Exam #1: Cell Biology I

Question 1

What are the three cellular constituents?

Answer 1

1) Organelles
2) Inclusions
3) Cytoplasmic Matrix (Cytosol)

Question 2

What are organelles?

Answer 2

Structural elements that confer functional attributes to the cell (membranous vs. non-membranous)

Question 3

What is the definition of the cytosol or cytoplasmic matrix?

Answer 3

• Cytosol is the portion of cytoplasm devoid of organelles & inclusions
• Cytoplasm is everything outside of the nucleus

Question 4

What are inclusions?

Answer 4

Nonliving entities found in the cytoplasm & nucleus that are not bound by a membrane

• Stored foods
• Pigments
• Crystalline

Question 5

What two foods are stored as inclusions, and which is not?

Answer 5

1) Glycogen (Carbohydrate)
2) Lipids (Fat)

• Protein is not stored as an inclusion

Question 6

Glycogen

Answer 6

• Stored as an inclusion
• Abundant in liver & striated muscle
• Demonstrated by the PAS reaction

Question 7

McArdle Disease

Answer 7

• 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

Question 8

Fat (lipid) Droplets

Answer 8

• Found in adipocytes, hepatocytes, muscle, & steroid secreting cells
• Accumulation in lipid storage disease & fatty liver

Question 9

What are exogenous pigments?

Answer 9

Pigments that come from outside the body

1) Carotene
2) Inhaled Dust
3) Tatoo

Question 10

Carotene

Answer 10

• Fat soluble orange colored pigment
• Carotene is found in CARROTS, sweet potatoes, & squash
• Responsible for the yellow-orange color of fat

Question 11

Carotenemia

Answer 11

• 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

Question 12

Anthracosis

Answer 12

• Accumulation of carbon particles in the lungs & regional lymph node
• Harmless

Question 13

Where are tattoo pigments stored?

Answer 13

Macrophages in the dermis of the skin

Question 14

What are endogenous pigments?

Answer 14

Pigments that come from within the body

1) Hemoglobin
2) Hemosiderin
3) Bilirubin
4) Melanin
5) Lipofusin

Question 15

What is hemosiderin?

Answer 15

• Brown iron storage protein that is found in macrophages of the spleen & liver
• Stained with prussian blue
• Accumulates in macrophages in CHF

Question 16

Hemosiderosis

Answer 16

• Increased deposition of hemosiderin in tissues

- Seen with increased iron in diet, impaired use of iron in the body, hemolytic anemia, & transfusions

Question 17

Hemochromatosis

Answer 17

Severe accumulation of iron due to a genetic defect resulting in excessive iron absorption or transfusion

Question 18

What are the three different types of melanin?

Answer 18

1) Eumelanin
2) Neuromelanin
3) Phaeomelanin

Question 19

Eumelanin

Answer 19

• Black-brown pigment
• Found in membrane limited granules of the epidermis & retina
• Increased production in response to UV

Question 20

Neuromelanin

Answer 20

• Black-brown pigment found in neurons
• Esp. Substantia Nigra
• Loss in PD

Question 21

Pheomelanin

Answer 21

• Red pigment of skin & hair

- NOT protective against UV radiation

Question 22

Lipofuscin

Answer 22

• 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

Question 23

What are nuclear inclusions an indication of?

Answer 23

Cytomegalovirus

Question 24

What are Reinke & Charcot-Bottcher inclusions, and where are they found?

Answer 24

• Crystalline Inclusions

- Testis ( Cell of Leydig & Sertoli cells)

Question 25

What are lipid rafts?

Answer 25

• 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

Question 26

How do lipid rafts change in cancer?

Answer 26

Increase in cholesterol, which increases lipid rafts

Question 27

What is simvistatin and how can it be used to treat cancer?

Answer 27

• Cholesterol inhibitor

- Induces apoptosis by a reduction in lipid raft formation