cell part 2 Flashcards
PARTS OF THE CELL
CELL MEMBRANE
CYTOPLASM
NUCLEUS
What’s in the cytoplasm?
Organelles
Cytosol
(Inclusion Bodies)
separates the interior and exterior environments of the cell
CELL MEMBRANE
is enclosed by the cell membrane components
CYTOPLASM
solid structures/ portions inside the cell
Organelles
liquid portion containing the organelles
Cytosol
not usually surrounded by plasma membrane contents are divers
Inclusion Bodies
largest organelle
not always circular/spherical in shape
NUCLEUS
LOCATION of NUCLEUS
Central or often Eccentric in some cells
accumulate fats, pushing the nucleus and other organelles to the periphery, compressing the nucleus and making the cell resemble a “signet ring”
Adipose cells
circular structure found inside the Nucleus
Nucleolus
- Most commonly stains used in histology
Hematoxylin and Eosin
Solid structures that do not perform specific function
INCLUSION BODIES
May or may not be present in the cell; often mistaken as organelles
INCLUSION BODIES
Most are stored nutrients or deposited waste product
INCLUSION BODIES
INCLUSION BODIES
Lipofuscin
Glycogen
Hemosiderin
Lipids/Fat globules
Melanin
When lipids and proteins inside the cells are oxidized, digested by the lysosome, solid waste products remains as
Lipofuscin
Yellow-brown pigment composed of residues of lysosomal digestion/cellular senescence (aging), thus also called “Wear and tear” pigment
Lipofuscin
Accumulates through the years
The older the cell the higher the content of lipofuscin.
Lipofuscin
if the cell with lipofuscin will undergo ____, the daughter cells will not contain any lipofuscin.
mitosis
Post-mitotic cells, or cells that do not divide or stopped dividing obviously contains a lot of accumulated lipofuscin.
Give 3 examples:
Neurons
Cardiac Muscles
Skeletal Muscles
Short-term storage form of glucose
Glycogen
Glycogen is stored in
(striated) skeletal muscles and liver
True oor False | Glycogen iis stained with H & E
False, it is stained with PAS - periodic acid schiff
Which inclusion body needs a special stain?
Glycogen - periodic acid schiff (imparts RED color to glycogen) seen using the light microscope
Iron-storage complex found within the cytoplasm of many cells.
Hemosiderin
Breakdown product of hemoglobin
Hemosiderin
Whenever red cells are destroyed, they release hemoglobin and it will be digested and become indigestible residue
Hemosiderin
Hemosiderin exhibits what color?
Brown
What color is lipofuscin?
Yellow-Brown
Form in the areas where RBCs are destroyed, like the spleen. (RBCs that are old loses cellular flexibility and trapped in the spleen for macrophage destruction)
Hemosiderin
where aged erythrocytes are phagocytosed
Spleen
Alveolar macrophages in the lung tissue - after pulmonary infection engulfs leaked hemoglobin after hemorrhage
Presence of ________ in the alveoli would tell you that there have been previous bleeding in the area of the lungs.
hemosiderin
If patient has tuberculosis, the tb bacilli will destroy the blood vessels, causing it to explode
To clear it up, alveolar macrophage will destroy rbc and hemoglobin will be digested → _________
hemosiderin
Usually nutritive inclusions that provide energy for cellular metabolism
Lipids/Fat globules
Mostly very huge that it consumes the majority of cytoplasmic volume
Lipids/Fat globules
Alcohol and xylene in the sample preparation dissolves the ____, and leaves empty spaces in the cell.
fats
Found in the skin tissues (stratified squamous epithelium)
Usually confused with lipofuscin, but ______ is predominant in the skin.
melanin
VESICULAR TRANSPORT:
Endocytosis & Exocytosis
Cellular process in which substances are brought into the cell (vesicular transport).
Internalized material is surrounded by an area of cell membrane which then buds off inside the cell to form a vesicle containing ingested material.
Controls the composition of the plasma membrane and the cellular response to changes in the external environment.
