Molecules Of Life Flashcards

1
Q

What is the ECM

A

Complex network of secreted macromolecules in the extra cellular space

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2
Q

Functions of the ECM

A

3D framework for organisation of tissues
Structural and biochemical support for cells
Adhesive substrate
Structure
Provides growth factors to their receptors
Sequesters and stores growth factors
Senses and transducers mechanical signals
Regulates, proliferation, differentiation, cell-cell interaction, migration

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3
Q

What does too much ECM cause

A

Fibrosis

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4
Q

What structure does ECM form when outside the cell

A

Fibres mesh

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5
Q

How much of the body’s protein is collagen

A

25%

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6
Q

What structure is formed by the 3 polypeptide chains in collagen

A

Triple helix

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7
Q

What amino acids are in collagen

A

Glycine, proline, hydroxyproline

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8
Q

What are the 2 main types of collagen

A

Fibrillar

Non fibrillary

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9
Q

What structure does fibrillar collagen form

A

Organised banded fibrils

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10
Q

What structures do non fibrillar collagen form

A

Microfibrils

Mesh like structures

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11
Q

Purpose of fibrillar collagen

A

Tensile strength

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12
Q

Purpose of non fibrillar collagen

A

Anchorage of cells

Filtration

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13
Q

What causes osteogenesis imperfecta

A

Genetic defect in collagen type 1 synthesis - converts glycine to bulky aa preventing folding

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14
Q

Nucleus purpose

A

Contains genome

Main site for dna/rna synthesis

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15
Q

Composition of nuclear membrane

A

Lamin, emerin, and nuclear pores

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16
Q

Nucleolus purpose

A

Makes ribosomal subunits from RNA & protein

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17
Q

What is a laminopathy

A

Disease due to defects in genes coding nuclear lamina

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18
Q

What does Hutchinson-Gilford cause

A

Premature aging

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19
Q

RER purpose

A

Protein synthesis - translation of rna to proteins
Transport of proteins
Folding of proteins

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20
Q

SER purpose

A

Carbohydrate and lipid synthesis
Ca2+ store
Contain enzymes that detoxify drugs

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21
Q

Golgi apparatus purpose

A

Synthesis of hormones and enzymes
Packing of hormones and enzymes
Receives lipids and proteins from er and dispatches to different locations

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22
Q

Lysosomes purpose

A

Autolysis

Autophagy

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23
Q

Peroxisomes purpose

A

Metabolism of fatty acids

Detoxification

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24
Q

What is autolysis

A

Degrading of whole cell after death

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25
Q

What is autophagy

A

Degrading of cellular organelles

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26
Q

Where are peroxisomes most often found

A

Liver and kidney

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27
Q

Where do lysosomes originate

A

Golgi

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28
Q

Mitochondria purpose

A

Generate ATP

control apoptosis

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29
Q

Components of cytoskeleton

A

Actin microfilaments
Intermediate filaments
Microtubules

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30
Q

Actin microfilament purpose

A

Cell movement
Cell shape
Organelle and vesicle transport

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31
Q

Intermediate filaments purpose

A

Tensile strength

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32
Q

Microtubule purpose

A

Pull apart cell in mitosis

Track movement of organelles and vesicles

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33
Q

Connective tissue purpose

A

Connects
Supports
Binds
Separates tissues/organs

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34
Q

What is the ECM

A

Material outside the cell

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35
Q

What syntheses the ECM

A

Connective tissue cells

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36
Q

ECM purpose

A
Scaffolding
Cell migration
Proliferation
Survival
Shape
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37
Q

2 main classes of macromolecules in the ECM

A

Glycosaminoglycans

Fibrous proteins

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38
Q

What is a glycosaminoglycan

A

Linear chain of 20-100s disaccharides usually linked to a protein to form a proteoglycan

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39
Q

What is produced when GAGs bind with water

A

Hydrated gels that fill space between cells and resist compressive forces

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40
Q

What do GAGs allow rapid diffusion of

A

Nutrients
Metabolites
Hormones

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41
Q

Collagen purpose

A

Tensile strength

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42
Q

Components of elastin

A

Tropoelastin

Fibrillin

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43
Q

Fibronectin purpose

A
Binds cells and ECM
Matrix organisation
Guiding cell migration
Development
Wound healing
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44
Q

Which tissues is the basement membrane found between

A

Epithelial

Connective

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45
Q

3 layers of basement membrane

A

Lamina Lucida
Lamina densa
Lamina fibroreticularis

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46
Q

Basement membrane purpose

A
Support
Anchoring 
Protection
Cell movement
Cell signalling
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47
Q

