HISTOLOGY (THE CELL) Flashcards
2 MAJOR components of cells
CYTOPLASM AND CELL MEMBRANE
located outside the nucleus
contains organelles and inclusions
Cytoplasm
fluid surrounding the cytoplasm bathing metabolically active structures
(organelles) which can either be membranous or nonmembranous
Cytosol
contains hundreds of enzymes (eg. is the glycolytic pathway) that produce
building blocks for larger molecules and break down small molecules to liberate
energy
Cytosol
Largest organelle within the cell
Contains the genome (along with enzymes necessary for DNA replication and
RNA transcription)
Nucleus
associated with ribosomes and the site of protein synthesis and modification of
newly synthesized proteins
Rough-surfaced endoplasmic reticulum (rER)
basophilic staining is caused by RNA [portion of cytoplasm that is stained with the basic
dye is referred to as ergastoplasm
Rough-surfaced endoplasmic reticulum (rER)
is highly developed in active secretory cells (cells that synthesize proteins destined to
leave the cells) such as plasma cells, glandular cells, osteoblasts
Rough-surfaced endoplasmic reticulum (rER)
involved in lipid and steroid synthesis but not associated with ribosomes
Smooth-surfaced endoplasmic reticulum (sER)/Sarcoplasmic
reticulum
functions in lipid metabolism
Smooth-surfaced endoplasmic reticulum (sER)/Sarcoplasmic
reticulum
well developed in cells that synthesize and secrete steroids such as adrenocortical cells
and testicular Leydig (interstitial) cells
Smooth-surfaced endoplasmic reticulum (sER)/Sarcoplasmic
reticulum
well-developed in the liver and contains a variety of detoxifying enzymes (they modify
and detoxify hydrophobic compounds such as pesticides and carcinogens by chemically
converting them into water soluble-conjugated products that can be eliminated from the
body)
Smooth-surfaced endoplasmic reticulum (sER)/Sarcoplasmic
reticulum
also involved in:
glycogen metabolism
membrane forming and recycling
Smooth-surfaced endoplasmic reticulum (sER)/Sarcoplasmic
reticulum
responsible for modifying, sorting, and packaging proteins and lipids for intracellular or
extracellular transport
functions in the post-translational modification, sorting, and packaging of proteins
Golgi apparatus
are rich in hydrolytic enzymes (enzymes are synthesized in the rER and sorted in the
Golgi apparatus)
represents a major digestive compartment in the cell
Lysosomes
agent used in the treatment and prevention of malaria, is a lysosomotropic agent
that accumulates in the lysosomes
Chloroquine
raises the pH of the lysosomal content = inactivates lysosomal enzymes
the drug concentrates in the acidic food vacuole of the malaria parasite (P.
falciparum) and interferes with its digestive processes, eventually killing the parasite
Chloroquine
have lysosomes that contain phagocytized bacteria and fragments of damaged cells
Macrophages
azurophilic granules represent lysosomes (in acute inflammation,
lysosomal enzymes are released directly into the extracellular space)
Neutrophils
is a debris-filled vacuole produced by the hydrolytic breakdown of the
contents of lysosomes that may remain for the entire life of the cell.
Residual bodies
in neurons, residual bodies are referred to as
age pigment/lipofuscin granules
absence of certain lysosomal enzymes can cause the pathologic accumulation of
undigested substrate in residual bodies leading to several
lysosomal storage
diseases
absence of beta hexosaminidase that catalyzes a
step in lysosomal breakdown of gangliosides in neurons
Tay-sachs disease
provide most of the energy to the cell by producing adenosine
triphosphate (ATP) in the process of oxidative phosphorylation — major site of ATP
synthesis
Mitochondria
a closed circular molecule that contains 13 enzymes
involved in the oxidative phosphorylation pathway, 2 rRNAs, and 22 tRNAs (used in the
translation of mitochondrial mRNA)
mitochondrial DNA
mitochondrias are present in all cells except
RBCs and terminal keratinocytes
surrounds a space called the matrix; rich in cardiolipin (makes the cell
impermeable to ions)
performs 3 important functions:
oxidation reactions of the respiratory electron-transport chain
synthesizes ATP
regulate transport of metabolites into and out of the matrix
Inner mitochondrial membrane
is in close contact with the cytoplasm; contains many voltage-dependent
anion channels (are permeable to uncharged molecules as large as 5000
daltons—allows passage of small molecule, ions, and metabolites but
cannot penetrate inner membrane)
Outer mitochondrial membrane
(part of mitochondria) space between the two membranes contains specific enzymes that use the ATP generated in the inner membrane such as: creatine kinase adenylate kinase cytochrome c (important in apoptosis) contains enzymes for β-oxidation of fatty acids and the citric acid (Krebs) cycle
Intermembrane space
small organelles involved in the production and degradation of H2O2 and degradation of
fatty acids
Peroxisomes
form the cytoskeleton (together with actin and intermediate filaments)
Microtubules
the continuous elongation (by adding tubulin dimers) and
shortening (by removing tubulin dimers)—constant remodeling process
dynamic instability