Lectures 1-5 Flashcards
Definition of bioenergetics
The study of the transformation of energy in living organisms
What is metabolism? (Definition)
The sum of all chemical reactions in the body
What are the two types of metabolic reaction?
Catabolic and anabolic
What is a catabolic reaction?
The breakdown/degradation of molecules
When molecules are broken down (e.g., carbs/fat and protein) they release energy
What is an anabolic reaction?
Synthesis of new molecules
The energy released from anabolic reactions can be used to build new molecules
Examples of catabolic pathways
Proteolysis
Lipolysis
Glycolysis
Glycogenolysis
Anything ending in lysis
Examples of anabolic pathways
Protein synthesis
Lipogenesis
Gluconeogenesis
Glycogenesis
Anything really ending in genesis/sis
How are catabolic and anabolic pathways regulated?
Substrate supply - food and other compounds
Hormonal control - switch on or turn off pathways and alter enzyme activity
Allosteric control - speed or slow enzyme activity
What is our body fueled by?
Adenosine Triphosphate (ATP)
What is ATP?
The energy currency of the cell
ATP is what we use to fuel all our metabolic reactions
What is the link between food and ATP?
The food we consume is digested and used to generate ATP
Look at structure of ATP
Lecture 1, slide 19
How do we generate ATP?
Look at on recap lecture 1, slide 21
Look at enzyme substrate thing
Recap, lecture 1, slide 22
When an enzyme is attached to the substrate what does it form?
It forms a complex
What does the enzyme catalyse the formation of after the enzyme has attached to the substrate and formed a complex?
The formation of a product
Interaction and specificity with enzymes can be explained in two ways, what are they?
Lock and key
Induced fit
What is lock and key (enzyme interaction and specificity)
The binding site has a complementary shape to the substrate
What is induced fit (enzyme interaction and specificity)
Contact between part of the binding site and the substrate induces a change in the shape of the active site to bind to the substrate
Look at examples of lock and key and induced fit
Lecture 1, slide 24
What is allosteric control? (Listen on recap)
Refers to a type of enzyme regulation involving the binding of a non-substrate molecule, known as the allosteric effector, at locations on the enzyme other than the active site
What is allosteric inhibition? (Listen on recap) (lecture 1, slide 27)
Where the allosteric effector binds to the allosteric site, causing the enzymes active site to alter, meaning that the enzyme cannot bind to the substrate
What is allosteric activation? (Listen on recap) (lecture 1, slide 27)
Where the allosteric effector binds to the allosteric site, causing the enzymes active site to change so that the enzyme is able to bind to the substrate
What is a good example of one of the most important allosteric regulatory effects?
When we go from a stand still to a sprint within milliseconds, (we require a huge amount of energy in a short period of time)
The active site enzymes are not quick enough to provide the energy, so the allosteric enzymes take charge
How is enzyme activity affected?
Substrate Concentration
pH
Enzyme concentration
Temperature
How does substrate concentration impact enzyme activity?
Increases and augments reaction rate up to a point
How does pH impact enzyme activity?
Can change active site structure and alter affinity for substances
How does enzyme concentration impact enzyme activity?
Increase can augment reaction rate because more active binding sites available (McLaren & Morton, 2011)
How does temperature impact enzyme activity?
Increase augments enzyme activity until ~37.5 degrees
How much ATP is stored in the muscle tissue?
40-50 grams
How quickly is all of the ATP that is stored in the muscles used up?
2-4 seconds
What are the anaerobic energy sources that can be used to resynthesise ATP?
Lecture 1, slide 31
ATP
Phosphocreatine
(PCr) (check if this is just phosphocreatine)
Anaerobic glycolysis
What are the aerobic energy sources that can be used to resynthesise ATP?
Aerobic glycolysis
Carbohydrate oxidation
Fat oxidation
Protein breakdown
Look at what you really need to know slide
Lecture 1, slide 32
What is an atom?
