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14/15/16 Flashcards

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Biology 101 flashcards
1
Q

Extracellular Matrix

A

Provides structural support to cells and tissues and plays important roles in regulating cell behaviour

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2
Q

Cell Wall

A

Determines cell shape and prevents cells from swelling/bursting as a result of osmotic pressure

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3
Q

Bacterial Cell Wall Shapes

A

Rod, spherical, spiral

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4
Q

Gram Negative Bacteria

A

Dual-membrane system with thin cell wall in between

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5
Q

Gram Positive Bacteria

A

One plasma membrane surrounded by a much thicker cell wall

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6
Q

Peptidoglycan

A

Main component of all bacterial cell walls, linear polysaccharide chains cross-linked by short peptides

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7
Q

Cell Wall and Antibiotics

A

Cell wall structure makes some bacteria vulnerable to some antibiotics

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8
Q

Penicillin

A

Inhibits the enzyme that forms the cross-links in the cell wall, preventing growth and synthesis

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9
Q

Bacterial Cytoskeletal Proteins

A

Regulate cell wall synthesis

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10
Q

FtsZ

A

Cytoskeletal protein that forms a ring structure at the site of bacterial cell division and directs synthesis of a new cell wall

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11
Q

What are cell walls of eukaryotes composed of?

A

Polysaccharides

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12
Q

Chitin

A

Forms fungal cell walls and exoskeletons of arthropods

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13
Q

Cell Walls of Algae and Higher Plants

A

Cellulose

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14
Q

Hemicelluloses

A

Highly branched polysaccharides H-bonded to the surface of cellulose microfibrils. Provide stability and mechanical strength.

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15
Q

Pectins

A

Branched polysaccharides with many negatively charged galacturonic acids. Cross-link microfibrils, negative charges bind positive ions to trap water molecules and form gels.

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16
Q

Microfibrils

A

36 cellulose chains joined in parallel, can extend for many micrometers in length, embedded in a matrix of proteins/pectins/hemicelluloses

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17
Q

Primary Cell Walls

A

Relatively thin and flexible to allow expansion of a growing cell, equal amounts of cellulose/hemicelluloses/pectins, randomly arranged cellulose fibres

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18
Q

Secondary Cell Walls

A

Laid down between plasma membrane and primary cell wall after cell wall growth has stopped, no pectins, 50-80% cellulose, highly ordered layers with a strong laminated structure

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19
Q

Lignin

A

Complex polymer of phenolic residues that gives strength and density to wood

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20
Q

Turgor Pressure/Hydrostatic Pressure

A

Water builds up in cell, eventually equalizing the osmotic pressure and preventing further influx of water, responsible for the rigidity of plant tissues

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21
Q

Auxins

A

Plant hormones that activate expansins to allow expansion

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22
Q

Expansins

A

Proteins that weaken regions of the call wall to allow expansion

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23
Q

Water and the Vacuole

A

Water flows into the cell and accumulates in a large central vacuole so the cell can expand without increasing the volume of the cytosol

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24
Q

Cellulose Synthase

A

Trans-membrane enzyme that synthesizes cellulose from UDP-glucose

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25
Q

Microtubules

A

Guide movement of cellulose synthase and define orientation of newly synthesized microfibrils

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26
Q

Cortical Microtubules

A

Define the direction of cell wall growth and expansion and ultimately the shape of the entire plant

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27
Q

CLASP

A

Binds the + end of microtubules to regulate stability. Mutations that inactivate CLAPS results in stunted plants.

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28
Q

Basal Laminae

A

Thin layers that epithelial cells rest on. Also surrounds muscle cells, adipose cells, and peripheral nerves.

