Module 2 Flashcards
1
Q
What does the first law of thermodynamics state?
A
The total energy in the universe is constant
2
Q
What is metabolism?
A
The chemical processes that occur in living cells and provide energy and molecules for life
3
Q
What type of process is the metabolism of food?
A
Exergonic process
4
Q
What is an endergonic reaction?
A
A reaction that requires energy input to proceed
5
Q
What is ATP?
A
A universal energy transfer molecule in cells
6
Q
What happens during ATP hydrolysis?
A
It releases free energy (‐ve ΔG) that can drive energetically unfavorable reactions
7
Q
What is free energy?
A
Energy available to do work
8
Q
Fill in the blank: Free energy is symbolized as _______.
A
G
9
Q
What does a negative ΔG indicate?
A
Energy is released by the reaction (exergonic)
10
Q
What does a positive ΔG indicate?
A
The reaction needs an input of energy (endergonic)
11
Q
What is the equation for the hydrolysis of ATP?
A
ATP + H2O → ADP + Phosphate + ENERGY
12
Q
What is the difference between spontaneous and non-spontaneous reactions?
A
Spontaneous reactions are exergonic (ΔG negative) and occur without energy input; non-spontaneous reactions are endergonic (ΔG positive) and require energy input
13
Q
Identify a spontaneous process: Cyclist rolling down a hill or Someone climbing a mountain?
A
Cyclist rolling down a hill
14
Q
In which type of reaction is energy stored as chemical energy?
A
Endergonic reaction
15
Q
What is the significance of the second law of thermodynamics?
A
The universe is becoming more disordered; to increase order, energy input is required
16
Q
What is an example of a process that requires energy to maintain order?
A
Photosynthesis
17
Q
What is the role of ATP in cells?
A
To transfer free energy between reactions
18
Q
Fill in the blank: The actual cellular ΔG for ATP hydrolysis is approximately _______ kJ/mol.
A
−57
19
Q
True or False: All endergonic reactions occur spontaneously.
A
False
20
Q
What type of energy transformation occurs during photosynthesis?
A
Light energy into chemical energy
21
Q
What is the significance of the chemical reaction A + B → C + D?
A
It represents a chemical reaction with reactants (A, B) and products (C, D)
22
Q
What is the relationship between the energy of reactants and products in an exergonic reaction?
A
Reactants have more energy than products (Gi > Gf)
23
Q
What is the relationship between the energy of reactants and products in an endergonic reaction?
A
Products have more energy than reactants (Gi < Gf)
24
Q
What do we call the process of building complex molecules from simple ones?
A
Biosynthesis
25
Fill in the blank: Energy is measured in _______.
Joules (J)
26
What is the role of energy in muscle contraction?
It requires energy to occur
27
What does free energy change (ΔG) indicate about a reaction?
It tells us whether a reaction is 'spontaneous'
## Footnote
ΔG does not provide information on the speed of the reaction.
28
What is activation energy (Eᴀ)?
The addition of energy that brings the system to a threshold where it can continue on its own.
29
How does activation energy affect reactions?
Activation energy prevents a reaction from proceeding until the threshold is reached.
30
What characterizes an exergonic reaction?
Products have less energy than reactants and exhibit a negative free energy change (-ΔG).
31
What is a catalyst?
A substance that increases the rate of a chemical reaction by lowering activation energy.
32
True or False: Catalysts are consumed in the reactions they catalyze.
False.
33
What are enzymes?
Biological catalysts that decrease activation energy and thus speed up biochemical reactions.
34
What is the role of the active site in enzymes?
The substrate binds to the active site, which is often a cleft in the protein structure.
35
Fill in the blank: Reactants are called _______ for enzymes.
substrates.
36
What happens to glucose when it enters a cell that needs energy?
It is reacted to produce carbon dioxide to fuel the cell.
37
What is the fate of glucose if the cell does not need energy?
It is converted into glycogen for storage.
38
What is the structure of an amino acid?
Amino group (NH2), carboxylic acid group (COOH), and a variable R group.
39
How are amino acids joined together?
By peptide bonds between the carboxylic acid group of one amino acid and the amino group of another.
40
What determines the properties of different amino acids?
The variable R group, which affects size, charge, and other properties.
41
What characterizes proteins in terms of their structure?
Proteins can be very long, folding into complex shapes based on their function.
