Bulk Transport

Question 1

Transport that involves the use of proteins

Answer 1

Bulk transport/Vehicular transport

Question 2

Two types of bulk transport

Answer 2

Endocytosis (particles move inward) and Exocytosis (particles move outward)

Question 3

“Cytosis” means

Answer 3

Movement

Question 4

Cell eating (cell engulfs the pathogen/molecule)

Answer 4

Phagocytosis

Question 6

Phagocytosis only occurs in ____

Answer 6

Immune cells and some protists

Question 7

Phagocytosis involves (6 steps)

Answer 7

1. Receptors on a phagocyte bind to large particles (microbes, dead cells, debris etc.)
2. The binding action triggers the plasma membrane to extend finger-like projections (pseudopods) forming a vesicle, known as a phagosome
3. The vesicle detaches from the plasma membrane and enters the cytoplasm
4. the phagosome fuses with a lysosome containing digestive enzymes
5. Digestive enzymes break down the engulfed particles. Digested solutes enter the cytoplasm.
6. Any remained undigested material is contained in a vesicle (residual body) which remains in the phagocyte’s cytoplasm

Question 8

Finger-like projections that forms vesicles (phagosomes)

Answer 8

Pseudopods

Question 9

Cell drinking, aka bulk-phase endocytosis

Answer 9

Pinocytosis

Question 10

Small amounts of extracellular fluid along with any dissolved solutes are taken up into the cell

Answer 10

Pinocytosis

Question 11

Fluid based, non-specific, occurs in most body cells

Answer 11

Pinocytosis

Question 12

Pinocytosis involves (4 steps)

Answer 12

1. Droplets of extracellular fluid w/ dissolved solutes collect in a pit at the surface of the cell
2. The plasma membrane extends around these fluid droplets, forming a vesicle that is drawn into the cytoplasm of the cell
3. This fluid-filled vesicle then fuses with a lysosome, which contains digestive enzymes
4. Finally, the digestive enzymes break down the extracellular fluid, and the digested solutes are released into the cytoplasm

Question 13

Uses receptor proteins to capture a specific target molecule

Answer 13

Receptor-mediated Endocytosis

Question 14

A highly selective form of endocytosis that begins when receptors on a cell’s surface binds specific substances and triggers the plasma membrane to form a vesicle around them, drawing them into the cell

Answer 14

Receptor-mediated endocytosis

Question 15

[TRUE or FALSE] Receptor-mediated endocytosis is a type of pinocytosis

Answer 15

True

Question 16

Receptor-mediated endocytosis involves (8 steps)

Answer 16

1. A ligand binds to a specific receptor on the cell’s plasma membrane, forming a ligand-receptor complex. Each receptor is associated with a protein known as clathrin on the membrane’s cytoplasmic side
2. Receptors and their clathrin are expressed in clathrin-coated pits
3. These clathrin-coated pits sink into the cell, forming a vesicle that contains the ligand-receptor complexes. These vesicles detach from the plasma membrane and enters the cytoplasm
4. Once in the cytoplasm, the clathrin molecules coating the outer edge of the vesicle leave and associate with new receptors on the plasma membrane
5. The uncoated vesicle fuses with an endosome, and the ligands and receptors separate, collecting at the opposite ends of the endosome
6. Sections of the endosome containing unbound receptors pinch off and form transport vesicles that return the receptors to the plasma membrane
7. Remaining vesicles (which now contain free ligands) fuse with a lysosome containing digestive enzymes
8. Finally, the lysosome’s digestive enzymes break the ligands down into smaller molecules, which are then released into the cytoplasm of the cell for other cell processes

Question 17

receptor-mediated endocytosis

Answer 17

ligand binds to receptor (ligand-receptor complex) -> each receptor is associated with clathrin on cytoplasmic side -> receptors and clathrin get into clathrin-coated pits -> pits sink into the cell and form a vesicle that contains ligand-receptors -> vesicles detach and enter the cytoplasm -> clathrin detach while uncoated vesicle fuses with endosome -> ligand-receptors separate (ligands go into lysosomes/golgi, receptors return to plasma membrane via vesicles) -> lysosome’s digestive enzymes break ligands down into smaller molecules, releasing them into the cytoplasm of the cell

Question 18

The regions of the plasma membrane in which receptors/clathrin are expressed

Answer 18

Clathrin-coated pits

Question 19

Substances taken up into cells by receptor-mediated endocytosis

Answer 19

Vitamins, antibodies, hormones, low-density lipoproteins (LDLs), and the iron-
transporter, known as transferrin, are all substances taken up into cells by receptor-mediated endocytosis.

Question 20

Process by which the cell secretes waste/proteins outward

Answer 20

Exocytosis

Question 21

Exocytosis is particularly integral in ____

Answer 21

Secretory cells (secrete products thru exocytosis) and neurons (for secreting neurotransmitters)

Question 22

Exocytosis involves (3 steps)

Answer 22

1. Membrane-bound vesicles form inside the cell from the Rough ER and Golgi apparatus//endosomes or lysosomes within the cytosol
2. The vesicles (w/ new proteins or waste products) move toward the plasma membrane
3. The plasma membrane and vesicular membrane fuse. Vesicle contents are expelled into extracellular fluid.

Question 23

Examples of exocytosis

Answer 23

The secretion of neurotransmitters, hormones, mucus, and digestive enzymes