chapter 4 Flashcards
what are anabolic reactions
they are required for growth and (building up)
what are catabolic reactions
they are required for breaking down
what is induced fit hypothesis
When the enzyme and substrate form a
complex, the structure of the enzyme is altered so that the active site of the enzyme fits around the substrate
what is activation energy
the energy a reaction needs to start up
what are intracellular enzymes
enzymes reacting inside the cell
what do extracellular enzymes do
break down large nutrients into small molecules outside the cell so nutrients can be absorbed
how is starch broken down
starch polymers is partially broken down into maltose (disaccharide)
the enzyme is called amylase
amylase produced by salivary glands
how is maltose broken down after its polymer (starch) has been broken down
broken down into glucose (monosaccharide)
the enzyme doing this is called maltase
what happens in the digestion of proteins
gets broken down into amino acids
trypsin is a type of protease
how does enzyme concentration effect reactions
the rate of reaction increases as enzyme concentration increases as there are more active sites for substrates to bind to, however increasing the enzyme concentration beyond a certain point has no effect on the rate of reaction as there are more active sites than substrates so substrate concentration becomes the
limiting factor
how does substrate concentration effect reactions
as concentration of substrate increases, rate of reaction increases as more enzyme-substrate complexes are formed. However, beyond a certain point the rate of reaction no longer increases as enzyme concentration becomes the limiting factor
how does temperature effect reactions
rate of reaction increases up to the optimum temperature, which is the temperature at which enzymes work at their maximum rate.
what’s an inhibitor
a substance which slows down or stops a reaction by affecting the binding of substrate to the enzymes. Inhibitors can either be reversible and irreversible
what’s an example of a irreversible inhibitor
Examples of irreversible inhibitors include heavy metal ions such as mercury and silver
which cause disulphide bonds within the protein structure to break, as a result causing the shape of the active site to change, thus affecting protein activity
what’s a reversible inhibitor
they bind to the active site through hydrogen bonds and weak ionic
interactions therefore they do not bind permanently. Reversible inhibitors can either be competitive or non-competitive.
what’s a competitive inhibitor
similar in structure to the substrate molecule therefore they bind to the active site of the enzyme, decreasing its activity as they compete with substrate for the enzyme. The amount of product formed remains the same, however the rate at which product formation occurs decreases. The higher the concentration of competitive inhibitor the lower the reaction rate. In
what’s a non competitive inhibitor
does not bind to the active site; it binds at another site on the enzyme known as the allosteric site. Binding of the non competitive inhibitors changes the shape of the active site therefore preventing the binding of the substrate. Increasing the
concentration of substrate has no effect on non-competitive inhibition.
what’s a co factor
a non-protein compound required for the enzyme’s activity to occur. There are three types of cofactors: coenzymes, activators and prosthetic groups
what’s a co enzyme
organic cofactors which do not bind permanently. They facilitate the binding of substrate to enzyme. Many coenzymes are vitamin derived
what’s a prosthetic group
permanently attached to the enzyme. For instance, haemoglobin contains a prosthetic haem group which contains iron, permanently bound to the molecule, which serves as a means of binding oxygen.
what’s an activator
are inorganic metal ions which temporarily binds to the enzyme and alters its active site, making the reaction more feasible. For instance, magnesium ion is an important
activator which is involved in processes such as shielding negative charge
role of enzymes
To catalyse reactions that affect metabolism at a cellular and whole organism level. They affect both structure and function.
Examples of stuff enzymes help with on the cellular level
Synthesis of cell components, synthesis of polymers from monomers, release of energy
Example of thing enzymes help with on the whole organism level
digestion
what does catalase do
Ensures that hydrogen peroxide is broken down to form oxygen and water so it doesn’t accumulate as hydrogen peroxide is toxic
what type of enzyme in catalase
intracellular
How is the formation of an enzyme-substrate complex good for the efficiency of the process?
Temporary bonds formed between R-groups in the active site and the substrate will put strain on the bonds within the substrate, making them easier to break.
How do enzymes speed up a reaction
they lower the activation energy because the enzymes help for molecules to collide successfully
what’s the effect when increasing the temp over optimum temp to an enzyme
Hydrogen bonds holding the tertiary structure break as the protein vibrates more, breaking bonds changes the tertiary structure and the shape of the enzyme, enzyme has been denatured, shape no longer complementary to the substrate, substrate can’t fit in the active site anymore
what is Q10
A measure of how much the rate increases with a 10 degrees celcius rise in temperature
Enzyme adaptations of organisms in extremely cold environments
enzymes are flexible which make them less stable
enzyme adaptations of organisms in extremely hot environments
more disulfide bonds
more hydrogen bonds
How extreme pHs affect enzymes
H+ ions can interact with polar and charged R groups, changing the concentration of H+ ions changes the degree of interaction, a higher concentration of H+ means the R groups will be able to interact with each other less, this breaks bonds and thus changes the shape of the enzyme,
whats the cofactor for amylase
Cl−
what is the prosthetic group for carbonic anhydrase
Zn2+
where can we find coenzymes
vitamins in diet