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29
Q

Extracellular Matrix

A

Embeds most animal cells, most abundant in CT, tough and fibrous proteins embedded in a gel-like polysaccharide

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30
Q

Adhesion Proteins

A

Link components of the matrix to one another and to attached cells

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31
Q

Tendon EM

A

High proportion of fibrous proteins

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32
Q

Cartilage EM

A

High level of polysaccharides that form a compression-resistant gel

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33
Q

Bone EM

A

Hardened by calcium phosphate crystals

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34
Q

Collagen

A

Major structural protein of EM, forms triple helices or repeat aa sequence Gly-X-Y

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35
Q

Glycine

A

Smallest amino acid, allows polypeptides to pack closely together in collagen

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36
Q

Proline

A

Frequently found in X position in collagen, stabilize helices

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37
Q

Hydroxyproline

A

Y position in collagen, stabilize helices, formed in ER by modification of proline in collagen polypeptide chains

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38
Q

Hydroxyl Groups in Collagen

A

Stabilize triple helix by forming H-bonds

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39
Q

Type I Collagen

A

Most abundant, forms collagen fibrils

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40
Q

Collagen Fibrils

A

Triple helical molecules form regular staggered arrays in them, strengthened by cross-links of lysine and hydroxylysine side chains, come together to form collagen fibres

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41
Q

Procollagens

A

Aid in assembly of fibrils outside the cell

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42
Q

Fibril-Associated Collagens

A

Bind to collagen fibrils and link them to one another and to other matrix components

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43
Q

Type IV Collagen

A

Mostly basal laminae, forms networks, Gly-X-Y repeats interrupted by short non-helical sequences to make them more flexible

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44
Q

Anchoring Fibrils

A

Link some basal laminae to underlying CTs

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45
Q

Elastic Fibres

A

Common in CT of organs that stretch and return to shape, made of elastin

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46
Q

Elastin

A

Cross-linked into a network to make elastic fibres, behaves like a rubber band

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47
Q

GAGs

A

Glycosaminoglycans, repeating units of disaccharides, form EM gels, highly negative because of sulphate groups, bind positive ions and trap water molecules to form hydrated gels, linked to proteins to form proteoglycans

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48
Q

Hyaluronan

A

Only GAG that is a single long polypeptide chain, synthesized at plasma membrane by a transmembrane hyaluronan synthase

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49
Q

Proteoglycans

A

GAGs linked to proteins, interact with hyaluronan to form large complexes in the extracellular matrix

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50
Q

Aggrecan

A

Major proteoglycan of cartilage, about 100 chains of chondroitin sulfate attached to a core protein

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51
Q

Fibronectin

A

Main adhesion protein of CT, often cross-linked into fibrils, binding sites for both collagen and GAGs to enable cross-linking

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52
Q

Laminin

A

Adhesion proteins in basal laminae, 3 ppc with rod-like domains and interspersed globular domains, subunits have binding sites for surface receptors and proteoglycans, can self-assemble into networks

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53
Q

Nidogen

A

Adhesion protein that also binds type IV collagen, tightly associated with laminins

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54
Q

Integrins

A

Transmembrane proteins that attach cells to the EM, heterodimers, bind to various components of the EM, anchor cytoskeleton to EM, can reversibly bind matrix components

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55
Q

Integrins as Heterodimers

A

Different combinations of subunits result in 24 different integrins

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56
Q

Types of Cell-Matrix Junctions

A

Focal adhesions and hemidesmosomes

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57
Q

Focal Adhesions

A

Bundles of actin filaments anchored to β subunits of integrins via other proteins, can be very stable or turn over rapidly as cells move

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58
Q

Hemidesmisomes

A

Anchor epithelial cells to basal laminae

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59
Q

How do integrins reversibly bind matrix components?

A

Due to their ability to change conformation between active and inactive states

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60
Q

How do animal cells modify their EM?

