CELL Flashcards
are the basic structural and functional units of all multicellular organisms.
Cells
Cells can be divided into TWO MAJOR COMPARTMENTS
Cytoplasm
Nucleus
where the organelles are embedded
Cytoplasm
stores the DNA and nucleolus
Nucleus
TWO BASIC TYPES OF CELL
EUKARYOTIC CELL
PROKARYOTIC CELL
with distinct membrane-limited nuclei surrounded by cytoplasm containing various membrane-limited organelles
EUKARYOTIC CELL
Unicellular eukaryotic cells
Fungi
It has no nuclear membrane, thus, nuclear material mixes with the rest of the cytoplasm
PROKARYOTIC CELL
present in prokaryotes that are important in
determining whether bacteria are gram
positive or gram negative
polysaccharide peptidoglycan
Difference in cell division between E and P
E= Mitosis
P= binary fission
Only human cell with flagella
Sperm cell
Main difference of types of cells
SIZE
P= 0.2-2.0 um
E= 10-100 um
Main difference of types of cells
NUCLEUS
P= no nuclear membrane or nucleoli
E= true nucleus
Main difference of types of cells
MEMBRANE-ENCLOSED ORGANELLE
P= Absent
E= Present
Main difference of types of cells
FLAGELLA
P= Consists of two protein building blocks
E= Complex, multiple microtubules
Main difference of types of cells
GLYCOCALYX
P= Present as a capsule or slime layer
E= present in some cells that lack a cell wall
Main difference of types of cells
CELL WALL
P= usually present; complex chemical composition
E= when present is chemically simple
Main difference of types of cells
PLASMA MEMBRANE
P= No carbohydrates and generally lack sterols
E= Sterols and carbohydrates as receptors
Main difference of types of cells
CYTOPLASM
P= No cytoskeleton or cytoplasmic streaming
E= Cytoskeleton with cytoplasmic streaming
Main difference of types of cells
RIBOSOMES
P= Smaller size (70s)
E= Larger size (80s); smaller size (70s) in organelles
Main difference of types of cells
CHROMOSOME (DNA)
P= single circular chromosome no histones
E= Multiple linear chromosome with histones
Main difference of types of cells
SEXUAL RECOMBINATION
P= none: transfer DNA only
E= meiosis
is located outside the nucleus
It contains organelles and inclusions in an aqueous gel called the cytoplasmic matrix
cytoplasm
The cytoplasm is located outside the nucleus
It contains organelles and inclusions in an aqueous gel called the
cytoplasmic matrix
Organelles are described as:
- Membranous
- Non-membranous
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
NUCLEUS
3-10 um
Largest organelle, visible nucleoli and chromatin pattern regions
Surrounded by two membranes, nuclear pore complexes , perinuclear cisternal space, euchromatin and heterochromatin obeservation
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
NUCLEOLUS
1-2 um
Roughly circular, basophilic, interphase observation with interference microscopy
Dense, nonmembranous structure containing fibrilar and granular material
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
PLASMA MEMBRANE
0.008-0.01
Not visible
External membrane and membranes surrounding membranous organelles , inner and outer electron dense later with intermediate electron-lucent layer
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
rER
5-10 um^2 (area)
Basophilic- ergastoplasm
Flattened sheets, sacs, and tubes of membranes with attached ribosomes
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
sER
Throughout cytoplasm
Not visible, cytoplasm in region of sER may exhibit distinct eosinophilia
Flattened sheets, sacs, and tubes of membranes without ribosomes
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
GOLGI APPARATUS
5-10 um^2 (area)
Sometimes observed as negative staining region, appears as networks in heavy metal stained preparations, living cells observation with interference
Stack of flattened membrane sheets, often adjacent to one side of nucleus
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
SECRETORY VESICLES
0.050-1.0
Only when large (zymogen in granules of pancreas)
Many small, membrane-bound, uniform diameter, polarize on one side of cell
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
MITOCHONDRIA
0.2-7
favorable situations e.g. liver and nerve cells- miniscule dark dots; living cells stained with janus green
two membrane system, cristae; tubular cristae in steroid producing cells
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
ENDOSOMES
0.02-0.5
Not visible
Tubulovesicular structures
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
LYSOSOMES
0.2-0.5
special enzyme histochemical staining
membrane bound electron dense vesicles
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
PEROXISOMES
0.2-0.5
Special enzyme histochemical staining
Membrane bound electron dense with crystalloid inclusions vesicles
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
CYTOSKELETAL ELEMENTS
0.006-0.025
observed when organized into large structures e.g. muscle fibrils
long linear staining pattern with width and features characteristic of each filament type
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
RIBOSOMES
0.0025
not visible
minute dark dots, often associated with the rER
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
GLYCOGEN
0.010-0.040
purple haze - toluidine blue stained specimens
nonmembranous extremely dense grapelike inclusions
characteristics appearance of organelles
SIZE
LIGHT MICROSCOPY
ELECTRON MICROSCOPY
LIPID DROPLETS
0.2-5 up to 80
readily visible when extremely large
e.g adipocytes; large empty holes in section
non membranous inclusions generally appear as avoid in the section
phospholipids form a bilayer in which the hydrophilic phosphate heads face outwards adhering the water, while the hydrophobic lipid tails aggregate inside what model
Amphipathic
is a lipid-bilayered structure visible with transmission electron microscopy.
