IB DP Biology Enzymes and metabolism Study Notes - New Syllabus
IB DP Biology Enzymes and metabolism Study Notes
IB DP Biology Enzymes and metabolism Study Notes at IITian Academy focus on specific topic and type of questions asked in actual exam. Study Notes focus on IB Biology syllabus with guiding questions of
- In what ways do enzymes interact with other molecules?
- What are the interdependent components of metabolism?
Standard level and higher level: 3 hours
Additional higher level: 2 hours
C1.1.1—Enzymes as catalysts
Enzymes: Nature’s Catalysts
What is a Catalyst? A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.1 This means that only small amounts of catalyst are needed to significantly speed up a reaction.
Inorganic Catalysts: Platinum is an example of an inorganic catalyst used in catalytic converters to reduce harmful emissions from vehicles.
Enzymes: Biological Catalysts: Enzymes are biological catalysts produced by living cells. They are essential for speeding up the biochemical reactions that are necessary for life.
Enzyme-Catalyzed Reactions: Enzymes convert substrates into products in a specific reaction. The general equation for an enzyme-catalyzed reaction is:
Substrates + Enzyme → Products
The Importance of Enzymes:
- Life Depends on Enzymes: If cells did not produce enzymes, the biochemical reactions that support life would occur at extremely slow rates. This would severely impact essential processes like respiration, digestion, growth, and movement.
Enzymes are crucial for life, enabling the rapid and efficient biochemical reactions that sustain cellular processes. Their catalytic activity is essential for the proper functioning of living organisms.
Some properties of enzymes are following: –
1. An enzyme speeds up a chemical reaction
Without enzyme: normal speed
With enzyme: higher speed
Reaction is sped up by a factor of \(10^8\) to \(10^{26}\)
100.000.000 to 100.000.000.000.000.000.000.000.000 FASTER
Chemical reactions cannot start by themselves
All reactions begin with breaking up of chemical bonds in substrate(s)
– They need an initial input of energy = ACTIVATION ENERGY
2. An enzyme reduces the energy needed to start a reaction
3. An enzyme is unchanged by the reaction
The enzyme can be used again and again Millions of times
C1.1.2—Role of enzymes in metabolism
Enzymes: Orchestrating the Metabolic Symphony
- Metabolism: A Complex Network: Metabolism encompasses all the chemical reactions occurring within an organism. These reactions are interconnected and form intricate pathways, converting one molecule into another through a series of steps.
- Enzyme Specificity: Almost every metabolic reaction is catalyzed by a specific enzyme. This specificity is a key feature of enzymes, distinguishing them from inorganic catalysts like platinum, which can catalyze multiple reactions.
- The Urea Cycle: An Example: The image shows a simplified representation of the urea cycle, a metabolic pathway involved in nitrogen waste removal. Each step in this cycle is catalyzed by a specific enzyme.
- Cellular Complexity and Enzyme Diversity: The vast number of metabolic pathways and the specificity of enzymes require cells to produce a large number of different enzymes. Even a simple prokaryotic cell synthesizes thousands of unique enzymes.
Enzymes are the workhorses of metabolism, driving the complex network of chemical reactions that sustain life. Their specificity and efficiency are crucial for the proper functioning of cellular processes and the overall health of the organism.
Names of enzymes very often end in –ase
Substrate Enzyme
Protein……………………Protease
Lipid………………………Lipase
Maltose……………………Maltase
Starch = Amylum…………Amylase