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Histo LEC > Cell Part 1 > Flashcards

Cell Part 1 Flashcards

1
Q

3 basic components of cells

A

Genetic material

Plasma membrane

Cytoplasm

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2
Q

Genetic material of prokaryotes is found in the

A

Nucleoid region

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3
Q

Genetic material of eukaryotes is found in the

A

Nucleus

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4
Q

Plasma membrane consists of

A

Lipids
Proteins
Carbohydrates

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5
Q

Lipids

A

Phospholipids
Cholesterol

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6
Q

= major constituents of membranes

Weighs how many percent

A

Proteins

50%

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7
Q

= proteins that are are incorporated directly within the lipid bilayer

A

Transmembrane or Integral

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8
Q

= proteins that are bound to one of the two membrane surfaces, particularly on the cytoplasmic side

A

Peripheral

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9
Q

The ___________ that envelops every eukaryotic cell consists of phospholipids, cholesterol, and proteins, with oligosaccharide chains covalently linked to many of the phospholipids and proteins.

A

plasma membrane (cell membrane or plasmalemma)

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10
Q

Functions as a selective barrier regulating the passage of materials into and out of the cell and facilitating the transport of specific molecules.

A

plasma membrane

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11
Q

also perform a number of specific recognition and signaling functions, playing a key role in the interactions of the cell with its environment

A

Membrane proteins

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12
Q

Functions of Plasma Membrane

A

Physical barrier

Selective permeability

Electrochemical gradients

Communication

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13
Q

Polar head group

A

Hydrophilic

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14
Q

Nonpolar tail (fatty acid chain)

A

Hydrophobic

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15
Q

= carbohydrate attached to a lipid

A

Glycolipid

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16
Q

= carbohydrate attached to a protein

A

Glycoprotein

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17
Q

True or False | phospholipids are amphipathic

A

True

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18
Q

True or False | Phospholipids are most stable when organized into a double layer (bilayer) with the hydrophobic fatty acid chains located in a middle region away from water and the hydrophilic polar head groups contacting the water

A

True

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19
Q

Is the amount of membrane cholesterol equal to the amount of the phospholipids?

A

• Yes. Membrane cholesterol is present in about the same amount as phospholipid.

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20
Q
  • contain high concentration of cholesterol and saturated FA (fatty acid)
A

Lipid rafts

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21
Q

The __________ model of membrane structure emphasizes that the phospholipid bilayer of a membrane also contains proteins inserted in it or associated with its surface (peripheral proteins) and that many of these proteins move within the fluid lipid phase.

A

fluid mosaic model

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22
Q

Examples of integral proteins

A

Channels, transporters, pumps, receptors

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23
Q

= transports small, nonpolar molecules directly through the lipid bilayer. Lipophilic (fat-soluble) molecules diffuse through membranes readily, water very slowly.

A

Simple Diffusion - Passive

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24
Q

= are multipass proteins forming transmembrane pores through which ions or small molecules pass selectively. Cells open and close specific _____ for Na+, K+, Ca2+, and other ions in response to various physiological stimuli.

A

Channels

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25
Q

Water molecules usually cross the plasma membrane through channel proteins called______.

A

aquaporins

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26
Q

= are transmembrane proteins that bind small molecules and translocate them across the membrane via conformational changes

A

Carriers

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27
Q

Movement of substances down a concentration gradient due to the kinetic energy of the substance; no expenditure of cellular energy is required; continues until equilibrium is reached (if unopposed)

A

PASSIVE PROCESSES

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28
Q

Unassisted net movement of small. Nonpolar substances down the concentration gradient across a selectively permeable membrane

Exchange of oxygen and carbon dioxide between blood and body tissues

A

Simple diffusion

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29
Q

Movement of ions and small, polar molecules down their concentration gradient; assisted across a selectively permeable membrane by a transport
protein

A

Facilitated diffusion

30
Q

Movement of ion down its concentration gradient through a protein channel

Na* moves through Na* channel into cell

A

Channel-mediated

31
Q

Movement of small, polar molecule down its concentration gradient by a carrier protein

Transport of glucose into cells by glucose carrier

A

Carrier-mediated

32
Q

Diffusion of water across a selectively permeable membrane

Direction is determined by relative solute concentrations: continues until equilibrium is reached

Solutes in blood in svstemic capillaries “pulls” fluid
from interstitial space back into the blood

A

Osmosis

33
Q

= are enzymes engaged in active transport, utilizing energy from the hydrolysis of adenosine triphosphate (ATP) to move ions and other solutes across membranes, against often steep concentration gradients.

A

Membrane pumps

34
Q

Because they consume ATP pumps, they are often referred to as____.

A

ATPases

35
Q

Movement of substances requires expenditure of cellular energy

A

Active processes

36
Q

Transport of ions or small molecules across the membrane against a concentration gradient by
transmembrane protein pumps

A

Active transport

37
Q

Movement or substance up its concentration gradient: powered directly by ATP

Ca- pumos transport Ca- out of the cell Na/K
Pump moves Na out of the cell and K* into the cell

A

Primary

38
Q

Movement of a substance up its concentration gradient powered by harnessing the movement of a second substance (eq, Na*) down its concentration gradient

A

Secondary

39
Q

Movement of substance up its concentration
gradient in the same direction as Na+

A

Symport

40
Q

Movement of substance up its concentration gradient in the opposite airection from Na’

A

Antiport

41
Q

each bind a single solute and transport it across the lipid bilayer.