plasma membrane
has hydrophilic heads and hydrophobic tails (fatty acid chain) what model
Fluid mosaic model
Plasma membrane composition
Phospholipid
Cholesterol
Protein molecules
CLINICAL SIGNIFICANCE of plasma membrane
dividing and dying cells, and during cell movement, often manifests as morphologic changes in the cell’s plasma membrane
Cell injury, in dividing and dying cells, and during cell movement, often manifests as morphologic changes in the cell’s plasma membrane, which results in the formation of plasma-membrane blebs aka
apoptotic bodies
is caused by the detachment of the plasma membrane from underlying actin filaments of the cell cytoskeleton.
Blebbing
act on actin filaments such as phalloidin and cytochalasin-B cause extensive membrane blebbing
Cytoskeletal poisons
are fungal metabolites that are toxic and poisonous to cytoskeleton; when an individual is exposed to these, he/she will suffer from cytoskeletal poisoning; induces apoptosis and eventually causes blebbing of cell
phalloidin and cytochalasin-B
elevated portion of plasma membrane; function for signaling which contains receptors
- described as “platforms surrounded by ocean of lipids”
- contains receptors that may function in cell recognition, metabolism, or hormone receptor binding,
Lipid raft
protein integrated in the lipid bilayer
integrated in the lipid bilayer
protein the ones attached to the surfaces; contains receptors (carbohydrates)
Peripheral protein
Functions of Plasma Membrane:
- Communication
- Intercellular connection
- Physical barrier
- Selective permeability
- Integral proteins are incorporated directly in the lipid bilayer can be viewed under electron microscope through the process called
Freeze fracture
enables us to cut the bilayer in its middle portion revealing now the E-face and
P- face
Freeze fracture
backed by Extracellular space; External (backed by the external environment of the cell)
E-face
backed by cytoplasm/Protoplasm
P-face
is more granular as viewed under electron microscope. It is in the_______ that we see a larger amount of integral protein
P-face
6 BROAD CATEGORIES OF INTEGRAL MEMBRANE PROTEINS
- Pumps
- Channels
- Receptor
- Linker
- Enzymes
- Structural Proteins
serves to transport certain ions (Na+, K+) and metabolic precursors of macromolecules actively across membranes.
Pump
allow the passage of small ions, molecules, and water across the plasma membrane in either direction
Channels
allow recognition and localized binding of ligands (molecules that bind to the extracellular surface of the plasma membrane)
Receptor
anchor the intracellular cytoskeleton to the extracellular matrix links a structure from the inside of a cell with a structure from the outside
Linker
catalyzing cellular reactions, and have a variety of roles in cell ATP synthase is the major protein of the inner mitochondrial membrane.
Enzymes
Aka “junctions in the cell” or “cell-to-cell junctions” Proteins that links one cell to another cell
Structural Proteins
Serve as selective barrier regulating the passage of materials into and out of the cell and facilitating the transport of specific molecules.
