1.
Oxidation-reduction reactions are complex ones. Find the true facts.
Correct Answer(s)
A. Also called redox reaction
B. Oxidation is the removal of electrons from an atom or molecule, which will produce energy and reduction is the gaining of electrons
D. Glucose is a reduced molecule
Explanation
The given answer provides three true facts about oxidation-reduction reactions. It states that oxidation-reduction reactions are also called redox reactions. It explains that oxidation is the process of removing electrons from an atom or molecule, which results in the production of energy. It also states that reduction is the process of gaining electrons. Lastly, it mentions that glucose is a reduced molecule, indicating that it has gained electrons.
2.
A ______ is en enzymatic RNA molecule that cut and splice RNA in ______ cells.
Correct Answer(s)
ribozyme, eukaryotic
Explanation
A ribozyme is an enzymatic RNA molecule that is capable of cutting and splicing RNA in eukaryotic cells. Ribozymes are unique because they possess both enzymatic and genetic functions, allowing them to catalyze specific reactions within the cell. In eukaryotic cells, ribozymes play a crucial role in various cellular processes, such as RNA processing and gene regulation. They are involved in the removal of introns from pre-mRNA molecules, which is essential for the production of functional mRNA. Therefore, the given answer correctly identifies ribozyme as the enzymatic RNA molecule that performs RNA splicing in eukaryotic cells.
3.
Competitive inhibitors fill the active site of an enzyme and compete with the normal substrate for the active site. They do that because their shape and chemical structure are similar to those of the normal substrate.
Correct Answer
A. True
Explanation
Competitive inhibitors are molecules that bind to the active site of an enzyme and hinder the binding of the normal substrate. They do this because they have a similar shape and chemical structure to the substrate, allowing them to compete for the active site. This competition ultimately reduces the enzyme's activity, as the inhibitor effectively blocks the substrate from binding and undergoing the catalytic reaction. Therefore, the statement that competitive inhibitors fill the active site of an enzyme and compete with the normal substrate for the active site is true.
4.
Which is not true about noncompetitive inhibitors?
Correct Answer
C. The enzyme activity remains the same all in all
Explanation
Noncompetitive inhibitors interact with a different site on the enzyme, known as the allosteric site, rather than the active site. This binding causes a change in the shape of the active site, rendering it nonfunctional. As a result, the enzyme activity is affected and decreases. Therefore, the statement that the enzyme activity remains the same all in all is not true for noncompetitive inhibitors.
5.
What are the factors that influence the enzymatic activity? (can chose more than one)
Correct Answer(s)
A. Competitive and noncompetitive inhibitors
B. pH: enzyme activity declines when above or below optimum pH of most enzymes
C. Temperature: rate of reaction declines beyond the optimal temperature because the enzyme loses its characteristics (tertiary configuration), called denaturation
D. Enzymatic activity increases as substrate concentration increases until the enzymes are saturated
Explanation
The factors that influence enzymatic activity include temperature, pH, substrate concentration, and the presence of competitive and noncompetitive inhibitors. Temperature affects enzymatic activity as the rate of reaction declines beyond the optimal temperature, leading to denaturation of the enzyme. pH also affects enzymatic activity as it declines when above or below the optimum pH for most enzymes. Enzymatic activity increases with substrate concentration until the enzymes become saturated. Additionally, the presence of competitive and noncompetitive inhibitors can also influence enzymatic activity.
6.
Metabolism is defined by the sum of all chemical reactions within a living organism. What is right to say concerning anabolism and catabolism?
Correct Answer
G. A, D, and E are correct
Explanation
Catabolism refers to the breakdown of complex organic molecules into simpler substances, while anabolism refers to the synthesis of complex molecules from simpler ones. Both catabolic and anabolic reactions require energy. The energy for these reactions is stored in ATP. Therefore, options A, D, and E are correct.
7.
ATP plays an important role as an intermediate between catabolism and anabolism. Why is that? (can pick more than one)
Correct Answer(s)
A. ATP stores energy derived from catabolic reactions and releases it later to drive anabolic reactions and perform other cellular work
D. When the terminal pHospHate group is split from ATP, adenosine dipHospHate (ADP) is formed, and energy is released to drive anabolic reactions
Explanation
ATP plays a crucial role as an intermediate between catabolism and anabolism because it stores energy obtained from catabolic reactions and releases it later to drive anabolic reactions and perform other cellular work. Catabolic reactions transfer energy from complex molecules like glucose, starch, and lipids to ATP. On the other hand, anabolic reactions transfer energy from ATP to complex molecules such as glycerol, fatty acids, and proteins. When the terminal phosphate group is split from ATP, it forms adenosine diphosphate (ADP) and releases energy, which is then utilized to drive anabolic reactions.
