Enzymes In Action Flashcards
What are amino acids?
Amino acids are the building blocks of all proteins and are vital biological molecules.
How can amino acids be described in terms of molecular structure?
Amino acids are monomers that combine to form larger molecules called polymers. Proteins are polymers.
What elements are found in all amino acids?
Nitrogen (N), Carbon (C), Hydrogen (H), and Oxygen (O). Some also contain Sulfur (S).
How many types of amino acids are there?
There are 20 different types of amino acids.
What is the difference between essential and non-essential amino acids?
Essential amino acids (9) must be obtained from the diet, while non-essential amino acids (11) can be synthesized by the body.
What are the functional groups in an amino acid?
- Hydrogen atom
- Amino group (-NH₂)
- Carboxyl group (-COOH)
- Variable R group
What role does the R group play in amino acids?
The R group is unique for each amino acid and determines its biochemical properties (e.g., positive, negative, polar, hydrophobic)
What determines the function of a protein?
The specific 3D structure (shape) of a protein determines its function.
What are enzymes?
Enzymes are protein molecules that act as biological catalysts, speeding up chemical reactions.
How are amino acids joined together?
Amino acids are joined via peptide bonds (a type of chemical bond)
How do two amino acids join together?
Two amino acids join via a peptide bond to form a dipeptide.
What type of reaction forms a peptide bond?
A condensation reaction, where a molecule of water is produced.
What is a monomer in protein structure?
An amino acid, which can combine to form polymers like proteins or polypeptides.
What are the four levels of protein structure?
- Primary structure (1°)
- Secondary structure (2°)
- Tertiary structure (3°)
- Quaternary structure (4°)
What defines the primary structure of a protein?
The number and sequence of amino acids in a polypeptide chain.
What happens in the secondary structure of a protein?
The polypeptide chain folds or coils into alpha helices and/or beta-pleated sheets.
What holds the secondary protein structure together?
Hydrogen bonds only
Q: Why are hydrogen bonds important in the secondary structure?
They determine the final shape of proteins, including enzymes.
What happens in the tertiary structure of a protein?
The polypeptide chain folds further into a specific complex 3D shape.
What determines how the polypeptide chain folds into its 3D shape?
The R groups on amino acids determine how the polypeptide chain folds into its specific three-dimensional shape
How is the 3D shape of a protein held together?
By bonds between R groups of different amino acids.
What are the three types of bonds that maintain the tertiary structure?
- Hydrogen bonds (between H and O)
- Ionic bonds (between oppositely charged R groups)
- Disulfide bridges (between cysteine amino acids)
Why is the tertiary structure of a protein essential?
The shape of the protein determines its function, including interactions with other molecules (e.g., active sites in enzymes).
How does the primary structure influence the tertiary structure?
The sequence of amino acids in the primary structure determines where bonds form and the specific 3D shape of the protein.
What is the quaternary structure of a protein?
When two or more polypeptide chains join together to form a functional protein.
Give an example of a protein with quaternary structure.
Haemoglobin, which consists of four polypeptide chains.
What bonds maintain the quaternary structure?
Hydrogen, ionic, and disulfide bonds link the polypeptide chains together
What is the primary structure of a protein?
The number and order of amino acids joined together through peptide bonds.
What is the secondary alpha helix structure?
The polypeptide chain is folded and held in place by hydrogen bonds, forming a coil.
What is the secondary beta sheet structure?
The polypeptide chain is folded and held in place by hydrogen bonds, forming a pleated sheet.
What is the tertiary structure of a protein ?
The structure involves further folding of the protein, held together by hydrogen, ionic, and disulfide bonds, giving it a specific shape.
What is the quaternary structure of a protein?
When two or more polypeptide chains are joined together to form a functional protein.
What do enzymes have that allows them to function?
An active site that fits a substrate.
What happens if the enzyme’s active site changes?
The substrate will no longer fit, and the enzyme will not function.
What is it called when an enzyme no longer functions due to a shape change?
Denatured
What are proteins made of?
Proteins are polymers of amino acids.
How are amino acids joined together?
By peptide bonds.
What reaction forms peptide bonds?
A condensation reaction.