Building blocks of all things (matter)
What is an element?
A pure substance which cannot be broken down into a simpler substance by a chemical reaction. It contains only one type of atom
How many elements are there on the periodic table?
Over 100 different elements
96% of body mass contains 4 elements, what are they?
Oxygen (65%)
Carbon (18%)
Hydrogen (10%)
Nitrogen (3%)
What do all organic compounds contain?
Carbon and hydrogen
Are protons positively or negatively charged?
Positive
Are electrons positively or negatively charged?
Negative
What is in the centre of an atom?
Protons and neutrons
Where are the electrons in relation to an atom?
They are around the nucleus
The electrons in the “cloud” are not random but are organised into a series of layers called what?
Shells and sub-shells
When is an atom most stable?
When it’s outermost shell or sub-shell is completely full of electrons
Electrons are shared in one of two ways, what are they?
Sharing electrons
Giving an electron
In terms of sharing electrons, how does “sharing electrons” work?
Where the atom combines with a new atom, leading to the formation of a covalent bond
In terms of sharing electrons how does “giving an electron” work?
The atom gives an electron to another atom / receives an electron from another atom. This leads to formation of an ionic bond
What is an ion?
An atom becomes an ion when it’s charge has been altered by losing or gaining an electron
What is it called when a normal atom becomes an ion?
Ionisation
Negatively charged ions are known as what?
Anions (electron gain)
Positively charged ions are known as what?
Actions (electron loss)
What is a large molecule called?
Macro…
What is a small molecule called?
Micro…
What is a molecule?
Contains two or more atoms chemically joined together
What is a compound?
A molecule composed of atoms from two or more different elements
What are the two types of compounds?
Organic
Inorganic
What is the difference between organic and inorganic compounds?
Organic compounds contain carbon, inorganic compounds contain no carbon
To see how atoms form the compounds we eat
Look at slide 11, lecture 2
What are chemical bonds?
They are how atoms join together
How are bonds formed?
Through the action of electrons, which are donated/taken from one molecule to another
What does ionic bond formation depend on?
Electronegativity (the attraction of an atom for electrons)
Look at how electronegativity of atoms vary
Slide 13, lecture 2
When do ionic bonds form?
When the difference in electronegativity between two atoms is very high >1.7
(The atom with the highest electronegativity pulls one or more electrons completely away from the other atom)
What are covalent bonds?
Sharing electrons with another atom
Look at covalent bond formation on recap
Slide 15-17 lecture 2
Go on recap
For slide 18 lecture 2
What is a polar covalent bond?
A bond in which one part of the molecule is more charged than the other
The electrons are not shared equally
These molecules are hydrophilic - excellent solvents
What is a non-polar covalent bond?
A bond in which the charged of each molecule are equal
The electrons are shared equally
Atoms from the same element are non-polar
What is the order of strength for covalent, ionic and hydrogen bonds?
Covalent is stronger than ionic, ionic is stronger than hydrogen
The breaking or making of a bond is called what?
A chemical reaction
When a bond breaks/forms and a chemical reaction occurs, what is produced?
Energy
So talking, walking etc is simply what?
Bonds between atoms being split or joined
There are several different types of chemical reactions in the body, what are they?
Check recap slide 21 to see which ones we need to know, lecture 2
Recap for slide 22
Lecture 2
What are redox reactions extremely important in?
Energy production, particularly in long duration exercise when ATP turnover is high
Look at slide 23 lecture 2
For most common redox reaction
When a molecule is oxidised what happens? In terms of gain/loss of electrons
It loses electrons
When a molecule is reduced what happens? In terms of gain/loss of electrons
It gains electrons
What does OIL RIG stand for?
Oxidation
Is
Losing electrons
Reduction
Is
Gaining electrons
Cell structure
Lecture 2 slide 26
What is the cytoplasm?
