1.
Questions 17-20 refer to our Elodea densa Lab. In our lab we experimented with Elodea densa plants and Bromothymol Blue (CO2 indicator) to determine whether or not plants can perform both cellular respiration and photosynthesis. The following diagram represents our experiment and the corresponding questions discuss elements of this experiment.(2.3) Which test tube was our control? Why did we need this control in our experiment? What did we learn from the results of the control trial?
2.
(2.3) What was the dependent variable in our experiment? What did we use to measure the dependent variable?
3.
(2.3) Test tubes #4 and #5 were kept in the dark. After three days, the Bromothymol blue (BTB) solution in these two tubes was light green/yellow. What does this tell us about the level of CO2 in these test tubes? What does this tell us about the type of reactions that the Elodea densa plants performed?
4.
(2.3) Do plants perform both photosynthesis and cellular respiration? [Make sure to use evidence from the experiment and your knowledge of plant cells to support your answer.]
5.
(2.4) Students perform a scientific investigation using several types of bacteria grown in liquid solutions. After allowing the bacteria to grow in the test tubes for several days, they observe that some of the bacteria are growing close to the surface of the liquid in the test tube, and some of the bacteria are growing at the bottom of the test tubes. Which cellular process does the bacteria growing close to the surface of the liquid in the test tube most likely use to produce energy?
Correct Answer
C. Aerobic respiration
Explanation
The bacteria growing close to the surface of the liquid in the test tube most likely use aerobic respiration to produce energy. Aerobic respiration is the process by which cells convert glucose and oxygen into carbon dioxide, water, and ATP (energy). Since these bacteria are growing close to the surface, they have access to oxygen, which is required for aerobic respiration. This process is more efficient and produces more energy compared to fermentation or anaerobic respiration, which do not require oxygen. Photosynthesis is not a likely process for bacteria as it is primarily used by plants and some bacteria to convert sunlight into energy.
6.
(2.4) Which step of respiration is found in both aerobic and anaerobic respiration?
Correct Answer
A. Glycolysis
Explanation
Glycolysis is the step of respiration that is found in both aerobic and anaerobic respiration. It is the initial step in the breakdown of glucose, where glucose is converted into pyruvate. This process occurs in the cytoplasm and does not require oxygen. In aerobic respiration, pyruvate is further broken down in the Kreb's Cycle and Electron Transport Chain, which occur in the mitochondria and require oxygen. In anaerobic respiration, pyruvate undergoes fermentation to produce either lactic acid or ethanol, depending on the organism. Therefore, the correct answer is glycolysis.
7.
(2.4). Energy is produced through the process of cellular respiration in all living organisms. Aerobic respiration occurs through the use of oxygen, while anaerobic respiration does not use oxygen. Which statement about anaerobic respiration is correct?
Correct Answer
C. Anaerobic respiration makes less energy (ATP) than aerobic respiration
Explanation
Anaerobic respiration makes less energy (ATP) than aerobic respiration because aerobic respiration utilizes oxygen, which allows for the complete breakdown of glucose and produces a large amount of ATP. In contrast, anaerobic respiration occurs in the absence of oxygen and only partially breaks down glucose, resulting in a smaller amount of ATP production.
8.
(2.4) A representation of a chemical reaction is shown below. What process is shown in this chemical reaction?
Correct Answer
C. Aerobic cellular respiration
Explanation
The representation of the chemical reaction shows the process of aerobic cellular respiration. This process occurs in the presence of oxygen and involves the breakdown of glucose to produce energy in the form of ATP. It is a common process in most living organisms, including humans, and is essential for their survival and functioning.
9.
(2.4) One way that humans can recycle is by creating compost piles in their gardens where they allow food waste to be decomposed. Compost piles can be classified as aerobic or anaerobic. The design of the compost piles determines whether the bacteria growing in it are aerobic or anaerobic. Which statement describes a compost pile in which bacteria perform anaerobic respiration?
Correct Answer
B. A compost pile that is covered so that gases cannot escape or enter
Explanation
A compost pile that is covered so that gases cannot escape or enter creates an anaerobic environment. Anaerobic respiration occurs in the absence of oxygen, and by covering the pile, oxygen is prevented from entering and gases produced during decomposition are trapped within the pile. This lack of oxygen promotes the growth of anaerobic bacteria, which break down the organic matter in the compost pile.
10.
(2.1) Glucose produced during photosynthesis is used during cellular respiration to yield ATP. What is the original source of energy used during photosynthesis to create glucose molecules?
Correct Answer
D. Light
Explanation
During photosynthesis, plants use light energy from the sun to convert carbon dioxide and water into glucose and oxygen. This process occurs in the chloroplasts of plant cells, where chlorophyll absorbs light energy. This light energy is then used to power the chemical reactions that convert carbon dioxide and water into glucose. Therefore, the original source of energy used during photosynthesis to create glucose molecules is light.
11.
(2.1) A diagram of energy transfer for the processes of photosynthesis is shown below. Which statement is true about the reactants in photosynthesis?
