Bioenergetics Flashcards
1
Q
Bioenergetics
A
Study of the transformation of energy in living organisms
2
Q
Metabolism
A
Sum of all chemical reactions in the body
3
Q
Catabolic
A
Breakdown/ degradation of molecules
4
Q
Examples catabolic
A
Proteolysis, lipolysis, glycolysis, glycogenolysis
5
Q
Anabolic
A
synthesis of new molecule
6
Q
Examples of anabolic
A
protein synthesis, lipogenesis, gluconeogenesis, glycogenesis
7
Q
How are enzymes pathways regulated?
A
• substrate supply - food & other compounds
• hormonal control - with on/off pathways & alter enzyme activity
• allosteric control - speed or slow enzyme activity
8
Q
ATP
A
- Fuels body
- used metabolic reactions
- all stores used up in 2-4 seconds
9
Q
How do we generate ATP?
A
• metabolic reactions rely on enzymes
• enzymes speedup reactions
• enzyme lower activation energy, initial energy required for the reaction to take place LG
10
Q
Lock & Ky
A
binding site has complementary shape to substrate(s)
11
Q
Induced fit models
A
contact between part of the binding site and the substrate induces a change in shape of the active site to bind to the substrate
12
Q
Enzyme activity can be affected by
A
• Substrate concentration
• pH
• Temperature
• Enzyme concentration
13
Q
Atom
A
Building block
14
Q
Element
A
pure substance which cannot be broken down into a simple substance by a chemical reaction
15
Q
Proton
A
+ charge
In nucleus
16
Q
Neutron
A
Neutral chase
in nucleus
17
Q
Electron
A
Negative charged
Outer shell
18
Q
Ion
A
atom becomes an ion when it is charged has been altered by losing or gaining an election
19
Q
Anion
A
Negative charged ion
20
Q
Cations
A
Positive charged ions
21
Q
Molecule
A
contains two or more atoms chemically joined together
22
Q
Compound
A
molecule composed of atoms from 2 or more different elements
23
Q
Ionic bonds
A
Ionic bonds
• giving an electron to another atom/receiving an electron from another atom
• depends on electronegativity
24
Q
Covalent bond
A
sharing electrons with another atom
• shared electrons between atoms fill shells
25
Order of strongest bond
Covalent > ionic > hydrogen
26
Redox reaction
If one molecule is oxidized, the other is reduced
When we generate large amounts of ATP, oxygen accepts electrons
27
Cytoplasm
• fluid in cell
• cytosol is fluid portion & energy generating reaction take place
28
Mitochondria
• organelle - site of respiration
• generates ATP
• Exercise increases the size of the mitochondria in the cell and also the number it contains
29
Cell membrane
The gatekeeper of the cell!
• Surrounds the whole cells
• Lipid bilayer – phospholipid, glycolipid, cholesterol
30
How does phosphocreatine system synthesise ATP?
- Breakdown of ATP to ADP activates creatine kinase
- enzyme catalyses reaction that adds pi group
- can resynthesises PCr quickly
31
Oxygen deficit
- Due to rapid need for energy
- energy comes from non-aerobic sources
32
PCr depletion
Only have finite stores hence why people take creatine supplements
33
Which metabolic pathways are activated during very high intensity exercise?
