Lectures 13-23 Ashley Garril Flashcards
1
Q
What is your metabolism?
A
Metabolism is the process by which your body converts what you eat and drink into energy. During this complex biochemical process, calories in food and beverages are combined with oxygen to release the energy your body needs to function
2
Q
What is a metabolic pathway?
A
A metabolic pathway is a series of connected chemical reactions that feed one another. The pathway takes in one or more starting molecules and, through a series of intermediates, converts them into products.
3
Q
What are catabolic pathways?
A
In contrast, cellular respiration breaks sugar down into smaller molecules and is a “breaking down,” or catabolic, pathway.
4
Q
What are anabolic pathways?
A
Photosynthesis, which builds sugars out of smaller molecules, is a “building up,” or anabolic, pathway
5
Q
What is the bacterial cell?
A
Bacteria are all single-celled. The cells are all prokaryotic . This means they do not have a nucleus or any other structures which are surrounded by membranes . … Bacteria also have small, closed-circles of DNA called plasmids present in their cytoplasm.
6
Q
What are bacterial cells made up of?
A
30% chemicals and 70% water
7
Q
Are our cells just stocks of chemicals?
A
No our cells have functions too such as movement, membrane transport, and chemical synthesis (WORK)
8
Q
What are the 3 forms of work in our cells?
A
Movement, Membrane transport, and Chemical synthesis
9
Q
What is a function of cells that is essential for life?
A
Cells need to move organelles around
10
Q
What are organelles?
A
Any of a number of organized or specialized structures within a living cell.
11
Q
True or False? Things moving inside a cell can cause the cell itself to move.
A
True .
12
Q
What is a cytoskeleton?
A
A microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.
13
Q
True or False? Cell migration is crucial for development.
A
True
14
Q
Which type of blood cells move around and eat things that aren’t meant to be in your body?
A
White blood cells
15
Q
If you had an infection what type of blood cells would you see an influx of in your body?
A
White blood cells
16
Q
What are Neutrophils?
A
Neutrophils are a type of white blood cell that helps heal damaged tissues and resolve infections. Neutrophil blood levels increase naturally in response to infections, injuries, and other types of stress.
17
Q
What is membrane transport?
A
Membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes
18
Q
What is 50% of the energy used by the brain used for?
A
To move Na+ and K+ across cell membranes.
19
Q
What causes muscle contraction in the body?
A
The muscle contraction cycle is triggered by calcium ions binding to the protein complex troponin, exposing the active-binding sites on the actin. As soon as the actin-binding sites are uncovered, the high-energy myosin head bridges the gap, forming a cross-bridge.
20
Q
What is the macromolecule of a sugar?
A
A polysaccharide
21
Q
What is the macromolecule of an amino acid?
A
A protein
22
Q
What is the macromolecule of a nucleotide?
A
A nucleic acid
23
Q
Can cells do work?
A
Yes
24
Q
How are molecules transformed?
A
They can be transformed via controlled environments of chemical reactions and by specific enzymes.
25
What is the reductionist approach?
An approach where you break the system down to its pieces to reason about it from the properties of these pieces
26
In a cell do multiple or single reactions occur?
Multiple as they do not occur in isolation
27
What is metabolic disequilibrium?
Metabolic equilibrium is a state in which metabolism is in a lower energy level such that no change can happen without the input of energy.
28
What is your metabolic map?
All the metabolic pathways in a cell that contribute to its metabolism.
29
What does catabolic mean?
Catabolic means "breaking down." Therefore it is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions
30
What does Anabolic mean?
Anabolic means "building up". Anabolic processes use simple molecules within the organism to create more complex and specialized compounds
31
Are catabolic or Anabolic reactions spontaneous?
Catabolic reactions are spontaneous and anabolic reactions are non-spontaneous
32
Out of catabolic and anabolic reactions which one yields energy and which involves an energy cost?
Catabolic reactions yield energy and Anabolic reactions involve energy costs.
33
What is energy coupling?
Energy coupling is transfer of energy from catabolism to anabolism, or transfer of energy from exergonic process to endergonic process.
34
True or False. Energy derived from catabolic pathways can be use to drive anabolic pathways.