PLASMA MEMBRANE
Has a role in keeping constant ion content off the cytoplasm
PLASMA MEMBRANE
Carry out a number of specific recognition and signaling functions
PLASMA MEMBRANE
an uncommon disorder that causes inflammation of the blood vessels in your nose, sinuses, throat, lungs and kidneys, auto immune disorder that attacks collagen causing hemoptysis
Granulomatosis with polyangiitis (previously known as Wegener’s granulomatosis)
MECHANISMS OF TRANSPORT ACROSS THE PLASMA MEMBRANE
Passive
Active
Vesicular
movement of small molecules that are unassisted; not requiring expenditure of energy
Passive transport
3 MAJOR TYPES OF PASSIVE TRANSPORT:
Simple diffusion
Facilitated diffusion
Osmosis
movement of ions and small, polar molecules down their concentration gradient across selectively permeable membrane
Facilitated diffusion
Facilitated diffusion movement of ions and small, polar molecules down their concentration gradient across selectively permeable membrane by a
transport protein.
is a transport protein that facilitates entry of ions into the membrane (active)
sodium-potassium pump
2 Classes of Transport Proteins
Carrier Proteins
Channel Proteins
transfer small, water-soluble molecules
they are highly selective, often transporting only one type of molecule
Examples: Na/K pump or H pump (active) and glucose carriers (passive)
Carrier Protein
also transfer small, water-soluble molecules.
usually contain a pore domain that serves as the ion- selectivity filter
transport can be regulated by membrane potentials, neurotransmitters or mechanical stress
good examples are gated channels
Channel Proteins
Channel Proteins transport can be regulated by
membrane potentials, neurotransmitters or mechanical stress
Channel proteins that are regulated by membrane potentials example
voltage gated ions
Channel proteins that are regulated by neurotransmitter example
ligand ions regulated by acetylcholine
Channel proteins that are regulated by mechanical stress example
seen in skin and ear that responds to vibration
diffusion of water across selectively permeable membrane.
Osmosis
movements of substances requiring expenditure of energy
ACTIVE PROCESSES
transport of ions or small molecules across the membrane against a concentration gradient by transmembrane protein pumps.
Active transport
a process that involves configurational changes in the plasma membrane at localized sites and subsequent formation of vesicles from the membrane (ENDO) or fusion of vesicles with the membrane (EXO)
VESICULAR TRANSPORT
2 MAJOR FORMS OF VESICULAR TRANSPORT:
a. ENDOCYTOSIS
b. EXOCYTOSIS
brings molecules and other substances into the cell It is associated with the formation and budding of vesicles from the plasma
membrane.
ENDOCYTOSIS
3 Different Mechanisms of Endocytosis
Pinocytosis
The nonspecific ingestion of fluid and small
protein molecules via small vesicles
Aka “cell drinking”
Pinocytosis
Is the separation of vesicle from
plasma membrane
vesicle scission
vesicle scission are facilitated by
Mechanoenzymes
Example of mechanoenzyme
GTPase enzyme – dynamin
ingestion of large particles such as cell
debris, bacteria and other foreign materials
aka “cell eating”
Phagocytosis
in phagocytosis plasma membrane sends out______________
to engulf phagocytosed particles into large
vesicles called phagosomes
pseudopodia
Phagocytosis is an __________ dependent endocytosis
Actin
Phagocytosis requires depolymerization and
repolymerization of the actin filaments
for
pseudopodal extension
Endocytosis that allows entry of specific molecules into the cell
Receptor-Mediated Endocytosis
accumulate in well defined
regions of the cell membrane
Cargo receptors
In receptor mediated processes, clathrin interacts with the cargo receptor
via another coating-protein complex,
_________ , which is instrumental in selecting
appropriate cargo molecules for transport
adaptin
is the movement of an organism or entity in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment.
Chemotaxis
are small soluble molecules that bind to receptors on leukocytes causing their stimulation, polarization, and locomotion, in part through the activation of the integrin adhesion molecules.
Chemoattractants
the medical term for when blood vessels in your body widen, allowing more blood to flow through them and lowering your blood pressure
Vasodilation
the passage of blood cells through the unruptured wall of a blood vessel into the surrounding tissues.
diapedesis
recognize and bind specific molecules such as cargo proteins that come in contact with the plasma membrane.
