22-28 lectures Flashcards
1
Q
what is the first law of thermodynamics?
A
the total energy within a system is constant.
energy cant b created nor destroyed.
energy can only be converted
2
Q
what complex compounds does food have?
A
lipids and proteins
3
Q
what does the breaking down of these complex compounds produce alot of?
A
heat
4
Q
what is anabolism?
A
uses ATP to do cellular work
turns ATP into ADP and Pi
this releases a large amount of energy that is used throughout the body
5
Q
what is catabolism?
A
the breaking of food and forming a high energy compound such as ATP that can be used through anabolism
6
Q
what are the 2 manners that the body can work in?
A
aerobic
anaerobic
7
Q
what pathway drives most of the other metabolic processes?
A
the gycolysis pathway
8
Q
what process is used in aerobic conditions?
A
oxidation phosphorylation
9
Q
what does the oxidation phosphorylation do?
A
helps produce lactic acid that can be used to oxidise to form ATP to used during aerobic tasks
10
Q
what compounds are oxidised in food to form ATP?
A
carbon compounds
11
Q
what does E intake =?
A
E expended + E stored
12
Q
what does E stored lead to?
A
weight gain
13
Q
how is weight gained?
A
if there is a higher energy intake than energy expended so it is stored
14
Q
how do we lose weight?
A
expend more energy than we are intaking so we have to use the energy that is stored
15
Q
what is leptin?
A
a signal peptide
16
Q
what does leptin do?
A
sends a signal to the brain when there is enough energy that is being stored so we can be full
17
Q
what is J?
A
joule
18
Q
what are joules?
A
energy required to push against 1 newton of force for 1 meter
19
Q
what does 1 cal equal?
A
4.184J
20
Q
what does 1 Cal equal?
A
4.184kJ
21
Q
how do we measure the energy is food?
A
a calorimetry
22
Q
what does a calorimetry do?
A
the combustion process in a controlled enviroment to see the released of energy from the food through experiments
23
Q
what varies the consumption of oxygen?
A
relation to the intensity of the activity and can be used to determine the amount of energy intake that is required
24
Q
what is indirect calorimetry?
A
the respiratory exchange ratio
25
what does the indirect calorimetry tell us?
the carbondioxide produced over the oxygen consumed which can tell us the metabolic rate of an individual
26
what is the RER?
the respiratory exchange ratio
27
what increases basal metabolism?
athletic training
late stage pregnancy
fever
drugs such as caffiene
hyperthyroidism
28
what decreases basal metabolism?
malnutrition
sleep
drugs such as B-blockers
hypothyroidism
29
what are the main macronutrients that contribute to energy production?
carbohydrates
proteins
fats
30
what does carbohydrate breakdown into?
monosaccarides
31
what does proteins breakdown into?
amino acids
32
what does nucleic acids breakdown into?
nucleotides
33
what does fats breakdown into?
FFAs, MAG, cholesterol
34
what is the gastrointestinal tract sometimes reffered to as?
elemertary tract
35
what body parts have digestive purposes to contribute to energy production?
the liver, pancreas, and the gallbladder
36
what does saliva do?
contains mucus and amylase which starts the digestion of carbhydrates
37
what happens with pepsin?
secreted into the stomach as pepsinogen as the inactive form
38
what enzymes are secreted by the pancreas?
digestive enzymes such as amylase, lipase and several proteases
39
what does the liver synthesis?
bile salts/acid which was important for fat digestion
40
what are the 2 main phases of digestion?
hydrolysis and absorbtion
41
what hydrolysises proteins?
proteases
42
what is amylopectin?
the main component of plant starch and is a large complex structure
need a specific enzyme to hydrolyse these
43
what is maltose?
present in honey
simple structure of 2 glucose monosaccarides to make a disaccaride
44
what are cellobiase and lactose .... pf eachother?
sterioisomers
45
what is cellobiase?
a repeating disaccharide unit in cellulose and is the type of arrangment of functional groups will make it look like there is a different yet it has the same chemical compound
46
what is sucrose?
a disaccaride made up of the monosaccarides fructose and glucose
47
what can fructose cause?
craving for calories to consume more and more materials
48
what does starch from plants consist of?
amylase and amylopectin
49
what is amylase?
a linear polymer of alpha (1-4) linked glucose units
50
where are the 1-4 glycogenic bonds located?
between the 1 and 4 carbon groups
51
what is amylopectin?
a branched polymer of alpha (1-4) and alpha (1-6) linked glucose units
52
what happens in starch digestion?
when enzyme amylase hydrolysises the glycocidic bonds into fragments
the fragments are hydrolysised further until we get small enough to be absorbed into the body
53
what happens in the final digestion of starch?
happens at the brus border where the intestinal epithelial cells produce maltose
54
how many enzymes are required to hydrolysise the different disaccarides an why are they different?
