BIOC2000 Lecture Notes - Lecture 21: Anabolism, Motility, Equilibrium Point
Lecture 21: Enzymology L1
Assumed knowledge
• The fundamental molecular structure of biological macromolecules
(already covered)
• Secondary structure of proteins (α-helix, β-sheet) & how proteins are
represented
• Conjugate acid/base forms and acid-base equilibria
- HA ⇌H+ +A-
B+H+ ⇌ HB
- HA+H2O⇌H3O+ +A-
B+H2O⇌ BH+OH-
• Familiarity with the terms:
- free energy, enthalpy,
entropy
-ΔG = ΔH – TΔS
• Reactions and binding
equilibria
• Simple rate equations
Enzymology
- deals with the
properties, activity,
and significance of
enzymes
- enzymes are
biological catalysts
that work on
substrates to produce
products
*will emphasize on how
enzyme structure
affects its function
CHARACTERISTICS OF LIFE
1. Organisation
- being structurally composed of one or more cells
- e.g. building biological complexity
find more resources at oneclass.com
find more resources at oneclass.com
2. Transformation of energy by the interconversion of chemical energy
and cellular
- e.g. breakdown of nutrients for energy and building blocks for
synthesis
3. Growth
- maintenance of a higher rate of anabolism (chemical reactions that
synthesize molecules in metabolism) than catabolism (biochemical
reactions that break down molecules in metabolism).
4. Adaptation
- the ability to change over time in response to the environment
- e.g. mechanical work: movement of molecules, cells, organisms
5. Response to stimuli
- often involves motion e.g. phototrophism (plants following the sun)
& chemotaxis (movement of a motile cell or organism in a direction
corresponding to a gradient of increasing or decreasing
concentration of a particular substance e.g. e.coli cell will move
towards a nutrient if it senses it)
- e.g. mechanical work: movement of molecules, cells, organisms
6. Reproduction
- the ability to produce new individual organisms
- e.g. replication & transfer of genetic information
7. Homeostasis
- regulation of the internal environment to maintain a constant state
- e.g. formation and maintenance of osmotic and electrical gradients
But chemical reactions do not necessarily happen (a) spontaneously (b) to
the required extent (c) or sufficiently quickly to support life as we know it.
We could talk about chemical reactions in terms of (a) rate constant (b) or
half-life
Uncatalysed reactions in the body can have a half life ranging from 5
seconds to millions of years – that’s why we have enzymes!
Q1: What determines whether a reaction will happen? i.e. whether it
is thermodynamically favourable (“spontaneous”)?
- the relative stability of substrates (reactants) and products
- the system will always move to a lower energy (more stable) state i.e.
Gibbs Free Energy of products has to be LOWER
- ΔG = ΔH - TΔS
- The free energy change determines whether a reaction is possible, i.e.,
thermodynamically favourable or “spontaneous”
A+B ⇌ C+D
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Assumed knowledge: the fundamental molecular structure of biological macromolecules (already covered, secondary structure of proteins ( -helix, -sheet) & how proteins are, conjugate acid/base forms and acid-base equilibria represented. G = h t s: familiarity with the terms, reactions and binding equilibria, simple rate equations enzymes the activity, significance of. Deals with properties, and enzymes are biological catalysts that on substrates to produce products. *will emphasize on how enzyme structure affects its function work. Being structurally composed of one or more cells. E. g. building biological complexity: transformation of energy by the interconversion of chemical energy and cellular. E. g. breakdown of nutrients for energy and building blocks for synthesis: growth. Maintenance of a higher rate of anabolism (chemical reactions that synthesize molecules in metabolism) than catabolism (biochemical reactions that break down molecules in metabolism): adaptation. The ability to change over time in response to the environment. E. g. mechanical work: movement of molecules, cells, organisms: response to stimuli.
