Exam #1: Cell Biology I Flashcards
What are the three cellular constituents?
1) Organelles
2) Inclusions
3) Cytoplasmic Matrix (Cytosol)
What are organelles?
Structural elements that confer functional attributes to the cell (membranous vs. non-membranous)
What is the definition of the cytosol or cytoplasmic matrix?
- Cytosol is the portion of cytoplasm devoid of organelles & inclusions
- Cytoplasm is everything outside of the nucleus
What are inclusions?
Nonliving entities found in the cytoplasm & nucleus that are not bound by a membrane
- Stored foods
- Pigments
- Crystalline
What two foods are stored as inclusions, and which is not?
1) Glycogen (Carbohydrate)
2) Lipids (Fat)
- Protein is not stored as an inclusion
Glycogen
- Stored as an inclusion
- Abundant in liver & striated muscle
- Demonstrated by the PAS reaction
McArdle Disease
- Accumulation of glycogen under the sarcolemma
- Symptoms include: cramping, exercise intolerance, myoglobin & creatine kinase elevations with exercise
- Caused by a defect in muscle glycogen phosphorylase
Fat (lipid) Droplets
- Found in adipocytes, hepatocytes, muscle, & steroid secreting cells
- Accumulation in lipid storage disease & fatty liver
What are exogenous pigments?
Pigments that come from outside the body
1) Carotene
2) Inhaled Dust
3) Tatoo
Carotene
- Fat soluble orange colored pigment
- Carotene is found in CARROTS, sweet potatoes, & squash
- Responsible for the yellow-orange color of fat
Carotenemia
- Build-up of carotene that follows prolonged and excessive consumption of carotene-rich foods, such as carrots, squash, and sweet potatoes
- Harmless & reversible
- Often mistaken for jaundice
Anthracosis
- Accumulation of carbon particles in the lungs & regional lymph node
- Harmless
Where are tattoo pigments stored?
Macrophages in the dermis of the skin
What are endogenous pigments?
Pigments that come from within the body
1) Hemoglobin
2) Hemosiderin
3) Bilirubin
4) Melanin
5) Lipofusin
What is hemosiderin?
- Brown iron storage protein that is found in macrophages of the spleen & liver
- Stained with prussian blue
- Accumulates in macrophages in CHF
Hemosiderosis
- Increased deposition of hemosiderin in tissues
- Seen with increased iron in diet, impaired use of iron in the body, hemolytic anemia, & transfusions
Hemochromatosis
Severe accumulation of iron due to a genetic defect resulting in excessive iron absorption or transfusion
What are the three different types of melanin?
1) Eumelanin
2) Neuromelanin
3) Phaeomelanin
Eumelanin
- Black-brown pigment
- Found in membrane limited granules of the epidermis & retina
- Increased production in response to UV
Neuromelanin
- Black-brown pigment found in neurons
- Esp. Substantia Nigra
- Loss in PD
Pheomelanin
- Red pigment of skin & hair
- NOT protective against UV radiation
Lipofuscin
- The aging pigment
- Yellow-brown insoluble pigment
- Indication of “wear & tear”
- Polymer of lipids and phospholipids complexed with proteins
- Accumulation is a measure of oxidative stress
- Accumulates in long-lived cells i.e. heart & neurons
What are nuclear inclusions an indication of?
Cytomegalovirus
What are Reinke & Charcot-Bottcher inclusions, and where are they found?
- Crystalline Inclusions
- Testis ( Cell of Leydig & Sertoli cells)
What are lipid rafts?
- Signaling platform
- Small area where sphingolipids & cholesterol are concentrated
- B/c this area is thick & molecularly unique, proteins aggregate here
- Protein aggregation lends itself to signal transduction
How do lipid rafts change in cancer?
Increase in cholesterol, which increases lipid rafts
What is simvistatin and how can it be used to treat cancer?
- Cholesterol inhibitor
- Induces apoptosis by a reduction in lipid raft formation
