L3

Question 1

Plasma membrane is … in diameter

Answer 1

5-6 nm

Question 2

przypomnienie nazw

Answer 2

– Fluid inside cell = intracellular fluid (ICF).

– Fluid outside cell = extracellular fluid (ECF).

Question 3

What determines the direction of transport across the cell membrane? (3)

Answer 3

1. The concentration gradient.
2. The charge of the molecule or ion.
3. The membrane potential.

These three factors together determine the electrochemical gradient

Question 4

Na+ : stężenie w ICF and ECF (mM)

Answer 4

ICF: 20
ECF: 145

Question 5

K+ : stężenie w ICF and ECF (mM)

Answer 5

ICF: 150
ECF: 4

Question 6

Ca2+ : stężenie w ICF and ECF (mM)

Answer 6

ICF: 2x10-4
ECF: 1.8

Question 7

Cl- : stężenie w ICF and ECF (mM)

Answer 7

ICF: 3
ECF: 114

Question 8

HCO3- : stężenie w ICF and ECF (mM)

Answer 8

ICF: 10
ECF: 31

Question 9

secondary active transport -

Answer 9

Cells exploit ion gradients to transport molecules against their electrochemical gradient.

Question 10

Secondary active transport is particularly important for the
transport of … across sheets of cells called … . The … lining of the intestine and kidneys tubules are good
examples.

Answer 10

amino acids and glucose epithelia

Question 11

Exocytosis Constitutive -

Answer 11

Performed by all cells to release components of the or just deliver newly-synthesized membrane proteins. It is the mechanism by which cells are able to insert new proteins such as carriers and ion channels into their cell membranes.

Question 12

Exocytosis Regulated -

Answer 12

Triggered by a chemical or electrical signal such as rise in intracellular Ca2+ e.g. hormone or neurotransmitter release.
It provides cells with a mechanism for precisely timed release of molecules into the extracellular space. All exocrine and endocrine cells use regulated secretion to control the timing and rate of release of their vesicles into the extracellular space.

Question 13

Phagocytosis -

Answer 13

(literally, cell-eating)

Absorption of solids, such as bacteria, viruses, or the remnants of cells which have undergone apoptosis.

Question 14

Pinocytosis -

Answer 14

(literally, cell-drinking)

how cells take in liquids”

Question 15

Receptor-mediated transport

Answer 15

Specific active event where the cytoplasm membrane folds inward to form coated pits.

Question 16

The sodium pump can be inhibited by a glycoside called …. that binds to the extracellular face of the protein.

Answer 16

ouabain

Question 17

Carriers of this type are called cotransporters and the transport itself is called … or …..

Answer 17

cotransport, coupled transport

Question 18

Certain carriers use the ionic gradient established by the sodium pump to provide the energy to move another molecule (e.g. glucose) against its concentration gradient. This process is known as …..

Answer 18

secondary active transport

Question 19

Many secretory cells are polarized so that one part of their membrane is specialized to receive a signal (e.g. a hormone) while another region is adapted to permit the fusion of secretory vesicles. The …. (e.g. those of the salivary glands) provide a clear example of this zonation.

Answer 19

acinar cells of exocrine glands

Question 20

Endocytosis -

Answer 20

membrane retrieval

Question 21

Pinocytosis -

Answer 21

cell drinking- traps some of the extracellular fluid

Question 22

Phagocytosis -

Answer 22

process by which specialized cells engulf foreign particles and cell debris. It is triggered when receptors on the cell surface recognize specific proteins on the surface of a foreign particle. The ingested material is digested in specific vacuoles called phagosomes.

Question 23

Most passive transport occurs via ion channels or carrier proteins and is sometimes called ….

Answer 23

facilitated diffusion

Question 24

Cells also transport ions and molecules “uphill” against their prevailing electrochemical gradients. This uphill transport requires a cell to expend metabolic energy either directly or indirectly and is called ……
All active transport involves carrier proteins and, in many cases, the activity of a carrier protein is directly dependent on metabolic energy derived from the hydrolysis of ATP

Answer 24

active transport

Question 25

Polar molecules (e.g. digestive enzymes) are packaged in membrane bound vesicles which can fuse with the plasma membrane to release their contents into the extracellular space in a process called ….

Answer 25

exocytosis

Question 26

Przypomnienie secretion

Answer 26

In some cases secretion occurs by simple diffusion through the plasma membrane - the secretion of steroid hormones by the cells of the adrenal cortex occurs in this way. This method of secretion is, however, limited to those molecules that can penetrate the lipid barrier of the cell membrane.