A

Carrier proteins

42
Q

= Movement of substance up its concentration gradient; powered directly by ATP

A

Primary Active Transport

43
Q

Transport by vesicles

A

Endocytosis
Exocytosis

44
Q

= a general process wherein macromolecules normally enter cells by being enclosed within folds of plasma membrane which fuse and pinch off internally as spherical cytoplasmic vesicles (or vacuoles).

A

ENDOCYTOSIS

45
Q

3 major types of endocytosis

A

Phagocytosis
Pinocytosis
Receptor mediated endocytosis

46
Q

“Cell eating”
the ingestion of particles such as bacteria or dead cell remnants.

A

Phagocytosis

47
Q

Ex: Blood derived cells, such as macrophages and neutrophils

Involves the extension from the cell of surface folds or pseudopodia which engulf particles such as bacteria, and then internalize this material into a cytoplasmic vacuole or phagosome.

A

Phagocytosis

48
Q

= an intracellular vacuole where fusion of the membranous folds encloses the bacterium in; merges with a lysosome for degradation of its contents

A

Phagosome

49
Q

“Cell drinking”
The cell membrane forms similar folds or invaginates (dimples inward) to create a pit containing a drop of extracellular fluid.

A

Pinocytosis

50
Q

The pit pinches off inside the cell when the cell membrane fuses and forms a pinocytotic vesicle containing the fluid.

A

Pinocytosis

51
Q

= pinocytosis - the latter process; accomplishes bulk transfer of dissolved substances across the cell.

A

Transcytosis

52
Q

Includes membrane proteins called receptors that bind specific molecules (ligands).
Receptors for many substances, such as low-density lipoproteins and protein hormones, are integral membrane proteins at the cell surface.
When many such receptors are bound by their ligands, they aggregate in one membrane region, which then invaginates and pinches off to create a vesicle or endosome containing both the receptors and the bound ligands.

A

Receptor-mediated endocytosis

53
Q

= a process that involves the movement of large molecules from inside to outside the cell

A

EXOCYTOSIS

54
Q

Vesicle formed or lost as material is brought into a cell or released from a cell

A

Vesicular transport

55
Q

Bulk movement of substance out of the cell by fusion of secretory vesicles with the plasma membrane

A

Exocytosis

56
Q

Bulk movement of substances into the cell by vesicles forming at the plasma membrane

A

Endocytosis

57
Q

Type of endocytosis in which vesicles are formed as particulate materials external to the cell are engulfed by pseudopodia

A

Phagocytosis

58
Q

Type of endocytosis in which vesicles are formed as interstitial fluid is taken up by the cell

A

Pinocytosis

59
Q

Type of endocytosis in which plasma membrane receptors first bind specific substances; receptor and bound substance then taken up by the cell

A

Receptor mediated Endocytosis

60
Q

SIGNAL RECEPTION & TRANSDUCTION: DIRECT CONTACT

A

Gap Junctions
Juxtacrine Signaling

61
Q

Where are Gap Junctions located?

A

found in the lateral part

62
Q

CATEGORIES OF SIGNALING PROCESSES:

A

Endocrine Signaling
Paracrine Signaling
Synaptic Signaling
Autocrine Signaling
Juxtacrine Signaling

63
Q

The signal molecules (here called hormones) are carried in the blood from their sources to target cells throughout the body

A

Endocrine Signaling

64
Q

The chemical ligand diffuses in extracellular fluid but is rapidly metabolized so that its effect is only local on target cells near its source

A

Paracrine Signaling

65
Q

A special kind of paracrine interaction
Neurotransmitters act on adjacent cells through special contact areas called synapses

A

Synaptic Signaling

66
Q

Signals bind receptors on the same cells that produced the messenger molecule

A

Autocrine Signaling

66
Q

Important in early embryonic tissue interactions, the signaling molecules are cell membrane-bound proteins, which bind surface receptors of the target cell when the two cells make direct physical contact.

Ligand is attached to the cell for cell-cell interaction

A

Juxtacrine Signaling

67
Q

3 IMPORTANT FUNCTIONAL CLASSES OF RECEPTORS

A

Channel-linked Receptors
Enzymatic Receptors
G-protein–Coupled receptors

68
Q

= open associated channels upon ligand binding to promote transfer of molecules or ions across the membrane

bind ligands such as neurotransmitters and open to allow influx of specific ions.

A

Channel-linked Receptors

69
Q

= ligand binding induces catalytic activity in associated peripheral proteins.

Activates enzymes

usually protein kinases that are activated to phosphorylate (and usually activate) other proteins upon ligand binding.

A

Enzymatic Receptors

70
Q

= upon ligand binding stimulate associated G-proteins which then bind the guanine nucleotide GTP and are released to activate other cytoplasmic proteins

bind ligand, changing the conformation of its G-protein subunit, allowing it to bind GTP, and activating and releasing this protein to in turn activate other proteins such as ion channels and adenyl cyclase.

A

G-protein–Coupled receptors

Histo LEC (26 decks)

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