIBOSOMES,


Lysosomes Proteosomes, Peroxisomes
Centrosomes , Centrioles

(newly discovered: VAULTS)

CYTOSKELETON: microfilaments , microtubules,
cellular extensions: CILIA , MICROVILLI,
FLAGELLA
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This is a ‘cartoon’ version of a typical or composite cell, to
demonstrate the various components
Slide 7
‘actual’ cells are of varying
shapes and sizes
Cell structures
 PLASMA MEMBRANE: separates the cell from its
surrounding environment
 Primary structure of a cell membrane is a double
layer of
PHOSPHOLIPID MOLECULES
 Heads are hydrophilic (“water loving”)
 Tails are hydrophobic (“water fearing”)
 Arrange themselves in BILAYERS in water
Cell membranes, cont
 CHOLESTEROL MOLECULES are
scattered among the phospholipids to
stabilize the membrane.
 Most of the bilayer is hydrophobic;
therefore water and water-soluble
molecules DO NOT pass through easily.
 Therefore, there are proteins which form
CHANNELS,
and
carrier proteins
The plasma (cell) membrane
From these choices, identify the structures:
A.
B.
C.
D.
Membrane channel protein
Hydrophobic tail
Cholesterol molecule
Microtubule
E. Glycoprotein
F Phospholipid molecule
G. Hydrophilic head
H. Lipoprotein
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Membrane proteins
 A cell controls what moves through the
membrane by membrane proteins embedded in
the phospholipid bilayer. ( carriers, channels)
 Some membrane proteins have carbohydrates
attached to them and, as a result, form
GLYCOPROTEINS that act as identification
markers
 Some membrane proteins are RECEPTORS
that react to specific chemicals,
hormones
such as
CYTOPLASM AND ORGANELLES
 Cytoplasm: gel-like internal substance of
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
cells that includes:
many organelles and
cytoskeletal structures, and
molecules of various types
suspended in a watery intracellular fluid
also called CYTOSOL
 The cytoplasm allows for movement of
molecules, etc
inside the cell
NUCLEUS

spherical body in center of cell; enclosed by
an envelope with many pores
 CONTAINS THE GENETIC MATERIAL –
 DNA MOLECULE within the
CHROMOSOME ALSO SEEN AS
CHROMATIN, when the cell is not dividing

(Interphase)
Also inside the nucleus: NUCLEOLUS made up of RNA, it produces
ribosomal subunits
NUCLEUS (cont.)
 Structure (cont.)
 Contains DNA (heredity molecules), which appear
as:
 Chromatin threads or granules in nondividing cells
 Chromosomes in early stages of cell division
 Functions of the nucleus are functions of
DNA determines
the structure and function of cells,
DNA molecules;
as well as heredity.
Nuclear pore complexes are
elaborate gateways in and out
of the nucleus >>>
MITOCHONDRIA, the
power houses of the cell
 Mitochondria (Figure 3-11)
 wall composed of inner and outer membranes
separated by fluid; enzyme molecules are attached
to both membranes
 The “power plants” of cells; mitochondrial enzymes
catalyze series of oxidation reactions that provide
most of a cell’s energy supply
(CELLULAR RESPIRATION)
 Each mitochondrion has a DNA molecule, which
allows it to produce its own enzymes and replicate
copies of itself
CYTOPLASM AND ORGANELLES
(cont.)
 Endoplasmic reticulum (Figure 3-5)
 Made of membranous, walled canals and flat,
curving sacs arranged in parallel rows
throughout the cytoplasm; extend from the
plasma membrane to the nucleus
 Proteins move through the canals,
and are packaged
Endoplasmic reticulum
ENDOPLASMIC RETICULUM
 Two types of endoplasmic reticulum
 Rough endoplasmic reticulum
 RIBOSOMES dot the outer surface of the membranous walls
 Ribosomes synthesize proteins, which are moved toward the Golgi
apparatus and then eventually leave the cell
Function in protein synthesis and intracellular
transportation
 Smooth endoplasmic reticulum
 No ribosomes border the membranous wall
 Functions in packaging and storage - steroids and various ions :

