CB 3

Question 1

Endocytosis

Answer 1

5 pathways

• macropinocytosis
• clathrin mediated endocytosis
• non coated mediated endocytosis
• caveolae mediated endocytosis
• phagocytosis

Question 2

macropinocytosis

Answer 2

occurs in thyroid cells as they take up thyroglobulin and dendritic cells

• actin based process
• nonspecific ingestion of fluids and solutes
• triggered by bacteria

Question 3

clathrin mediated endocytosis

Answer 3

occurs at clathrin coated pits, dynamin is required to pinch of the vesicle, can be mediated by receptors or not

Question 4

cholesterol

Answer 4

taken up by clathrin mediated endocytosis in the form of LDL

Question 5

coated pits

Answer 5

clathrin mediated endocytosis

• cargo receptors located here
• adaptin associates
• coated vesicles form and become quickly uncoated after formation

Question 6

atherosclerosis

Answer 6

occurs when there is a decrease or defect in the LDL receptor
(clathrin mediated endocytosis)

Question 7

non coated mediated exocytosis

Answer 7

Shiga and Cholera toxins

Question 8

phagocytosis

Answer 8

• cell eating, ingestion of large particles via receptors
• dependent on actin
• doesn’t need clathrin
• phagosomes
• fuse with lysosomes

Question 9

Secretion

Answer 9

• exocytosis
• porocytosis
• exosomes
• exsosome like vesicles

Question 10

exocytosis

Answer 10

bulk secretion

sectretion of cellular synthetic products like proteins, enzymes, hormones, and neurotransmitters

Question 11

secretory vesicles

Answer 11

perform in exocytosis
formed by the golgi, fuse with plasma membrane
in charge of intracellular trafficking

Question 12

2 pathways of exocytosis

Answer 12

constitutive

regulated

Question 13

constitutive exocytosis

Answer 13

continous secretory processes, secretory product is not stored in secretory granules

Question 14

regulative exocytosis

Answer 14

secretory product is stored in secretory vesicles until a signal causes the product to be secreted

Question 15

porocytosis

Answer 15

involved with secretion

release of neurotransmitters

Question 16

exosomes & vesicles

Answer 16

• secretory products are released into the extracellular environment
• discard unneeded membrane proteins
• some tumors release exosomes and may represent a biomarker

Question 17

ribosomes

Answer 17

basophillic
involved in protein synthesis
occur as: indv granules, polyribosomes that can be free or attached
NOT found in mature erythrocytes

Question 18

free polyribosomes

Answer 18

polysomes
mRNA + ribosomes
protein synthesis for use in the cell
hemoglobin, mitochondrial proteins, peroxisomal proteins

Question 19

rough ER

Answer 19

membranous, basophillic
intracellular network of cisternae
continuous with outer membrane of nuclear envelope that is studded with ribosomes

Question 20

polyribosomes involved with Co translational translocation

Answer 20

attached to rER, translocation of growing polypeptide chains

• signal recognition polypeptide
• signal recognition particle and SRP receptor
• protein translocator
• *post translational translocation requires chaperone proteins

Question 21

Post Translational Functions

Answer 21

• synthesis of proteins for secretion, membrane proteins, and lysosomal proteins
• synthesis of enzymes assosciated with sER
• modification of proteins like adding carbs to make glycoproteins

Question 22

ER stress

Answer 22

accumulation of unfolded misfolded proteins in the ER cisterna

Question 23

Unfolded protein response

Answer 23

1- chaperone protein synthesis increases
2-decreased synthesis of proteins
3- misfolded proteins are exported from ER to cytosol and then get degraded by proteasomes
4- caspases are activated which leads to apoptosis

Question 24

alpha antitrypsin deficiency

Answer 24

AAT- mutant protein aggregates in ER

Question 25

Targeting signals

Answer 25

- sequences of amino acids in the protein | - direct proteins to their target compartments by binding to receptors that are specific to organelles

Question 26

smooth ER

Answer 26

lacks polyribosomes, acidophillic, continuous with rER, cisternae are more tubular

Question 27

functions of smooth ER

Answer 27

- cholesterol homeostasis via HMG coa reductase - steroid synthesis - phospholipid synthesis - glycogenolysis

Question 28

von gierke disease

Answer 28

defect of glucose 6 phosphatase or glucose 6 transporter | symptoms: liver enlargement, hypoglycemia, increased lactate

Question 29

ethanol ingestion

Answer 29

increases the sER volume and cytochrome p450 enzymes which leads to a greater rate of its detoxification

Question 30

syntheis of phospholipids

Answer 30

occurs on cytosolic lipid monolayer | phospholipid translocators catalyze the flip flop of phospholipids from one monolayer to the other

Question 31

malignant hyperthermia

Answer 31

causes a rapid rise in body temp and muscle rigidity, mutant ryanodine 1 receptor, excessive movement of Ca from SR into the cytoplasm, SR-Ca pump

Question 32

***FUNCTIONS OF RER

Answer 32

- synthesis of proteins for secretion, insertion into membranes, and lysosomal proteins - synthesis of sER enzymes - protein modification - cells actively involved with protein synthesized are well endowed with rER

Question 33

*****SMOOTH ER functions

Answer 33

- steroid synthesis - cholesterol homeostasis - synthesis of phospholipids - detox of drugs - storage, release, uptake calcium ions in striated muscle