Cargo receptors
are recognized by adaptin that helps select and gather appropriate complexes for transport into cells.
Cargo receptor–molecule complexes
Clathrin molecules then bind to the adaptin–
cargo receptor–molecule complex to assemble into a shallow basketlike cage and form a
coated pit.
Clathrin interactions then assist the plasma
membrane to change shape to form the coated pit that becomes pinched off from the plasma membrane dynamin as a
coated vesicle.
a GTPase that will pinch off the
vesicle from the plasma membrane
Dynamin
After budding and internalization of the vesicle, the coat proteins
Removed
the process by which a vesicle moves from the cytoplasm to the plasma membrane, where it discharges its contents to the extracellular space
synthesize molecules and other molecules leave the cell
EXOCYTOSIS
2 General Pathways Concerning Exocytosis
Constitutive Pathway
Regulated Secretory Pathway
substances designated for export are continuously delivered in transport vesicles to the plasma membrane (similar to pinocytosis)
Constitutive Pathway
TEM reveals that cells that do constitutive pathway lack
secretory granules
Constitutive pathway is seen in secretion of
immunoglobulins by plasma cells and of procollagen by fibroblasts
a regulatory event (hormonal or neural stimulus) must be activated for secretion to occur
Regulated Secretory Pathway
Regulated Secretory Pathway seen in specialized cells, such as
endocrine and exocrine cells and neurons
Newly synthesized proteins from the rough endoplasmic reticulum are delivered in_________ to the Golgi apparatus.
COP-II– coated vesicles
After additional modification in the
Golgi apparatus, sorting, and packaging, the final secretory product is transported to the plasma membrane in vesicles that form from the
the trans-Golgi network (TGN).
Membrane bound organelles
Endosomes, Lysosomes, endoplasmic reticulum, ribosomes, mitochondria, Golgi apparatus, peroxisomes,
just like lysosome, but do not contain hydrolytic enzyme
vacuoles that surround the materials that were internalized during endocytosis
ENDOSOMES
are membrane enclosed compartments associated with all the endocytic pathways
Early Endosomes
Early Endosomes Cellular localization:
found in the more peripheral cytoplasm
Early Endosomes Morphology:
have a tubulovesicular structure
Early Endosomes State of acidification:
exhibits only a slightly acidic environment (pH 6.2 to 6.5) than the cytoplasm of the cell
Early Endosomes Function:
to sort and recycle protein internalized
by endocytic pathways
the ________ the endosomes in the cell, the _________ they are
DEEPER: MORE ACIDIC
are vesicles originating in early endosomes travelling to deeper structures in the cytoplasm
Typically mature into lysosomes
Late Endosomes
Late Endosomes Cellular localization
central or deeper portion of the cell; positioned near the Golgi
apparatus and the nucleus
Late Endosomes Morphology:
have a more complex structure and often exhibit onion-like internal membranes
Late Endosomes State of acidification:
more acidic, averaging pH 5.5
endocytosed proteins are transported
via
multivesicular bodies (MVB)
TWO DIFFERENT MODELS that explain
the origin and formation of the endosomal
compartments in the cell:
Stable Compartment Model
Maturation Model
describes early and late endosomes as stable cellular organelles
Early endosomes, late endosomes, and
lysosomes are separate organelles
Stable Compartment Model
early endosomes are formed then matures to late endosomes and then to lysosomes.
Maturation Model
Lysosome biogenesis, two types
CONSTITUTIVE SECRETORY PATHWAY
ENDOSOMAL GOLGI-DERIVED COATED VESICLE SECRETORY PATHWAY
Shows the maturation model of lysosomal formations
A continuous process
CONSTITUTIVE SECRETORY PATHWAY
Shows the stable compartment model because lysosomal proteins are both delivered separately in early and late endosomes
ENDOSOMAL GOLGI-DERIVED COATED VESICLE SECRETORY PATHWAY
Lysosomes are Membrane-limited vesicles that contain about
40 hydrolytic enzymes.
Lysosomal enzymes are synthesized in the rER and sorted in the Golgi apparatus based on their binding ability to
M-6-P receptors.
