Middle School Life Science : Cycling of Matter and Energy in Ecosystems
Study concepts, example questions & explanations for Middle School Life Science
All Middle School Life Science Resources
Example Questions
Example Question #21 : Cycling Of Matter And Energy In Ecosystems
Where does most of Earth's nitrogen exist?
in animal waste
in living organisms
in the soil
in the atmosphere
in the atmosphere
The answer is "in the atmosphere."
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #22 : Cycling Of Matter And Energy In Ecosystems
Nitrites and nitrates in the soil are converted by bacteria into a form usable by plants through the process of ______.
ammonification
fixation
nitrification
denitrification
fixation
The answer is "fixation."
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #23 : Cycling Of Matter And Energy In Ecosystems
Nitrogen can be changed into a form plants can use by which of these?
lightning
bacteria
all of these
decomposers
all of these
The answer is "all of these."
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #4 : Describe The Flow Of Matter In The Nitrogen Cycle
According to this diagram, what must happen to amino acids, ammonia, and urea before they can be used by plants?
nitrification and denitrification
some quantities are already usable
ammonification
fixation
some quantities are already usable
The answer is "some quantities are already usable" because there is an arrow showing the direction of matter straight to plants from amino acids, ammonia, and urea.
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #24 : Cycling Of Matter And Energy In Ecosystems
When animals die what happens to the nitrogen in their bodies?
Decomposers help break it down into a form usable by plants.
It dissolves completely.
It evaporates into the air.
Rain causes denitrification to break it down into plant nutrients.
Decomposers help break it down into a form usable by plants.
The answer is "decomposers help break it down into a form usable by plants."
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #6 : Describe The Flow Of Matter In The Nitrogen Cycle
What is eutrophication and how is it caused?
Eutrophication occurs when an aquatic system has an overabundance of nutrients. It is most often caused by an excessive amount of bacteria in the soil, performing nitrogen fixation at an increased rate.
Eutrophication occurs when an aquatic system has a lack of nutrients. It is most often caused by human activity like farming, maintaining golf courses and other activities that can lead to fertilizer run off.
Eutrophication occurs when an aquatic system has an overabundance of nutrients. It is most often caused by human activity like farming, maintaining golf courses and other activities that can lead to fertilizer run off.
Eutrophication occurs when an aquatic system has a lack of nutrients. It is most often caused by an excessive amount of bacteria in the soil, performing nitrogen fixation at an increased rate.
Eutrophication occurs when an aquatic system has an overabundance of nutrients. It is most often caused by human activity like farming, maintaining golf courses and other activities that can lead to fertilizer run off.
The answer is "Eutrophication occurs when an aquatic system has an overabundance of nutrients. It is most often caused by human activity like farming, maintaining golf courses and other activities that can lead to fertilizer run off."
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #25 : Cycling Of Matter And Energy In Ecosystems
True or false: Atmospheric nitrogen is easily taken up and used by plants and animals.
True
False
False
The answer is "false." Most of the nitrogen in the atmosphere is unavailable for use by organisms. In order for plants and animals to be able to use nitrogen, N2 gas must first be converted to a different form.
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #26 : Cycling Of Matter And Energy In Ecosystems
What do organisms primarily use nitrogen for?
energy
cellular respiration
none of these
all of these
production of proteins
production of proteins
The answer is "production of proteins." The ammonia produced by nitrogen fixing bacteria is used to make proteins.
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #27 : Cycling Of Matter And Energy In Ecosystems
How do synthetic fertilizers effect the nitrogen cycle?
Synthetic fertilizers add excessive nitrogen to areas, and the runoff causes eutrophication.
all of these
Synthetic fertilizers add nitrogen to the soil in a form usable by plants to help them grow, increasing agricultural production.
none of these
Excess nitrate from synthetic fertilizers can leach out of the soil, enter streams and rivers, and ultimately make its way into our drinking water.
all of these
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
Example Question #28 : Cycling Of Matter And Energy In Ecosystems
What process belongs in the blank in the image?
restoration
assimilation
re-nitrification
organization
assimilation
The answer is "assimilation."Organisms like plants, fungi and certain bacteria that cannot fix nitrogen gas (N2) depend on the ability to assimilate nitrate or ammonia for their needs.
The nitrogen cycle describes the flow of the element nitrogen on Earth. Most of Earth’s nitrogen exists in the atmosphere, but it can be moved into the soil through a process called “fixation.” Fixation usually occurs with the help of bacteria, but can also be done by lightning. Bacteria help nitrites and nitrates change into a form of nitrogen used by plants to help them grow. Animals get their nitrogen by eating plants. Animal waste contains nitrogen but needs to be fixed by bacteria as well. Additionally, when animals die their nitrogen reserves are broken down by decomposers where it can again be used by plants. Denitrification is the process where nitrogen in the soil returns to the atmosphere as a gas.
All Middle School Life Science Resources