Purpose of tight epithelial junctions

A

Prevent passage of molecules across epithelium

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48
Q

Purpose of adherens epithelial junction

A

Tether adjacent cells together

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49
Q

Purpose of desmosomal epithelial junctions

A

Resist mechanical stress

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50
Q

Purpose of gap junctions

A

Allow passage of small molecules between cells

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51
Q

Purpose of hernidesmosome epithelial junctions

A

Anchor epithelium to basal lamina

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52
Q

What are cilia

A

Motile structures

Project from apical surface of some epithelia

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53
Q

What is the central core of a cilia called

A

Axoneme

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54
Q

Types of cilia

A

Pseudopodia
Lamellipodia
Filipodia

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55
Q

Pseudopodia purpose

A

Temporary projection

Allow crawling

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56
Q

Lamellipodia purpose

A

Cell migration for wound healing - eg migration of fibroblasts

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57
Q

Filipodia purpose

A

Sense surrounding environment

Direct fibroblasts in wound healing

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58
Q

Macromolecules in ECM

A

Collagen
Elastin
Glycoproteins
Proteoglycans

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59
Q

What’s is the ECM

A

3d gelatinous bed for cells to live in

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60
Q

How many families of collagen are there

A

19

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61
Q

How much of the total protein mass in the body is collagen

A

25%

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62
Q

Structure of collagen

A

Triple helix of 3 peptide chains

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63
Q

Amino acid code of collagen

A

Glycine-X-Y

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64
Q

Fibril forming collagen types

A

1 2

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65
Q

Network forming collagen types

A

4 6

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66
Q

Osteogenesis imperfetta cause

A

Defect in collagen type 1

Single base change - glycine converted to more bulky acid

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67
Q

Osteogenesis imperfetta effects

A
Fragile bones
Thin skin
Abnormal teeth
Weak tendons
Blue looking sclera
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68
Q

Elastin purpose

A

Gives flexibility for blood vessels, lungs, ligaments, skin

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69
Q

Which contains more valine - collagen or elastin

A

Elastin

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70
Q

2 Abundant amino acids in elastin and collagen

A

Glycine

Proline

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71
Q

Marfan syndrome cause

A

Fibrillin misfolded causing changes to ECM properties

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72
Q

What covers elastin fibres

A

Fibrillin

Gives stability

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73
Q

Marfan syndrome symptoms

A
Tall stature
Long arms and legs
Spider fingers
Loose joints
Eye problems
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74
Q

Glycoproteins purpose

A

Cell surface receptors

Strengthens, supports, and distributes ECM

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75
Q

Fibronectin purposes

A

Cell adhesion
Migration
Shape
Differentiation

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76
Q

Laminin purpose

A

Cell adhesion
Cell migration
Cytoskeleton organisation

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77
Q

What are the gel forming components of ECM

A

Proteoglycans

78
Q

Proteoglycan composition

A

Peptide chains W covalently bound sugars and GAG extensions

79
Q

Why do proteoglycans draw and hold water

A

Negative charge on GAG chains

80
Q

What gives proteoglycans compressive strength

A

Holding water

81
Q

How much of proteoglycans are carbohydrate

A

95%

82
Q

Major cell adhesion classes

A

Integrins
Ig superfamily members
Cadherins
Selectins

83
Q

Basic mechanism of cell migration

A

Polymerisation of actin filaments - gives protrusive force
New adhesions rapidly linked to network of actin filaments
Combined activity of actin movement generates tension - pulls cell body foreword
Forces produced by contractile network and actin filaments - retracts trailing edge

84
Q

What happens to actin filaments to create a protrusive force

A

Polymerisation

85
Q

What force pulls the cell body foreword in cell migration

A

Tension generated by actin

86
Q

What can occur if cells migrate without ECM

A

Cell detachment and apoptosis

87
Q

Steps of leukocyte extravasation

A

Chemo attraction
Rolling adhesion
Tight adhesion
Transmigration

88
Q

What allows cancer cells to migrate and invade surrounding tissues

A

Cleavage of cell adhesions molecules

Degrade ECM

89
Q

What allows epithelial to mesenchymal metastasis

A

Breakdown of basement membrane
Loss of cell adhesion
Loss of apoptosis

90
Q

Carbohydrate formula

A

C H2 O

91
Q

Carbohydrate purpose

A

Energy source
Stabilising - glycoproteins
Ligands for immune system - bacterial lipopolysaccaride