ENDOCYTOSIS
ENDOCYTOSIS
Phagocytosis
Pinocytosis
Receptor-Mediated Endocytosis
Play key roles in nutrient uptake, cell signaling, and cell shape changes
The vesicle formed as part of the cell membrane.
ENDOCYTOSIS
Engulfment of bacteria, protozoa, dead cells, and unneeded extracellular constituents such as cell debris and other foreign materials
Phagocytosis
What cells do phagocytosis?
Neutrophils and macrophages
“Cell drinking”; Fluid-phase endocytosis.
Small invaginations of the cell membrane form and entraps fluids which are then enclosed in vesicles.
Pinocytosis
THE ENGULFED SUBSTANCE MUST BE METABOLIZED
Nonspecific ingestion of fluid and small protein molecules via small vesicles, usually smaller than 150 m in diameter.
Performed by virtually every cell in the organism, and it is constitutive.
Pinocytosis
The mechanism proposed for vesicle formation in pinocytosis is associated with the presence of ______ and _____ proteins that are found in lipid rafts.
caveolin and flotillin proteins
Allows entry of specific molecules into the cell by binding of ligand/target molecule to the receptors causing widely dispersed receptors to aggregate
RECEPTOR-MEDIATED ENDOCYTOSIS
These regions, which are represented by the lipid rafts in the plasma membrane, eventually become _______.
coated pits
is the process by which a vesicle moves from the cytoplasm to the plasma membrane, where it discharges its contents to the extracellular space.
EXOCYTOSIS
Sorting and packaging the secretory product into transport vesicles that are destined to fuse with the plasma membrane.
Recycling of vesicles back to cell membrane
EXOCYTOSIS
Site for intracellular digestion and turnover of cellular compartments
Lysosomes
Membrane-bound digestive organelle that is rich in hydrolytic enzymes:
Proteases
Nucleases
Glycosidases
Lipases
Phospholipases
Site for ATP production
Mitochondria
Mitochondria Numerous in
Striated Cardiac muscle cells
Cells of the proximal convoluted kidney tubules
Middle piece of the sperm
Contains 13 enzymes involved in oxidative phosphorylation pathways, 2 rRNAs and 22 tRNAs used in translocation of mitochondrial mRNA
mitochondria
Continuous with the outer nuclear membrane. o Studded with ribosomes.
ROUGH ENDOPLASMIC RETICULUM
- series of interconnected sacs found within the endoplasmic reticulum.
Cistern/Cisternae
Cistern of RER =
SACCULAR
Devoid of ribosomes, thus the name “smooth”
SMOOTH ENDOPLASMIC RETICULUM
Cistern of SER=
Tubular
Functions:
Lipid synthesis
Drug and Alcohol Metabolism
Sequesters Calcium in the muscles (Sarcoplasmic reticulum)
SMOOTH ENDOPLASMIC RETICULUM
Modify, store and package proteins synthesized from the rough ER until such time protein will become functional/ mature.
Golgi apparatus
Determine where the protein is transported
Golgi apparatus
- set of membrane bound sacs/ folds IN GOLGI APPARATUS
Cisternae
2 Faces of Golgi apparatus
cis-Golgi network (CGN)
trans-Golgi network (TGN)
The flattened cisternae located closest to the rER represent the forming face.
Faces the rough ER
Receives the vesicles containing immature proteins from the rough ER
cis-Golgi network (CGN)
The cisternae located away from the rER represent the maturing face.
Where the packaged proteins exit out
trans-Golgi network (TGN)
Not an organelle but a small abundant protein complex present in cytoplasm
An enzyme that degrades, denatured, misfolded, and non-functional polypeptides into small polypeptides and amino acids.
Proteasomes
Removes proteins that are no longer useful in the cell.
Cylindrical structures
Composed of rings of proteases enzymes
Terminal ends of the structure recognizes proteins with ubiquitin attached
Proteasomes
protein that searches for any denatured or misfolded protein.
Ubiquitin
Main function is to produce the mitotic spindle fiber during cell division
Centrioles
Two non-membranous cylindrical structures composed of microtubules
Composed of __ _____microtubules each
Centrioles
9 triplets