42
How do enzymes interact with substrates?
They bring substrates in contact with different amino acids or position them favorably for reaction.
43
What is the significance of metabolic pathways in relation to enzymes?
Each reaction is energized/catalyzed by a specific enzyme, allowing metabolic control.
44
What happens to energy during the conversion of glucose in metabolic pathways?
Energy is captured as ATP rather than being released as heat.
45
True or False: Enzymes change the ΔG of reactions.
False.
46
What type of model can represent protein structures?
Ribbon model and space-filling model.
47
What type of molecule is an enzyme?
A protein
48
Where does an enzyme reaction occur?
At the active site
49
What are the 3 ways that enzymes can impact substrate?
* Bringing the substrate into contact with different amino acids
* Can put the substrate into a favourable position to react
* Put pressure on the reactant
50
What are the 6 steps in catalytic cycle of an enzyme:
1. Substrates enters the active site
2. Substrates are held with weak bonds
3. The active site lowers the activation energy
4. Substrates are converted into products
5. Products are released
6. Active site is available
51
What type of bonds hold substrates to the active site of an enzyme?
Hydrogen and ionic bonds
52
True or false: Enzymes change the ΔG in metabolic pathways.
False (they only change the activation energy, not the ΔG)
53
What do strands of amino acids group together to form?
Proteins
54
What is a metabolic pathway?
A series of chemical reactions in living cells where the first reactant produces products for the next reactant
## Footnote
Usually involves many chemical reactions strung together.
55
What is the first step in a hypothetical metabolic pathway?
Start with a precursor molecule
## Footnote
This precursor undergoes a series of reactions to produce intermediate molecules and finally a product.
56
What can metabolic pathways involve in terms of complexity?
Intermediate molecules may join other pathways or molecules from other pathways may join this pathway
## Footnote
This can lead to complex interactions between different metabolic pathways.
57
What types of molecules are involved in the metabolism of energy-rich compounds?
* Carbohydrates
* Fats
* Proteins
## Footnote
All these can be used as energy sources and have related metabolic pathways.
58
What was the state of the Earth's atmosphere up to approximately 2.3 billion years ago?
Anaerobic
## Footnote
Organisms at that time relied on glycolysis to obtain small amounts of ATP from glucose.
59
What significant evolutionary event is referred to as the Oxygen Revolution?
The evolution of cyanobacteria that performed efficient oxygenic photosynthesis
## Footnote
This led to increased levels of oxygen in the atmosphere.
60
What were the consequences of the Oxygen Revolution for early organisms?
Many organisms did not survive due to their inability to deal with increased oxygen levels
## Footnote
This resulted in the evolution of new metabolic pathways.
61
What are the metabolic processes evolved after the Oxygen Revolution?
* Citric acid cycle
* Oxidative phosphorylation
## Footnote
These processes are used in the metabolism of carbohydrates, fats, and proteins.
62
How much ATP can be produced per glucose molecule through oxidative phosphorylation for humans?
~28 ATPs
## Footnote
Humans typically make around 28 ATP from these processes.
63
What is the key danger associated with oxygen?
It is a strong oxidising molecule
## Footnote
This can lead to rapid energy release as seen in processes like burning wood.
64
What did aerobic metabolism in bacteria eventually evolve into?
Mitochondria in eukaryotes
## Footnote
This development allowed for a shared aerobic pathway among animals, plants, fungi, and bacteria.
65
What organisms share aerobic pathways?
Animals, plants, fungi, and bacteria
66
67
68
What is glycolysis?
The first pathway of the metabolism of sugars.
69
What is the starting molecule for glycolysis?
Glucose (6C)
70
What happens to glucose during glycolysis?
Glucose (6C) is split into
--> 2x 3-carbon sugars and then oxidised into
--> 2x pyruvate molecules.
--> PLUS produces 2x ATP
71
Why is blood glucose maintenance important?
To ensure all cells have adequate energy supply.
72
What role does insulin play in glucose metabolism?
It increases the intake of glucose into cells.
73
What are the consequences of too little glucose?
Insufficient energy to run all metabolic processes.
74
What can happen if there is too much glucose?
It can be toxic.
75
Where does glycolysis occur?
In the cytosol of all cellular organisms.
76
Does glycolysis require oxygen?
No, it does not need oxygen.