- Phosphocreatine
- anaerobic glycolysis
34
What is the PREDOMINANT pathway activated for a given task; these pathways NEVER work in isolation
Glycolysis
35
The metabolic pathways activated during intermittent exercise such as team sports
- Glycolysis
- krebs
- ETC
36
possible causes of fatigue during high-intensity during high intensity and intermittent exercise
stores of PCr limited
Increase in ADP inhibits
37
glycolysis
breakdown of glucose to produce energy
38
what hormones regulate glycolysis
insulin(activator) and glucagon(inhibitor)
39
What happens in anaerobic conditions
Build up in pyruvate increases lactic acid production
40
How much ATP does glycolysis produce
2 ATP (net)
41
How much NADH is produced in glycolysis
2
42
glycogenesis
formation of new glycogen
addition of glucose molecules together to form branches
43
glycogenolysis
breakdown of glycogen
break of glucose molecule
44
muscle stores of glycogen
2% by weight is glycogen
largest store in body
released as glucose-6-phosphate
45
liver stores of glycogen
10% by weight is glycogen
controls blood glucose levels
46
phosphorlysis
breaking up of glycogen molecule by adding phosphoric group
47
glycogen
can only be stored as branches of glucose polymer
having several branches means that they be broken down for glucose molecule
48
Krebs cycle
eight reactions in mitochondria
is an aerobic process
49
function of Krebs cycle
- oxidation pathway for carbs, lipids, proteins
-generate energy or intermediates for ETC
- provides several precursor molecules for other metabolic pathways
50
link reaction
converts pyruvate to acetyl coenzyme A
51
When is the Krebs cycle activated?
when oxygen is present
PDH activates it
52
what enzyme regulates links reaction
PDH
53
When is PDH activated
exercise
PDH phosphatase
54
when is PDH inhibited
PDH kinase
exercise
55
What is the starting molecule I Krebs cycle and what do you end up with
Starts- acetyl coenzyme A
Ends- Oxaloacetate
56
How much ATP produced in one cycle
1
57
NADH and FADH2 production in Krebs cycles
NADH-3
FADH2- 1
used in ETC
58
ETC
redox reaction
59
substrate level phosphorylation
generate ATP from both glycolysis and Krebs
60
oxidative phosphorylation
process of using high energy electron carries to generate ATP
61
how is ETC regulated
Hormonal or allosteric regulation absent
increase in NADH, ADP, Pi
62
How much ATP is produced in ETC
38
63
Where does ETC happen?
mitochondria
64
What are the roles of NADH and FADH2 in ETC?
electrons from coenzyme used for redox reaction
65
How does the protein complex on ETC function- where is the electron affinity greatest?
electrochemical gradient that leads to the creation of ATP
final electron acceptor
66
how is ETC regulated?
by the proton gradient between the inner membrane and the mitochondrial matrix
67
What types of exercise utilise the ETC?
low-intensity long endurance
68
characteristics of protein showing sigmoidal kinetics
- composed of 2 or more sub units
- subunits can exist in 2 different shapes
-first substate binds to site and increases affinity for 2nd substrate
69
Allosteric protein
binding of the negative effector to its ligand binding site prevents the enzyme's active site from becoming accessible to the substrate
70
Positive modulator
binding of the positive effector to its ligand binding site makes the enzyme's active site more accessible to the substrate
71
Gluconeogenesis
takes place in the liver
several substrate covered to glucose
72
When is Gluconeogenesis activated?
After 30-40 minutes of exercise when energy in the body is low because glucose hasn't been consumed
73
What tissue does Gluconeogenesis occur in?
Liver
74
How many irreversible reactions in glycolysis does gluconeogenesis have to overcome?
3 reaction
75
What substrates can be used in Gluconeogenesis?
Lactate, amino acid( glutamine & alanine) glycerol
76
pentose phosphate pathway
can be used to oxidase glucose
no ATP required
NADPH formed
77
What are the end products of pentose phosphate pathway?
phosphate and pentose
78
how is pentose phosphate pathway regulated?
redox state of the NADP couple
79
what is the free amino acid pool and what feeds into it?
- substrates of protein synthesis and the products of protein breakdown
- food and protein degradation
80
What is transamination?
enables all AA to be formed
transferring amine group to a keto acid to for AA
81
What is oxidative deamination
removing the amine group from a newly AA resulting is transamation
82
What is the urea cycle?
Any AA body doesn't used are removed in liver
degrading AA convert to ammonia
ammonia converted to urea in the liver
excreted through kidney
83
protein synthesis
formation of new proteins
84
protein degradation
breakdown of proteins into AA's
85
how much protein do we lose a day?
35-100g
86
Why is protein synthesis important for athletes ?
