Biochemical Basics Flashcards
Describe how protein conformation relates to enzyme action and how factors such as temperature and pH affect it.
the conformation of the protein determines the enzyme produced. this structure can be altered by a change in pH as it can affect the bonds in the protein. A temperature change affects the vibration of the bonds and can also lead to denaturing
Describe how enzymes catalyse reactions through lowering the free energy of chemical reactions as a consequence of the interactions between the substrate and the enzyme at the active site.
the energy needed to form the high energy intermediate is reduced. it is in this position that bonds are maximally strained.
Describe how the catalytic activity of enzymes can be explained by the nature of the amino acids present at the active site and how vitamins are modified to produce coenzymes and increase the diversity of reactions that enzymes catalyse.
the side chains of the amino acids at the active site bind to the substrate. substrate binds through hydrophobic, electrostatic interactions & hydrogen bonds. the active site is the cleft or crevice of a polypeptide chain
coenzymes activate enzymes or can carry electrons or molecular groups. little activity without the presence on an enzyme
Describe how the kinetic properties of enzymes are described by the Michaelis Menten equation and know the meaning of the terms S, V, Vmax and Km. (You do not have to be able to derive the equation).
S - substrate
V - velocity
Vmax - reaction rate when the enzyme is fully saturated by substrate
Km - michaelis menten constant, half inital rate of Vmax
Describe how enzyme activity can be represented in a graphical form (The Michaelis Menten Curve and the Lineweaver Burk plot).
the lineweaver burk plot is used to find Km and Vmax
competitve inhibition - Km increased, Vmax the same
uncompetitve inhibition - Km reduced, Vmax reduced
non-competitve inhibtion - Km the same, Vmax reduced
Describe how enzyme inhibitors change the kinetic parameters of an enzyme catalysed reaction and how these changes can be used to identify how an inhibitor acts on the enzyme
inhibitors decrease reaction velocity, inhibitors can be synthesised as theraputic agents. inhibitors can bind covalently or non covalently. can be competitive, non-competive or uncompetative.
Describe a simple structure for a 5 minute medical interview.
greet patient, explain purpose of interview, get consent for interview, ask for description of presenting complaint, obtain medical and drug history, social and family history, get patients ideas, concerns an expectations, summarise info and close session
Describe how the structure and kinetic properties of allosteric enzymes differ from other enzymes and how these properties are altered by positive and negative effector molecules.
allosterically regulated enzymes are composed of multiple subunits. the allosteric effector changes the catalytic site to complement substrate, inhibitor decreases enzyme activity. inhibitor changes shape of catalytic site so it is no long complementary.
Describe how the physiological role of enzymes can be explained in terms of their kinetic properties.
some enzymes can acheive a higher maximum rate such as catalase, which nears the hypothetical highest rate. the amount of substrate that can bind to enzymes is determined by what their use is in the body, such as the rate of production of a product
Understand the simple presentation of data.
guassian distribution - symmetric about the mean. It shows that data about the mean are more frequent than data far from the mean. Appears as a bell curve. 95% of data is within two standard deviations of the mean.
Understand the importance of statistical testing.
it helps us to know if our null hypothesis is extremely unlikely or likely. this can be used to find risk factors with diseases.
Define hazard ratio.
The ratio of the hazard rates corresponding to conditions described by two levels of an independent variable. Comparison of risk to control group.
Apply the concept of ‘reference range’ to clinical data.
the range of values that is deemed normal for a physiologic measurement in healthy persons
Suggest some reasons for elevated serum AP, GGT and LD enzymes.
AP - The highest concentration of AP is present in liver and bone; an elevated AP concentration is therefore generally attributed to either liver or bone disease.
GGT - liver diseases, hepatitis or cirrhosis, congestive heart failure, diabetes, or pancreatitis. They may also be caused by alcohol abuse or use of drugs that are toxic to the liver.
LD - Anemia, kidney disease, Liver disease, Muscle injury, Heart attack, Pancreatitis, Infections, including meningitis, encephalitis, and infectious mononucleosis (mono), Certain types of cancer, including lymphoma and leukemia.
To be able to discuss the nature of membranes in a biological system
lipid structures, phospholipid bilayer, flexible, self sealing, selectively permeable, separate environments