A

Via enzymes that modify glycosaminoglycans and proteases that digest collagen

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61
Q

Metalloproteases

A

Digest a variety of matrix proteins, play important roles in normal movements of cells during development and in the growth and metastasis of cancers

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62
Q

First Metalloprtease

A

Discovered in tadpole tails during metamorphosis

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63
Q

Cell Adhesion Molecules

A

Mediate cell-cell adhesion, selectins/integrins/immunoglobin superfamily/cadherins

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64
Q

Selectins

A

Mediate transient interactions between leukocytes and endothelial cells or blood platelets, bind to oligosaccharide ligands on endothelial cells

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65
Q

Heterophilic Interaction

A

An adhesion molecule on one cell recognizes a different molecule on another cell (ex: binding of ICAMs to integrins)

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66
Q

ICAMs

A

Intercellular adhesion molecules, members of the immunoglobin superfamily

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67
Q

Homophilic Interactions

A

An adhesion molecule on one cell binds to the same molecule on another cell (ex: binding between N-CAMs)

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68
Q

N-CAMs

A

Neural cell adhesion molecules, homophilic binding contributes to associations between nerve cells during development

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69
Q

Cadherins

A

Mediate homophilic interactions, basis of stable adhesion junctions linking the cytoskeletons of adjacent cells

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70
Q

Adherens Junctions

A

Link actin filaments of adjacent cells

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71
Q

Nectin

A

Can form homophilic and heterophilic interactions, present at adherent junctions, form links to the actin cytoskeleton

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72
Q

Desmosomes

A

Link intermediate filament cytoskeletons of adjacent cells

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73
Q

Tight Junctions in Epithelial Cell Sheets

A

Form a seal that prevents free passage of molecules and ions between cells, separate apical and basolateral domains of the plasma membrane by preventing free diffusion of lipids and membrane proteins, provide minimal adhesive strength between cells, formed by a network of protein strands that continues around the entire cell

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74
Q

Gap Junctions

A

Regulated channels through the plasma membrane, allow ions and small molecules to diffuse freely

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75
Q

Connexon

A

6 connexins, a cylinder with an open aqueous pore in its center, align between adjacent cells to form open channels between the two cytoplasms

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76
Q

Electrical Synapse

A

Specialized gap junctions on nerve cells, allow rapid passage of ions between 2 nerve cells

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77
Q

Middle Lamella

A

Pectin-rich region, acts as glue to hold adjacent cells together

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78
Q

Plasmodesmata

A

Analogous gap junctions for adjacent plant cells to communicate through cytoplasmic connections, form by incomplete separation of daughter cells following mitosis, plasma membrane of one cell is continuous with that of its neighbour to create a channel between the two cytosols, open and close to regulate passage

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79
Q

Plasma Membrane

A

Defines cell boundary and separates it from the environment, selective barrier that determines composition of the cytoplasm, mediates interactions between cell and environment

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80
Q

Bilayer in Electron Micrographs

A

Polar heads appear as dark lines because they bind the electron-dense metal stains, fatty acid tails are lightly stained

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81
Q

Mammalian Red Blood Cells and Membrane Structure

A

Useful model for studies, no nuclei or internal membranes so easy to isolate pure plasma membranes

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82
Q

Glycolipids

A

Only in outer leaflet of bilayer with carbohydrate portions exposed on the cell surface

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83
Q

Double Bonds in Fatty Acids of the Membrane

A

Make kinks in the chain and keep them from packing together

84
Q

Cholesterol

A

Affects membrane fluidity and is involved in formation of functional domains in the membrane, clusters in small semisolid patches (lipid rafts)

85
Q

% Weight of Plasma Membrane

A

50% lipid and 50% protein but proteins are much larger

86
Q

Integral Membrane Proteins

A

Inserted into the lipid bilayer, dissociate only by reagents that disrupt hydrophobic interactions

87
Q

Detergents

A

Amphipathic molecules with hydrophobic and hydrophilic groups that can solubilize integral membrane proteins

88
Q

Transmembrane Proteins

A

Integral membranes that span the lipid bilayer with portions exposed on both side