2
because of where the linkage and the arrangments of the disaccarides
55
what is Kwashiorkor?
the presentation where diets can be difficient in proteins which has a lack of amino acids and can have a range of effects on the human body
56
what does the lack of proteins in the body do?
causes an osmotic imbalance in the gastrointestinal system causing the abdomen to swell due to the retention of water
also leads to the level of albumin being low
57
are proteases active or inactive?
inactive
58
what activates the proteases?
cleavage of peptides from there structure
59
what differs the structure of the amino acids?
the side chains
60
what are the 2 stages of protien digestion that occurs?
endopeptidase
exopeptidase
61
what does endopeptidase do?
attacks the peptide bonds within the protein polymer
62
what does exopeptidase do?
attacks the peptide bonds at the end of protein polymer
63
what are the 2 ways that pepsinogen?
-introduced to acid
-pepsin can hydrolysis the unactive pepsinogen to fold and become active
64
what is the pathway to activate proteases?
additional proteases hydrolyses tripsinogen which can hydrolyses chymotrysinogen and procarboxypeptidase to all become active in the pancreas
65
what is TAG?
triacylglycerol
66
what is triacylglycerol?
a cholesterol ester with high amoiunts of fatty acids that promotes the shape of the molecule
67
what are lipid fats?
hydrophobic
so they dont mix with liquids
68
what is used to help digest lipid fats?
bile salts from cholesterol which are stored in the gall bladder
69
what properties does bile salts have?
hydrophobis and hydrophillic which are used to breakdown lipid molecules
70
what is bilerubin?
a breakdown product of haem and gives bile its colour
71
what does bile contain?
water, bile acids, electrolytes, phospholipids, cholesterol, bile pigments
72
where is bile salts synthesized and stored?
it is synthesized in the liver and stored in the gall bladder
73
what do polypeptide hormones create?
a signal t help stimulate the food that has been intaken and is being digested
74
what is lipid enzymes used for?
the breakdown of lipid components of the food that has been taken up
75
what is the pancreatic lipase enzyme?
used to bind to the lipase and enhances the activate to hydrolysis the monoacylglycerol
76
what is the hydrolysis of the monoacylglycerol important for?
getting fats into the body so it can be utilized
77
what do bile salts do?
arrange to form michelles type structures that stabilize the triacylglycerol and are then absorbed across the membrane
78
what is absorbance dependant on?
efficiency of the GI tract
79
what maximises the surface of the GI tract?
the villi and microvilli
80
what does fat malabsorbtion lead to?
excess of fat and fat soluable vitamins in faeces
this causes a condition that interfers with bile or pancreatic lipase secretions
81
what is xenical?
a potent inhibitor of pancreatic lipase
its a mode of action to make covalent interaction with the enzyme and blocks the function of the lipase
82
what structures does fat go into after it has crossed the plasma membrane?
chylomicrons
83
what do chylomicrons do?
move fat into the lymph and overall getting it into the blood stream
84
what are lipoproteins?
complexes that have evolved to stabilize lipids for transporting in the blood to tissues
85
what are proteins that have many functions?
apoproteins
86
what are some of the functions of apoproteins?
structural assembly, ligands for cell surface receptors and enzyme cofactors for lipoprotein lipase
87
what are the 4 main classes of lipoproteins?
chylomicrons, very low density, low density, high density
88
what is VLDL?
very low density lipoproteins
89
what is LDL?
low density lipoproteins
90
what is HDL?
high density lipoproteins
91
what is needed to make a chemical sequence for TAG synthesis?
co-enzyme A to activate them so that the metabolism can be achieved
92
what is CoA synthesised from?
pantothenate, ATP and cystine
93
what is CoA?
