In the Krebs cycle, how is citric acid formed? (1 point)
Pyruvic acid molecules
• are broken down by an acetyl group.
Enzymes combine
• hydrogen ions, oxygen, and electrons.
Acetyl-CoA joins with
• a large molecule called oxaloacetic acid.
Carbon dioxide bonds
• with a chain of coenzyme A.
The correct answer is:
Acetyl-CoA joins with a large molecule called oxaloacetic acid.
The following are steps of cellular respiration except (1 point)
O glycolysis
• the Krebs cycle
• electrolysis
electron transport chain
The correct answer is:
Electrolysis
Which molecule provides the activation energy that starts glycolysis? (Not which molecule is broken down during glycolysis)
(1 point)
• АТР
• sugar
• carbon dioxide
• water
?
The molecule that provides the activation energy that starts glycolysis is ATP (adenosine triphosphate).
During which phase of cellular respiration is carbon dioxide released? (1 point)
electron transport chain
• glycolysis
• digestion
• Krebs cycle
Which statement is true? (1 point)
Endotherms cannot insulate (stop heat loss from) their bodies and can only control their body temperature involuntarily.
Ectotherms cannot insulate (stop heat
• loss from) their bodies and can only control their body temperature by choice.Ectotherms can insulate (stop heat loss from) their bodies and can control their body temperature by choice.
Endotherms can insulate (stop heat
• loss from) their bodies but can only control their body temperature by choice.
The correct statement is:
Endotherms can insulate (stop heat loss from) their bodies but can only control their body temperature by choice.
Which activity uses ATP to raise body temperature? (1 point)
• shivering
• hibernating
• panting
• storing fats
The correct answer is:
Shivering
In the Northern Hemisphere, climate scientists observe seasonal changes in carbon dioxide concentration with the highest levels measured in May and the lowest levels measured in October. Hypothesize how photosynthesis can affect these changes. Explain your answer in three to five sentences. (Remember:
1. Leaves, in the Northern Hemisphere, appear on trees in the Spring and fall from trees in the Autumn. 2. Leaves are where photosynthesis occurs. 3. How does photosynthesis effect carbon dioxide?) (4 points)
In the Northern Hemisphere, during the spring and summer months, the leafy trees and plants go through a process called photosynthesis. Photosynthesis is the process by which plants use sunlight, carbon dioxide, and water to produce glucose and release oxygen. As more leaves appear on trees during this time, there is an increase in the overall photosynthetic activity occurring. This leads to a higher rate of carbon dioxide absorption from the atmosphere by the leaves. Therefore, the concentration of carbon dioxide in the atmosphere decreases during this period as it is being utilized by plants for photosynthesis. In contrast, during the autumn months, leaves start to fall from trees, reducing the overall photosynthetic activity. This leads to a decrease in carbon dioxide absorption by plants, causing the concentration of carbon dioxide in the atmosphere to rise. This seasonal fluctuation in carbon dioxide levels is primarily influenced by the cycle of leaf growth and shedding, which directly affects the rate of photosynthesis occurring in the Northern Hemisphere.
Plants in different environments have challenges that only they have.
For example, the growth of a plant in a rainforest (e.g., an orchid) might be more affected by different things than a plant in a desert (e.g., a succulent). In three to five
sentences, compare environmental challenges that could affect the photosynthetic process of a rainforest plant versus a desert plant. (4 points)
Rainforest plants face challenges such as competition for sunlight due to dense vegetation, high humidity leading to increased risk of fungal and bacterial infections, and reduced availability of nutrients due to rapid decomposition. In contrast, desert plants have to adapt to extreme heat and limited water availability, leading to adaptations like succulence, reduced leaf surface area to minimize water loss, and specialized water storage structures. These challenges affect the photosynthetic process differently - rainforest plants must compete for light and nutrients, while desert plants need to cope with limited water resources and high temperatures that can affect their photosynthetic efficiency.
In 3 to 5 sentences, describe the relationship between a glucose molecule and the products it makes during cellular respiration. (4 points)
During cellular respiration, a glucose molecule is broken down to produce energy in the form of ATP. In the first step of cellular respiration, glycolysis, glucose is converted into two molecules of pyruvate. These pyruvate molecules then enter the mitochondria for further processing. In the Krebs cycle, the pyruvate molecules are fully broken down to release carbon dioxide and generate energy-rich molecules like NADH and FADH2. Finally, during the electron transport chain, the NADH and FADH2 molecules donate their electrons to the chain, leading to the production of ATP and water as byproducts. Overall, the glucose molecule is gradually oxidized to release energy and forms carbon dioxide and water as waste products during cellular respiration.
Remember the law of conservation of mass. The human body uses cellular respiration to make energy.
Using the chemical equation for cellular respiration, explain how the amounts of oxygen and carbon dioxide inhaled by the lungs is different from the amounts exhaled.
Explain your answer in 1-2 sentences. (2 points)