89
Q

GPI Anchors

A

Added to C terminus of some proteins in the ER, glycosylated and exposed on the cell surface

90
Q

Glycocalyx

A

Carbohydrate coat formed by the oligosaccharides of glycolipids and glycoproteins, protects cell surface from ionic and mechanical stress, forms a barrier to invading microorganisms

91
Q

Amendments to the Fluid Mosaic Model

A

Mobility of many plasma membrane proteins is restricted, membranes are composed of distinct domains that have different structural and functional roles

92
Q

Domains of Plasma Membranes

A

Apical and basolateral

93
Q

Apical Surface of SI

A

Covered in microvilli that increase surface area for absorption

94
Q

Basolateral Surface of SI

A

Mediates transfer of absorbed nutrients to the blood

95
Q

Separation of Apical and Basolateral Domains

A

Proteins must be restricted to their appropriate domains to maintain functions, tight junctions separate the domains, membrane proteins can move within each but can’t cross over

96
Q

Lipid Rafts

A

Transient structures in which specific proteins can be concentrated to facilitate interactions

97
Q

Caveolae

A

Small lipid rafts that start as invaginations of the plasma membrane

98
Q

Facilitated Diffusion

A

Direction of movement determined by concentration gradients, no energy required

99
Q

Carrier Proteins

A

Bind molecules on one side of the membrane then undergo conformational changes that allow the molecule to pass through and be released on the other side (sugars, amino acids, nucleosides)

100
Q

Channel Proteins

A

Form open pores through. the membrane to allow free diffusion of any molecule of the appropriate size and charge

101
Q

Glucose Transporters

A

Function by alternating between 2 conformational states, glucose-binding site is alternately exposed on the outside and inside of the cell

102
Q

Glucose Concentration in the Cell

A

Rapidly metabolized in the cell so concentration remains low inside the cell and glucose is transported in, reversed in liver cells

103
Q

Porins

A

Channel proteins that form open pores in the membrane that allow molecules to pass freely

104
Q

Aquaporins

A

Allow water molecules to cross the membrane rapidly, impermeable to charged ions to allow passage of water without affecting electrochemical gradients

105
Q

Ion Channels

A

Opening and closing is responsible for transmission of electrical signals, transport is extremely rapid, well studied in nerve and muscle cells, highly selective

106
Q

Ligand-Gated Channels

A

Open in response to binding of neurotransmitters or other signalling molecules

107
Q

Voltage-Gated Channles

A

Open in response to changes in electric potential across the plasma membrane

108
Q

Ion Pumps

A

Use energy from ATP hydrolysis to actively transport ions across the plasma membrane to maintain concentration gradients

109
Q

Na+ and the Cell

A

Pumped in

110
Q

K+ and the Cell

A

Pumped out, plasma membrane has open K+ channels so flow of K+ makes the largest contribution to resting membrane potential

111
Q

Nernst Equation

A

Describes the relationship between ion concentration and membrane potential

112
Q

Action Potentials

A

Nerve impulses that travel along axons, membrane depolarizes as they travel (-60 to +30 mV in less than a millisecond)

113
Q

Active Transport

A

Molecules are transported against their concentration gradients, energy is provided by a coupled reaction

114
Q

Ion Pumps

A

Active transport of ions against their electrochemical gradients

115
Q

ABC Transporters

A

Have highly conserved ATP-binding domains or ATP-binding cassettes, transport nutrients and waste into (prokaryotes) and out of cells (both)

116
Q

MDR Transporters

A

Product of the multidrug resistance gene, remove toxic foreign compounds from cells, high levels in cancer cells and can remove a variety of chemo drugs

117
Q

CF Gene

A

Encodes a protein in the ABC transporter family but a mutation interferes with the proper folding of the protein, defective Cl- transport in epithelial cells results in super thick and sticky mucus that obstructs respiratory pathways