co-enzyme A
94
what is the lowest lipoprotein?
chylo because they have alot of TAG compared to the amount of protein
95
how can we tell the lipoprotein composition?
in clinical plasma samples to be analysed by native gel electrophoresis
96
what do labs measure in lipoproteins?
total cholesterol, HDL, triglycerides-used to identify dyslipidemia
97
how can we estimate the LDL?
total cholesterol - HDL - triglycerides
98
what are the 2 major lipid transport pathways?
exogenous
endogenous
99
what is the exogenous pathway?
shipping around the body
100
what is the endogenous pathway
dealing with lipid molecules such as storing in tissues for energy production functions
101
where do chylomicrons return to?
the liver to be used again
102
what is the liver important for?
lipid transformation and the process of storing and using fats
103
where is the lipoprotein lipase found?
endothelial surface of capillaries
104
what does lipoprotein lipase do?
hydrolysises TAG in lipoproteins to 2-monoacylglycerol and fatty acids
105
what activates lipoprotein lipase?
apoCII
106
what can defects in either apoCII or lipoprotein lipase lead to?
elevated levels of chylomicrons and plasma triacylglycerol
107
what is FH?
familial hypercholesterolemia
108
what does FH do?
common form of hyperlipidemia which leads to premature athersclerosis
109
what causes FH?
a defect in LDL receptor genes
110
is LDL good or bad?
bad
111
is HDL good or bad?
good
112
how can we treat FH?
statins to lower LDL and increase HDL
113
why is LDL considered the bad cholesterol?
as it has large levels of cholesterol that usually has secondary effects amoung the host that consumed it
114
why can sugar diffuse across cell membranes?
they are highly water soluable
115
what does sugar require to diffuse across the cell membrane?
a specific transporter protein anchored in the membrane that form pores in the membrane
116
what are the 2 types of transporters?
active and facilitated
117
what are active transporters?
moving against the concentration gradient that needs energy from ATP to do so
118
what is facilitated transporters?
a passage down the concentrtion gradient
119
what is GLUT 2?
a facilitated transporter found in the liver, pancreas, kidney and intestinal epithelial
120
what is SGLT 1?
a secondary active transporter and is found in intestinal epithelium
121
how does SGLT1 and GLUT 2 work for glucose transport?
used to move glucose into the epithelial cell in a glucose/Na+ co-transporter and GLUT 2 is used to move glucose out of a cell
122
what is SGLT 1 used for?
move both Na+ and glucose into the cell increasing the concentration of both within the cell
123
what pumps Na+ out of the epithelial call to maintain a low Na+ in the cell?
Na+/K+ ATPase
124
what does it mean for SGLT 1 is Na+ is needed to move glucose into the cell?
SGLT 1 is an active transporter
125
how many K+ are pumped into a cell for every 3Na+ pumper out via ATPase?
2
126
what causes a conformational change to enable the transport of the Na+ followed by K+?
hydrolysis of ATP and phosphorylation of the ATPase transporter
127
where does GLUT 4 transport to?
glucose into the muscles and adipose tissue
128
where does GLUT 3 transport to?
glucose to the brain
129
what is the PepT1 membrane transporter?
absorbs di- and tri- peptides in the small intestine by co-transport with H+ ions
130
what does cytoplasmic peptidase do?
further digests the di and tri peptides into individual amino acids
131
where do amino acids go once absorbed into the epithelial cell?
exported into the blood circulation
132
what does transepithelial transport?
absorbed amino acids into the small intestine from the lumen
133
what is transepithelial?
semi-specific Na+ dependant transport system
134
what does Na+ dependant transporters transport?
both Na+ and amino acids
135
what is lactose intolerant?
a lack of lactase
136
what can a lack of lactase do?
causes bloating, flatulence and diarrheoa due to fermetation of lactose by intestinal bacteria
137
what does pancreatitis lead to?
inappropriate activation of zymogens resulting in self digestion
138
what are stomach ulcers?
due to the breakdown of the mucosa which normally protects against protease action
139
what does cystic fibrosis cause?
malabsorption
140
what does coeliac disease lead to?
malabsorption
141
what happens in cystic fibrosis?
it causes mucous secretions which block the pancreatic duct and secretion of pancreatic enzymes
142
how can we avoid cystic fibrosis?
