4.1 Biochemical pathways for chemical metabolism Flashcards
What are enzymes?
Catalysts in biochemical pathways
Are enzymes soluble in water?
Yes, most of the time
What is a substrate?
A molecule that an enzyme acts upon
What is an enzyme-substrate complex?
A structure where a substrate has bound with an enzyme
What is the structure of an enzyme?
A bundle of amino acids, forming the shape
What is enzyme specificity?
This determines how specific an enzyme is to its substrate.
What are the two models that can present enzyme specificity?
Lock and Key model and Induced-fit model
Explain the lock and key model
Only one size fits the shape; enzyme like a lock, substrate like a key; active site is assumed rigid
Explain the induced-fit model
Active site is assumed to be flexible and can fit around substrate tightly; active site is not complementary to substrate
What is a biochemical pathway?
The regulation of metabolic reactions; occurs in pathways that involve series of regulated steps controlled by enzymes; it is a negative feedback loop
Define catalytic power
The ability of an enzyme to increase the rate of a biochemical reaction, compared to the reaction occurring without the enzyme present
What is catabolism?
An exergonic reaction that releases energy and heat (exothermic); involves breaking down of a substrate and is involved in cellular respiration
What is anabolism?
An endergonic reaction that requires energy, making it endothermic; involves synthesis of new molecules and is involved in photosynthesis
What is activation energy?
An input of energy to start a reaction; enzymes allow for activation energy to reduce, so less energy is required from the body
What structure forms when a substrate binds to the active site of an enzyme?
An enzyme substrate complex
What model of enzyme so if it’s looks like a lock fitting in a key
Lock and key model
What model of enzyme specificity is similar to a glove changing shape as a hand slips into it?
The induced-fit model
What type of loop is a metabolic reaction?
A negative feedback loop
Is catabolism exergonic or endergonic?
Exergonic
Is anabolism exergonic or endergonic?
Endergonic
Is energy required or released in catabolism?
Energy is released
Is energy required or released in anabolism?
Energy is required
Is catabolism the break down or synthesis of substrate?
The breakdown of substrate
Is anabolism the breakdown or synthesis of substrate?
Synthesis of substrate
Is photosynthesis an example of catabolism or anabolism?
Anabolism
Is cellular respiration an example of catabolism or anabolism?
Catabolism
Is catabolism exothermic or endothermic?
Exothermic
Is anabolism exothermic or endothermic?
Endothermic
Define cellular metabolism
The sum of metabolic reactions in a cell
Define anabolic reaction
A reaction in which atoms and small molecules are joined together to make larger molecules; requires an initial input of energy so they can start to form new chemical bonds
Define endergonic reaction
A reaction that requires an initial input of energy to get them started
Define endothermic reaction
A reaction where light energy is absorbed from the surroundings and used to form bonds in a formed molecule
Define catabolic reaction
Complex molecules are broken down into simpler molecules; spontaneous reactions that do not require and initial input of energy.
Define exergonic reaction
A reaction that does not require an initial input if energy
Define exothermic
A reaction that releases energy
Define reactants
The inputs of a chemical reaction
What are cofactors/ coenzymes?
Molecules that assist enzymes
Define catalyst
A substance that increases the rate of a reaction without itself undergoing any permanent chemical change
What is photosynthesis?
The process by which photoautotrophs capture light energy and use it to convert water and carbon dioxide to glucose and oxygen
Where does photosynthesis occur?
In chlorophyll molecules of plants
What is glycogen?
The stored form of glucose in animals
How is glucose stored for long term?
Glycogen in animals, starch in plants
What is cellular respiration?
The process of breaking down glucose either completely in aerobic respiration using oxygen, or incompletely in anaerobic respiration when no oxygen is used
What is the purpose of cellular respiration?
To release the energy stored in the bonds of glucose to form the energy storage molecule adenosine triphosphate (ATP)
What is adenosine triphosphate (ATP)
The ‘energy bank’ of cells,which can make energy available to cells when it’s needed
What is the structure of ATP?
Contains an adenosine molecule, attached to a sugar group (ribose), which is bound to a chain of 3 phosphate groups
How is ATP formed?
By the addition of a phosphate group to an adenosine diphosphate (ADP) molecule in a reversible reaction catalysed by an enzyme ATP synthase
What is ADP?
A low-energy compound that when a phosphate group is added to it, it is converted into ATP for energy storage
What is ATP synthase
An enzyme that provides energy for the cell through the synthesis of ATP
Where does cellular respiration occur?
In the chronological and mitochondria
What is the outputs of anaerobic cellular respiration in plants?
Ethanol, carbon dioxide and 2ATP
What are the outputs of anaerobic cellular respiration in animals?
Lactic acid and 2ATP
