CHAPTER 3
By: Bailey
WHAT IS CELL THEORY?
CELL THEORY
o Cells are building blocks for plants and animals
o Cells are produced by division for preexisting cells
o Cells are the smallest object that perform physiological functions
o Each cell maintains homeostasis at cellular level
o Homeostasis at the tissue, organ, system, and individual levels reflects the
combined and coordinated actions of many cells
o *Homeostasis- the maintenance of a relatively constant internal
environment
COMPARE FLUID CONTENTS OF
CELL WITH THE
EXTRACELLULAR FLUID
FLUID CONTENT
Cytosol
 High concentration of potassium
 Relatively high concentrations of
dissolved proteins (enzymes that
regulate metabolic operations)
 Contains dissolved nutrients, ions,
soluble and insoluble proteins and
waste products
 Contains small quantities of
carbohydrate and large reserves of
amino acids and lipids
Extracellular
 High concentration of sodium
 All body fluid not within the cell
 Plasma and interstitial fluid are
included in this
CELL MEMBRANE
CELL MEMBRANE
Str ucture
Composed of
I.
Phospholipids
II. Proteins
III. Glycolipids
IV. Cholesterol
* Cytosol is what mostly makes up the
cell. Surrounding that is the
Phospholipid bilayer, and within that
layer are the proteins and channels
Impor tance
I.
Separates the inside of the cell
from the surrounding
extracellular fluid
II. Controls the entry of ions and
nutrients, and eliminates waste
and the release of secretory
products
III. Let’s the cell respond and
recognize to molecules in its
environmental
IV. Gives tissues a stable structure
CELL AND THEIR
ENVIRONMENT
INTERACTION WITH
ENVIRONMENT
 A cell needs to maintain homeostasis
 It does this through the cell membrane
 Taking in nutrients and obtaining water
balance and giving off waste
 These all are from the environment that
need to be taken in or let into the
environment from the cell
STRUCTURE AND FUNCTION
ORGANELLES
Cell Membraneisolation,
protection,
sensitive,
organization
Cytosoldistributes
materials by
diffusion
ORGANELLES
Nonmembranous
Organelles
Membranous
Organelles
• Cytoskeleton
• Microtubules
• Microfilaments
• Microvilli
• Cilia
• Centrioles
• Ribosomes
• Nucleus
• Endoplasmic reticulum
• Rough ER
• Smooth ER
• Golgi Apparatus
• Lysosomes
• Peroxisomes
NONMEMBRANOUS
• Cytoskeleton- strength,
movement of cellular
structures and material
• Microtubules- gives strength
to the cell
• Microfiliments-slender
protein strand
• Microvilli-absorption of
extracellular fluid
• Cilia- movement of
materials over surface
• Centrioles- movement of
chromosomes during cell
division
• Ribosomes- protein
synthesis
MEMBRANOUS
• Mitochondria- protein synthesis
• Nucleus- control of
metabolism; stores and
processes genetic info.
• Nucleolus- site of RNA
synthesis
• Endoplasmic Reticulumsynthesis of secretory products;
intracellular storage and
transport
• Rough ER- secretory protein
synthesis
• Smooth ER- lipid and
carbohydrate synthesis
• Golgi apparatus-storage,
alteration and package of
secretory product and lysosomes
• Lysosomes- intercellular removal
of damaged organelles or of
pathogens
• Peroxisomes- neutralization of
toxic compounds
ENERGY WITHIN CELLS
MITOCHONDRIA
Mitochondria
Mitochondria is the power house
of the cell, it makes and stores
the “power” so the cell can
function properly
How it prefor ms that…
1. The organelle has a double
membrane; the first surrounds the
entire cell, the second surrounds
the inner which has many folds
called cristae
2. Cristae increases the surface area
exposed to the fluid contents,
matrix
* Metabolic enzymes - Protein-based
substances that promote change in
bodily cells…
3. Matrix contains metabolic
enzymes that perform the
reactions that provide energy for
cellular function
NUCLEUS AS CONTROL CENTER
NUCLEUS
• The nucleus is surrounded by the nuclear envelope
which separates it from the cytosol
• Within the nuclear envelope are perinuclear space
• These allow the nucleus to receive information about
conditions and activities in the cytosol
NUCLEOPLASM
The nucleoplasm contains ions, enzymes, RNA and DNA
nucleotides, proteins, small amounts of RNA and DNA
I.
These DNA strands form a chromosome
II. These are then “read” by the nucleus controls by the process
of “regulation of protein synthesis”
III. What is read from the chromosome, the nucleus then tells the
cell what needs done and what to do
LIFE CYCLE
LIFE CYCLE
Life cycle- Go Phase, G1 Phase, S
Phase, G2 Phase, Gm Phase,
Mitosis
INTERPHASE
• Go Phase- the cell has normal functions (indefinite time)
• G1 Phase- the cell grows, duplicates its organelles, and
preforms protein synthesis (8 or more hours)
• S Phase- the cell’s DNA is replicated and synthesis’s its
histones (6-8 hours)
• G2 Phase- the cell undergoes protein synthesis’s (2-5 hours)
• Gm Phase- where the cell undergoes mitosis
MITOSIS
• Prophase (stage 1)- the nuclear envelope disappears
• Metaphase (stage 2)- chromatids move through metaphase
plate; microtubules of the spindle apparatuses attaches to each
centromere
• Anaphase (stage 3)- the chromatid pairs separate and the
daughter chromosomes move toward the opposite ends to the
cell
• Teleophase (stage 4)- the nuclear membranes form, the nuclei
enlarge, chromosomes gradually uncoil; once the
chromosomes disappear, nucleoli reappear and the nuclei
resemble those of the interphase cell
IMPORTANCE TRANS -MEMBRANE
POTENTIAL
TRANS-MEMBRANE POTENTIAL
 It measures the millivolts across the cell membrane for
potential difference that could result from uneven distribution
of the positive and negative ions across a cell membrane
 A membrane enzyme called the sodium-potassium pump
actively transports ions to compensate for the sodium and
potassium leaks
 This pump uses the energy of ATP to move sodium and
potassium against their electrochemical gradients
 The pump compensates for the sodium and potassium leaks,
keeping the resting membrane potential at -70 millivolts
HOW CELLS ATTACH
METHODS OF ATTACHMENT
 Gap Junction- two cells are held together by an interlocking of membrane
proteins, the result is a narrow passage way that lets small molecules and
ions pass from cell to cell
 Tight Junction- partial fusion of the lipid portions of the two cell
membranes, providing mechanical strength, but blocking the water or
solutes between cells
 Intermediate Junction- the opposing cell membrane, while maintaining
distinct, are held together by a thick layer of proteoglycans
 Desmosomes- the opposing cell membranes reinforced by a network of
intermediate filaments that lock the two together , a dense concentration of
filament beneath the cell membrane at a desmosomes anchor it to the
cytoskeleton
 Junction Complex- when all types of junctions including desmosomes are
together in one location
VOCABULARY
VOCAB.