118
Q

Glucose Transporters in the Apical Domain of Intestine Epithelial Cells

A

Transport 2 Na+ and one glucose into the cell, flow of Na+ down its electrochemical gradient provides the energy for the uptake of glucose against its concentration gradient

119
Q

Glucose Transporters in the Basolateral Domain of Intestine Epithelial Cells

A

Glucose is transferred to the underlying connective tissue and blood capillaries by facilitated diffusion, driven by Na+-K+ pumps

120
Q

Symport

A

Transport of 2 molecules in the same direction

121
Q

Uniport

A

Transport of a single molecule

122
Q

Antiport

A

Transport of 2 molecules in opposite directions

123
Q

Endocytosis

A

Allows cells to take up macromolecules, fluids, and large particles like bacteria. Material is surrounded by an area of plasma membrane that buds off inside the cell to form a vesicle containing the ingested material.

124
Q

Phagocytosis

A

Cell eating, binding of a particle to receptors on cell surface triggers extension of pseudopodia that surround the particle and fuse to form a phagosome

125
Q

Phagolysosomes

A

Phagosomes fuse with lysosomes and material is digested by acid hydrolases

126
Q

Phagocytosis in Amoebas

A

Used to capture bacteria as food

127
Q

Phagocytosis in Multicellular Animals

A

Used as a defence against invading microorganisms and to eliminate aged or damaged cells, WBCs in mammals

128
Q

Macropinocytosis

A

Uptake of extracellular fluids in large vesicles

129
Q

Lamellipodia

A

Sheet-like projections of the plasma membrane that curve into open cups, used in macropinocytosis

130
Q

Clathrin-Mediated Endocytosis

A

Mechanism for selective uptake of specific macromolecules

131
Q

Clathrin-Coated Pits

A

Specialized regions to which macromolecules bin to cell surface receptors, bud from the membrane with the help of dynamin to form clathrin-coated vesicles that fuse with early endosomes

132
Q

LDL Particles

A

Low density lipoprotein, form of cholesterol transport through the bloodstream

133
Q

Clathrin-Independent Endocytosis

A

Does not involve specific membrane receptors or coated vesicles

134
Q

What do many cancers arise from?

A

Problems in signalling pathways that control normal cell proliferation

135
Q

Direct Cell-Cell Signalling

A

Direct interaction of a cell with its neighbour

136
Q

Endocrine Signalling

A

Signalling molecules or hormones are secreted by specialized endocrine cells and carried through the circulation to target cells at distant body sites

137
Q

Paracrine Signalling

A

Molecules released by one cell act on neighbouring target cells (ex: neurotransmitters)

138
Q

Autocrine Signalling

A

Cells respond to signalling molecules that they produce themselves, abnormal leads to cancer

139
Q

T Lymphocytes

A

Respond to antigens by making a growth factor that drives their own proliferation, amplifying the immune response

140
Q

Cancer Cell

A

Produces a growth factor that it also responds to, driving its own unregulated proliferation

141
Q

Intracellular Receptors

A

Respond to small hydrophobic molecules that can diffuse across the plasma membrane

142
Q

Steroid Hormones

A

Synthesized from cholesterol, directly regulate gene expression

143
Q

Corticosteroids

A

From the adrenal gland, glucocorticoids and mineralocorticoids

144
Q

Glucocorticoids

A

Stimulate production of glucose

145
Q

Mineralocorticoids

A

Act on the kidneys to regulate salt and water balance

146
Q

Ecdysone

A

An insect hormone that triggers metamorphosis of larvae to adults

147
Q

Brassinosteroids

A

Plant steroid hormones that control several processes, including cell growth and differentiation

148
Q

Thyroid Hormone

A

Synthesized from tyrosine in the thyroid gland, important in development and metabolism

149
Q

Vitamin D3

A

Regulates Ca2+ metabolism and bone growth

150
Q

Retinoic Acid and Retinoids

A

Synthesized from vitamin A, important in vertebrate development

151
Q

Glucocorticoid Binding

A

Bound to Hsp 90 chaperones in the absence of hormone, glucocorticoid binding displaces Hsp90 and leads to binding of regulatory DNA sequences

152
Q

Hormone Binding

A

In absence of hormone, thyroid hormone receptor is associated with a corepressor complex and represses transcription of target genes. Hormone binding results in activation of transcription.