8.
All but one is false about the components of enzymes.
Correct Answer
D. The enzyme-substrate complex formed by the temporary binding of enzymes and reactants enables the collisions to be more efective and increases the activation energy of the reaction.
Explanation
Enzymes are biological catalysts that can speed up chemical reactions without being permanently altered themselves. They are specific, meaning they can only catalyze specific reactions. Enzymes have an active site, which is a region where the reactants, called substrates, bind temporarily to form an enzyme-substrate complex. This complex allows for more effective collisions between the reactants, increasing the likelihood of a reaction occurring. Additionally, the formation of the enzyme-substrate complex increases the activation energy of the reaction, making it easier for the reaction to proceed.
9.
What are the products made during the Krebs cycle?
Correct Answer(s)
A. 6 NADH
C. 4 CO2
F. 2 FADH2
H. 2 Guanosine tripHospHate (GTP)
Explanation
During the Krebs cycle, also known as the citric acid cycle, several products are produced. These include 6 NADH, 2 FADH2, 4 CO2, and 2 Guanosine triphosphate (GTP). NADH and FADH2 are electron carriers that will go on to participate in the electron transport chain. CO2 is a waste product that is released during cellular respiration. GTP is a high-energy molecule that can be used to generate ATP. These products are essential for the efficient production of energy in the form of ATP during cellular respiration.
10.
What are the products made during glycolysis? (can chose more than one)
Correct Answer(s)
A. 2 Adenosine tripHospHate (ATP)
B. 2 H2O
D. 2 NADH
E. 2 Pyruvic acids
Explanation
During glycolysis, the products formed are 2 Adenosine triphosphate (ATP), 2 NADH, 2 Pyruvic acids, and 2 H2O. ATP is a high-energy molecule that is used as a source of energy in cellular processes. NADH is an electron carrier that is used in the production of ATP in the later stages of cellular respiration. Pyruvic acid is a three-carbon compound that is further processed in the citric acid cycle. Water is produced as a byproduct of the chemical reactions that occur during glycolysis. Therefore, the correct answer includes all of these products.
11.
Aerobic respiration, anaerobic respiration and fermentation compared.
Correct Answer
H. B, E, and F are false
Explanation
Fermentation can be either aerobic or anaerobic, so it does not require O2. NAD+ is being reduced in fermentation, glycolysis, and the Krebs cycle. Glycolysis is an anaerobic pathway for the oxidation of glucose. Therefore, the correct answer is that B, E, and F are false.
12.
Possible alternatives to glycolysis are:
Correct Answer(s)
A. Pentose pHospHate pathway
D. Entner-Doudoroff pathway
Explanation
The pentose phosphate pathway and the Entner-Doudoroff pathway are both alternative pathways to glycolysis. The pentose phosphate pathway is involved in the production of pentose sugars and reducing power in the form of NADPH, while the Entner-Doudoroff pathway is used by certain bacteria to break down glucose and produce pyruvate. The Calvin-Benson cycle is a pathway used by plants during photosynthesis to fix carbon dioxide, the Krebs cycle is involved in the oxidation of acetyl-CoA and the production of energy, and the Embden-Meyerhof pathway is another name for glycolysis itself.
13.
An amphibiotic pathway is a metabolic pathway that functions in both anabolism and catabolism.
Correct Answer
A. True
Explanation
An amphibiotic pathway is a metabolic pathway that can perform both anabolism (building complex molecules from simpler ones) and catabolism (breaking down complex molecules into simpler ones). This means that the pathway can be involved in both the synthesis and breakdown of molecules, depending on the needs of the cell or organism. Therefore, the statement that an amphibiotic pathway functions in both anabolism and catabolism is true.
14.
Lipids and proteins catabolism
Correct Answer
F. None is false
Explanation
The given statement "None is false" means that all of the statements mentioned in the question are true. This implies that lipases do break down fat into fatty acids and glycerol components, proteases and peptidases break down proteins into amino acids, and transamination, decarboxylation, and dehydrogenation reactions convert the amino acids to be catabolized. Therefore, there is no false statement in the given options.
15.
Bonus question: we are ready for tomorrow's test.
Correct Answer
B. False, never ready for that.
Explanation
The given statement "False, never ready for that" contradicts the initial statement "we are ready for tomorrow's test." This suggests that the person believes they are not prepared for the test.