Most common enzymes in lysosomes are
hydrolases:
i proteases
ii nucleases
iii phosphatases
iv phospholipases
v sulfatases
vi β-glucuronidase
Lysosomal membrane has unusual phospholipid structure that contains cholesterol and a unique lipid called
lysobisphosphatidic acid
Lysosome Membrane proteins:
a. lysosome-associated membrane proteins
(lamps)
b. lysosomal membrane glycoproteins (lgps)
c. lysosomal integral membrane proteins (limps)
an agent used in the treatment and
prevention of malaria, is a lysosomotropic agent that accumulates in the lysosomes
Chloroquine
PATHWAYS OF MATERIAL DELIVERY FOR
INTRACELLULAR DIGESTION IN LYSOSOMES
Extracellular large particles
Extracellular small particles
Intracellular particles
Extracellular large particles such as bacteria, cell debris, and other foreign materials are engulfed in the process of
phagocytosis
Extracellular small particles such as extracellular proteins, plasma-membrane proteins, and ligand– receptor complexes are internalized by
pinocytosis and receptor-mediated endocytosis
Intracellular particles such as entire organelles, cytoplasmic proteins, and other cellular components are isolated from the cytoplasmic matrix by endoplasmic reticulum membranes, transported to lysosomes, and degraded by
autophagy
is a process in which the cell uses lysosomes to dispose of excess or nonfunctioning organelles or membranes. Membrane that appears to emerge from the SER encloses the organelles to be destroyed, forming an autophagosome that then fuses with a lysosome for digestion of the contents.
Autophagy
3 WELL-CHARACTERIZED PATHWAYS OF
AUTOPHAGY:
Macroautophagy
Microautophagy
Chaperone-mediated autophagy
A portion of the cytoplasm or an entire
organelle is first surrounded by the isolation
membrane of endoplasmic reticulum, to
form a vacuole called an autophagosome
which matures into lysosomes.
Macroautophagy
which fuses with a lysosome for digestion of the enclosed material
Autophagosome
Cytoplasmic proteins are degraded in a
slow, continuous process under normal
physiologic condition.
Small cytoplasmic soluble proteins are
internalized by invagination of the
lysosomal membrane.
Microautophagy
This process is activated during nutrient
deprivation and responsible for the
degradation of approximately 30% of
cytoplasmic proteins in organs such as
the liver and kidney
Chaperone-mediated autophagy
Chaperone-mediated autophagy requires assistance from specific cytosolic chaperones such as
heat-shock chaperone protein called hsc73.
active organelles, are generally somewhat larger and have more heterogenous appearance in the TEM because of the wide variety of materials they may be digesting
Heterolysosomes
a debris-filled vacuole resulting
from hydrolytic breakdown of the contents of
lysosomes
Residual body
Residual body can accumulate as
lipofuscin
is used by cells to destroy abnormal proteins that are misfolded, denatured, or contain abnormal amino acids.
Proteasome-mediated degradation
Proteasome-mediated degradation also degrades normal short-lived regulatory
proteins that need to be rapidly inactivated and degraded such as
mitotic cyclins that regulate cell cycle
progression, transcriptional factors, tumor
suppressors, or tumor promoters
PROTEASOME COMPLEX
aka
26s Proteasome complex
26s Proteasome complex has the following components
a. 19s regulatory protein
b. 20s core protein
c. 19s regulatory protein
This degradation pathway involves tagging proteins destined for destruction by a polyubiquitin chain and its subsequent degradation in proteasome complex with the release of free reusable ubiquitin molecules.
Proteasome-mediated degradation.
Ubiquitin in the presence of ATP is activated by a complex of three ubiquitin-activating enzymes _________________ to form a single polyubiquitin chain that serves as the degradation signal for the 26S proteasome complex.