The fluid in the cell - often referred to as everything expect the nucleus
What is cytosol
The fluid portion (of cytoplasm) & several important energy generating reactions take place here
What is mitochondria?
An organelle - the energy currency of the cell (check this)
What does the mitochondria generate?
More ATP than any other part of the cell in the matrix
What does exercise do to mitochondria?
Increases the size of mitochondria in the cell and also the number it contains
What is the cell membrane?
The gatekeeper of the cell
Surrounds the whole cells
Lipid bilateral - phospholipid, glycolipid, cholesterol
Look at what you really need to know
Slide 30 lecture 2
Structure of ATP etc
Lecture 3 slide 3
Slide 5
Lecture 3
Contribution of different energy systems to overall energy production
Slide 6 lecture 3
What is glycolysis?
The metabolic pathway that we use to turn glucose into energy
Can glycolysis generate energy without the need for oxygen? (Be anaerobic)
Yes
Very high intensity exercise requires what? (In terms of ATP)
An extremely high rate of ATP generation
Why are aerobic metabolic pathways (to create O2) not used very high intensity exercise?
The rapid demand in ATP means there is not enough time to rely on aerobic metabolic pathways
What molecule does high intensity exercise rely on?
Phosphocreatine
How much phosphocreatine is stored in the muscles?
120g
What is phosphocreatine degradation?
The breakdown of PC to generate ATO
Creative kinase reaction
Slide 10 lecture 3 - recap
What enzyme catalyses the reaction of ADP -> ATP + creatine
Creatine kinase
How long can PCr only fuel the body for?
Approximately 10-14 seconds of exercise
Do PCr concentrations ever reach 0?
No
Why do PCr concentrations never reach 0?
Your body has a fail safe mechanism to avoid this
What foods contain creatine?
Egg, red meat, fish (eg salmon)
How does creatine supplement work?
It increases intramuscular stores of creatine. This should theoretically improve performance because these stores will not then be depleted so quickly
The need for rapid energy creates what?
An oxygen deficit
How long does it take to fully resynthesise PCr stores?
3-5 minutes
What does the resynthesis of PCr require?
Oxygen and blood flow
What happens to PCr resynthesis when blood flow and therefore oxygen supply is blocked?
PCr resynthesis is inhibited
Is the aerobic energy system always contributing?
Yes, very small amounts at times but yes
What is the contribution of the aerobic energy system during 10 seconds of exercise or less?
3%
What is the contribution of the aerobic energy system during 30 seconds of exercise or less?
15%
What is the contribution of the aerobic energy system during 60-90 seconds of exercise or less?
55%
What is the contribution of the aerobic energy system during 60-90 seconds of exercise or more?
70%
What adaptations does sprint training obtain?
Increase glycolysis utilisation
Increase enzyme activity
Increase transport proteins
What energy sources does high intensity intermittent exercise (football) use?
Both aerobic and anaerobic
What happens to the contribution of anaerobic glycolysis after as little as 4 or 5 all out 6 second sprints?
It starts to fall
Recap
Slide 23 lecture 3
Recap
Lecture 3 slide 24 + 25 + 26 + 27
What causes metabolic fatigue during high intensity intermittent sports?
Acidosis Impaired calcium function Build up of H+ Reactive oxygen species (recap wtf it is) Increase in extracellular potassium Muscle glycogen depletion PCr depletion
Do energy systems ever work in isolation? If not then what changes?
No
Merely the contribution of each energy system
What you really need to know slide
Lecture 3
What is glycolysis?
The breakdown of glucose to produce energy
What does glycolysis involve?
The breaking apart a 6 carbon molecule of glucose to a 3 carbon molecule of pyruvate
Can every cell in the body generate energy from glycolysis?
Yes
Why is glycolysis often seen as the emergency energy pathway?
Because energy can be generated rapidly
In cells that don’t have mitochondria, is glycolysis the only energy pathway?
Yes
Glycolysis is primarily regulated by two main hormones, what are they?