77
How many chemical reactions are there in glycolysis?
9 chemical reactions.
78
What is released for every mole of glucose metabolised in glycolysis?
A lot of energy.
79
What is the process of oxidation in glycolysis?
Glucose is oxidised to release energy.
80
What is the relationship between oxidation and reduction reactions?
If one molecule loses electrons, another must gain them.
OIL - Oxidation is loss
RIG - reduction is gain
81
What is the free-energy change of glycolysis?
-1870 kJ per mole of glucose.
82
What happens to electrons lost from glucose during glycolysis?
They are captured by reducing NAD+ to NADH.
83
What is NADH?
A reduced form of NAD+.
84
What is the first phase of glycolysis focused on?
Activation of sugars.
85
What is the energy source for activating glucose?
Energy released during removal of Pi from ATP.
86
Fill in the blank: Glycolysis has _____ phases.
4 phases.
87
True or False: Glycolysis is an endergonic process.
False.
88
What are the 4 phases of Glycolysis?
1. Activation of sugars
2. Cleavage of fructose
3. Oxidation of glyceraldehyde
4. Production of ATP
89
89
What is photosynthesis?
Light energy into chemical energy
## Footnote
Photosynthesis is the process by which plants convert light energy into chemical energy, primarily in the form of carbohydrates.
89
What is the equation for photosynthesis?
nCO2 + nH20 --> carbohydrate + n02
## Footnote
The specific equation typically involves carbon dioxide and water converting into glucose and oxygen.
90
What is a chloroplast?
Membrane-bound organelle responsible for photosynthesis
## Footnote
Chloroplasts are specialized organelles found in plant cells where photosynthesis occurs.
91
How many membranes do chloroplasts have?
3
## Footnote
The three membranes are the outer membrane, inner membrane, and thylakoid membrane.
92
What is the stroma in chloroplasts?
The matrix/inside the membrane of the chloroplast
## Footnote
The stroma contains enzymes and is where the Calvin cycle takes place.
93
What are the inputs and outputs of the light reactions in photosynthesis?
Input: H2O
Output: O2
## Footnote
Water is split to release oxygen during the light reactions.
94
What are the inputs and outputs of the Calvin Cycle?
Input: CO2
Output: Carbohydrates/sugars
## Footnote
The Calvin Cycle converts carbon dioxide into sugars.
95
How is ATP recycled during photosynthesis?
ATP --> ADP + Pi --> ATP
## Footnote
ATP is continuously recycled between the light reactions and the Calvin cycle.
96
How is NADPH recycled during photosynthesis?
NADPH --> NADP+ --> NADPH
## Footnote
NADPH is generated in the light reactions and used in the Calvin cycle.
97
What role do photosystems play in photosynthesis?
They are the plant cell 'solar panels'
## Footnote
Photosystems are large protein complexes containing chlorophyll that capture light energy.
98
What are the two types of photosystems?
Photosystem 1 (PS I) and Photosystem 2 (PS II)
## Footnote
These photosystems work together in the light reactions of photosynthesis.
99
What colour light do the electrons in the photosystem absorb?
Electrons in chlorophyll absorb red and blue light
## Footnote
This absorption raises the energy levels of the electrons.
100
What is the reaction center of a photosystem?
A special pair of chlorophyll molecules
## Footnote
The reaction center is where high-energy electrons are transferred to a primary electron acceptor.
101
What is produced when water is split in photosynthesis?
Oxygen + hydrogen ions
## Footnote
This process occurs during the light reactions, allowing plants to release oxygen.
102
What is the role of NADP+ reductase in photosynthesis?
Creates NADPH in the stroma
## Footnote
NADP+ reductase uses electrons to reduce NADP+ to NADPH, which is essential for the Calvin cycle.
103
What enzyme is responsible for carbon fixation in the Calvin Cycle?
Rubisco
## Footnote
Rubisco catalyzes the reaction that incorporates CO2 into organic molecules.
104
What are the three phases of the Calvin Cycle?
1. Carbon Fixation
2. Reduction
3. Regeneration
## Footnote
Each phase plays a distinct role in converting CO2 into carbohydrates.
105
What is produced during the reduction phase of the Calvin Cycle?
Glyceraldehyde 3-phosphate (G3P)
## Footnote
G3P is a three-carbon sugar that can be used to form glucose and other organic molecules.
