Enzymes Flashcards
What is anabolism?
Building of molecules
What is catabolism?
Digestion of molecules
What is responsible for the activities of the cells?
Energy and enzymes
What activities are energy and enzymes responsible for in the cell?
Transport of millions of proteins and vesicles moving between organelles
What is energy?
The ability to do work or cause change.
What is potential energy?
Energy stored in an object
What is chemical energy?
Potential energy in a chemical reaction
What is kinetic energy?
Energy of an object in motion
How is energy measured?
In joules
What is the first law of thermodynamics?
Energy can be transferred and transformed, but not created or destroyed
What is the second law of thermodynamics?
Every energy transfer or transformation increases the entropy of the universe
What is entropy?
Disorder of the universe
What is free energy?
The portion of a system’s energy that is available to do work
Why do systems tend to change spontaneously?
To meet a more stable State
What kinds of systems are rich in free energy that have the tendency to change to the opposite?
Unstable systems
What is the relationship with energy, stability and work capacity when there is a lot of free energy?
When there is more free energy, the system is less stable and work capacity is greater.
When there is less free energy, how does this affect the stability and work capacity?
There is more stability and less work capacity
What are exorgonic chemical reactions?
Chemical reactions that release energy
Whet kind of reaction is there a digestion of polymers? (Exo or endo)
Exorgonic
Is catabolism or anabolism involved in hydrolysis?
Catabolism
What kinds of chemical reactions are spontaneous with less organization and lower energy state?
Exorgonic
What reactions require an input of energy?
Endergonic
What kind of chemical reactions build polymers, have more organization and a higher energy state?
Endergonic
Is dehydration synthesis catabolism or anabolism?
Anabolism
What kind of reaction is cellular respiration?
Spontaneous
What kind of reaction is photosynthesis? (Sponanteous or not)
Non-spontaneous
What kind of systems are organisms?
Endorgonic
What do organisms need energy for?
Synthesis/building of biomolecules, reproduction, movement and active transport
What are the 3 main types of work done in the cell?
Mechanical chemical and transport
How do cells manage energy resources to do work?
By energy coupling
What is energy coupling?
Using an exorgonic process to drive an enclorgonic one
How are the bonds between phosphate groups broken?
Hydrolysis
What does ATP stand for?
Adenosine triphosphate
What is the cell’s main energy source?
ATP
What is ATP made of?
Adenine, ribose and 3 phosphates
What kind of process is the addition of phosphates?.
Endorgonic
What happens when ATP is hydrolyzed?
It becomes ADP
What does ADP stand for?
Adenosine diphosphate
What are features of ADP?
Only a good short term energy storage, too reactive, transfers pi too easily
How do chemical reactions start?
Non-spontaneously with required energy like a spark
What is activation energy?
The amount of energy needed to destabilize the bonds of a molecule
What is a catalyst?
A substance that can change the rate of a reaction without being altered in the process
What is an enzyme?
A biological catalyst made of protein and rRNAthat facilitates chemical reactions by increasing the rate of reaction without being consumed, reducing activation energy and without changing free energy
What kind of enzymes build molecules and what kind break down molecules and what kind speed up reactions?
Synthesis enzymes build molecules ( anabolic )
digestion enzymes break down molecules (catabolic)
and catalysts speed up reactions
What is a substrate?
The reactant that an enzyme acts on
How do an enzyme form an enzyme substrate complex?
Enzymes bind to their substrates forming an enzyme substrate complex
What is the active site?
Where the substrate binds
What do enzymes have building affinity for?
Substrates and only bond specific things like functional groups
What is the key to enzyme action?
Specificity
What is the induced fit in an enzyme?
Enzyme fits snugly around substrates in a clasping handshake
How are enzymes used in reactions?
Enzymes aren’t completely used up or changed by reactions. They are usually only used temporarily then re-used for the same reaction with other molecules
How much enzyme is needed to help in reactions?
Very little
Why do enzymes need to be certain shape?
Enzymes are specific helpers to specific reactions so they need the right shape for the job
What does sucrase do?