Insulin (activator)
Glucagon (inhibitor)
Can glycolysis be anaerobic and aerobic?
Yes
During sever intensity exercise, or when the PCr system has been depleted, we are heavily reliant on what to provide energy?
Anaerobic glycolysis
How many reactions (stages) does glycolysis have?
10
Reactions 1-5 for glycolysis are termed what? And why?
The investment phase. This is because here ATP is used
Reactions 6-10 for glycolysis are termed what? And why?
The pay off phase. This is because ATP is generated
Where does anaerobic glycolysis take place?
The cytosol
Slides 7-10, lecture 4
Stages of glycolysis
Large amounts of pyruvate increases what?
Lactic acid production
If lots of pyruvate creates lots of lactic acid, then extensive reliance on anaerobic glycolysis produces what?
Large amounts of lactic acid
Slide 12
Lecture 4
What is glycogenesis?
Formation of new glycogen
What is glycogenolysis?
Breakdown of glycogen
When is glycogenesis most likely to occur?
When there is glucose in the cell and insulin has been secreted
Process of elongation
Slide 16, lecture 4
Glycogen can only be stored as what?
Branches of glucose polymers
Glucose polymers have several branches, what does this mean?
That they can be broken down to glucose molecules rapidly
What happens when 11 or more glucose chains have been formed?
They can start to branch
Slide 18 lecture 4
Recap
When does glycogenolysis occur?
During times such as fasting
During glycogenolysis what happens to glucose?
Glucose starts to be removed from the glycogen chain via phosphorolysis
During glycogenolysis, when glycogen is removed from the glycogen chain what are they broken down into?
10% are broken down into glucose
90% are broken down to glucose-1-P
What is an important enzyme in glycogenolysis?
Glycogen phosphorylase - assumes to be rate limiting step
Slide 21-23, lecture 4
Recap
What is the whole point of glycogenolysis?
To convert branches glycogen molecules into straight ones
What happens to glycogenolysis in skeletal muscle during high intensity exercise? (Eg 800m)
It is significantly upregulated
When is glycogenesis activated?
After a CHO meal
What does glycogenesis form?
Forms new glycogen for storage?
How does glycogenesis form new glycogen for storage?
By adding glucose molecules together to form branches
When is glycogenolysis activated?
When fasting/high intensity exercise
What does glycogenolysis do?
Breaks down glycogen stores for energy
How does glycogenolysis break down glycogen stores for energy?
By breaking off glucose molecules one by one to be used in glycolysis
What happens to glycogenolysis in terms of exercise intensity
It increases with exercise intensity
How quickly can glycogenolysis be activated?
Within 1 second of the onset of exercise
What you really need to know slide
Slide 28 lecture 4
What does TCA stand for in the TCA cycle?
Tricarboxylic acid
What is the TCA cycle also known as?
The Krebs cycle
How many reactions does the Krebs/TCA cycle involve?
8
Where do the 8 reactions in the TCA/Krebs cycle take place?
The mitochondria (think it’s matrix of…)
Is the TCA/Krebs cycle aerobic/anaerobic?
It is an aerobic process that requires O2
What are the functions of the Krebs/TCA cycle?
Oxidation pathway for CHO/lipids/proteins
Generates energy or intermediates (NADH) to be used in the electron transport chain for energy
Provides several precursor molecules for other metabolic pathways
What does the TCA/Krebs cycle start with?
Acetyl co-A
What can eventually form Acetyl co-A (what enters the Krebs/TCA cycle)
Glucose (CHO)
Triacyglycerides (fats)
Amino acids (proteins)
What is formed at the end of glycolysis (TCA/Krebs cycle bit) that can enter the mitochondria for conversion to…
Pyruvate
Acetyl-CoA
What is the reaction called where pyruvate is converted into Acetyl co-A?
The link reaction?
What are the products of the link reaction where pyruvate forms Acetyl co-A?