106
How many G3P molecules are needed to regenerate Ribulose biphosphate?
5 G3Ps
## Footnote
These G3P molecules are recycled to continue the cycle.
107
Name the 3 chloroplast membranes
* outer membrane
* inner membrane
* Thylakoid membrane
108
What is the thylakoid membrane?
The membrane-bound compartments inside chloroplasts and cyanobacteria
109
What is the importance of the thylakoid membrane?
It is the location of light reactions
110
Where are the photosystems located?
They are embedded in the Thylakoid membrane
111
How are the photosystems connected?
Via an electron transport chain (starting with PSII)
112
113
114
What happens if an enzyme is missing?
Leads to defects in Metabolic Pathways
## Footnote
Mutation in a gene for a metabolic enzyme causes issues in metabolic processes.
115
What accumulates if Enzyme 1 is defective or absent (A --> B)?
A accumulates
## Footnote
A may be toxic and can cause disease.
116
What is deficient if Enzyme 1 is defective or absent (A --> B)?
B deficient
## Footnote
B may be required for normal metabolic function and can cause disease.
117
What is Phenylketonuria (PKU) caused by?
A defective enzyme
## Footnote
PKU is managed through diet, specifically low protein intake.
118
How is Phenylketonuria managed?
Through diet
## Footnote
Low protein (low Phe, high Tyr) starting at age 3 weeks.
119
Is there a cure for Phenylketonuria?
No cure
## Footnote
PKU must be managed to avoid detrimental effects on the brain.
120
Why is curing genetic diseases challenging?
Your genome is in every cell
## Footnote
It is replicated every time your cells replicate, making it hard to fix.
121
What technology can be used to correct genetic defects?
Gene editing technology (e.g., CRISPR/Cas9)
## Footnote
It can cut out defective DNA and replace it with good DNA.
122
Has gene editing technology been successful in humans?
Still very far away for humans
## Footnote
Success has been noted in mice for muscular dystrophy.
123
What ethical consideration exists regarding gene editing?
Ban on using this technology on human embryos
## Footnote
Significant ethical considerations are involved in gene editing.
124
What is lactase persistence?
Continued lactase production into adulthood
## Footnote
This condition arises from a mutation that alters lactase regulation.
125
When did the mutation for adult lactose tolerance occur?
7,000-9,000 years ago
## Footnote
This coincides with the domestication of cattle.
126
Where is the geographical prevalence of the lactase persistence mutation focused?
Around Europe
## Footnote
This area shows a high frequency of the mutation.
127
What happens without lactase in mammals?
Lactose is not digested
## Footnote
Instead, it is fermented by gut microbes.
128
Where does the mutation for lactase persistence occur?
Approximately 14,000 bp upstream
## Footnote
It affects the gene regulation area, not the lactase gene itself.
129
What is an example of a beneficial mutation for humans?
Adult lactose persistence
129
How does NSW perform the newborn screening program?
Via single blood samples (heel prick)
130
131
What is the process of breaking down foods called?
Digestion
## Footnote
Involves mechanical and chemical degradation.
132
What type of degradation involves chewing?
Mechanical degradation
## Footnote
It is part of the digestion process.
133
What is required to break down carbohydrates, proteins, and fats during digestion?
Digestive enzymes
## Footnote
Essential for chemical degradation.
134
What is peristalsis?
The contraction and relaxation of muscles that push food along the GI tract.
## Footnote
Involves circular and longitudinal muscles.
135
What happens to energy-yielding nutrients during the final stage of digestion?
They are disassembled for absorption.
## Footnote
Includes carbohydrates, proteins, and fats.
136
In what form do carbohydrates need to be consumed after digestion?
Sugars
## Footnote
They are broken down into simpler forms.
137
What form do proteins take once they are digested?
Amino acids
## Footnote
Essential for various bodily functions.
138
How long does meal digestion typically take?
3-4 hours
## Footnote
Varies based on meal composition.
139
Where does the absorption of nutrients primarily occur?
Small intestine
## Footnote
Main site for nutrient absorption.
140
What are goblet cells responsible for in the intestine?
Releasing mucus that protects the intestine surface/villi.
## Footnote
Important for maintaining gut health.
141
What structures in the small intestine facilitate nutrient absorption?
Villi and microvilli
## Footnote
Increase surface area for absorption.
