Cell Part 1

Question 1

3 basic components of cells

Answer 1

Genetic material

Plasma membrane

Cytoplasm

Question 2

Genetic material of prokaryotes is found in the

Answer 2

Nucleoid region

Question 3

Genetic material of eukaryotes is found in the

Answer 3

Nucleus

Question 4

Plasma membrane consists of

Answer 4

Lipids
Proteins
Carbohydrates

Question 5

Lipids

Answer 5

Phospholipids
Cholesterol

Question 6

= major constituents of membranes

Weighs how many percent

Answer 6

Proteins

50%

Question 7

= proteins that are are incorporated directly within the lipid bilayer

Answer 7

Transmembrane or Integral

Question 8

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

Answer 8

Peripheral

Question 9

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

Answer 9

plasma membrane (cell membrane or plasmalemma)

Question 10

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

Answer 10

plasma membrane

Question 11

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

Answer 11

Membrane proteins

Question 12

Functions of Plasma Membrane

Answer 12

Physical barrier

Selective permeability

Electrochemical gradients

Communication

Question 13

Polar head group

Answer 13

Hydrophilic

Question 14

Nonpolar tail (fatty acid chain)

Answer 14

Hydrophobic

Question 15

= carbohydrate attached to a lipid

Answer 15

Glycolipid

Question 16

= carbohydrate attached to a protein

Answer 16

Glycoprotein

Question 17

True or False | phospholipids are amphipathic

Answer 17

True

Question 18

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

Answer 18

True

Question 19

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

Answer 19

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

Question 20

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

Answer 20

Lipid rafts

Question 21

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.

Answer 21

fluid mosaic model

Question 22

Examples of integral proteins

Answer 22

Channels, transporters, pumps, receptors

Question 23

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

Answer 23

Simple Diffusion - Passive

Question 24

= 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.

Answer 24

Channels

Question 25

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

Answer 25

aquaporins

Question 26

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

Answer 26

Carriers

Question 27

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)

Answer 27

PASSIVE PROCESSES

Question 28

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

Answer 28

Simple diffusion

Question 29

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

Answer 29

Facilitated diffusion

Question 30

Movement of ion down its concentration gradient through a protein channel Na* moves through Na* channel into cell

Answer 30

Channel-mediated

Question 31

Movement of small, polar molecule down its concentration gradient by a carrier protein Transport of glucose into cells by glucose carrier

Answer 31

Carrier-mediated

Question 32

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

Answer 32

Osmosis

Question 33

= 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.

Answer 33

Membrane pumps

Question 34

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

Answer 34

ATPases

Question 35

Movement of substances requires expenditure of cellular energy

Answer 35

Active processes

Question 36

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

Answer 36

Active transport

Question 37

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

Answer 37

Primary

Question 38

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

Answer 38

Secondary

Question 39

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

Answer 39

Symport

Question 40

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

Answer 40

Antiport

Question 41

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

Answer 41

Carrier proteins

Question 42

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

Answer 42

Primary Active Transport

Question 43

Transport by vesicles

Answer 43

Endocytosis Exocytosis

Question 44

= 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).

Answer 44

ENDOCYTOSIS

Question 45

3 major types of endocytosis

Answer 45

Phagocytosis Pinocytosis Receptor mediated endocytosis

Question 46

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

Answer 46

Phagocytosis

Question 47

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.

Answer 47

Phagocytosis

Question 48

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

Answer 48

Phagosome

Question 49

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

Answer 49

Pinocytosis

Question 50

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

Answer 50

Pinocytosis

Question 51

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

Answer 51

Transcytosis

Question 52

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.

Answer 52

Receptor-mediated endocytosis

Question 53

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

Answer 53

EXOCYTOSIS

Question 54

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

Answer 54

Vesicular transport

Question 55

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

Answer 55

Exocytosis

Question 56

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

Answer 56

Endocytosis

Question 57

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

Answer 57

Phagocytosis

Question 58

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

Answer 58

Pinocytosis

Question 59

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

Answer 59

Receptor mediated Endocytosis

Question 60

SIGNAL RECEPTION & TRANSDUCTION: DIRECT CONTACT

Answer 60

Gap Junctions Juxtacrine Signaling

Question 61

Where are Gap Junctions located?

Answer 61

found in the lateral part

Question 62

CATEGORIES OF SIGNALING PROCESSES:

Answer 62

Endocrine Signaling Paracrine Signaling Synaptic Signaling Autocrine Signaling Juxtacrine Signaling

Question 63

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

Answer 63

Endocrine Signaling

Question 64

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

Answer 64

Paracrine Signaling

Question 65

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

Answer 65

Synaptic Signaling

Question 66

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

Answer 66

Autocrine Signaling

Question 66

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

Answer 66

Juxtacrine Signaling

Question 67

3 IMPORTANT FUNCTIONAL CLASSES OF RECEPTORS

Answer 67

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

Question 68

= 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.

Answer 68

Channel-linked Receptors

Question 69

= 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.

Answer 69

Enzymatic Receptors

Question 70

= 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.

Answer 70

G-protein–Coupled receptors