taking supplements containing pancreatic enzymes such as pancreatin which is a pancreas extract
143
what is coeliac disease?
of the small intestine
body reacts to gluten protien present in wheat
antibodies react with transglutaminase and villi are flattened so nutrient arent absorbed
144
what can coeliac disease lead to?
gastrointestinal syptoms
145
what does intestinal endonuclease enzymes do?
hydrolyses the phosphodiester bonds linking individual nucleotides
146
what does intestinal exonuclease enzymes do?
release individual nucleotides
147
what happens to individual nucleotides?
they are absorbed via nucleotide transporters
148
what links individual nucleotides together?
phosphodiester bonds in nucleic acid polymers
149
what is beriberi?
thymon deficiency
150
what causes beriberi?
a lack of vitamins in their diets for example thiamine (vitamin B1) deficiency
151
what can anti-inhibitors of thiamine do?
either destroy thiamine in the gut or inhibit the receptors and absorbtion
152
what are vitamins and minerals effective to?
co-factors and coenzymes
153
what are vitamins?
accessory substances
from food and are needed in the body
they are organic substances which means that they are made by plants and animals
154
why are vitamins hard to test in the lab?
they are very fragile and will breakdown in heat or UV
155
what are minerals?
inorganic elements that come from soil and water and are absorbed by plants or eaten by animals
156
what is the primary differece between organic and inorganic compounds?
organic compounds always contain carbon while inorganic compounds do not contain carbon
157
can we make vitamins in our bodies?
no
158
what are the 2 ways that vitamins can be?
water-soluable
fat-soluable
159
what is the only vitamin we can make ourselves?
vitamin D through our skin from UV rays
160
what are water-soluable vitamins?
absorbed by portal blood and is generally excreted in the urine when plasma levels exceed renal threshold
not stored in large quantities in body tissues
161
what are fat-soluable vitamins?
enter lymphatic system as part of a chylomicron
they are stored in larger quantites in the body tissue
they can from food with fats in them
they are digested like fats through michelles and absorbed in the small intestine and later absorbed into the blood
162
what tissue stores the fat-soluable vitamins and why?
adipose tissue
because they dont excrete as easy as water soluable vitamins
163
which type of vitamins have a higher chance to lead to toxicity?
fat-soluable vitamins
164
what is vitamin C?
an antioxidant
165
how much of our body weight is mineral?
4%
166
what are mineral responsible for?
structual functions involving skeleton and soft tissues and regulatiing functions including neuromuscular transmission, blood clotting, oxygen transport and enzymatic activity
167
what are the 2 classes of minerals?
major and minor
168
what are major minerals?
we eat alot of major minerals
found in a great abundance in the body
169
how many major minerals does an adult need?
100mg/d
170
what can a lack of calcium lead to?
rickets
171
what is rickets?
lack of calcium
softening of the bones in kids only
172
what is osteoporosis?
the demineralization within the bones within the body
173
how many minor minerals do we have in our body?
100 milligrams
174
what do enzymes do?
make reactions works faster as they lower the activation energy
175
how do enzymes lower the activation energy?
binding to the substrate at a location on the enzyme called the active site
176
what do enzymes need if they cant catabolise a reaction by themselves?
they need the help of co-enzymes and co-factors to function properly
177
what are co-enzymes?
organic carrier molecules
they are involved in transferring things from one molecule to another
178
where are many vitamins derrived from?
vitamins
179
what are co-factors?
the general term for small molecules required for the activity of their associated enzyme
these dont transfer things but are more likely to stabilize or are used to convert substrate into products
180
what does DNA polymerase enzymes do?
helping with DNA synthesis
uses positive charge Mg ion as a co factor to stabilize the negative charge
181
why are DNA very negatively charged?
due to the negatively charged phosphate groups
182
what is thiamine a coenzyme for?
forming thiamine pyrophosphate in a variety of metabolic processes
plays a role in ATP production and nucleic acid which is used in DNA and RNA synthesis
183
what is TPP?
thiamine pyrophosphate
184
what can a lack of thiamine lead to?
negative impacts on the energy production and nutrient metabolism which can be life threatening
185
what does thiamine consist of?
an aminopyrimidine ring linked to a thiazole ring by a methylene bridge
186
what turns thiamine into TPP?
