Enzymes Flashcards
What are biomolecules?
Biomolecules are organic molecules. There are four main types of biomolecules. Three groups are important calorie suppliers (proteins, carbohydrates, and lipids). The fourth group stores the genetic material (DNA or nucleic acids >DNA + RNA).
What are the functions of these groups of biomolecules?
Carbohydrates: Serve as direct energy supply. Make up dietary fibres. Serve as identification tags on membranes.
Proteins: Make up the bulk of our body such as the muscles for example. Help to defend our body against diseases. Accelerate chemical reactions.
Lipids (fats): Are the main component of membranes. Insulate important organs such as the eye or the kidneys. Serve as energy supply and energy storage.
DNA (Nucleic acids >DNA + RNA): Store all the genetic material.
What is special about proteins?
Proteins are very diverse concerning structure and function. However, the basic building blocks are always the same 20 different amino acids. The shape of a protein is critical to its function, many different types of chemical bonds may be important in maintaining this shape. Changes in temperature and pH, as well as the presence of certain chemicals, may disrupt a protein`s shape and cause it to lose functionality, a process called denaturation.
Proteins are made up of one or more linear chains of amino acids, each of which is called a polypeptide.
How do we get the three-dimensional structure (tertiary structure) of a mature, functional protein?
The tertiary structure is primarily due to to interactions between the R groups of the amino acids that make up the protein. An R group interaction that contributes to tertairy structure is for example hydrogen bonding.
What is an enzyme?
An enzyme is a biological catalyst, meaning that it speeds up biochemical reactions. Most enzymes are proteins.
How do enzymes exactly work?
Enzymes act on one or more compounds (called the substrate or reactant). Different enzymes participate in different types of reactions and may break down, link up, or rearrange their substrates. >Catabolic reaction: a substrate is broken down (digestion, cellular respiration).
What happens then with the substrate?
When a substrate attains the required activation energy (minimum energy required to start a chemical reaction), it will change into the product. >Anabolic reaction: several substances build up a product (protein synthesis, photosynthesis. The part of the enzyme`s surface into which the substrate in bound and undergoes reaction is known as the active site.
What is the source of activation energy?
The source of activation energy is typically heat, with reactant molecules absorbing thermal energy from their surroundings. This thermal energy speeds up the motion of the reactant molecules.
What is special about enzymes?
Enzymes perform the critical task of lowering a reaction`s activation energy - that is, the amount of energy that must be put in for the reaction to begin.
Which factors may have an effect on the active site and the enzyme`s function?
There are two main factors that have an effect on the active site and the enzyme`s function:
- Temperature
- pH value
What is the pH value?
The pH-value is a measure of acidity and alkalinity of water-soluble substances. A pH value is a number from 1 to 14, with 7 as the middle (neutral) point. Values below 7 indicate acidity which increases as the number decreases, 1 being the most acidic. Values above 7 indicate alkalinity which increases as the number increases, 14 being the most alkaline.