Muscle hypertrophy
help with resistance training
87
transcription
copy information encoded in a gene and duplicate it
88
translation
form the amino acids chain, rely on genetic code
89
codons
anti codons
tRNA
codons- RNA triplet codes
anti codons - complementary codon on tRNA
tRNA- carry amino acid
90
What are the 2 pathway for protein degradation?
lysosomal pathway and ubiquitin pathway
91
Saturated fatty acids
no carbon double bonds
straight, tightly packed
solid at room temp
92
unsaturated fatty acids
at least 1 carbon double bond
less tightly packed
liquid at room temp
93
mono and poly unsaturated
mono- one double bond
poly- more than one
94
lipoproteins
lipids surrounded by protein
after digestion used to transport lipids around the body to different tissues
95
lipolysis
breakdown of TAG into 3 fatty acids and 1 glycerol
each fatty acid broken down by different hormone
regulated by enzymes
96
What activates lipolysis during exercise?
adrenaline
97
What are the different hormones that break down fatty acids?
ATGL
HSL
MGL
98
When is ATP generation with lipids more than carbs?
all the time but takes longer
99
Beta-oxidation
carbon chains of fatty acid removed
obtain acetyl coenzyme A
occurs in mitochondria matrix
requires oxygen
100
What does malonyl CoA do and why is it revenant?
Is an enzyme that joins acyl and carnitine together
important regulator of CAT1 activity
101
Fatty acid synthesis
Acetyl CoA synthesised to form malonyl CoA
by Acetyl CoA breaks into OAA and citrates
citrate then breaks into OAA and CoA
CoA converted to maloynl CoA
102
What molecule is an important regulator of FA synthesis and FA degradation
ACC (Acetyl-CoA carboxylase
103
Under what circumstances would FA be promoted?
After eating due to an increase in fatty acids and increase in insulin released
104
how are triglycerides formed?
insulin promotes the uptake of fatty acids and glucose into adipose tissue
in adipose tissue glucose covered with glycerol and 3 fatty acids form ester bonds with glycerol
105
What are ketone bodies?
the fuel source for the brain when glucose low
used when high fatty acids are in use
e.g acetoacetic acid, 3-hydroxybutyric, acetone
106
When are ketone bodies increased in the body?
during hunger
reduced carb availability
starvation
prolonged exercise
107
hormones
the chemical messenger that regulates and coordinate activity within the body
108
Endocrine hormones
produced in one tissue
travel through circulation to reach the target cell
109
Paracrine hormones
produced in one cell
travels short distance to neighbouring target cells
110
Autocrine hormones
produced in cell which is also target cell
111
kinase
adds phosphate group to substrate
112
phosphatase
removes phosphate group from substrate
113
phosphorylase
transfer inorganic phosphate to substrate
114
hormonal cascade
stimulus- CNS- hypothamlus- anterior pituitary-specific target endocrine gland- metabolic effects
115
endocrine hormones differ in...
- solubility
- mechanism in action
- speed of action
116
steroid hormones
- transport in the blood bound to specific transport proteins
- binds to a receptor on the cell surface
- hormone enters the target cell
- binds to specific receptors within cell
- hormones receptor complex binds to specific regions of DNA
- influence transcription
117
Peptide and catecholamine hormones
- transport in free form in blood
- bind to specific cell surface receptors
- hormones doest enter cell
- second messenger model
118
glucagon
- released from alpha cells in pancreases
- signals lack of glucose
- main target is liver and adipose tissue
119
adrenaline
- synthesis in adrenal gland
- released in fight or flight response
provides source of energy to tissues in times of stress
120
G protein activation of adenylate cyclase
121
insulin
released from B cells of pancreas
signals high plasma glucose
main target in liver and skeletal muscles
122
tyrosine specific kinases
transmembrane receptor proteins
when ligand binds there is change in shape
initiates cascades
123
PIP3-PKB casade
124
What does the binding of glucagon cause?
