34 Questions
What is the process of breaking down large molecules into smaller ones referred to as?
Catabolism
What is the main source of energy for cells?
Carbohydrates
What is the ratio of hydrogen atoms to oxygen atoms in carbohydrates?
2:1
What is the process of building up small molecules into larger ones referred to as?
Anabolism
What are the smaller molecules formed when complex carbohydrates are broken down?
Monosaccharides
What is the term for the chemical reactions that take place in cells?
Metabolism
What type of molecules are formed when many simple sugars join together?
Polysaccharides
What is the most common fat that is stored in the body?
Triglyceride
What is the function of enzymes in metabolism?
To control the chemical reactions that occur in the body
What is the main component of nucleic acids such as RNA and DNA?
Nucleotides
What is the role of water in metabolism?
To facilitate chemical reactions
What is the purpose of catalysts in chemical reactions?
To decrease the activation energy
What type of compounds are formed when two simple sugars join together?
Disaccharides
What is the function of vitamins in metabolism?
To act as coenzymes for chemical reactions
What is the characteristic shape of proteins due to?
The folding of the chain
What type of compounds are not based on a carbon chain?
Inorganic compounds
what is activation energy
the amount of energy needed for reacting particles to collide to break the bonds
whats the purpose of a catalyst and why is it useful
to decrease the amount of energy needed to break the bonds; hence lower activation energy, so more particles will have enough energy to react, making the reaction happen at a faster rate. Enzymes allow chemical reactions to occur at a fast enough rate at body temperature for the body to function. Without enzymes, the reactions would be too slow
whats the purpose of a catalyst and why is it useful
to decrease the amount of energy needed to break the bonds; hence lower activation energy, so more particles will have enough energy to react, making the reaction happen at a faster rate. Enzymes allow chemical reactions to occur at a fast enough rate at body temperature for the body to function. Without enzymes, the reactions would be too slow
what is the name for the molecule on which an enzyme acts
substrate
what is the name for the molecule on which an enzyme acts
substrate
Each enzyme will combine with only one particular substrate and is therefore involved in only one specific reaction. This occurs because the enzyme and its substrate have characteristics that are complementary to one another; that is, the enzyme and the substrate have a shape and a structure that allow them to fit together.
True
what are the two types types of models that describe how enzymes function
lock and key model and the induced fit model
what does the lock and key model state
the shape of the enzyme (key) is always complementary to the shape of the substrate (lock). Therefore, the two will fit exactly to form the enzyme-substrate complex
what does the induced fit model state
when the enzyme and substrate join, they form weak bonds that cause the shape of the enzyme to change, creating complementary shapes
what does the induced fit model state
when the enzyme and substrate join, they form weak bonds that cause the shape of the enzyme to change, creating complementary shapes
Each enzyme will combine with only one particular substrate and is therefore involved in only one specific reaction. This occurs because the enzyme and its substrate have characteristics that are complementary to one another; that is, the enzyme and the substrate have a shape and a structure that allow them to fit together.
True
Increasing substrate concentration also increases the rate of the reaction. This occurs because there will be more substrate molecules coming into contact with the enzyme molecules. However, increasing the substrate beyond a certain concentration will cease to have an effect because the active sites on all the enzyme molecules will be fully occupied.
True
The products of the reaction must be continually removed, otherwise the rate of the reaction will slow because it becomes more difficult for the substrate molecules to make contact with the enzyme molecules.
True
Temperature influences enzyme activity. The rate of most chemical reactions increases as temperature increases. This is true of most enzyme reactions but only within a limited temperature range. Because enzymes are proteins, beyond about 45–50°C their structure changes; they are denatured. As the shape of the enzyme is crucial for its functioning, denatured enzymes are inactive. The temperature at which an enzyme works best is called the optimum temperature. For most enzymes in the human body, this is 30°C to 40°C.
True
Enzymes are very sensitive to the pH of the medium in which a reaction is taking place. Each enzyme has an optimum pH at which it will work most effectively.
True
Many enzymes require cofactors. what do they do
They change the shape of the active sit so that the enzyme can combine with the substrate. Without a cofactor the enzyme molecule i intact, but cannot function.
what are non-protein organic cofactors called
coenzymes
what are enzyme inhibitors
substances that slow or stop the enzyme's activity. they may be used by cells to control reactions so that products are produced in specific amounts
Study Notes
Metabolism
- Metabolism refers to all chemical reactions that occur in cells and organisms.
- It consists of two types of chemical reactions: catabolic and anabolic reactions.
- Catabolic reactions involve breaking down large molecules into smaller ones, releasing energy, and are exemplified by digestion.
- Anabolic reactions involve building larger molecules from smaller ones, requiring energy, and are exemplified by protein synthesis.
Organic Compounds
- Organic compounds contain a carbon chain, hydrogen atoms, and may include oxygen, nitrogen, and sulfur atoms.
- Carbohydrates are a major source of energy for cells, containing carbon, hydrogen, and oxygen atoms in a 2:1:1 ratio.
- Simple sugars (monosaccharides) include glucose, fructose, and galactose, which can combine to form disaccharides and polysaccharides (e.g., starch and glycogen).
- Lipids, including fats and oils, are another energy source, broken down to fatty acids and glycerol, which can enter the glycolysis pathway.
- Proteins are composed of amino acids, with enzymes playing a crucial role in controlling metabolic reactions.
Amino Acids and Proteins
- Amino acids contain an amino group and a carboxylic acid group, which react to form a peptide bond when combined.
- There are 20 different amino acids, differing in their side chain structure.
- Proteins are long chains of amino acids, with their type and order determined by DNA code.
- Proteins have a characteristic shape due to chain folding.
Nucleic Acids and Inorganic Compounds
- DNA consists of two chains of nucleotides containing deoxyribose, storing inherited information in the nucleus.
- RNA is a single strand of nucleotides containing ribose, carrying information from DNA to the ribosomes for protein production.
- Inorganic compounds do not contain a carbon chain, with examples including water, minerals, and vitamins.
- Water is essential for metabolism as a fluid for substance dissolution and reaction medium.
- Minerals and vitamins are important for enzyme function, cofactors, and ATP production.
Chemical Reactions and Catalysts
- Chemical reactions require a minimum energy (activation energy) and correct atomic orientation for particles to react.
- Catalysts, such as enzymes, decrease the activation energy, allowing reactions to occur faster without being consumed.
- Enzymes, as biological catalysts, enable chemical reactions to occur at a suitable rate at body temperature.
This quiz covers the two types of chemical reactions in cells, including catabolic and anabolic metabolism, and their roles in breaking down and building up molecules.
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