Molecules Of Life Flashcards
1
Q
What is the ECM
A
Complex network of secreted macromolecules in the extra cellular space
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
3
Q
What does too much ECM cause
A
Fibrosis
4
Q
What structure does ECM form when outside the cell
A
Fibres mesh
5
Q
How much of the body’s protein is collagen
A
25%
6
Q
What structure is formed by the 3 polypeptide chains in collagen
A
Triple helix
7
Q
What amino acids are in collagen
A
Glycine, proline, hydroxyproline
8
Q
What are the 2 main types of collagen
A
Fibrillar
Non fibrillary
9
Q
What structure does fibrillar collagen form
A
Organised banded fibrils
10
Q
What structures do non fibrillar collagen form
A
Microfibrils
Mesh like structures
11
Q
Purpose of fibrillar collagen
A
Tensile strength
12
Q
Purpose of non fibrillar collagen
A
Anchorage of cells
Filtration
13
Q
What causes osteogenesis imperfecta
A
Genetic defect in collagen type 1 synthesis - converts glycine to bulky aa preventing folding
14
Q
Nucleus purpose
A
Contains genome
Main site for dna/rna synthesis
15
Q
Composition of nuclear membrane
A
Lamin, emerin, and nuclear pores
16
Q
Nucleolus purpose
A
Makes ribosomal subunits from RNA & protein
17
Q
What is a laminopathy
A
Disease due to defects in genes coding nuclear lamina
18
Q
What does Hutchinson-Gilford cause
A
Premature aging
19
Q
RER purpose
A
Protein synthesis - translation of rna to proteins
Transport of proteins
Folding of proteins
20
Q
SER purpose
A
Carbohydrate and lipid synthesis
Ca2+ store
Contain enzymes that detoxify drugs
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
22
Q
Lysosomes purpose
A
Autolysis
Autophagy
23
Q
Peroxisomes purpose
A
Metabolism of fatty acids
Detoxification
24
Q
What is autolysis
A
Degrading of whole cell after death
25
What is autophagy
Degrading of cellular organelles
26
Where are peroxisomes most often found
Liver and kidney
27
Where do lysosomes originate
Golgi
28
Mitochondria purpose
Generate ATP
| control apoptosis
29
Components of cytoskeleton
Actin microfilaments
Intermediate filaments
Microtubules
30
Actin microfilament purpose
Cell movement
Cell shape
Organelle and vesicle transport
31
Intermediate filaments purpose
Tensile strength
32
Microtubule purpose
Pull apart cell in mitosis
| Track movement of organelles and vesicles
33
Connective tissue purpose
Connects
Supports
Binds
Separates tissues/organs
34
What is the ECM
Material outside the cell
35
What syntheses the ECM
Connective tissue cells
36
ECM purpose
```
Scaffolding
Cell migration
Proliferation
Survival
Shape
```
37
2 main classes of macromolecules in the ECM
Glycosaminoglycans
| Fibrous proteins
38
What is a glycosaminoglycan
Linear chain of 20-100s disaccharides usually linked to a protein to form a proteoglycan
39
What is produced when GAGs bind with water
Hydrated gels that fill space between cells and resist compressive forces
40
What do GAGs allow rapid diffusion of
Nutrients
Metabolites
Hormones
41
Collagen purpose
Tensile strength
42
Components of elastin
Tropoelastin
| Fibrillin
43
Fibronectin purpose
```
Binds cells and ECM
Matrix organisation
Guiding cell migration
Development
Wound healing
```
44
Which tissues is the basement membrane found between
Epithelial
| Connective
45
3 layers of basement membrane
Lamina Lucida
Lamina densa
Lamina fibroreticularis
46
Basement membrane purpose
```
Support
Anchoring
Protection
Cell movement
Cell signalling
```
47
Purpose of tight epithelial junctions
Prevent passage of molecules across epithelium
48
Purpose of adherens epithelial junction
Tether adjacent cells together
49
Purpose of desmosomal epithelial junctions
Resist mechanical stress
50
Purpose of gap junctions
Allow passage of small molecules between cells
51
Purpose of hernidesmosome epithelial junctions
Anchor epithelium to basal lamina
52
What are cilia
Motile structures
| Project from apical surface of some epithelia
53
What is the central core of a cilia called
Axoneme
54
Types of cilia
Pseudopodia
Lamellipodia
Filipodia
55
Pseudopodia purpose
Temporary projection
| Allow crawling
56
Lamellipodia purpose
Cell migration for wound healing - eg migration of fibroblasts
57
Filipodia purpose
Sense surrounding environment
| Direct fibroblasts in wound healing
58
Macromolecules in ECM
Collagen
Elastin
Glycoproteins
Proteoglycans
59
What’s is the ECM
3d gelatinous bed for cells to live in
60
How many families of collagen are there
19
61
How much of the total protein mass in the body is collagen
25%
62
Structure of collagen
Triple helix of 3 peptide chains
63
Amino acid code of collagen
Glycine-X-Y
64
Fibril forming collagen types
1 2
65
Network forming collagen types
4 6
66
Osteogenesis imperfetta cause
Defect in collagen type 1
| Single base change - glycine converted to more bulky acid
67
Osteogenesis imperfetta effects
```
Fragile bones
Thin skin
Abnormal teeth