induces a conformational change in the intracellular part of the receptor which results in interaction with other proteins in the membrane to effect enzyme activity
125
What is glucagon receptor
Gsa
126
What is adrenaline receptors and what do they imitate?
beta adrenergic - cAMP-PKA pathway
alpha adrenergic - phospholipase C-PKC pathway
127
what does adrenaline cause?
decrease blood flow to skin
contracts smooth muscle in skin
cause smooth muscle in lungs to relax
causes increase in heart rate
128
what is insulin receptor ?
tyrosine receptor kinase
129
what does insulin stimulate?
glycogenesis and lipogenesis
130
Adipose- carb metabolism
Energy production
Nadph production
Glycerol phosphate production
131
Adipose - lipid metabolism
Fatty acid synthesis
Acylylycerol synthesis
Lipolysis
Energy production
132
Muscle-carb metabolism
Glycogen synthesis/ degradation
Energy production
133
Muscle-lipid metabolism
Energy production
134
Muscle -protein metabolism
Protein synthesis/ degradation
Alanine production
135
Liver-carb metabolism
interconversion of monosaccharides
glycogen synthesis/degradtion
energy production
gluconeogenesis
pentose metabolsim
136
Liver- lipid metabolisim
fatty acid synthesis
energy production
ketone body formation
137
Liver- protein metabolism
transamination/ deamination
protein synthesis
urea cycle
138
what is the responsibility of insulin?
uptake and utilisation and storage of nutrients when concs of blood rise
e.g blood conc are not too high
139
What s the responsibility of glucagon?
raising blood glucose concentrations if they fall too low
cause other nutrietns to be used as a source of energy
main target is liver and adipose tissue
140
Insulin effect on the liver
stimulates glycogenesis
inhibits glycogenolysis
141
insulin effect on muscle
stimulate glucose uptake
stimulates glycogenesis
inhibits glycogenolysis
142
insulin effect on adipose
stimulates glucose uptake
stimulate lipogenesis
inhibits lipolysis
143
Glucagon &adrenaline effect onliver
stimulate glycogen degradation
inhibit glycogen synthesis
increase blood glucose
144
Glucagon &adrenaline effect on muscle
no glucagon receptor
stimulate glycgoen degradtion
inhibit glycogen synthesis
increase energy from glucose
145
Effect of insulin, glucagon, adrenaline on lipolysis in adipose
degradation of TAG each stage releases a fatty acid
glucagon and adrenaline activate ATGL and HSL
insulin inhibits ATGL and HSL
146
what does the iron in haem do?
cause the binding of oxygen
147
Myoglobin
single molecule
found in muscle
high affinity of oxygen
148
Haemoglobin
4 sub units- alpha and beta
can bind to 4 o2
binding curve is sigmoidal
149
What kinetics does myoglobin follow
Michaelis-Menton Kinetics of oxygen binding
150
Michaelis-Menton Kinetics of oxygen binding
high saturation with oxygen at high ppo2
relsease o2 as ppo2 falls
151
Haemoglobin affintity
High saturation of Hb with o2 at po2 of lung
low saturation of Hb at po2 of tissues so o2 is released at tissues
152
Allosteric effector for haemoglobin
BPG acts as a negative effector
so more oxygen is delivered to tissues
BPG conc increases when insufficient oxygen is getting to tissues
153
foetal haemoglobin
made of 4 units- alpha and gamma
binds to oxygen more strongly because of low affinity to BPG
as oxygen has to travel from maternal blood to foetal blood
154
Sarcomere
made up of thick and thin myofilaments
stretches between 2 Z discs
leads to different density under microscope
155
thin filaments
protein actin
polymerises to form long strands which then form a 2-standed helical filement
F actins capped to prevent elongation
troponin and tropomyosin- both attached
156
thick filemants
protein myosin
2 identical heavy and 4 light chains
head domains specialised to ATPases
157
muscle contraction initated by?
calcium
158
Stage 1 muscle contraction
ATP binds to myosin head causing myosin to lose affintiy for actiin
159
Stage 2 muscle contraction
myosin head folds around th ATP causong flexion on myosin molecule neck
ATP is hydrolyed to ADP & Pi
Head binds to new actin sub-unit
160
Stage 3 muscle contraction
Pi released from myosin caused conformational change
power stroke- allows myosin to return to original conformation
161
Stage 4 muscle contraction
ADP released to complete cycle
162
What transmitter is used to send signal from nerve to muscle?
acetylcholine
163
Where is calcium released from?