True
35
What is ATP?
an organic compound that provides energy to drive many processes in living cells, e.g. muscle contraction, nerve impulse propagation, and chemical synthesis.
36
What is NADH?
A cofactor that is central to metabolism. Found in all living cells. NADH is a crucial coenzyme in making ATP
37
What is NADPH?
NADPH is a product of the first stage of photosynthesis and is used to help fuel the reactions that take place in the second stage of photosynthesis. NADPH helps carry electrons and protons driven by sunlight into new carbon-carbon bonds, creating sugar molecules
38
What is the difference between NADH & NADPH?
NADPH is the reduced form of NADP
39
How are metabolic pathways regulated?
VIA enzymes, allosterically, covalently, and genetically.
40
What is glycolysis?
Glycolysis is the metabolic pathway that converts glucose C₆H₁₂O₆, into pyruvate, CH₃COCOO⁻, and a hydrogen ion, H⁺. The free energy released in this process is used to form the high-energy molecules ATP and NADH
41
What is the citric acid cycle?
a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins, into adenosine triphosphate and carbon dioxide
42
What is oxidative phosphorylation?
the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing the chemical energy of molecular oxygen, which is used to produce adenosine triphosphate. In most eukaryotes, this takes place inside mitochondria.
43
What are enzymes?
a substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction
44
How do cells control their mechanisms?
Through regulating enzymes which ensures they have the materials and energy to do work and hence stay alive.
45
What is delta G in biochemistry?
The delta G of a reaction is the free energy of the final state minus the free energy of the initial state, making it is independent of the reaction pathway. However, the value of delta G provides no information on the rate of a reaction.
46
What do you need to be able to do work?
Energy
47
Can cells/organisms make energy?
No. Following the first law of thermodynamics that energy can only be transferred not created or destroyed.
48
What is the first law of thermodynamics?
states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another.
49
True or False? Living organisms must obey the laws of physics.
True.
50
What does energy transformation enable?
It enables work
51
What are the two main types of energy?
Kinetic energy (Light, Heat) and potential energy (Chemical)
52
What is the second law of thermodynamics?
It states that the state of entropy of the entire universe, as an isolated system, will always increase over time. The second law also states that the changes in the entropy in the universe can never be negative.
53
What does greater order mean?
That there will be lower entropy, therefore, the system is unstable.
54
What is Free energy? (G)
Gibbs free energy (G) is a measure of the maximum available work that can be derived from any system under conditions of constant temperature (T) and pressure (P).
55
How do you calculate delta G (Gibbs free energy)?
delta G = G(final state) - G(starting state)
56
What does a positive delta G (Gibbs free energy) mean?
Reactions with a positive ∆G need an input of energy in order to take place (are non-spontaneous
57
What does a negative delta G (Gibbs free energy) mean?
Reactions with a negative ∆G release energy, which means that they can proceed without an energy input (are spontaneous)
58
What are exergonic reactions?
An exergonic reaction is a chemical reaction where the change in the free energy is negative, indicating a spontaneous reaction. Energy is released.
59
True or False? ATP is a cells energy shuttle?
True
60
What is ATP hydrolysis?
ATP hydrolysis is the catabolic reaction process by which chemical energy that has been stored in the high-energy phosphoanhydride bonds in adenosine triphosphate is released by splitting these bonds, for example in muscles, by producing work in the form of mechanical energy.
61
Is ATP hydrolysis an exergonic or endergonic reaction?
exergonic
62
What are endergonic reactions?
an endergonic reaction is a chemical reaction in which the standard change in free energy is positive, and an additional driving force is needed to perform this reaction. Non-spontaneous reaction, energy is absorbed.
63
How does coupling occur in ATP?
The transfer of a phosphate
64
True or False? Catabolic pathways stop the production of ATP from ADP and Pi
False
65
What do enzymes do to chemical reactions?
Lower Ea and speed up the reaction.
66
Which is more stable ATP or ADP and pi, and why?
ATP is an unstable molecule in unbuffered water, in which it hydrolyses to ADP and phosphate. This is because the strength of the bonds between the phosphate groups in ATP is less than the strength of the hydrogen bonds (hydration bonds), between its products (ADP and phosphate), and water.
67
Can living organisms use heat energy to do work?
Cells in living organisms don't use heat as a source of energy because a thermal gradient would be needed. Cells maintain homeostasis.