Correct Answer
D. pHotosynthesis reactants are low energy molecules being built up into larger molecules to store energy; cellular respiration reactants are high energy molecules being broken down into smaller molecules to release energy.
Explanation
In photosynthesis, the reactants are low energy molecules (such as carbon dioxide and water) that are being built up into larger molecules (such as glucose) to store energy. On the other hand, in cellular respiration, the reactants are high energy molecules (such as glucose) that are being broken down into smaller molecules (such as carbon dioxide and water) to release energy. This explanation highlights the difference in the reactants and processes involved in photosynthesis and cellular respiration.
12.
(2.1) Which of the following is a product of photosynthesis and a reactant for cellular respiration?
Correct Answer
C. Sugars (like glucose)
Explanation
Sugars (like glucose) are a product of photosynthesis and a reactant for cellular respiration. During photosynthesis, plants convert sunlight, carbon dioxide, and water into glucose and oxygen. Glucose is then used as a source of energy during cellular respiration, where it is broken down to produce ATP, the main energy currency of cells. Therefore, sugars like glucose play a crucial role in both processes, making them the correct answer.
13.
(2.1) Mitochondria and chloroplasts are important energy-related organelles. What is the main difference in the processes performed by these organelles?
Correct Answer
A. Mitochondria release energy from sugars like glucose; chloroplasts use solar energy to make sugars like glucose.
Explanation
Mitochondria and chloroplasts are both organelles involved in energy production, but they have different processes. Mitochondria release energy from sugars like glucose through a process called cellular respiration. On the other hand, chloroplasts use solar energy to perform photosynthesis, which converts carbon dioxide and water into sugars like glucose. Therefore, the main difference between these organelles is that mitochondria release energy from sugars, while chloroplasts use solar energy to produce sugars.
14.
(2.5) A representation of the carbon cycle is shown below. Look at this chart carefully. If the amount of the atmospheric carbon dioxide were decreased, what would be the most direct effect on an ecosystem?
Correct Answer
C. Producers would have less material for making food
Explanation
If the amount of atmospheric carbon dioxide were decreased, producers would have less material for making food. This is because carbon dioxide is a key component in photosynthesis, the process by which producers convert sunlight into energy-rich molecules. With less carbon dioxide available, producers would have a limited supply of raw materials for photosynthesis, which would ultimately result in a decrease in their ability to produce food.
15.
(2.5) Another representation of the carbon cycle is shown in the diagram below. Which two processes would cause an increase in carbon dioxide?
Correct Answer
A. Respiration and the burning of fossil fuels
Explanation
Respiration is the process by which living organisms release carbon dioxide into the atmosphere as a byproduct of cellular respiration. The burning of fossil fuels, such as coal, oil, and natural gas, also releases carbon dioxide into the atmosphere. Both respiration and the burning of fossil fuels contribute to an increase in carbon dioxide levels in the atmosphere, making them the two processes that would cause an increase in carbon dioxide.
16.
(2.1) The diagram below shows a relationship between photosynthesis and cellular respiration. Which statement best describes the relationship and interdependence of photosynthesis and cellular respiration?
Correct Answer
B. The reactants of pHotosynthesis are the products of cellular respiration.
Explanation
The reactants of photosynthesis, which are carbon dioxide and water, are the products of cellular respiration. This means that the products of cellular respiration, which are carbon dioxide and water, are used as the reactants in photosynthesis. Therefore, there is a direct relationship and interdependence between photosynthesis and cellular respiration, where the products of one process are used as the reactants in the other process.
17.
(2.1) Oxygen plays an incredibly important role in cellular respiration. Which of the following best describes that role?
Correct Answer
A. Oxygen accepts H at the end of the electron transport chain and forms H2O
Explanation
Oxygen accepts H at the end of the electron transport chain and forms H2O. In cellular respiration, oxygen is the final electron acceptor in the electron transport chain. It combines with hydrogen ions to form water (H2O). This process is crucial for the production of ATP, the energy currency of the cell. Without oxygen, the electron transport chain would not be able to function properly, leading to a decrease in ATP production and ultimately affecting cellular respiration.
18.
(2.1) Molecules like NADH, NADpH, and FADH2 are incredibly important to cellular processes like photosynthesis and cellular respiration. Which of the following best describes the roles these molecules?
Correct Answer
D. Within pHotosynthesis and cellular respiration, they carry chemical energy from one reaction to another.
Explanation
Molecules like NADH, NADPH, and FADH2 play a crucial role in cellular processes like photosynthesis and cellular respiration. They do not act as reactants or products of these processes, nor do they provide the initial chemical energy to start them. Instead, these molecules function as carriers of chemical energy, transferring it from one reaction to another within photosynthesis and cellular respiration.
19.
(2.2) Which of the following shows an example of precision but NOT accuracy?
Correct Answer
B. B
20.
(2.6) Which of the following represents an anabolic reaction?
Correct Answer
A. A
Explanation
Anabolic reactions are metabolic processes that build larger molecules from smaller ones, requiring energy input. Option A represents an anabolic reaction because it shows the synthesis of larger molecules from smaller ones, indicating the building of complex molecules.