In response to nerve stimulus it is released from sarcoplasmic reticulum
164
How is calcium returned to sarcoplasmic reticulum?
Ca/ATPase
165
When do the Na+ released in muscle contraction?
when impulse flows down nerve
166
What happens once Na+enters axon?
depolarisation due to voltage-gated Ca2+ channels
Ca2+ flows into axon terminal releases acetylcholine
acetylcholine passes over synatpic cleft binds to receptors on muscle cells
167
What does acetylcholine bind to?
Nicotinic acetylcholine receptors
168
What happens once acetylcholine reaches muscle cell receptors?
Na+ and K+ enter depolarising the membrane
voltage gated Na+ channels all throughout till linked T-tubules
activates protein in t-tubule
169
What happens once Ca2+ is released from channels into sarcoplasm?
binds to TN-C
which initates muscle contraction
170
How many carbon atoms does a molecule of fructose contain?
6
171
Which transporter sits at the contraluminal side of the epithelial cells in the small intestines to assist in the absorption of carbohydrates?
Glut 4
172
Where does the digestion of lipids/fat start and what is the name of the enzyme?
Mouth; lipase
173
Without the presence of co-morbities, what does the body mass index (BMI) of a person need to be in order to qualify for bariatric surgery?
> 35
174
Is gastric band procedure a reversible procedure
Yes
175
In what bariatric surgery, what is the name of the surgery called where a large part of the stomach is bypassed by attaching the top of the stomach is attached to the small intestine?
Roux - en Y
176
Bypass surgery can increase the risk of malnutrition due to incomplete digestion and absorption. Malnutrition of which of the following nutrient is least likely to occur following bypass surgery?
Carbs
177
Insulin is secreted in which specific cells?
Beta-cells in pancreas
178
Insulin stimulates the activity of what enzyme at the site of adipose tissue to 1. take up triglycerides derived from food into the tissue and 2. inhibit the release of free fatty acids into the blood.
1. lipoprotein lipase 2. Hormone-sensitive lipase
179
How much is the energy potential that is stored in liver glycogen?
400 kcal
180
A patient has a blood glucose concetration at the end of the 2h OGTT of 10.9 mmol/L. In what category does this patient fall in terms of blood glucose homeostasis?
Impaired glucose tolerance
181
Glucagon triggers a(n) [1] in blood glucose concentrations. The [2] is the responsible organ for this effect. The condition in which this metabolic response occurs is in the [3]
1. Increase 2. Liver 3. Postabsorptive state
182
What is the main energy source that a 100-m sprint athlete uses during their sport?
ATP-PCr
183
Which of these best illustrates the definition of metabolism?
The sum of all reactions in the body
184
Your friend is deficient in iron, what micronutrient would you recommend they start to consume alongside iron-rich foods?
Vitamin C
185
What are the 4 most common elements in living things?
Carbon, oxygen, nitrogen, hydrogen
186
Which of these is an anabolic reaction?
Gluconeogenesis
187
How do enzymes speed up metabolic reactions?
Lower the activation energy
188
Positively charged ions are known as
Cations
189
The chemical formula of glucose is C6H12O6. How many molecules, elements and atoms does glucose have?
1 Molecule, 3 elements and 24 atoms
190
What are the 3 main ways that metabolism is regulated?
Substrate control
Hormonal control
Allosteric control
191
How much ATP do we have stored in the muscle in grams?