92
Q

Why are polysaccharides often poorly defined

A

Synthesised by enzymes without a template

93
Q

What is a chiral centre

A

An asymmetric carbon with covalent bonds to 4 different groups

94
Q

What’s an enantiomer

A

Pair of isomers that are mirror images

95
Q

What are the 2 forms of a monosaccharide with 1 asymmetric carbon

A

D form

L form

96
Q

What is the d form of a monosaccharide

A

OH group attached to right of single asymmetric carbom

97
Q

What is the L form of a monosaccharide

A

OH group attached to left of single asymmetric carbon

98
Q

2 stereoisomers of ring glucose

A

ALPHA anomer - OH below ring

BETA Anomer - OH above ring

99
Q

What is a disaccharide

A

Monosaccharide combines by glycosidic bond

100
Q

What is an oligosaccharide

A

3-10 joined monosaccharides

101
Q

What is a sugar phosphate

A

Sugar with OH replaced by phosphate

102
Q

What’s an amino sugar

A

Sugar with OH replaced by amine group

103
Q

What’s a deoxy sugar

A

Sugar with O removed

104
Q

What type of reaction forms a glycosidic bond

A

Dehydration

105
Q

What enzymes catalyse glycosidic bond formation

A

Glycosl transferases

106
Q

Primary locations of glycogen

A

Liver

Muscles

107
Q

Linkages in glycogen

A

Alpha 1,4 - main linkages

Alpha 1,6 - side chains

108
Q

Heparin purpose

A

Activates Serpin the main inhibitant of thrombin

109
Q

What type of molecule is heparin

A

GAG

110
Q

Where is heparin produced

A

Endothelial cells at site of damage

111
Q

What type of molecule are blood antigens a b and o

A

Oligosaccharides

112
Q

Which receptors recognise lipo polysaccharides

A

Molecular pattern recognition receptors

113
Q

Enzyme cofactor

A

Non protein component

114
Q

Prosthetic group

A

Non dissociable factor of enzyme

115
Q

Apoenzyme

A

Lacks cofactor

Inactive

116
Q

Holoenzyme

A

With cofactor

Active

117
Q

Coenzyme

A

Dissociable non protein

118
Q

Proenzyme/zymogen

A

Enzyme in inactive state

119
Q

What process activates enzyme

A

Proteolytic conversion

120
Q

What does the Michaelis Menten Equation do

A

Relates V0 to substrate concentration

121
Q

What is VMax

A

Maximum enzymatic activity

122
Q

Km equation

A

VMax/2

123
Q

What does a high Km show

A

Weak substrate binding

124
Q

Effect of increasing enzyme concentration

A

Linear Reaction rate increase

125
Q

Effect of increasing substrate concentration

A

Increases rate until plateau

126
Q

Isoenzyme

A

Different versions of same enzyme

Catalyse same reaction in different tissues

127
Q

Differences between isoenzymes

A

Different kinetic properties

Produced by different genes

128
Q

Diagnostic enzymes

A

Looking at amount of enzymes in blood to determine amount of damage in a tissue

129
Q

Lipid uses

A

Compartmentalisation
Plasma membranes
Energy production

130
Q

Enzyme for fatty acyl chain synthesis

A

Fatty acid synthase

131
Q

Ends of fatty acid names

A

Methyl end - omega

Carboxyl end - delta

132
Q

Essential fatty acids

A

Omega 3

Omega 6

133
Q

Composition of triglycerides

A

Fatty acids + glycerol

134
Q

Which molecule is takes longer to catabolise - triglyceride or glycogen

A

Triglycerides

135
Q

What is the head of a phospholipid made of

A

Choline
Phosphate
Glycerol

136
Q

Amphiphilicity meaning

A

Associate by themselves in water

137
Q

Forms of phospholipid structures

A

Bilayer
Micelle
Liposome

138
Q

Which phospholipids form micelles

A

Single fatty acid tail

139
Q

Where are membrane lipid monolayers found

A

Fat droplets

140
Q

Fluid mosaic model properties

A
Barrier
Compartmentalisation 
Contain several lipid components 
Leaflets usually asymmetric
Contain membrane proteins
141
Q