142
What circulatory system is responsible for transporting absorbed nutrients?
Circulatory System
## Footnote
Nutrients enter the bloodstream.
143
What is the role of the lymphatic system in nutrient transport?
One-way route for fluid from tissue spaces to enter the blood.
## Footnote
Transports large fats and fat-soluble vitamins.
144
What influences the health and regulation of the GI tract?
Age, disease, and malnutrition
## Footnote
All can impact digestive health.
145
How many bacteria are estimated to live in the GI tract?
10 trillion
## Footnote
More bacteria than human cells.
146
What does the stability and resilience of a person's microbiome reflect?
Their health
## Footnote
Microbiome plays a crucial role in health.
147
What are some essential functions of a healthy GI tract?
* Digestion
* Keeping gut healthy
* Dealing with pathogenic organisms
## Footnote
Essential for overall health.
148
What health issues may be influenced by the health of the GI tract?
* Obesity
* Inflammatory bowel disease
## Footnote
Ongoing research in these areas.
149
Which body system transports glucose and amino acids to cells?
Circulatory system
150
Which body system transports fats and fat-soluble vitamins?
Lymphatic system
151
152
153
What is the approximate percentage of water in the human body?
~60%
154
What is the approximate percentage of fat in the human body for males and females?
~20/35% (M/F)
155
What are the six nutrient classes that compose food?
* Water
* Carbohydrates
* Lipids
* Proteins
* Vitamins
* Minerals
156
What are some examples of non-nutrients and other compounds that foods can contain?
* Fibres
* Phytochemicals
* Pigments
* Additives
* Alcohols
* (Others)
157
What are macronutrients?
Nutrients needed in high quantities: carbohydrates, proteins, fats
158
How are energy-yielding nutrients measured?
In kilojoules (kJ) or kilocalories (kcal or cal)
159
What is the energy equivalence of 1 kcal in kilojoules?
4.2 kJ
160
True or False: Alcohol is considered a nutrient because it provides high calories.
False (it has no nutritional value!)
161
What are the three categories of micronutrients?
* Water
* Vitamins
* Minerals
162
What is the role of vitamins in the body?
Assist enzymes to release energy from carbohydrates, fats, and proteins
163
Why are micronutrients essential despite being needed in smaller quantities?
They are essential to live but do not yield energy
164
What does the science of nutrition study?
Nutrients and other substances in foods and the body's handling of them
165
What are Nutrient Reference Values (NRVs)?
Standards defining amounts of energy, nutrients, dietary components, and physical activity for health
166
List the components of Nutrient Reference Values (NRVs).
* Recommended Daily Intake (RDI)
* Estimated Average Requirements (EARs)
* Adequate Intake (AI)
* Upper Level of Intake (UL)
167
What does the Estimated Energy Requirement (EER) represent?
Average daily energy intake to maintain energy balance and good health
168
What is the Acceptable Macronutrient Distribution Range (AMDR) for carbohydrates?
45-65% kilojoules
169
What is the Acceptable Macronutrient Distribution Range (AMDR) for fat?
20-35% kilojoules
170
What is the Acceptable Macronutrient Distribution Range (AMDR) for protein?
15-25% kilojoules
171
What are the six basic principles of planning a diet?
* Adequacy
* Balance
* Kilojoule control
* Nutrient density
* Moderation
* Variety
172
What does the Australian Guide to Healthy Eating (AGTHE) emphasize?
Building a diet from clusters of foods that are similar in nutrient content
173
What is the role of thiamin (Vitamin B) in metabolism?
Part of coenzyme thiamin pyrophosphate (TPP) involved in glucose metabolism
174
What can happen if there is a deficiency in thiamin?
* Glucose metabolism stops
* Reduced ATP synthesis
* Increased pyruvate and lactate
* Enlarged heart and heart failure
* Beriberi
175
What foods are good sources of riboflavin (Vitamin B2)?
* Milk
* Bread
* Cereal
* Dark green leafy vegetables
176
What is the coenzyme form of riboflavin?
FAD (flavin adenine dinucleotide)
177
What foods are high in niacin (Vitamin B3)?
* Meat
* Legumes
* Wholegrains
* Mushrooms
* Potatoes
* Tomatoes
178
What is a significant condition caused by niacin deficiency?
Pellagra (four D's = diarrhoea, dermatitis, dementia, and death)