2 phosphate groups added an
187
where can thiamine be found in?
seeds, beans, pork, spinach, cornflour and breakfast cereals
188
what can cause thiamine deficicnecy?
insufficient intake in the diet can be caused by low absorbtion or high excretion rates than normal which can be due to alcohol dependance, HIV/AIDS, medication
189
who is most likely to have thiamine deficiency?
alcoholics
190
what are some symptoms of thiamine deficiency?
weight loss, anorexia, confusion, muscle weakness and cardiovascular symptoms
191
what is ATF?
anti-thiamine factors
192
what does ATF do to thiamine?
reacts with thiamine to form an oxidised, inactive product
193
what is the currency of the cell?
ATP
194
what makes ATP the main currency of energy?
the high energy bonds as the phosphate is removed and the energy is released
195
where does the energy to bond the phosphates back onto the ADP?
the oxidation of fats and glucose makes a small amount of energy
196
what is delta G?
Gibbs free energy
197
what can the gibbs free energy tell us?
the relative abundance of the substrates and products, and the enrgy stored in the chemical bonds of the products and substrates
198
what happens if delta G is less than 0 for A to B?
reaction is spontaneous, energy is released, it is energetically favouable
199
what happens if delta G is equal to 0 for A to B?
reaction is at equalibrium, and there is no change in energy
200
what happens is delta G is greater than 0 for A to B?
reaction is not spontaneous, energy is released, it is energetically unfavourable
201
what is the favourable reaction of ATP?
the breaking of the phosphate group and releasoing energy
202
what is the delta g of the ATP hydrolysis?
-30kJ/mol
203
what i the delta G of ATP synthesis?
30kJ/mol
204
what is delta G o?
delta G under standard conditions at pH of 7
205
what does 1 mol of protons pH?
pH 0
206
what is it if the delta G is negative after adding 2 delta Gs from two reactions together?
the reaction is energetically favourable and the coupled reaction can happen
207
what is it if the delta G is positive after adding 2 delta Gs from two reactions together?
the reaction is energetically unfavourable and the coupled reaction will not work
208
what happens in redox reactions?
one molecule is oxidised and loses an electron and the other is reduced as it accepts the electron from the other
209
what is the reducing reagent in a redox reaction?
the molecule that is oxidised
210
what is the oxidising agent of a redox reaction?
the molecule that is reduced
211
what do biological redox reactions often involve?
the transfer of hydrogen atoms
212
in the oxidation of sugar, where is energy captured to synthesis ATP?
at each little step of the reaction process
213
what are the enzyemes that catalyse redox reactions in biologiocal conditions?
dehydrogenases
214
what helps the energy released in feul molecules?
oxidation reactions
215
what is NAD?
nicotinamide adenine dinucleotide
216
what is NAD derrived from?
niacin (vitamin B3)
217
what does NAD do?
its a co-enzyme that accepts a hydrogen and an electron in metabolic pathways
it undergoes a 2-electron reduction reaction
218
what does NAD pick up in a 2-electron reaction?
a proton and an electron to become NADH
219
what is FAD?
flavin adenine dinucleotide
220
what is FAD derrived from?
riboflavin (vitamin B2)
221
what does FAD do?
accepts 2 hydrogens in pathways
222
what are flavin coenzymes doing?
tightly bound to the proteins with which they interact
223
what is CoA derrived from?
pantothenic acid (vitamin B5)
224
what does CoA carry?
no electrons but they carry aycl groups (chains of carbon)
225
what are the 2 forms of CoA?
free co-enzyme
acyl group attached
226
what is the process that oxidises glucose?
glycolysis
227
where does gylcoilysis occur?
in the cytoplasm within eukaryotes, everything else happens in the mitochondria
228
what cells can use glucose as energy?
every cell
229
what is an essential fuel for RBCs?
glucose
230
why does RBCs rely on glucose?
because they dont have mitochondria so they dont have any other pathways
but they do have cytoplasm so they are able to oxidise glycolysis
231
why is glucose the perferred feul of the brain?
as it is high energy requirements as the brain has to fire alot of action potentials
glucose can get across the blood brain barrier and fatty acids cannot
232
why is glucoswe the favoured feul of the eyes?
