Subcellular Organization 9/15/15

Question 1

Transcytosis

Answer 1

The movement of endocytosed vesicles from one side of the cell to another (often apical to basal)

Question 2

Pinocytosis

Answer 2

“Cell drinking” fluid endocytosis

Small particles are brought into the cell, forming an invagination, and then suspended within clathrin-coated vesicles.

Question 3

Potocytosis

Answer 3

“Cell-sipping”

Receptor-mediated endocytosis in which small molecules are transported across the plasma membrane of a cell. The molecules are transported by caveolae (invaginations of the plasma membrane, rather than clathrin-coated vesicles) and are deposited directly into the cytosol.

Question 4

Catabolism

Answer 4

The set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy, or used in other anabolic reactions.

Question 5

Plasma membrane

Answer 5

Amphipathic (hydrophobic lipid core and hydrophilic head group) barrier separating the cytosol from the outside world.

Also called plasmalemma

Question 6

Function of plasma membrane

Answer 6

1) Protection
2) Nutrient acquisition (ion and metabolite transport, fluid-phase and receptor-mediated uptake of macromolecules)
3) Communication (cell-ligand, cell-matrix, and cell-cell interactions)

Question 7

Ligand

Answer 7

An ion or molecule (functional group) that binds to a central metal atom to form a coordination complex which serves some biological purpose.

Question 8

Phosphatidylcholine

Answer 8

Phospholipid forming outer leaflet of plasmalemma

Question 9

Phosphatidylserine

Answer 9

Phospholipid forming inner leaflet of plasmalemma, has a net negative charge.

When flipped to outside of membrane, signals apoptosis.

Question 10

Phosphatidylethanolamine

Answer 10

Phospholipid forming inner leaflet of plasmalemma

Question 11

Phosphatidylinositol

Answer 11

Phospholipid found on either side of plasmalemma, for intracellular signaling in inner leaflet, for linking proteins to the membrane in outer leaflet

Question 12

Sphingomyelin

Answer 12

Phospholipid found mostly in outer plasma membrane

Question 13

Glycocalyx

Answer 13

“Cell coat,” the extracellular face of the plasma membrane that forms the mechanical and chemical cellular barrier and plays an important role in cell-matrix and cell-cell interactions (eg. sperm-egg attachment, blood clotting, lymphocyte recirculation, inflammatory response)

Question 14

Basic cell attributes

Answer 14

1) Self-replicating capacity
2) Protection from the environment
3) Nutrient acquisition
4) Communication
5) Movement
6) Renewal of senescent molecules
7) Molecular catabolism
8) Energy generation

Question 15

Paracrine signaling

Answer 15

Form of extracellular signaling that affects other cells in the immediate vicinity. Involves minimal diffusion, with rapid signal degradation, rapid cell uptake, or rapid entrapment by the extracellular matrix.

Question 16

Autocrine signaling

Answer 16

Cell signaling that can influence that same cell. Often a means of entrainment or feedback.

Question 17

Synaptic signaling

Answer 17

Type of extracellular signaling where activated neural tissue secretes neurotransmitters at a specialized cell junction (synapse) onto target cells

Question 18

Endocrine signaling

Answer 18

Extracellular signaling targeting cells at a distance, normally through the release of a mediator into the blood stream

Question 19

Gap junction

Answer 19

Narrow hydrophilic channel that effectively connects the cytoplasm of two adjacent cells, permits cell-cell signaling between the two.

Question 29

Phagocytosis

Answer 29

“Cellular eating”

Generally used when referring to macrophages and neutrophils, which ingest invading organisms or dead cell fragments