Why are phospholipid membranes permeable

A

Leaflets are asymmetric

142
Q

What does the head of cholesterol associate with

A

Head group of glycerphospholipids

143
Q

Cholesterol composition

A

Hydrophilic head
Rigid steroid ring
Hydrophobic hydrocarbon tail

144
Q

What does the tail of a cholesterol intercalated with

A

Acyl chains of glycerophospholipids

145
Q

How does cholesterol impact membrane properties

A

Increased packing density

Decreased permeability

146
Q

Effect of cholesterol in sphingolipid membranes

A

Reduces packing density

Increases fluidity

147
Q

Lipid raft composition

A

Sphingomyelin

Cholesterol

148
Q

Lipid raft purpose

A

Limit lateral diffusion

Permit clustering of proteins and lipids W shared function

149
Q

Glycolipid composition

A

Sugar head group

Ceramide

150
Q

Glycolipid purpose

A

Protect cell from environment
Cell-cell communication
Localisation of lipid rafts

151
Q

Cholesterol uses

A

Membranes
Precursor mol
Atherosclerosis

152
Q

Which molecules is cholesterol a precursor for

A

Vitamin D
Bile salts
Sex hormones
Steroids

153
Q

What do statins do

A

Decrease cholesterol synthesis

154
Q

What do phytosterols do

A

Reduce cholesterol uptake

155
Q

What is ATP

A

Adenosine triphosphate

156
Q

How is ATP formed

A

Phosphorylation of ADP and AMP

157
Q

How much of the coding section of the human genome codes for membrane proteins

A

30%

158
Q

What proportion of drugs target membrane proteins

A

50%

159
Q

Membrane protein purposes

A
Ion channels
Transporters
Anchors
Receptors
Enzymes
160
Q

Types of membrane proteins

A

Single/multiple pass alpha helix proteins

Rolled up beta sheet

161
Q

Anchors of membrane proteins

A

Amphiphilic alpha helix
Lipid
Association by non covalent interaction W membrane protein

162
Q

Lipid anchor composition

A

Long chain fatty acids

Cholesterol

163
Q

How are lipid anchors connected to proteins on cell surface

A

Covalent bonds

164
Q

Lipid anchor use

A

Recruit/detach extracellular proteins from membrane

165
Q

Integral membrane protein properties

A

Diffuse laterally
Can change conformation
Can be internalised
Can be recycled

166
Q

What are membrane channels

A

Continuous pore through membrane

Can be selective

167
Q

What type of movement occurs in membrane channels

A

Bulk flow

168
Q

Types of membrane transporters

A

Passive transporters

Active transporters

169
Q

How do passive transporters move solute

A

Solute binds -> conformational change -> solute exposed to other side of membrane

170
Q

How do active transporters move solute

A

ATP binds -> conformational change -> exposes solute to other side of membrane

171
Q

Do passive transporters transport up or down concentration gradients

A

Down

172
Q

Do active transporters transport up or down concentration gradients

A

Up or down

173
Q

Do channels transport up or down concentration gradients

A

Down

174
Q

Coupled transport

A

Energy from movement of 1 ion down an electrochemical gradient provides energy for movement of another ion up electrochemical gradient

175
Q

What type of transport is coupled transport

A

Secondary active transport

176
Q

What is antiport coupled transport

A

Ions move in opposite directions

177
Q

What is symport coupled transport

A

Both Ions move in same direction

178
Q

Primary active transport

A

ATP hydrolysis causes uphill ion transport

179
Q

Secondary active transport

A

Translocation of solute up concentration gradient due to movement of another solute down its transportation gradient

180
Q

Types of secondary active transport

A

Symport

Antiport

181
Q

Which cells are bile salts moved across by specific receptors

A

Epithelial

182
Q

Progressive familial intrahepatic cholestasis

A

Caused by defects in ABCB11 bile and other primary active transporters
Symptoms - jaundice, dark urine, appetite loss, enlarged liver, enlarged spleen, fatal

183
Q

Cystic fibrosis transmembrane regulator purpose

A

Reduces viscosity of surface mucous

184
Q

Cystic fibrosis transmembrane regulator action

A

Releases Cl- -> induces flow of Na+ and H2O in same direction

185
Q

What is the cystic fibrosis transmembrane regulator

A

Cl- channel

186
Q

Where are cystic fibrosis transmembrane regulators found

A

Plasma membrane of epithelial cells in lungs, intestine, and pancreas

187
Q

What mutation causes cystic fibrosis

A

Autosomal recessive mutation to CFTR

188
Q

How does the CF mutation effect the CFTR

A

Impair folding of channel

Impair opening of channel

189
Q

What causes CF symptoms

A

Increases mucous viscosity

190
Q

CF impacts

A

Reduces epithelial cell function
Chronic infection
Inflammation
Fibrosis

191
Q

CF treatments

A

Lumacraftor

Ivacraftor