153
Q

NO

A

Nitric oxide, paracrine signalling molecule in nervous/immune/circulatory systems, can cross plasma membrane and alter activity of enzymes, synthesized from arginine, action is local bc extremely unstable

154
Q

Guanylyl Cyclase

A

Main target of NO, binding of NO stimulates synthesis of a second messenger (cyclic GMP)

155
Q

Second Messenger

A

Molecule that relays a signal from a receptor to a target inside the cell

156
Q

NO in Circulatory System

A

Can signal dilation of blood vessels

157
Q

NO in Muscles

A

Diffuses to smooth muscles and stimulates cGMP production

158
Q

cGMP

A

Induces muscle cell relaxation and blood vessel dilation

159
Q

CO as a Signalling Molecule

A

In nervous system, related to NO and acts similarly as a neurotransmitter and mediator of blood vessel dilation

160
Q

Neurotransmitters

A

Carry signals between neutrons or between neutrons and other cells, released when an action potential arrives at the end of the neuron, neurotransmitters then diffuse across the synaptic cleft and bind to receptors on the target cell surface

161
Q

Neurotransmitters and the Plasma Membrane

A

Hydrophilic so can’t cross and must bind to cell surface receptors, binding opens the channels

162
Q

G Proteins

A

A major group of signalling molecules that link cell surface receptors to intracellular responses

163
Q

Peptide Hormones

A

Include insulin, glucagon, and pituitary gland hormones

164
Q

Neuropeptides

A

Secretes by some neurons

165
Q

Neurohormones

A

Natural analgesics that decrease pain responses, bind to the same receptors on brain cells as morphine does

166
Q

NGF

A

Nerve growth factor, regulates development and survival of neurons

167
Q

EGF

A

Epidermal growth factor, stimulates cell proliferation, prototype for the study of growth factors

168
Q

PDGF

A

Platlet-derived growth factor, stored in blood platelets and released during blood clotting at the site of a wound, stimulates proliferation of fibroblasts that contribute to regrowth of the damaged tissue

169
Q

Cytokines

A

Regulate development and differentiation of blood cells and activities of lymphocytes during the immune response

170
Q

Membrane-Anchored Growth Factors

A

Remain with the plasma membrane and function as signalling molecules in direct cell-cell interactions

171
Q

Eicosanoids

A

Lipid signalling molecules that include prostaglandins, prostacyclin, thromboxanes, and leukotrienes. Break down rapidly and act in autocrine or paracrine pathways. Synthesized from arachidonic acid.

172
Q

Arachidonic acid

A

Converted to prostaglandin H2, catalyzed by cyclooxygenase

173
Q

Cyclooxygenase

A

Target of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs)

174
Q

Prostaglandins

A

Inhibiting synthesis reduces inflammation and pain

175
Q

Thromboxane

A

By inhibiting synthesis, aspirin reduces lately aggregation and blood clotting so small doses are prescribed for stroke prevention

176
Q

Aspirin and NSAIDs

A

Been found to reduce frequency of colon cancer by inhibiting synthesis of prostaglandins that stimulate cell proliferation

177
Q

Forms of Cyclooxygenase

A

COX-1 and COX-2

178
Q

COX-1

A

Forms of cyclooxygenase that results in normal production of prostaglandins

179
Q

COX-2

A

Forms of cyclooxygenase that results in increased prostaglandin production associated with inflammation and disease, selectively inhibited by some drugs

180
Q

Gibberellins

A

Plant hormone for stem elongation

181
Q

Auxins

A

Plant hormone for cell elongation by weakening the cell wall, also regulate aspects of plant development (cell division and differentiation), controls gene expression

182
Q

Ethylene

A

Plant hormone for fruit ripening

183
Q

Cytokinins

A

Plant hormone for cell division

184
Q

Abscisic Acid

A

Plant hormone for onset of dormancy

185
Q

How do auxins control gene expression?