40-50
192
Name 3 mechanisms of fatigue during high intensity exercise
PCr depletion
Reactive oxygen species
Sodium-potassium dysfunction
193
When performing exercise involving, several, maximal, repeated sprints (e.g., hockey or basketball), lipids are the predominant compounds oxidized to provide energy? TRUE OR FALSE
False
194
What are the two main hormones that regulate glycolysis?
Insulin & glucagon
195
Which is the activator and which is the inhibitor out of insulin and glucagon?
activator- insulin
inhibitor- glucagon
196
Conversion of pyruvate to acetyl CoA:
is irreversible
197
What is glycogenolysis?
breakdown of glycogen
198
Complete the following: In glycolysis....
There are three irreversible reactions
199
Fill in: Pyruvate phosphatase [1] pyruvate dehydrogenase (PDH)
Activates
200
In the TCA cycle, 3 NADH molecules are produced: TRUE & FALSE
True
201
Where in the cell is the electron transport chain located?
Inner membrane of the mitochondria
202
Do we generate more energy from oxidative or substrate level phosphorylation?
oxidative
203
Does throwing a shot put derive energy from substrate level phosphorylation or oxidative phosphorylation?
Substrate
204
Which of the following is a catabolic reaction involving carbohydrate?
Glycogenolysis
205
In which part of the cell does the TCA cycle take place?
mitochondria
206
Which of these best describes covalent bond formation:
Electrons are shared between the atoms
207
Full PCr resynthesis occurs within 1-3 minutes. Is this statement true or false?
False
208
One full cycle of the TCA cycle generates:
1 ATP, 3 NADH, 1 FADH2
209
Which of these statements about the electron transport chain is NOT true:
A cellular increase in NAD+ and ATP encourages the electron flow through the chain
210
Gluconeogenesis refers to:
The formation of glucose from non-carbohydrate
211
During prolonged aerobic exercise, such as a marathon race what is malonyl CoA
Malonyl CoA will be inhibited
212
Describe the difference between transcription and translation and identify in which cell organelle the latter process takes place
Transcription is when information is copied from a gene to form mRNA. This mRNA is taken to the ribosomes, where translation takes places. Translation is the formation of new proteins
213
Name 3 biological functions of proteins:
Enzymes, hormones, structural
214
What do we call a chain of amino acids linked together?
protein
215
Transamination involves transferring an ....... to a ..... to form a new amino acid
a-amino group
keto acid
216
Aminotransferases are enzymes that:
Catalyse the reaction that produces new amino acids in transamination
217
Building bigger muscles (Hypertrophy) is dependent on the balance between protein ..... and protein
......
synthesis
breakdown
218
Protein translation takes place in which organelle of the cell?
ribosome
219
After a resistance exercise session, messenger-RNA is increased true or false?
true
220
What are the two main pathways for muscle protein degradation in the body?
Ubiquitin pathway
Correct answer
Lysomal pathway
221
Which one of the below codons is the most common ‘start codon’ for protein translation?
AUG
222
The rate of carbohydrate oxidation is highest at which of the following exercise intensities?
85% of VO2max
223
Name a sporting event in which ATP is derived mostly derived from the ATP-phosphocreatine (PCr) pathway?
100m sprint or shot putt
224
Ketone bodies can be used as an alternative fuel source when glucose levels are low. Which two of these molecules are ketone bodies?
3-hydroxybutyrate
Acetoacetate
225
Why is the ATP yield from a lipid molecule much greater than from a carbohydrate molecule?
contains more carbons
226
Identify 3 metabolic pathways associated with carbohydrate metabolism.
Glycolysis
Glycogenolysis
Glycogenesis
Gluconeogenesis
227
Name at least 3 functions of proteins in the body.
Form new muscle cells
Form synthetic pathways
Form plasma proteins, immune cells and haemoglobin
Form new enzymes
Form DNA
228
Identify 3 non-carbohydrate substrates that can be converted to glucose to produce ATP.
Alanine
Lactate
Glutamine
Glycerol
229
What are the two major pathways for protein degradation in the body and after what types of exercise are they likely to be highly active?