Cytology- the study of the structure and function of cells
Transmission electron microscopy- show fine structures of cell membranes and
intracellular structures
Scanning electron microscopy- where electrons bounce off exposed surfaces,
creates 3D perspective
Extracellular fluid- a watery medium that is on the outside of cells
Cell membrane- outer boundary of the cell
Plasma membrane- another term for cell membrane
Phospholipid bilayer- a cell membrane
Peripheral proteins- attached to the inner membrane surface
Integral proteins- embedded in the membrane
Channels- formed by integral proteins the let water molecules, and other objects
pass through it
Cytoplasm- A general term for the material inside of the cell
VOCAB.
Intermediate filaments- provides strength, support, and transports materials
within the cytoplasm
Neurofilaments- found in nerve cells and provide structure and support
Thick Filaments- massive strand composed of myosin protein subunits
Microtubules- hollow tubes built from the globular proteins
Tubulin- globular protein
Microvilli- small finger-shaped projections of the cell membrane
Centrioles- is a cylindrical structure composed of short microtubules
Centrosome- cytoplasm surrounding
Cilia- contain nine pairs of microtubules surround a central pair
VOCAB.
Cytoplasm- A general term for the material inside of the cell
Cytosol- or intracellular fluid- dissolved nutrients, ions, soluble, and insoluble
proteins and waste products.
Organelles- structures that perform specific functions within the cell
Inclusions- masses of insoluble materials
Non-membranous organelles- in contact with cytosol
Membranous Organelles- surrounded by lipid membranes that isolates them from
the cytosol
Cytoskeleton- an internal protein framework the gives the cytoplasm strength and
flexibility
Microfilaments- slender proteins strands composed of the protein actin
Actin- a protein found in microfilaments
Myosin- a protein
VOCAB.
Basal Body- an anchored compact for cilia
Flagella- moves cells through the surrounding fluids
Ribosomes- small, dense structure that cannot be seen; they manufacture proteins
Free ribosome- one type of ribosome where its proteins scatter throughout the
cytoplasm
Fixed ribosome- attached to the endoplasmic reticulum, its proteins enter here
Mitochondria- small organelle that have a double membrane; makes energy for the
cell
Cristae- second inner membrane that contains numerous folds
Matrix- fluid contents of mitochondrion
Respiratory enzyme- produces most of the ATP generated from the
mitochondrion
Nucleus- the control center for the cell
Nuclear envelope- surrounds the nucleus and separates it from the cytosol
Perinuclear space- a narrow passage within the nuclear envelope
VOCAB.
Nuclear pores- large pores that permit the movement of ions and small
molecules,but too small for DNA
Nucleoplasm- fluid contents of the nucleus
Chromosomes- contain DNA strands
Histones- proteins that bind to DNA strands
Nucleosome- a structure that forms when DNA strands wind around histones
Chromatin- made when chromosomes tangle fine filaments
Endoplasmic reticulum- a network of intracellular membranes
Cisternae- formed by the endoplasmic reticulum; reservoir for water
Rough reticulum- where newly made synthetic proteins undergo chemical
modification
Smooth reticulum- synthesis of lipids and carbohydrates
VOCAB.
Golgi apparatus- synthesis and packing, renewal or modification of the cell
membrane
Transfer vesicles- how material moves from saccule to saccule
Secretory vesicles- vesicles that contain secretion that will be discharged
Lysosomes- vesicles filled with digestive enzymes; defense against disease
Endocytosis- the process of lysosomes in greater detail
Peroxisomes- smaller then lysosomes; absorb and neutralize toxins
Gated- regulate the passage of materials that travel through channels
Glycocalyx- protects cell membrane; function as receptors; keeps immune
system from attacking body
Permeability- objects can pass through it
Impermeability- objects cannot pass through it
Freely permeable- object can pass through without any trouble is said to be
Selectively permeable- permits the passage of some materials
VOCAB.
Diffusion- net movement of material from an area where it’s concentrated
from high to low
Concentration gradient- the difference between low and high concentration
Osmosis- the response to the difference in diffusion
Osmotic pressure- force of water movement
Hydrostatic pressure- when pressure is can prevent the entry of molecules
Osmotic concentration/osmolality- total solute concentration in a solution
Tonicity- used when describing osmotic concentration
Isotonic- same solute concentration low and high
Hypotonic- solution has a lower then the cytoplasm
Hemolysis- when a cell burst or explodes
Hypertonic-when concentration is higher than the cytoplasm