as there is not many blood vessels in the eye so it doesnt interfer with light that enters the eye so the eye has mainly cytoplasm
233
why does red muscle cells use fats?
as it has alot of mitochondria
234
what are red muscle good for and why?
aerobic conditions as the mitochondria need oxygen
235
why does white muscle cells use glucose?
no mitochondria so needs no oxygen is needed
236
what is white muscle good for and why?
anaerobic conditions as they dont have mitochondria so no oxygen is needed
237
what happens in glycolysois?
splitting of glucose
the 6 carbon glucose goes to 2 molecules of 3 carbon pyruvate
238
where is energy conserved in the first stages of glycolysis?
in ATP and NADH
239
what are the 2 phases of glycolysis?
the investment phase
energy payoff phase
240
what happens in the investment phase of glycolysis?
we have to put a little energy into get a molecule into the right form, this activates our glucose
241
what happens in the energy payoff phase of glycolysis?
when we produce 4 ATP and the NAD+ goes to 2 NADH as the glucose becomes pyruvate molecules
242
what catalyses the gluose bonding to the phosphate?
hexokinase
243
what does hexokinase do?
can couple the reaction to the hydrolysis of the ATP and we add the delta G and then the reaction becomes energetically favourable so the reaction can occur
244
what is the delta go of the hexokinase reaction in glycolysis?
-16kJ/mol
245
what is the second step of glucose activation?
the rearrangment which is a unfavouarbale reaction but the reaction still happens as the opathway is energetically favourable
246
what is the delta G in the second step of glucose activation?
+1.6kJ/mol
247
what does G-6-P go to?
F-6-P
248
what does phosphofructose do?
uses ATP hydrolysis to turn F-6-P into FBP
249
what is the delta G of the phosphofructose reation?
-14kJ/mol
250
what does aldolase catalysises?
the splitting reaction as it cleaves our molecule and splits it from 1 six carbon and 2 phophates into 2 three carbons and 1 phosphate molecules
251
what are the 2 products made in the splitting reaction?
DHAP and G-3-P
G-3-P is used so since DHAP isnt used it becomes a G-3-P to be used
252
what is the ATP synthesis equation?
ADP + Pi
253
what is SLP?
substrate level phosphorylation
254
what does SLP do?
its the direct use of energy from a substrate molecule to drive the synthesis of ATP
255
how do we release the energy to drive the SLP?
the clevage of a high energy phosphate ester bond on a substrate so we use ATP
256
what does oxidation of G-3-P do?
NAD+ is reduced to NADH and during this a phosphate is then added onto the substrae so now there is 2 high level bonds onto the substrate
257
what does G-3-P go to?
BPG
258
what happens to the phosphate from the BPG?
chopped off and then added back onto the ATP molecule
this cleavage of the phosphate group releases energy so its energetically favourable
259
what is the delta G when we chop the phosphate off the BPG?
-49.3kJ/mol
260
what does BPG go to?
3PG
261
what is arsenic poisoning?
when there is arsenic in the body and it subsitutes for a phosphate and prevents the reaction from capturing the energy that is released
so there is no net gain of ATP in this glycolysis
262
what is 3PG rearranged into and why?
2PG and the PEP
to get the moecule into a form that enables the following reactions
263
what is PEP?
a phosphate group cleaved off by pyruvate kinase to make pyruvate
264
what is the delta G of the coupled reaction of 3PG?
-31.9kJ/mol
265
what is the overall delta G of the turning glucose into pyruvate?
-73.3kJ/mol so the reaction is energetically favourable
266
what is pyruvate converted into to go into the citric cycle?
caetyl-CoA
267
where does pyruvate getting converted into acetyl-CoA occur?
in the mitochondria matrix
268
what happens to the energy in the pyruvate to acetyl-CoA reaction?
NAD+ is reduced to NADH which releases energy and this energy adds CoA to the molecule to then be fed into the citric acid cycle
269
what does the citric acid cycle require?
oxygen because its an aerobic oxidation
270
what does fates of pyruvate in anaerobic glycolysis oxidise?
NADH to NAD+ and no ATP is getting made to turn pyruvate into lactate
271
what does lactate do to muscles?
makes them feel fatigued
272
what does the lactate formation allow?
the regeneration of NAD+
273
what does lactate dehydrogenase reaction oxidise?
NADH
