Topic 1B Biological molecules and transport in cells Flashcards
qWhat is an enzyme?
A large protein that acts as a biological catalyst.
What is the purpose of an enzyme?
Reduce the need for high temperatures so enzymes speed up and are used for the useful chemical reactions in the body.
What is a catalyst?
A substance which increases the speed of a reaction, without being changed or used up in the reaction.
How are enzymes adapted for their purpose?
They are made up of proteins all proteins are made up of chains of amino acids. These are folded into unique shapes which is needed to do their job.
What needs to happen for a reaction to catalyse?
Enzymes only catalyse for one specific reaction for this to happen the substrate has to fit into its active site if it doesn’t it won’t catalyse.
What is an active site?
The part of an enzyme where a substrate molecule binds.
How does temperature effect enzymes?
Change in temperature it changes the rate of an enzyme-catalysed reaction.
What is the effect of hot temperatures on a reaction?
If a reaction gets too hot it will increase the rate at first but will break bonds holding the enzyme together therefore the enzymes active site changes shape and the substrate won’t fit the enzyme is denatured.
What temperature are enzymes most active?
37° (optimum temperature in human body)
How does substrate concentration effect reactions?
Higher the concentration, faster reaction because enzyme will more likely meet up and react with a substrate molecule.
Why does pH affect an enzyme?
If too high or low pH interferes with bonds holding enzyme together, this changes shape of active site and denatures the enzyme. (Optimum pH) For many enzymes optimum pH is 7.
Summarise the process to investigate enzymatic reactions
Starch detected using iodine solution if present will change from a browny-orange to blue-black.
How do you calculate rate of reaction?
Rate=1000/Time
What happens to enzymes in breakdown reactions?
The big molecules (Carbohydrates, proteins, lipids) need to be broken down into smaller components to be used for growth and other life processes.
What are carbohydrases?
Carbohydrase’s convert carbohydrates into simple sugars. Amylase is an example of of a carbohydrase, it breaks down starch.
What are proteases?
Proteases enzymes catalyse the conversion of proteins into amino acids.
What are lipases?
Lipases enzymes catalyse the conversion of lipids into glycerol and fatty acids.
What happens to enzymes in synthesis reactions?
They need to catalyse the reactions using their smaller components. Which is different to the ones used to breakdown reactions.
What are carbohydrates?
Carbohydrates can be synthesised by joining together simple sugars.
What are proteins?
Made by joining amino acids together. Enzymes catalyse to do this.
What are lipids?
Enzymes are also used in the synthesis of lipids from fatty acids and glycerol.
What is diffusion?
Particles spreading from an area of high concentration to an area of lower concentration. It happens in solutions and gases because particles can move freely.
Explain the role if cell membranes
They hold the cell together and let stuff in and out. They are partially permeable.
What does partially permeable mean?
It means that they let some molecules through but not others. Small things can defuse through cell membranes (oxygen, glucose, amino acids and water). But big things cannot (starch and proteins).