Synthesizes certain lipids and carbohydrates and creates
membranes for use throughout the cell
 Removes and stores calcium ions from the cell’s interior
RIBOSOMES:
make protein!
 Many are attached to the rough endoplasmic
reticulum
 and many lie
FREE, scattered throughout the
cytoplasm
 Each ribosome is a nonmembranous structure made of
two pieces, a large subunit and a small subunit;
 each subunit is composed of rRNA
and protein
Ribosomes
make protein
 Ribosomes in the E.R. make
proteins for “export,” or for the
plasma membrane;
 FREE ribosomes make proteins for
the cell’s ‘domestic’,
internal use
Ribosomes, two subunits
GOLGI APPARATUS
 Membranous organelle consisting of cisternae stacked
on one another and located near the endoplasmic
reticulums (Figure 3-7)
 Processes protein molecules from the endoplasmic
reticulum (Figure 3-8)
 Processed proteins leave the final cisterna in a vesicle;
contents may then be secreted to outside the cell
(Janitors of the cells):
Lysosomes, peroxisomes,
and Proteosomes
 LYSOMOMES ; solid waste compactors and
incinerators , for cellular debris and foreign
invaders.
------ Abnormalities may lead to
cellular injury and death
 PEROXISOMES:
chemical detoxifiers; TOXINS,
such as ethanol
 PROTEOSOMES : Recycle PROTEINS
LYSOSOMES
 Lysosomes (Figure 3-9)
 Made of microscopic membranous sacs that
have “pinched off” from Golgi apparatus
 THE CELL’S OWN DIGESTIVE
SYSTEM; enzymes in lysosomes digest the
protein structures of defective cell parts,
including plasma membrane proteins, and
particles that have become trapped in the
cell
PEROXISOMES
act as
detoxifiers
 Peroxisomes
 Small membranous sacs containing
enzymes that detoxify harmful substances
that enter the cells
 Often seen in kidney and liver cells
PROTEASOMES BREAKDOWN
DEFECTIVE PROTEINS
 Proteasomes (Figure 3-10)
 Hollow protein cylinders found throughout the cytoplasm
 Break down abnormal or misfolded proteins and normal
proteins no longer needed by the cell (and that may cause
disease)
 Break down protein molecules one at a time by tagging each
molecule, unfolding the protein as it enters the proteasome ,
and then breaking apart peptide bonds, RELEASING THE
AMINO ACIDS ,
 WHICH ARE THEN AVAILABLE FOR RECYCLING !!!!!!
CYTOSKELETON
 The cell’s internal supporting
framework;
 made of rigid, rodlike pieces that
provide support and allow movement
and
 mechanisms that can move the cell
or its parts (Figure 3-14)
CYTOSKELETON (cont.)
 Centrosome (Figure 3-16)
 near the nucleus
 coordinates the building and breaking apart of
microtubules in the cell
 Nonmembranous structure also called the microtubule
organizing center
 Plays an important role during cell division
 General location of the centrosome is identified by the
centrioles
CYTOSKELETON (cont.)
 Cell extensions
 Cytoskeleton forms projections that
extend the plasma membrane
outward to form tiny, fingerlike
processes
 Three types of these processes; each
has specific functions (Figure 3-18)
CYTOSKELETON (cont.)
 Microvilli: found in epithelial cells that line
the intestines and other areas where
absorption is important; help increase the
surface area manyfold
Cytoskelton, cell extensions
 Cilia and flagella: cell processes that
have cylinders made of microtubules
and molecular motors at their core
 Cilia are shorter and more numerous than
flagella; cilia have coordinated oarlike
movements that brush material past the cell’s
surface
 FLAGELLA are found only on human sperm
cells; flagella move with a tail-like movement
that propels the sperm cell forward
Ciliated respiratory epithelium
Flagellated spermatazoa
CELL CONNECTIONS
 Cells are held together by fibrous nets that
surround groups of cells
 (e.g., muscle cells), or
 cells have direct connections to each other
 Three types of direct cell connections
(Figure 3-20)
CELL CONNECTIONS: DIRECT
 DESMOSOME
 Fibers on the outer surface of each desmosome interlock with
each other; anchored internally by intermediate filaments of
the cytoskeleton
 Spot desmosomes are like “spot welds” at various points
connecting adjacent membranes
 Belt desmosomes encircle the entire cell
 Gap junctions: membrane channels of adjacent plasma
membranes adhere to each other; have two effects
 Form gaps or “tunnels” that join the cytoplasm of two cells
 Fuse two plasma membranes into a single structure
 TIGHT JUNCTIONS
 Occur in cells that are joined by “collars” of tightly fused
material
 Molecules cannot permeate the cracks of tight junctions
 Occur in the lining of the intestines and other parts of the body
where controlling what gets through a sheet of cells is
important