A

By binding to and activating a receptor associated with a ubiquitin ligase

186
Q

Intracellular Signal Transduction

A

Surface receptors regulate intracellular enzymes, which then transmit signals from the receptor to a series of additional intracellular targets

187
Q

G Protein-Coupled Receptors

A

Signals are transmitted via guanine nucleotide-binding proteins (G proteins). Binding of ligand induces conformational change that allows cytosolic domain to activate G protein on inner face of plasma membrane. Activated G protein then dissociates from receptor and carries the signal to an intracellular target.

188
Q

cAMP

A

Cyclic AMP - a second messenger that mediates responses in many hormones

189
Q

Heterotrimeric G Proteins

A

3 subunits of G proteins (alpha, beta, gamma)

190
Q

G Protein Alpha Subunit

A

Binds guanine, which regulates G protein activity, bound to GDP in the inactive state in a complex with beta and gamma. Hormone binding to the receptor exchanges GTP for GDP

191
Q

Protein Kinase A in Glycogen Metabolism

A

Phosphorylase kinase is activated and in turn activates glycogen phosphorylase, which catalyzes glycogen breakdown. Glycogen synthase is inactivated so glycogen synthesis is blocked.

192
Q

Signal Amplification

A

Binding of a hormone molecule leads to activation of many intracellular target enzymes

193
Q

cAMP in Animal Cells

A

Increases in cAMP activate transcription of genes that have a regulatory sequence called cAMP response element

194
Q

cAMP and Odour

A

A second messenger in sensing smells. Odorant receptors are G protein-coupled and stimulate adenylyl cyclase that leads to increased cAMP. cAMP opens Na+ channels in the plasma membrane, leading to initiation of a nerve impulse.

195
Q

Cyclic GMP

A

Second messenger, mediates biological responses such as blood vessel dilation

196
Q

cGMP in Vertebrate Eye

A

Converts visual signals to nerve impulses

197
Q

Rhodopsin

A

Photoreceptor in retinal rod cells, G protein-coupled receptor, activated when light is absorbed by the associated molecule

198
Q

Transducin

A

G protein activated by rhodopsin that stimulates cGMP phosphodiesterase

199
Q

cGMP phosphodiesterase

A

Leads to decreased levels of cGMP

200
Q

Tyrosine Kinases

A

Cell Surface receptors that phosphorylate their substrates on tyrosine residues

201
Q

Receptor Tyrosine Kinases

A

Includes receptors for most polypeptide growth factors. All have N-terminal extracellular ligand-binding domain, transmembrane alpha helix, and cytosolic C-termincal domain with protein-tyrosine kinase activity

202
Q

Binding of Ligands to Receptor Tyrosine Kinases

A

Binding to extracellular domains activates the cytosolic kinase domains, resulting in phosphorylation of both the receptors and intracellular target proteins that propagate the signal

203
Q

Roles of Autophosphorylation

A

Phosphorylation of tyrosine in the catalytic domain increases protein kinase activity. Phosphorylation of tyrosine outside the catalytic domain creates binding sites for other proteins that transmit signals downstream from the activated receptors.

204
Q

Downstream Signalling Molecules

A

Have domains that bind to specific phosphotyrosine-containing peptides of the activated receptors

205
Q

SH2 Domains

A

Domain on downstream signalling molecules

206
Q

Non-Receptor Tyrosine Kinases

A

Stimulate intracellular tyrosine kinases with which they are noncovalently associated

Cell Bio (3 decks)

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