Weak tendons
Blue looking sclera
```
68
Elastin purpose
Gives flexibility for blood vessels, lungs, ligaments, skin
69
Which contains more valine - collagen or elastin
Elastin
70
2 Abundant amino acids in elastin and collagen
Glycine
| Proline
71
Marfan syndrome cause
Fibrillin misfolded causing changes to ECM properties
72
What covers elastin fibres
Fibrillin
| Gives stability
73
Marfan syndrome symptoms
```
Tall stature
Long arms and legs
Spider fingers
Loose joints
Eye problems
```
74
Glycoproteins purpose
Cell surface receptors
| Strengthens, supports, and distributes ECM
75
Fibronectin purposes
Cell adhesion
Migration
Shape
Differentiation
76
Laminin purpose
Cell adhesion
Cell migration
Cytoskeleton organisation
77
What are the gel forming components of ECM
Proteoglycans
78
Proteoglycan composition
Peptide chains W covalently bound sugars and GAG extensions
79
Why do proteoglycans draw and hold water
Negative charge on GAG chains
80
What gives proteoglycans compressive strength
Holding water
81
How much of proteoglycans are carbohydrate
95%
82
Major cell adhesion classes
Integrins
Ig superfamily members
Cadherins
Selectins
83
Basic mechanism of cell migration
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
What happens to actin filaments to create a protrusive force
Polymerisation
85
What force pulls the cell body foreword in cell migration
Tension generated by actin
86
What can occur if cells migrate without ECM
Cell detachment and apoptosis
87
Steps of leukocyte extravasation
Chemo attraction
Rolling adhesion
Tight adhesion
Transmigration
88
What allows cancer cells to migrate and invade surrounding tissues
Cleavage of cell adhesions molecules
| Degrade ECM
89
What allows epithelial to mesenchymal metastasis
Breakdown of basement membrane
Loss of cell adhesion
Loss of apoptosis
90
Carbohydrate formula
C H2 O
91
Carbohydrate purpose
Energy source
Stabilising - glycoproteins
Ligands for immune system - bacterial lipopolysaccaride
92
Why are polysaccharides often poorly defined
Synthesised by enzymes without a template
93
What is a chiral centre
An asymmetric carbon with covalent bonds to 4 different groups
94
What’s an enantiomer
Pair of isomers that are mirror images
95
What are the 2 forms of a monosaccharide with 1 asymmetric carbon
D form
| L form
96
What is the d form of a monosaccharide
OH group attached to right of single asymmetric carbom
97
What is the L form of a monosaccharide
OH group attached to left of single asymmetric carbon
98
2 stereoisomers of ring glucose
ALPHA anomer - OH below ring
| BETA Anomer - OH above ring
99
What is a disaccharide
Monosaccharide combines by glycosidic bond
100
What is an oligosaccharide
3-10 joined monosaccharides
101
What is a sugar phosphate
Sugar with OH replaced by phosphate
102
What’s an amino sugar
Sugar with OH replaced by amine group
103
What’s a deoxy sugar
Sugar with O removed
104
What type of reaction forms a glycosidic bond
Dehydration
105
What enzymes catalyse glycosidic bond formation
Glycosl transferases
106
Primary locations of glycogen
Liver
| Muscles
107
Linkages in glycogen
Alpha 1,4 - main linkages
| Alpha 1,6 - side chains
108
Heparin purpose
Activates Serpin the main inhibitant of thrombin
109
What type of molecule is heparin
GAG
110
Where is heparin produced
Endothelial cells at site of damage
111
What type of molecule are blood antigens a b and o
Oligosaccharides
112
Which receptors recognise lipo polysaccharides
Molecular pattern recognition receptors
113
Enzyme cofactor
Non protein component
114
Prosthetic group
Non dissociable factor of enzyme
115
Apoenzyme
Lacks cofactor
| Inactive
116
Holoenzyme
With cofactor
| Active
117
Coenzyme
Dissociable non protein
118
Proenzyme/zymogen
Enzyme in inactive state
119
What process activates enzyme
Proteolytic conversion
120
What does the Michaelis Menten Equation do
Relates V0 to substrate concentration
121
What is VMax
Maximum enzymatic activity
122
Km equation
VMax/2
123
What does a high Km show
Weak substrate binding
124
Effect of increasing enzyme concentration
Linear Reaction rate increase
125
Effect of increasing substrate concentration
Increases rate until plateau
126
Isoenzyme
Different versions of same enzyme
| Catalyse same reaction in different tissues
127
Differences between isoenzymes
Different kinetic properties
| Produced by different genes
128
Diagnostic enzymes
Looking at amount of enzymes in blood to determine amount of damage in a tissue
129
Lipid uses
Compartmentalisation
Plasma membranes
Energy production
130
Enzyme for fatty acyl chain synthesis
Fatty acid synthase
131
Ends of fatty acid names
Methyl end - omega
| Carboxyl end - delta
132
Essential fatty acids
Omega 3
| Omega 6
133
Composition of triglycerides
Fatty acids + glycerol
134
Which molecule is takes longer to catabolise - triglyceride or glycogen
Triglycerides
135
