C1.1 Flashcards
Define catalyst.
a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
State the role of enzymes in the chemical reactions on which life is based.
Enzymes are proteins that act as catalysts to make the rate of chemical reactions faster and more efficient.
- lower the activation energy for a reaction to take place
Enzymes _______ chemical reactions without being altered. Therefore, enzymes can be ______.
speed up, reused
Define metabolism
The sum of all chemical reactions in an organism.
Define specificity in relation to enzyme structure and function.
The enzyme’s active site can only bind with specific substrates. The ability of an enzyme to select a specific substrate from a range of chemically similar compounds is known as specificity. Charges have to align (+)(-) and shape has to fit together as a puzzle piece. The enzyme can then break the substrate or mold the substrates together.
Outline how control of metabolism is regulated by enzymes.
The cell can control a metabolic pathway by the presence or absence of a particular enzyme. Cells have evolved to use feedback inhibition to regulate enzyme activity in metabolism.
Negative feedback loops doesn’t mean it’s a bad thing - refers to dampening or reversal of a condition.
Positive feedback loops doesn’t mean it’s a good thing - refers to increasing or amplifying change of a condition.
Contrast anabolic and catabolic reactions.
Anabolism:
- builds molecules for body to function
- require energy input
- endergonic reaction
- condensation (water is produced)
Catabolism:
- breaks down big complex molecules into smaller, easier to absorb molecules.
- releases energy
- exergonic reaction
- hydrolysis (water is consumed)
List three examples of anabolic processes.
- photosynthesis (sunlight to plant food)
- peptide bond formation (links connect amino acids to form polypeptide chains, which fold into functional proteins)
- glycosidic bond (covalent chemical bonds that hold together a glycoside -sugar molecules attached to another molecule)
List three examples of catabolic processes.
- cell respiration (a series of chemical reactions that break down glucose to produce ATP)
- digestion
- oxidation (a process that occurs when atoms or groups of atoms lose electrons)
Outline properties of globular proteins.
- always soluble in water
- often have a spherical or roundish shape
Explain the relationship between enzyme structure and enzyme specificity, including the structure and function of the active site.
- structure/specificity is primarily defined by the enzyme’s shape and the characteristics of its active site (consequence of its amino acid sequence - R groups)
- active site: The part of the enzyme where the substrate binds
Outline the stages of enzyme catalysis of a chemical reaction.
-enzyme-substrate are in same area
-enzyme binds with substrate in active site
-catalysis - join or break substrate
-product release
Describe the induced fit model of enzyme binding.
states that when a substrate binds to an active site, the enzyme changes shape slightly, to accommodate the substrate and create an ideal fit for catalysis.
Explain the role of random collisions in the binding of the substrate with the enzyme active site.
faster-moving substrates are more likely to randomly collide with an active site (and a reaction can occur).
Compare enzyme and substrate movement involved in reactions that occur in the cytoplasm, with large substrates and with immobilized enzymes.
glycolysis-uses enzymes to break down sugar molecules for cell respiration, takes place in cell cytoplasm (intracellular).
Discuss variation in specificity of different enzymes.
Enzymes are highly specific so different enzymes are needed to bind and carry of chemical reactions
Define denaturation.
an enzyme that has loss of function or is non-functional in reactions due to its change in shape.
Outline the causes and effects of denaturation on enzyme structure and function.
-causes: deviations from optimal temperature and pH
-when an enzyme loses its native conformation, or three-dimensional structure, rendering it non-functional (unable to bind to substrate and catalyze product formation)
Graphs of temperature, pH, substrate concentration along with enzyme activity
Google docs
Explain the effects of temperature on enzyme structure and function with reference to collision theory, temporary and permanent denaturation.
Temp: Raising temperature speeds up a reaction (allows for more collision between substrate and enzymes to bind), and lowering temperature slows down a reaction. However, extreme high temperatures can cause an enzyme to lose its shape (denature) and stop working.
Explain the effects of
pH
on enzyme structure and function with reference to collision theory, temporary and permanent denaturation.
pH: Each enzyme has an optimum pH range.
(1-6) acidic environment
(8-14) basic environmenet
Changing the pH outside of this range will slow enzyme activity.
Explain the effects of substrate concentration on enzyme structure and function with reference to collision theory, temporary and permanent denaturation.
Increasing substrate concentration also increases the rate of reaction to a certain point. Once all of the enzymes have bonded substrates, any substrate increase will have no effect on the rate of reaction, as the available enzymes will be saturated and working at their maximum rate.
Identify the manipulated (independent), responding (dependent) and controlled variation in experiments of enzyme catalyzed reactions.
independent - concentration of enzyme, the concentration of the substrate, the temperature, and the addition of an inhibitor
dependent - rate of reaction
control - enzyme activity
State the unit for enzyme reaction rate.
one micromole of substrate per minute (ex. micromol/min)
