1.
Cellular Respiration begins with _____________.
Correct Answer
A. Glycolysis
Explanation
Cellular respiration is the process by which cells convert glucose into usable energy in the form of ATP. It begins with glycolysis, which occurs in the cytoplasm and does not require oxygen. During glycolysis, glucose is broken down into two molecules of pyruvate, generating a small amount of ATP and NADH. This is the first step in cellular respiration and is followed by either aerobic respiration (in the presence of oxygen) or anaerobic respiration (in the absence of oxygen), depending on the cellular conditions.
2.
Fermentation is a set of anaerobic pathways in which pyruvic acid is converted into other organic molecules in the cytoplasm.
Correct Answer
A. True
Explanation
The statement is true because fermentation is indeed a set of anaerobic pathways that occur in the cytoplasm of cells. During fermentation, pyruvic acid, which is produced through glycolysis, is converted into other organic molecules such as lactic acid or ethanol. Unlike aerobic respiration, fermentation does not require oxygen and is therefore considered an anaerobic process.
3.
When organic compounds are broken down and energy is released, what is that using a high energy molecule called?
Correct Answer
A. ATP
Explanation
ATP (adenosine triphosphate) is a high-energy molecule that is used as a source of energy in cells. When organic compounds are broken down, ATP releases its stored energy by breaking off a phosphate group, converting it into ADP (adenosine diphosphate). This release of energy powers various cellular processes. Phosphate is not a high-energy molecule itself, but it is a component of ATP and is involved in the transfer of energy. Therefore, the correct answer is ATP.
4.
After glycolysis occurs, the products (pyruvate) can follow three pathways.
Correct Answer
B. False
Explanation
After glycolysis occurs, the products (pyruvate) can follow two pathways: aerobic respiration or fermentation. In aerobic respiration, pyruvate enters the mitochondria and undergoes further reactions to produce ATP through the citric acid cycle and oxidative phosphorylation. In fermentation, pyruvate is converted into either lactic acid or ethanol, depending on the organism. Therefore, the statement that the products of glycolysis can follow three pathways is false.
5.
Pathways that operate without the presence of oxygen are called _______
Correct Answer
C. Anerobic pathways
Explanation
Pathways that operate without the presence of oxygen are called anaerobic pathways. These pathways are able to generate energy in the absence of oxygen by utilizing alternative metabolic processes. In anaerobic pathways, glucose is broken down through a process called glycolysis, which produces a small amount of ATP. This is in contrast to aerobic pathways, which require oxygen and can produce a much larger amount of ATP through processes such as the Krebs cycle and oxidative phosphorylation. Therefore, the correct answer is anaerobic pathways.
6.
When one six-carbon molecule of glucose is oxidized through glycolysis, what is created?
Correct Answer
B. Pyruvic acid
Explanation
During the process of glycolysis, one molecule of glucose is broken down into two molecules of pyruvic acid. This occurs in the cytoplasm of the cell and is the first step in both aerobic and anaerobic respiration. Pyruvic acid can then be further oxidized in the mitochondria to produce energy in the form of ATP through the citric acid cycle and oxidative phosphorylation. Therefore, the correct answer is Pyruvic acid.
7.
________ is a product of alcoholic fermentation.
Correct Answer
A. Ethyl alcohol
Explanation
Ethyl alcohol is a product of alcoholic fermentation. Alcoholic fermentation is a metabolic process in which yeast or other microorganisms convert sugars, such as glucose, into ethanol (ethyl alcohol) and carbon dioxide. This process is commonly used in the production of alcoholic beverages, such as beer and wine. Therefore, ethyl alcohol is the correct answer as it is the end product of alcoholic fermentation.
8.
Aerobic cellular respiration (inside the mitochondria) has two stages.
Correct Answer
A. True
Explanation
Aerobic cellular respiration does indeed have two stages. The first stage is glycolysis, which occurs in the cytoplasm and breaks down glucose into pyruvate. The second stage is the citric acid cycle (also known as the Krebs cycle), which takes place inside the mitochondria and further breaks down the pyruvate to produce energy-rich molecules such as ATP. Therefore, the statement "Aerobic cellular respiration (inside the mitochondria) has two stages" is true.