E1, E2, and E3
Loss of proteasome function because of
mutations in the system of ubiquitin activating enzymes that leads to a decrease in protein degradation and their subsequent
accumulation in the cell cytoplasm
example of diseases
Angelman syndrome and Alzheimer’s disease
is a genetic disorder. It causes delayed development, problems with speech and balance, intellectual disability, and, sometimes, seizures. People with _________ often smile and laugh frequently, and have happy, excitable personalities
Angelman syndrome
Angelman syndrome is a severe neurological disorder characterized by mental retardation, absent speech, ataxia, seizures, and hyperactivity. The gene affected in this disorder is
UBE3A, the gene encoding the E6-associated protein (E6AP) ubiquitin-protein ligase.
is thought to be caused by the abnormal build-up of proteins in and around brain cells
Alzheimer’s disease
One of the proteins involved in Alzheimer’s is called_________ , deposits of which form plaques around brain cells. The other protein is called________ , deposits of which form tangles within brain cells.
amyloid
tau
Accelerated degradation of proteins by
overexpressed proteins involved in system examples are infections with
human papilloma virus
Discovery of specific proteasome inhibitors holds promise for treatment of
cancers and certain viral infections
convoluted membranous network
Extends from the surface of the nucleus to the cell
membrane
Encloses a series of intercommunicating channels and sac, called cisternae
ENDOPLASMIC RETICULUM
prominent in cells specialized for protein
synthesis
consists of saclike and parallel stacks of flattened
cisternae
has attached polyribosomes
basophilic due to attached ribosomes
Rough Endoplasmic Reticulum
The _________ in secretory cells is the light
microscopic image of the organelle called the
rough endoplasmic reticulum (rER).
ergastoplasm
Protein synthesis the two processes
Transcription
Translation
production of proteins by the cell begins
within the nucleus in which the genetic code
for a protein is transcribed from DNA to pre mRNA then to mRNA after post transcriptional modifications
Transcription
in which the coded message contained in
the mRNA is read by ribosomal complexes to
form a polypeptide. — Polyribosome
complex (polysome) are formed by binding
of single cytoplasmic mRNA to many
ribosomes
Translation
Proteins synthesized in the RER can have several destinations
a. Intercellular storage
b. Provisional storage in cytoplasmic vesicles prior to exocytosis
c. Integral membrane proteins
1- antitrypsin deficiency can lead to?
emphysema (COPD) and impaired liver function.
protects the lungs from
neutrophil elastase
alpha 1-antitripsin
necessary to digest cells or
bacteria in the lungs to promote healing
neutrophil elastase
Site of protein synthesis which will be transmitted to Golgi complex for packaging and secretion out of the cell
RIBOSOME
Inhibits protein synthesis by attacking ribosomes
Antibiotics
Ribosomes in cytosol has
four segments of rRNA and
approximately 80 different proteins
Polyribosomes are intensely basophilic due to
the phosphate groups that act as polyanions.
Several types of antibiotics inhibit protein
synthesis by binding to different portions of bacterial ribosomes
— Examples:
aminoglycosides (streptomycin)
macrolides (erythromycin)
lincosamides (clindamycin
tetracyclines
chloramphenicol
lack bound polyribosomes
continuous with RER
cisternae are often more tubular and appear as interconnected channels
Smooth Endoplasmic Reticulum (SER)
Macrophages of the liver
Kupffer cells
monocyte-derived macrophages (MoMϕs).
Macrophages of the lungs
Alveolar macrophages
interstitial macrophages (IM) act as gatekeepers of the vasculature and lung interstitium
Macrophages of the skin
langerhans
Macrophages of the nervous
microglia
Macrophages of the kidney
mesangial cells
Macrophages of the connective tissues
histiocytes
Macrophages of the bones
osteoblasts
Macrophages of the spleen
littoral cells
- Glycogen and lipid metabolism
- Detoxification reactions of potentially harmful
exogenous molecules - Temporary Ca2+ sequestration
- Phospholipids and steroids synthesis
Smooth Endoplasmic Reticulum (SER)
Can be caused by the failure of sER to convert bilirubin to bile
Jaundice
GOLGI APPARATUS is named after
Camilo Golgi
generally, it is located near the ER and is the principal “traffic director” for cellular proteins.
GOLGI APPARATUS
small membrane-enclosed carriers where material from RER move to the Golgi
apparatus
Transport vesicles
Transport vesicle merge with golgi-receiving region, which is known as the
cis face
Shipping or______ , larger saccules or vacoules carry completed protein products to organelles away from the golgi
trans face
Proteins and lipids undergo a series of posttranslational modifications that involve
remodeling of _____________ previously added in the rER as they travel through the Golgi stacks.