Breaks down sucrose
What does protease do?
Breaks down proteins
What do lipases do?
Break down lipids
What do DNA polymerases do?
Break down DNA
What is a metabolic pathway?
A pathway that has many steps which begin with a specific molecule and end with a product that is catalyzed by a specific enzyme
What are biosynthetic pathways divided into?
Catabolic and anabolic pathways
What do catabolic pathways do?
They release energy by breaking down complex molecules into simpler compounds
What do anabolic pathways do?
They consume energy to build complex molecules from simpler ones like amino acids to form proteins
What affects/denatures enzyme action?
Incorrect protein structure, temperature and ph
What is the optimum temperature of enzymes?
In between 35°c to 40°c
What is the relationship between the optimum temperature of enzymes and the number of collisions between enzymes and substrates?
When the enzymes is at the optimum temperature, there is the greatest number of collisions between enzymes and substrates
What does raising the temperature above the optimum do to enzymes?
It denatures the enzyme
What does lowering the optimum temperature do to enzymes?
It makes molecules slower with lower amount of collisions
What does change in ph do to enzymes?
Denatures the enzyme and disturbs the hydrogen bonds since ph of most human enzymes are between 6-8
What is the ph in pepsin?
3
What is the ph in trypsin?
8
What are the other factors that affect enzyme function?
Enzyme concentration, substrate concentration and salinity
What happens as you increase the amount of enzymes?
The reaction rate increases as well
What happens over some time as the enzyme is increased?
Eventually enzyme rate levels off as the substrate becomes the limiting factor
Why do substrates become the limiting factor as enzyme concentration is increased?
The enzymes can’t always find the substrates
What happens as you increase the substrate?
The reaction rate increases as the increased amount of substrate will collide more frequently with the enzyme
When do reaction rates level off when the substrate concentration has increased?
When all enzymes have active sites engaged
What does salinity describe?
The salt concentration of an enzyme
What does changes in salinity do?
Add and removes cations and anions, disrupts the bonds , attractions between amino acids and denatures proteins
What are enzymes intolerant of?
Extreme salinity
What is an activator?
A compound that helps enzymes
What are the types of activators?
Co factors and coenzymes
What are cofactors?
non-protein in organic compounds and ions bound within the enzyme molecule
What are examples of cofactors?
Calcium, potassium, copper and iron
What are co enzymes?
Non-protein organic molecules that bind temporarily or permanently to enzyme near active site.
What are inhibitors?
Molecules which reduce enzyme activity
What are the type of inhibitors?
Competitive, non-competive, feedback and irreversible
What inhibitors compete for the ‘‘active” site?
Competitive inhibitors
What inhibitor is penicillin and dissulfram cantabuse an example for and their uses?
Penicillin blocks enzyme bacteria used to build cell walls the and other is used to treat chronic alcoholism. They are both competitive inhibitors.
How can competitive inhibitors be overcome?
By increasing the substrate concentration, so the solutionis saturated by the substrate
What are non- competitive inhibitors?
Inhibitor that bind to sites other than the active site
Where does the allosteric inhibitor bind?
To an allosteric site
What causes a conformational change?
The allosteric inhibitor binding to an allosteric site so the active site would no longer be considered functional
What do cancer drugs do?.
They inhibit enzymes involved in DNA synthesis to stop DNA production as well as the division of more cancer cells
What are irreversible inhibitors?
This is when the inhibitor binds permanently to an enzyme
What type of inhibitor permanently changes the shape of the enzyme?
Irreversible inhibitors
What kind of inhibitor is cyanide and what does it do?
An irreversible inhibitor of the chromosome, stopping the production of ATP
What are feedback-inhibitors?
The end products of metabolic pathways that shuts it down
What do feedback inhibitors lead to?
Negative and positive feedback
What is negative feedback?
An accumulation of end product that slows the process that produces that product
What is the less common feedback?
positive Feedback
What is positive feedback?
Feedback that produces an end product which speeds up production