What is the primary structure of a protein?
A sequence of amino acids in a polypeptide chain.
What is the secondary structure of a protein?
The folding of the polypeptide chain due to hydrogen bonds, forming alpha helices and beta pleated sheets.
What is the tertiary structure of a protein?
The 3D folding of the polypeptide due to hydrogen bonds, ionic bonds, and disulfide bridges
What is the quaternary structure of a protein?
The arrangement of two or more polypeptide chains into a functional protein.
What is the role of a catalyst in a chemical reaction?
A catalyst increases the rate at which chemical reactions occur but remains unchanged or unaffected by the reaction. They take part in the reaction but do not get used up.
What is the equation summarizing a chemical reaction?
Reactants → Products
What must happen for a reaction to occur?
The reactants must collide with both energy greater than or equal to the activation energy and with the correct orientation. Only a small number of collisions lead to a chemical reaction.
What is activation energy?
The minimum energy required for collisions to break the bonds in the reactants and lead to a reaction.
How does increasing concentration affect the rate of reaction?
A greater number of reactant particles means more frequent collisions between reacting particles, leading to a faster reaction.
How does increasing surface area affect the rate of reaction?
More frequent collisions will occur between reacting particles, leading to a faster reaction.
What are the four ways of increasing the rate of reaction?
- Increasing concentration (greater number of reactant particles) → More frequent collisions will occur between reacting particles, leading to a faster reaction.
- Increasing surface area of a solid reactant → More frequent collisions will occur between reacting particles, leading to a faster reaction.
- Increasing temperature → The particles will have more energy and will move faster; therefore, there will be more collisions.
How does increasing temperature affect the rate of reaction?
The particles will have more energy and move faster, leading to more collisions.
How does increasing temperature affect the rate of reaction?
The particles will have more energy and move faster, leading to more collisions.
How does adding a catalyst affect the rate of reaction?
It shows activation energy with and without an enzyme catalyst, as well as the energy levels of reactants and products.
What does the energy profile diagram show?
It shows activation energy with and without an enzyme catalyst, as well as the energy levels of reactants and products.
Why are enzymes specific?
Enzymes have a specific tertiary structure. They have a specifically shaped active site which is complementary to the substrate. This means that enzymes are specific; for example, the enzyme peptidase can only catalyse the breakdown of protein and would not be able to break down starch.”
What is the key point about enzyme–substrate specificity?
Each enzyme will have a different substrate which is complementary to its active site. There are thousands of different enzymes within the specialised cells that make up our body’s tissues, and each of these enzymes controls a different biochemical reaction.”
What happens when the substrate binds to the enzyme?
The substrate will bind to the enzyme active site forming an ‘enzyme–substrate complex.’ A chemical reaction takes place in the enzyme–substrate complex and the substrate is converted into product. This then leaves the active site of the enzyme, leaving the enzyme intact to bind to another substrate molecule.”
what is the role of an enzyme in a reaction ?
an enzyme catalyses a reaction by binding to a substrate and lowering the activation energy required for the reaction.
what does complementary shape refer to in enzyme activity ?
the enzyme’s active site has a specific shape that fits the substrate perfectly, allowing a successful collision.
what happens when a substrate binds to an enzyme ?
an enzyme substrate complex forms , where the substrate is held in place by the enzymes active site.
what occurs at the enzyme’s active site during the reactions ?
the substrates bonds are broken, leading to the formation of the product.
why is it important to measure the initial rate of reaction ?
because as the reaction proceeds, reactants are used up, and the reaction slows down. measuring the initial rate provides accurate data on reaction speed .
what happens after the enzyme catalyses the reaction ?
the product is released ,and the enzyme remains unchanged ,ready to catalyse another reaction.
what happens to the substrate concentration as the reaction progresses ?
it decreases , which slows down the reaction.
how does an enzymes concentration change during a reaction ?
the enzyme remains at a constant concentration , unlike the substrate , which gets used up.
what does the dashed line in the reaction graph represent ?
it represents the gradient used to calculate the initial rate of reaction
why does the reaction rate plateau in the graph ?
because the substrate is used up, meaning no more can be formed.