CO2
Creates 1 NADH
What catalyses the link reaction of pyruvate to Acetyl co-A?
Pyruvate dehydrogenase (PDH)
What is pyruvate dehydrogenase?
It is a group of enzymes (not really important at this level)
Does PDH have both an active and inactive form?
Yes
What is the active form of PDH?
Non-phosphorylated
What is the inactive form of PDH?
Phosphorylated
What does PDH kinase do?
It is the enzyme that keeps PDH inactive
When is PDH kinase upregulated?
When energy in the cell is plentiful or demand is low
What is the role of PDH phosphatase?
It is the enzyme that activated PDH
When is PDH phosphatase activates?
When energy in the cell is low
During exercise what happens to PDH?
It is activated
What are magnesium and calcium in relation to PDH?
They are both allosteric regulators of PDH
When is PDH activated?
When energy in the cell is low
When is PDH inhibited?
When energy in the cell is plentiful
What does PDH activation activate?
The TCA/Krebs cycle via glycolysis
When we use PDH, which fuel source for energy are we becoming more reliant on?
Carbohydrate
What does it mean when NAD+ is reduced to NADH? (The same is true for FAD+ to FADH2)
It means that it gains an electron from the hydrogen
What are NADH and FADH2 essentially?
They are essentially electron carriers
Learn steps of the TCA/Krebs cycle
Lecture 5, slide 14
How many molecules of ATP are generated via the TCA/Krebs cycle?
1
At A-level it said 2?
What are the products of one cycle of the TCA/Krebs cycle?
1 ATP
3 NADH
1 FADH2
What happens to NADH and FADH2 after the Krebs/TCA cycle?
The go to the electron transport chain
Is the TCA/Krebs cycle an aerobic or anaerobic process?
It is an aerobic process
Several of molecules in TCA cycle can be used for other reactions
Lecture 5, slide 18-23
Look at what you need to know slide
Lecture 5, slide 34
Glycolysis is often seen as the ‘emergency’ energy pathway because it can generate energy rapidly:
True/False
True
Glycolysis:
A) Occurs in the mitochondria
B) Generates 8 ATP
C) Generates 2 NADH molecules
D) Is the primary energy pathway during a 10km race
C) Generates 2NADH molecules
Glycolysis has:
A) 10 reactions, 3 of which are irreversible
B) 8 reactions, none of which are irreversible
C) 10 reactions, 2 of which are irreversible
D) 10 reactions, none of them are irreversible
A) 10 reactions, 3 of which are irreversible
Gluconeogenesis is activated by hunger:
True/False
True
Glycogen is stored in the:
A) Liver only
B) Muscle, liver
C) Muscle, liver, adipose tissue
D) Liver, adipose tissue
B) Muscle, liver
Is Glycolysis an anaerobic or aerobic process:
A) Anaerobic
B) Aerobic
C) Both
D) Neither
C) Both
During high intensity exercise glycogenolysis is:
A) Inhibited
B) Upregulated
C) Unchanged
B) Upregulated
In glycogenolysis, which organ(s) convert glycogen to glucose?
A) Skeletal Muscle
B) Liver and Skeletal Muscle
C) Liver
D) Liver and adipose tissue
C) Liver
Double check
Pyruvate dehydrogenase (PDH):
A) Is inhibited by NAD+
B) Is active when phosphorylated
C) Is regulated by PDH kinase and PDH phosphatase
D) Catalyses the production of pyruvate from Acetyl co-A
C) Is regulated by PDH kinase and PDH phosphatase
What is glycogenesis?
The formation of glycogen from sugar
What is glycolysis
The breakdown of glucose by enzymes, releasing energy and pyruvic acid
What is gluconeogenesis?
The generation of glucose from non-carbohydrate carbon substrates
What is glycogenolysis?
The breakdown of glycogen into glucose
What is the structure of ATP?
Adenine-ribose-P-P-P
