Chapter 3 Review
By: Austin
Basics Concepts
 Cells are the building blocks of all plants and
animals.
 Cells are produced by the division of preexisting
cells.
 Cells are the smallest units that perform all vital
physiological functions.
 Each cells maintains homeostasis at the cellular
level.
 Homeostasis at the tissue, organ system, and
individual levels reflects on the combined and
coordinated actions of many cells.
Studying Cells
O Cytology- is the study of the structure and
functions of cells.
Transmission Electron Microscopy
•The electrons pass through an ultrathin section to strike a photographic
plate. The result is a transmission electron micrograph (TEM). It shows
the fine structure of cell membranes and intracellular structures.
Scanning Electron Microscopy
•The electrons bounce off the exposed surfaces to create a scanning
electron micrograph (SEM). Although it provides less magnification, it
provides a three- dimensional perspective on the cell structure.
Cell Anatomy
O The cell membrane is what separates the extracellular
fluid from the cytosol and cellular organelles.
O The extracellular fluid is a watery medium that our cells
float in.
O The cytosol, which is inside the cell, contain dissolved
nutrients, ions, soluble and insoluble proteins, and
waste products of the cell.
O The organelles are structures that perform specific
functions inside the cell.
Cell Membrane
 The cell membrane forms the outer
boundary of the cell. It is made up of
phospholipids, proteins, glycolipids, and
cholesterol.
 Its functions include physical isolation,
regulation of exchange with environment,
sensitivity, and structural support.
The cell and its environment
 The cell membrane controls all
communication with its environment
because it has to maintain homeostasis
within the cell.
 The cell membrane controls osmotic
concentration.
 The cell membrane controls everything in
and out of the cell depending on a cell’s
permeability.
Cellular Organelles
Organelle
Function
Cell Membrane
Protection, isolation from environment
Cytoskeleton
Internal support
Flagella, microfilaments
Locomotion
Nucleus
Regulation of activity
Microtubules
Internal transport
Exocytosis
Waste disposal
Mitochondria
Energy source
Lysosomes
Defense against invasion
Centrosome
Reproduction
Cell Energy
O Mitochondria have an outer membrane and an
inner membrane that contains many folds called
cristae. The cristae increase the area exposed to
the matrix, which contain metabolic enzymes
that perform reactions that provide energy.
O Respiratory enzymes produce ATP through the
breakdown of organic molecules in a series of
reactions that consume oxygen and generate
carbon dioxide.
The Nucleus
 The nucleus directs the processes that take place
in the cytosol.
 Chemical communications between the nucleus
and cytosol go through the nuclear pores.
 The nucleus controls cellular operations through
its regulation of protein synthesis.
 The nucleolus synthesize the components of
ribosomes.
 The nucleoplasm contains ions, enzymes, RNA
and DNA nucleotides, proteins, and small
amounts of DNA and RNA.
Cell Life Cycle
• The first phase is interphase then comes
prophase were the two centrioles move to
opposite poles. Then the nucleus dissolves in
prophase and the chromosomes are lined up
during metaphase. In anaphase the
chromosomes are pulled apart to opposite
poles. Then in telophase the nucleus
reappears around the chromatid and
cytokinesis begins and two new daughter cells
are formed.
Cell Life Cycle
Interphase
Telophase
Anaphase
G-1 Phase
Mitosis
Metaphase
S Phase
G-2 Phase
Prophase
Cell Division
Cell Life Cycle Terms
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Cell Division
Mitosis
Somatic Cells
Reproductive Cells
Interphase
G-o Phase
G-1 Phase
G-2 Phase
S Phase
DNA Replication
DNA Polymerase
Ligases
G-2 Phase
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G-m Phase (Mitosis)
Prophase
Chromatids
Centromere
Spindle Fibers
Metaphase
Metaphase Plate
Anaphase
Daughter chromosomes
Telophase
Cytokinesis
Mitotic Rate
Stem Cell
Transmembrane potential
o Transmembrane potential depend on two
factors one passive and one active:
o The passive factor is the membrane
permeability for sodium and potassium.
o The active factor is the presence of the
sodium-potassium exchange pump in the
membrane surface.
o The cell membrane regulates what enters
and leaves the cell.
Cell Attachment
O Cell attachment to one another occur at cell
junctions; there are four types of cell
junctions gap junctions, tight junctions,
intermediate junctions, and desmosomes.
Gap Junctions
 Gap junctions is when two cells are held
together by an interlocking of membrane
proteins.
 Gap junctions normally occur in cardiac
muscle and smooth muscle tissue and
occasionally between nerve cells.
Tight Junctions
 In a tight junction there is a partial fusion of
the lipid portions of the two cell membranes.
 Tight junctions are the strongest intracellular
connection.
 They provide mechanical strength and block
the passage of water and solutes between
cells.
 Mainly there found where extracellular fluid
is different. i.e. digestive tract
Intermediate Junctions
• At an intermediate junction the opposing cell
membranes are held together by a thick
layer of proteoglycans.
• This is called intracellular cement; while
hyaluronic acid is the most important one.
• This adds strength and helps stabilize the
shape of the cell.
Desmosomes
 Desmosomes contain a very thin
proteoglycan layer between the opposing
cell membranes, reinforced by filaments
that lock the two cells together.
 These are very strong and can resist
stretching and twisting.
 Mainly between the cells in the superficial
layers of the skin.
Structure
Composition
Function
Cell Membrane Lipid bilayer, containing phospholipids,
steroids, and proteins
Isolation, protection,
sensitivity, organization
Cytosol
Fluid component of cytoplasm
Distributes materials by
diffusion
Cytoskeleton:
Microtubules
Microfilaments
Proteins organized in fine filaments or
slender tubes
Strength, movement of
cellular structures and
materials
Microvilli
Membrane extensions containing
microfilaments
Absorption of extracellular
materials
Cilia
Membrane extensions containing
microtubules in 9x2 arrangement
Movement of materials over
surface
Centrioles
Two centrioles each composed of
microtubules in 9x3 array
Movement of chromosomes
during cell division
Ribosomes
RNA + protein
Protein Synthesis
Mitochondria
Double membrane, with inner fold enclosing
metabolic enzymes
Produce 95% of ATP
required by cell.
Structure
Composition
Function
Nucleus
Nucleoplasm containing nucleotides,
enzymes, and nucleoproteins
surrounded by nuclear envelope
Control of metabolism; storage
and processing genetic
information
Nucleolus
Dense region in nucleoplasm
Site of RNA synthesis
Endoplasmic
Reticulum
Network of membranous channels
extending throughout the cytoplasm
Synthesis of secretory products;
intracellular storage and
transportation
Rough ER
Ribosomes attached to membranes
Secretory protein synthesis
Smooth ER
Lacks attached ribosomes
Lipid and carbohydrate synthesis
Golgi Apparatus Series of stacked, flattened
membranes(saccules) containing
chambers(cisternae)
Storage, alteration, and
packaging of secretory products
and lysosomes.
Lysosomes
Vesicles containing powerful digestive
enzymes
Intracellular removal of damaged
organelles or of pathogens
Peroxisomes
Vesicles containing degradative
enzymes
Neutralization of toxic compounds