secretion in a cell

Question 1

what is a phagosome

Answer 1

vesicle formed around a particle engulfed by a phagocyte via phagocytosis

Question 2

which process involves smaller invaginations of the cell membrane which fuse and entrap extracellular fluid and its dissolved contents.

Answer 2

pinocytosis

Question 3

do pinocytotic vesicles pinch off from the membrane

Answer 3

yes

Question 4

what is transcytosis

Answer 4

type of transcellular transport in which various macromolecules are transported across the interior of a cell

Question 5

during receptor mediated endocytosis what do the the vesicle invaginate as

Answer 5

coated vesicle

Question 6

what is the major polypeptide that coats the vesicles during receptor mediated endocytosis

Answer 6

clathrin

Question 7

what do the clathrin molecules interact with

Answer 7

struts of a geodesic dome

Question 8

what are caveolae

Answer 8

invaginations produced by type of receptor-mediated endocytosis prominent in very thin cells

Question 9

where do the vesicles fuse in receptor mediated endocytosis after pinching off from the membrane

Answer 9

they fuse with the endosomal compartment

Question 10

what is a dynamic collection in the peripheral cytoplasm of membranous tubules and vacuoles

Answer 10

endosomal compartment

Question 11

which diverse peripheral proteins are caveolins associated with

Answer 11

cavins

Question 12

the clathrin molecules separate from the coated vesicles and are thrown away. true or false

Answer 12

false, they are recycles back into the membrane to form new coated pits

Question 13

what is the function of Rab proteins (G proteins) in the endosomal compartment

Answer 13

directs vesicle trafficking along small GTPases that bind guanine nucleotides and associated proteins

Question 14

what enzyme binds guanine and associated protein during vesicle trafficking

Answer 14

GTPase

Question 15

what triggers exocytosis

Answer 15

increase in cytosolic Ca ions

Question 16

Membrane fusion during exocytosis is highly regulated, true or false

Answer 16

true. selective interactions between several specific membrane proteins

Question 17

which secretions is used for products that are released from cells continuously, as soon as synthesis is complete

Answer 17

constitutive secretions.

Question 18

when do regulated secretions occur

Answer 18

in response to signals coming to the cells, such as the release of digestive enzymes from pancreatic cells in response to specific stimuli

Question 19

what secretions are used for collagen subunits in the ECM (extracellular matrix molecules)

Answer 19

constitutive secretions

Question 20

what is an example of regulated secretion

Answer 20

release of digestive enzymes from pancreatic cells in response to specific stimuli

Question 21

where does regulated exocytosis of stored products from epithelial cells usually occur

Answer 21

apical domains of cells, constituting a major mechanism of glandular secretion

Question 22

what are the three exocrine glands

Answer 22

apocrine
merocrine
holocrine

Question 23

which type bud their secretions off through the plasma membrane producing extracellular membrane-bound vesicles

a) merocrine
b) apocrine
c) holocrine

Answer 23

apocrine.
merocrine- secretions of that cell are excreted via exocytosis from secretory cells into an epithelial-walled duct or ducts and then onto a bodily surface or into the lumen
holorcine- secretions released by the rupture of the plasma membrane, which destroys the cell and results in the secretion of the product into the lumen

Question 24

what is process of membrane movement and recycling called

Answer 24

membrane trafficking

Question 25

what is the importance of membrane trafficking

Answer 25

for physiologically important processes such as reducing blood lipid levels

Question 26

what is endocrine signaling

Answer 26

involves a signaling molecule, a hormone, secreted by an endocrine cell and transported through the circulation to act on distant target cells

Question 27

what is paracrine signaling

Answer 27

mediated by a molecule acting locally to regulate the behavior of a nearby cell

Question 28

what is autocrne signaling

Answer 28

cells responding to signaling molecules that they themselves produce

Question 29

name the two types of paracrine signaling

Answer 29

1. Neurotransmitter or synaptic cell signaling | 2. Juxtacrine cell signaling is contact dependent signaling

Question 30

what is an example of neuroendocrine signaling

Answer 30

Norepinephrine acting on hepatocytes or adipocytes

Question 31

give an example of paracrine signaling

Answer 31

Glucagon and somatostatin acting on adjacent cells of the islets of Langerhans that secrete insulin

Question 32

give an example of juxtacrine cell signaling

Answer 32

immunologic synapse when antigen-presenting cells and a T cell are in contact with each other

Question 33

give an example of autocrine signalling

Answer 33

response of cells of the immune system to foreign antigens or growth factors that trigger their own proliferation and differentiation

Question 34

what does abnormal autocrine signaling cause

Answer 34

unregulated growth of cancer cells

Question 35

what regulates the release of a targeting hormone

Answer 35

negative or positive feedback action

Question 36

name four major intracellular signaling pathways

Answer 36

cAMP Ca calmodulin JAK-STAT integrin actin pathway

Question 37

name four more intracellular signalling pathways

Answer 37

cGMP phospholipid Ca pathway Ras, Raf and MAP kinase pathway NF-κβ transcription factor pathway

Question 38

what is the effector protein for cAMP

Answer 38

adenyl cyclase

Question 39

DAG and IP3 are examples of what

Answer 39

secondary messengers

Question 40

what do ionic changes or second messengers do

Answer 40

amplify the first signal and trigger a cascade of enzymatic activity

Question 41

what enzyme is usually activated during cascade effects

Answer 41

kinase (enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates)

Question 42

what leads to more focused amplification of activity.

Answer 42

when 2nd messengers retained locally by scaffold proteins