Lysomal pathway
Ubiquitin pathway
Exercise that causes muscle damage
230
If glucose is not provided from food or fluids, name 3 metabolic pathways that will become more activate to supply ATP?
Lipolysis
Gluconeogenesis
Pentose phosphate pathway
Glycogenolysis
231
What is the major metabolic pathway responsible for producing ATP during 1) a vertical jump, 2) a 400 m running race, and 3) a stage race in the Tour de France?
Vertical jump – ATP-PCR
400 race – anaerobic glycolysis (glycolysis will do)
Tour de France race – aerobic metabolism/oxidation/electron transport chain/oxidative phosphorylation/beta-oxidation.
232
Place the following metabolic pathways in order of which produces the most to least ATP molecules
Most - Electron transport chain
TCA cycle
Least - Pentose phosphate pathway
233
Does lipolysis increase or decrease during high intensity exercise? and what are the main causes of this change?
Lipolysis decreases as exercise intensity increases
In part due to redistribution of blood flow to the exercising muscles as opposed to adipose tissue
Transport of fatty acids into the mitochondria for oxidation is inhibited
Reduction in carnitine available to react with acyl CoA to be transported into the mitochondrial matrix
234
Name at least 3 ways in which metabolic pathways are controlled (upregulated/inhibited) in the body?
By hormones
By the supply of substrates
By allosteric activation
By the nervous system
235
What is the difference between an endocrine, paracrine and autocrine hormone?
Endocrine - produced in one tissue (gland) and travel through circulation to reach a target cell which has a receptor for that hormone
Paracrine hormones – produced in one cell and travel only a short distance to reach a neighbouring target cell which has a receptor for that hormone
Autocrine hormones – produced in a cell which is also the target cell for that hormone
236
Identify 2 oxygen carrying proteins and describe the main function in the body of at least one of these proteins
Myoglobin and haemoglobin
Myoglobin stores oxygen in the muscle
Haemoglobin transports oxygen from the lungs to the tissue
237
Describe the physiological explanation why an individual is not able to sprint a marathon.
Energy demand (rate of energy generated per time unit) is very high during sprinting
Rate of energy supply to meet demand has to come from PCr, which has limited storage, and glycolysis, which in absence of oxygen is converted to lactate and produces H+ in the reaction. A drop in pH is a cause of fatigue.
So, reaching task failure quickly. To prevent task failure, body has to use other (aerobic) systems but the rate of energy supply is much lower, meaning that running speed has to be lowered.
238
Which of the following metabolic processes is a catabolic reaction?Proteolysis
Glycogenesis
Lipogenesis
Protein synthesis
Proteolysis
239
Organic compounds contain carbon. Is this statement true or false?
true
240
Atoms are made up of neutrons, protons and which other component?
electrons
241
Adaptations to aerobic exercise incluldes:
An Increase in the number and size of mitochondria in the cell
242
Approximately how many grams of ATP do we have stored in the muscles?
40 – 50 grams
243
Which of the following sporting events require higher amounts of free fatty acids be metabolized for energy, also known as lipolysis?
An ultra-marathon running race
244
At which of the following exercise intensities do the highest absolute rates of fat oxidation occur?
60 – 70 % of VO2max
245
Which molecule acts as a shuttle by transporting free fatty acids into the mitochondrial matrix for fat oxidation?
Carnitine
246
Select the correct statement. Fatigue during prolonged duration, aerobic exercise, such as a marathon race, occurs because:
Depletion of glycogen stores
247
Which of the following statements regarding glycolysis is true?
It is the predominate energy pathway activated during a 400 m running race
248
Which of the following metabolic pathways generates the least number of net ATP molecules?
Gluconeogenesis
249
While running the London marathon running race, most of the ATP would be derived from which of the following energy pathways?
Oxidative phosphorylation
250
Which of these hormones INCREASES if you drink a carbohydrate sports drink during exercise? (1 Mark)
Insulin
251
Which of these metabolic pathways is activated during aerobic exercise?