9.
The________ breaks down the 2 pyruvates generating 2 ATP molecules.
Correct Answer
C. Kreb's Cycle
Explanation
The Kreb's Cycle, also known as the citric acid cycle, is responsible for breaking down the 2 pyruvates generated during glycolysis. This cycle occurs in the mitochondria and produces 2 ATP molecules, along with other energy-rich molecules like NADH and FADH2. The Kreb's Cycle is a crucial step in cellular respiration, as it completes the breakdown of glucose and prepares the energy-rich molecules for the final stage of respiration, the electron transport chain.
10.
When pyruvic acid is produced through glycolysis, it is transported across the __________.
Correct Answer
A. Mitochondrial membrane
Explanation
Pyruvic acid is a product of glycolysis, which occurs in the cytoplasm of the cell. In order for pyruvic acid to enter the next stage of cellular respiration, which is the Krebs cycle, it needs to cross the mitochondrial membrane. The mitochondrial membrane acts as a barrier between the cytoplasm and the mitochondrial matrix, where the Krebs cycle takes place. Therefore, the pyruvic acid is transported across the mitochondrial membrane to enter the mitochondrial matrix for further processing.
11.
Where are the electron transport chains in mitochondria?
Correct Answer
D. Inner membranes
Explanation
The electron transport chains in mitochondria are located in the inner membranes. These inner membranes are folded structures called cristae, which provide a large surface area for the electron transport chains to carry out their function of generating ATP through oxidative phosphorylation. The inner membranes also contain other components of the respiratory chain, such as cytochromes and ATP synthase, which are essential for the electron transport process. Therefore, the electron transport chains are primarily found in the inner membranes of mitochondria.
12.
The actual number of ATP molecules generated varies from cell to cell depending on the efficiency of the cells.
Correct Answer
A. True
Explanation
The statement is true because the number of ATP molecules generated can vary between different cells due to differences in their efficiency. ATP is produced during cellular respiration, a process that occurs in the mitochondria. The efficiency of this process can be influenced by various factors, such as the availability of oxygen and nutrients, as well as the overall health and functioning of the cell. Therefore, it is expected that the actual number of ATP molecules generated will differ from cell to cell.
13.
Where does the Krebs Cycle take place?
Correct Answer
C. Matrix
Explanation
The Krebs Cycle, also known as the citric acid cycle, takes place in the matrix of the mitochondria. The matrix is the innermost compartment of the mitochondria, surrounded by the inner membrane. This is where the majority of the reactions of the Krebs Cycle occur, leading to the production of energy-rich molecules such as ATP. The outer membrane and stroma are not involved in the Krebs Cycle.
14.
Which is the correct order for cellular respiration?
Correct Answer
A. Glycolysis, Krebs Cycle, Electron Transport Chain
Explanation
The correct order for cellular respiration is Glycolysis, Krebs Cycle, Electron Transport Chain. Glycolysis is the first step in cellular respiration where glucose is broken down into pyruvate. The Krebs Cycle follows, where pyruvate is further broken down and carbon dioxide is produced. Finally, the Electron Transport Chain occurs, where electrons from the previous steps are used to generate ATP, the energy currency of the cell.
15.
Adding sugar to yeast in warm water increases the rate of fermentation.
Correct Answer
A. True
Explanation
Adding sugar to yeast in warm water increases the rate of fermentation because yeast feeds on sugar to produce energy and carbon dioxide. The warm water helps to activate the yeast and speed up the fermentation process. The sugar provides a food source for the yeast, allowing it to produce more carbon dioxide and alcohol. Therefore, the addition of sugar in warm water promotes a faster and more efficient fermentation.
16.
The gas that was being captured in the balloon in the yeast fermentation experiment was ____________
Correct Answer
D. Carbon dioxide
Explanation
In the yeast fermentation experiment, carbon dioxide is the gas that is being captured in the balloon. During fermentation, yeast breaks down sugar to produce energy, and one of the byproducts of this process is carbon dioxide. This gas is released into the surrounding environment, but when a balloon is placed over the container where the fermentation is taking place, it captures the carbon dioxide, causing the balloon to inflate. Therefore, carbon dioxide is the correct answer.