N-linked oligosaccharides
means thread
mitos
usually depicted as lozenge-like or sausage-like organelles. It is a membrane-enclosed organelle, each with the general structure of the plasma membrane, and with arrays of enzymes specialized for cellular respiration (burning glucose) and production of cellular energy (ATP)
MITOCHONDRIA
Mitochondria possess two membranes that delineate distinct compartments.
- Inner mitochondrial membrane surrounds a space called the matrix
- Outer mitochondrial membrane is in close
contact with the cytoplasm
a series of infoldings in the inner mitochondrial membrane
Cristae
are spherical organelles enclosed by a single
membrane and named for their enzymes producing and degrading hydrogen peroxide, H2O2
PEROXISOMES
Peroxisomes contain oxidative enzymes
Oxidases
Catalase
removes hydrogen atoms that are
transferred to molecular O2 producing H2O2
Oxidases
Peroxisomes forms in two ways:
budding of the precursor vesicles from the ER or
Growth and division of preexisting peroxisomes
breakdowns H2O2, which is potentially
damaging to the cell
Catalase
Found in cells that store product until its release by exocytosis is signaled by metabolic, hormonal, or neural message
SECRETORY GRANULES
with dense content of
digestive enzymes
Zymogens granules
A structure that confer cell rigidity to help maintain cell shape
MICROTUBULES
MICROTUBULES, fine tubular structures also organized into large arrays called ________ in the cilia and flagella
axonemes
MICROTUBULES are polymeric structures composed of equal parts of
alphatubulin and beta- tubulin
CYTOSKELETON is composed of
MICROTUBULES
MICROFILAMENTS
INTERMEDIATE FILAMENTS
Functions of microtubules
Intracellular vesicular transport
Movement of cilia and flagella
Attachment of chromosome to the mitotic
spindle
Cell elongation and movement
Maintenance of cell shape
composed of actin
allow cellular motility and most contractile activity in cells
MICROFILAMENTS
MICROFILAMENTS function
Anchorage and movement of membrane protein
Formation of the structural core of microvilli
Locomotion of cells
Extension of cell processes (e.g., pseudopodia during phagocytosis)
rope-like filaments, intermediate in size between
microtubules and microfilament
Diameter: averaging 10 nm
INTERMEDIATE FILAMENTS
Six major classes of intermediate filaments
- Keratin
- Vimentin
- Neurofilament
- Lamins
- Desmin
- Glial filaments
INTERMEDIATE FILAMENTS
present only in epithelial cells
Keratin
INTERMEDIATE FILAMENTS
found in most cells derived from
mesenchyme
Vimentin
INTERMEDIATE FILAMENTS
present in cell body and processes of
neurons
Neurofilament
INTERMEDIATE FILAMENTS
form the nuclear lamina inside the nuclear
envelope
Lamins
INTERMEDIATE FILAMENTS
found in almost all muscle cells
Desmin
INTERMEDIATE FILAMENTS
Glial Fibrillary Acidic Proeteins (GFAP),
present in glial cells
Glial filaments
have little or no metabolic activity, but contain accumulated metabolites or other substances not enclosed by membrane
o Fat droplets
o Glycogen granules
o Lipofuscin
o Hemosiderin
CYTOPLASMIC INCLUSIONS
CYTOPLASMIC INCLUSIONS include
Centrosome
Centrioles
Flagella
Cilia
centrosphere or cell center
specialized zone of the cytoplasm containing the
centrioles
center of activity associated with cell division
called diplosome in nondividing cells
EM: hollow cylinder closed at one end and open at the other
Centrosome
self-duplicating organelles that exhibit
continuity from one cell generation to another
Double in number immediately before cell division
Prominent in mitosis
Essential for the formation of cilia and flagella
Serve as basal bodies and sites of epithelial cilia
Centrioles
long, semi-rigid, helical, hollow tubular structures mostly composed of protein, flagellin
Show undulating wave (moving smoothly up and down) type of movement
Flagella
Hair-like processes
Very numerous in:
– Epithelial cells of upper RT
– Parts of female and reproductive tracts
– Ependymal lining the cavities of the CNS
Cilia