What is the head of a phospholipid made of
Choline
Phosphate
Glycerol
136
Amphiphilicity meaning
Associate by themselves in water
137
Forms of phospholipid structures
Bilayer
Micelle
Liposome
138
Which phospholipids form micelles
Single fatty acid tail
139
Where are membrane lipid monolayers found
Fat droplets
140
Fluid mosaic model properties
```
Barrier
Compartmentalisation
Contain several lipid components
Leaflets usually asymmetric
Contain membrane proteins
```
141
Why are phospholipid membranes permeable
Leaflets are asymmetric
142
What does the head of cholesterol associate with
Head group of glycerphospholipids
143
Cholesterol composition
Hydrophilic head
Rigid steroid ring
Hydrophobic hydrocarbon tail
144
What does the tail of a cholesterol intercalated with
Acyl chains of glycerophospholipids
145
How does cholesterol impact membrane properties
Increased packing density
| Decreased permeability
146
Effect of cholesterol in sphingolipid membranes
Reduces packing density
| Increases fluidity
147
Lipid raft composition
Sphingomyelin
| Cholesterol
148
Lipid raft purpose
Limit lateral diffusion
| Permit clustering of proteins and lipids W shared function
149
Glycolipid composition
Sugar head group
| Ceramide
150
Glycolipid purpose
Protect cell from environment
Cell-cell communication
Localisation of lipid rafts
151
Cholesterol uses
Membranes
Precursor mol
Atherosclerosis
152
Which molecules is cholesterol a precursor for
Vitamin D
Bile salts
Sex hormones
Steroids
153
What do statins do
Decrease cholesterol synthesis
154
What do phytosterols do
Reduce cholesterol uptake
155
What is ATP
Adenosine triphosphate
156
How is ATP formed
Phosphorylation of ADP and AMP
157
How much of the coding section of the human genome codes for membrane proteins
30%
158
What proportion of drugs target membrane proteins
50%
159
Membrane protein purposes
```
Ion channels
Transporters
Anchors
Receptors
Enzymes
```
160
Types of membrane proteins
Single/multiple pass alpha helix proteins
| Rolled up beta sheet
161
Anchors of membrane proteins
Amphiphilic alpha helix
Lipid
Association by non covalent interaction W membrane protein
162
Lipid anchor composition
Long chain fatty acids
| Cholesterol
163
How are lipid anchors connected to proteins on cell surface
Covalent bonds
164
Lipid anchor use
Recruit/detach extracellular proteins from membrane
165
Integral membrane protein properties
Diffuse laterally
Can change conformation
Can be internalised
Can be recycled
166
What are membrane channels
Continuous pore through membrane
| Can be selective
167
What type of movement occurs in membrane channels
Bulk flow
168
Types of membrane transporters
Passive transporters
| Active transporters
169
How do passive transporters move solute
Solute binds -> conformational change -> solute exposed to other side of membrane
170
How do active transporters move solute
ATP binds -> conformational change -> exposes solute to other side of membrane
171
Do passive transporters transport up or down concentration gradients
Down
172
Do active transporters transport up or down concentration gradients
Up or down
173
Do channels transport up or down concentration gradients
Down
174
Coupled transport
Energy from movement of 1 ion down an electrochemical gradient provides energy for movement of another ion up electrochemical gradient
175
What type of transport is coupled transport
Secondary active transport
176
What is antiport coupled transport
Ions move in opposite directions
177
What is symport coupled transport
Both Ions move in same direction
178
Primary active transport
ATP hydrolysis causes uphill ion transport
179
Secondary active transport
Translocation of solute up concentration gradient due to movement of another solute down its transportation gradient
180
Types of secondary active transport
Symport
| Antiport
181
Which cells are bile salts moved across by specific receptors
Epithelial
182
Progressive familial intrahepatic cholestasis
Caused by defects in ABCB11 bile and other primary active transporters
Symptoms - jaundice, dark urine, appetite loss, enlarged liver, enlarged spleen, fatal
183
Cystic fibrosis transmembrane regulator purpose
Reduces viscosity of surface mucous
184
Cystic fibrosis transmembrane regulator action
Releases Cl- -> induces flow of Na+ and H2O in same direction
185
What is the cystic fibrosis transmembrane regulator
Cl- channel
186
Where are cystic fibrosis transmembrane regulators found
Plasma membrane of epithelial cells in lungs, intestine, and pancreas
187
What mutation causes cystic fibrosis
Autosomal recessive mutation to CFTR
188
How does the CF mutation effect the CFTR
Impair folding of channel
| Impair opening of channel
189
What causes CF symptoms
Increases mucous viscosity
190
CF impacts
Reduces epithelial cell function
Chronic infection
Inflammation
Fibrosis
191
CF treatments
Lumacraftor
| Ivacraftor