68
How does ATP hydrolysis occur in a cell?
ADP is combined with a phosphate to form ATP in the reaction ADP+Pi+free energy→ATP+H2O. The energy released from the hydrolysis of ATP into ADP is used to perform cellular work, usually by coupling the exergonic reaction of ATP hydrolysis with endergonic reactions.
69
What are coupled reactions?
Many chemicals' reactions are endergonic (i.e., not spontaneous ( ΔG>0 )) and require energy to be externally applied to occur. However, these reaction can be coupled to a separate, exergonic (thermodynamically favorable ΔG<0 ) reactions that 'drive' the thermodynamically unfavourable one by coupling or 'mechanistically joining' the two reactions often via a share intermediate.
70
True or False? Enzymes allow a reaction to make more product.
False, Enzymes allow the reaction to occur faster.
71
What does substrate specific mean in terms of enzymes?
Enzymes are highly selective catalysts, meaning that each enzyme only speeds up a specific reaction
72
What does highly regulated mean in terms of enzymes?
A regulatory enzyme is an enzyme in a biochemical pathway which, through its responses to the presence of certain other biomolecules, regulates the pathway activity.
73
What is the most abundant enzyme on earth?
Rubisco, Grant studies it
74
What does the lysozyme enzyme do?
Lysozyme is a special enzyme found in tears, saliva, sweat, and other body fluids. It destroys bacteria that attempt to enter our body through these passageways. In the case of tears, they protect our eyes from bacterial invaders.
75
True or False? Enzymes allow a reaction to make more product.
False, Enzymes allow the reaction to occur faster.
76
What is a phosphorylated intermediate?
The key to coupling exergonic and endergonic reactions is the formation of this phosphorylated intermediate, which is more reactive than the original unphosphorylated molecule. Phosphorylation is an effective way of regulating proteins.
77
What kind of energy cost is there to make ATP from ADP?
For every ATP transported out, it costs 1 H+. Producing one ATP costs about 3 H+. Therefore, making and exporting one ATP requires 4H+.
78
What is activation energy, Ea?
Activation energy is the minimum amount of energy required to initiate a reaction.
79
What is the active site of an enzyme?
In biology, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate (binding site) and residues that catalyse a reaction of that substrate (catalytic site).
80
What are the ways that enzymes lower Ea?
1. The enzyme may hold the substrates in such a way as to distort the substrate bonds closer to their form in the transition state. 2. The enzyme may create a charge distribution opposite to that of the transition state. 3. The enzyme may reduce the reaction entropy ΔS‡ by bringing substrates together in the correct orientation to react. 4. 4. The enzyme may provide a completely different chemical pathway for the reaction.
81
What are isoenzymes?
Isozymes are enzymes that differ in amino acid sequence but catalyse the same chemical reaction.
82
What is feedback inhibition?
Feedback inhibition is a cellular control mechanism in which an enzyme's activity is inhibited by the enzyme's end product. This mechanism allows cells to regulate how much of an enzyme's end product is produced
83
What are substrate molecules?
The substrate is a molecule upon which an enzyme acts. Enzymes catalyse chemical reactions involving the substrate(s).
84
What is the lock and key model?
The lock and key model assumes that the active site of the enzyme and the substrate are equal shaped. It supposes that the substrate fits perfectly into the active site of the enzyme.
85
What is the catalytic cycle?
The catalytic cycle of an enzyme action occurs in the following steps: The substrate binds to the active site of the enzyme through weak interactions (H-bonds, Ionic bonds). The binding of the substrate induces a change in the shape of the enzyme molecule, and the active site can lower Ea and speed up reactions. Products are formed and then the products are released by the active site. The active site is then available for the next products.
86
What is the optimal pH?
The optimal pH of an enzyme is the pH at which it is most active. Enzymes can be thought of as biological catalysts that control many physiology related chemical reactions in the body of an organism. An enzyme will work most efficiently at or near its optimum pH.
87
What does low temp mean in terms of reaction rates of enzymes?
Rate of reaction is slow.
88
What does high temp mean in terms of reaction rate of enzymes?
Enzyme breaks down (totally denatures)
89
True or False? The optimal pH almost always reflects the temperature of its natural surroundings.