Lipolysis
252
The intermediate, NADH, is converted to NAD+ in which type of chemical reaction?
Oxidation reaction
253
Which of the below is a key enzyme for glycolysis activation during high intensity exercise?
Phosphofructokinase
254
Select the correct answer from the options below: Glycolysis….
Has 10 stepwise reactions
255
The ‘link’ reaction in the tricarboxylic (TCA) cycle involves which two molecules? Select two.
Pyruvate
Acetyl CoA
256
Creatine kinase is an enzyme that catalyzes the reaction for which metabolic energy pathway?
PCr system
257
Lipolysis is:
The breakdown of triglycerides
258
What is the name of the enzyme that breaks down glycogen for oxidation during glycogenolysis?
Glycogen phosphorylase
259
What is the name of the enzyme that sits at the end of the electron transport chain and transports hydrogen ions into the mitochondria for oxidation?
ATP synthase
260
Which of the following statements about energy generation through the electron transport chain is correct?
At complex I, NADH is oxidized to NAD+
261
Transcription is the process by which mRNA is taken from the nucleus to form a new protein true or false
false
262
If a cell has a low energy status, such as when fasting, which of the following molecules will be accumulating?
ADP
263
Select the correct statement from the options below: Glycogenesis is….
The formation of glycogen for storage
264
The ‘link reaction’ is catalyzed by which enzyme?
Pyruvate dehydrogenase
265
The molecule malonyl CoA inhibits beta-oxidation. Is this statement true or false?
true
266
Select the correct answer from the options below: Transamination is ...
Is the process by which other amino acids are formed
267
Which of these best describes how paracrine hormones function?
They are produced in one cell and travel only a short distance to reach a neighboring target cell
268
Steroid proteins are transported in blood bound to specific transport proteins. Is this statement true or false?
true
269
In response to the nerve stimulus Ca2+ is released from which part of the cell to initiate muscle contraction?
Sarcoplasmic reticulum
270
Which of the following best describes the role of myoglobin?
Stores oxygen in the muscle
271
In muscle contraction, when Na+ enters the muscle through the acetylcholine receptor it [Blank] the membrane? Select the missing word from the options below.
Depolarises
272
Describe 3 steps that are part of the process of lipolysis
1. Triglycerides breaks down to diacylglycerol (catalysed by Adipose triglyceride lipase)
2. diacylglycerol breaks down to monoacylglycerol (catalysed by hormone sensitive lipase)
3. Monoacylglycerol breaks down to glycerol and fatty acid (catalysed by Monoacylglycerol lipase)
273
What is the net energy yield in gluconeogenesis, glycolysis and the TCA cycle
Gluconeogenesis = -6 ATP
TCA cycle = 1 ATP
Glycolysis = 2 ATP
274
When is gluconeogenesis activated, what are the substrates involved, and where does this process take place?
Activates after 30-45 mins of steady state exercise or when fasting/hungry/haven’t eaten for a while/glucose availability in the cell is low
Lactate, amino acids and glycerol can be used to generate glucose in gluconeogenesis
This process takes place in the liver
275
Describe the basic structure of skeletal muscle.
Made up of bundles of long, thin, multinucleated cells called muscle fibres (myofibres)
These are filled with cell cytoplasm called sarcoplasm
Sarcoplasm filled with tightly packed structures called myofibrils
Myofibrils consist of a large number of contractile units called sarcomeres
A sarcomere is composed of a number myofilaments of two types – light or thin (actin) and heavy or thick (myosin)
276
What are allosteric enzymes and how do they function in metabolism.
Allosteric enzymes bind to ligand binding sites other than the active site and in doing so alter the activity of the other ligand binding sites on the molecule, either deactivating or activating them, therefore altering their function and affinity.
Binding of effector influences affinity of the protein sub-units for the ligand
Positive effectors increase affinity
Negative effectors decrease affinity
Allosteric enzymes show cooperativity and sigmoidal kinetics