True
90
What are some of the cofactors required for catalysts in some enzymes?
Inorganic ions: Fe, Zn, Cu. Complex organic molecules: vitamins, NAD+, and FAD
91
What is enzyme inhibition?
An enzyme inhibitor is a molecule that binds to an enzyme and decreases its activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors
92
What are irreversible inhibitors?
Irreversible inhibitors usually covalently modify an enzyme, and inhibition can therefore not be reversed. Irreversible inhibitors often contain reactive functional groups such as nitrogen mustards, aldehydes, haloalkanes, alkenes, Michael acceptors, phenyl sulfonates, or fluorophosphonates.
93
What are reversible inhibitors?
Reversible inhibitors attach to enzymes with non-covalent interactions such as hydrogen bonds, hydrophobic interactions and ionic bonds. Multiple weak bonds between the inhibitor and the active site combine to produce strong and specific binding. These inhibitors can be easily removed by dilution or dialysis.
94
What is genetic control of enzymes?
Genetic control of enzyme activity refers to controlling transcription of the mRNA needed for an enzyme's synthesis. aka whether they exist or not.
95
What is allosteric control?
help to control the cellular metabolism. Aka controls how active these enzymes are
96
What is covalent control?
Enzymes can be regulated by transfer of a molecule or atom from a donor to an amino acid side chain that serves as the acceptor of the transferred molecule. (addition or removal of a phosphate group)
97
What is proteolytic activation?
the activation of an enzyme by peptide cleavage. The enzyme is initially transcribed in a longer, inactive form. In this enzyme regulation process, the enzyme is shifted between the inactive and active state.
98
What is allosteric regulation?
Allosteric regulation occurs when an activator or inhibitor molecule binds at a specific regulatory site on the enzyme and induces conformational or electrostatic changes that either enhance or reduce enzyme activity.
99
True or False? Enzymes have an optimal PH and temperature at which they work best.
True
100
What is induced fit (Enzymes)?
the Induced-Fit Hypothesis states that the shape of Active Sites are not exactly Complementary, but change shape in the presence of a specific substrate to become Complementary.
101
What are uncompetitive inhibitors?
an enzyme inhibitor binds only to the complex formed between the enzyme and the substrate. Uncompetitive inhibition typically occurs in reactions with two or more substrates or products
102
What are competitive inhibitors?
an inhibitor that resembles the normal substrate binds to the enzyme, usually at the active site, and prevents the substrate from binding. A competitive inhibitor diminishes the rate of catalysis
103
What are non-competitive inhibitors?
Noncompetitive inhibitor can bind to an enzyme with or without a substrate at different places at the same time. It changes the conformation of an enzyme as well as its active site, which makes the substrate unable to bind to the enzyme effectively so that the efficiency decreases.
104
What is the difference between competitive and non-competitive inhibitors?
The main difference is that in competitive inhibition, the inhibitor binds directly to the active site of the enzyme. ... In non-competitive inhibition, the inhibitor binds to a site on the enzyme that is NOT the active site
105
What are allosteric activators?
Effectors that enhance the protein's activity
106
What are allosteric inhibitors?
Effectors that decrease the proteins activity
107
True or False? Phorphoralysation activates enzymes.
True and False. Yes it can activate enzymes but it also can deactivate enzymes.
108
What are Isoenzymes?
Enzymes that catalyse the same reaction but have different amino acid structures.
109
What does the hydrolysis of zymogens and proenzymes do?
Activate the enzymes
110
True or False? We can use heat and light energy to do work?
False
111
What is the inner structure of the mitochondria folded into?
Structures called Cirstaes.
112
What is the inter-membrane space of the mitochondria?
the region between the inner membrane and the outer membrane of a mitochondrion or a chloroplast
113
What is the matrix space of the mitochondria?
In the mitochondrion, the matrix is the space within the inner membrane. The word "matrix" stems from the fact that this space is viscous, compared to the relatively aqueous cytoplasm.
114
What is glycolysis?
the breakdown of glucose by enzymes, releasing energy and pyruvic acid.
115
Where does glycolysis occur?
Glycolysis occurs in the cytosol of the cell. It is metabolic pathway which creates ATP without the use of oxygen but can occur in the presence of oxygen as well.
