topic 1.1 Flashcards
(73 cards)
What do plants require nitrogen for?
For example, plants require nitrogen to make protein, nucleic acids (DNA), and chlorophyll.
What elements must nitrogen be combined with for plants to use it?
plants can use nitrogen only when it is combined with other elements, such as hydrogen and oxygen.
What percentage of air is nitrogen, and in what form is it present?
Air is about 78% nitrogen in the form of nitrogen gas N₂(g).
Why can’t plants use free nitrogen directly?
plants can’t use this “free” nitrogen directly. It has to be “fixed” in compounds with other elements.
plants can’t use this “free” nitrogen directly. It has to be “fixed” in compounds with other elements.
Nitrogen fixation is the process of changing free nitrogen so that the nitrogen atoms can combine with other elements to form compounds that organisms can use.
Which types organisims are primarily responsible for nitrogen fixation in the soil?
bacteria
Where are some of these bacteria located in plants like beans, clover, and alfalfa?
Some of these bacteria are located in the root nodules
What happens to nitrogen-containing compounds after nitrogen fixation?
plants use them
How do animals acquire nitrogen?
Animals then eat the plants that have used the nitrogen containing coumpounds.
What complex substances do animals create using nitrogen from plants?
Their bodies use the nitrogen in the compounds to make more complex substances, such as proteins and nucleic acids (DNA).
How do decomposers contribute to the nitrogen cycle?
Decomposers break down these large nitrogen containing molecules in dead organisms and animal waste into simpler nitrogen compounds in the soil.
How is nitrogen released back into the atmosphere in the nitrogen cycle?
This nitrogen is released back into the air as free nitrogen, and the cycle begins again.
What role do bacteria play in breaking down nitrogen compounds in the soil?
Eventually some nitrogen containing compounds are broken down further by other bacteria in the soil.
How do human activities, like driving cars, affect environmental processes?
use resources, consume energy, and emit pollutants on a substantial scale
What is pollution, and how does it impact living things?
Pollution is any change in the environment that produces a condition that is harmful to living things.
Why is smog caused by vehicle exhaust emissions harmful to humans and animals?
it makes it hard for people and other animals to breathe.
How do forest fires produce pollution?
Forest fires produce similar chemical pollution to smog
what are types of natural polution
Naturally occurring pollutants include ash, soot, sulphur dioxide, salt spray, volcanic, combustion gases
top 3 most common human caused pollutions
air pollution, water pollution, and land pollution
What are some examples of human activities that change the concentration of chemicals in the environment?
Growing crops, disposing of solid waste, treating wastewater, manufacturing products, and driving vehicles
What is the purpose of fertilizers
A fertilizer is a substance that enriches soil so that plants will grow better.
What are the main nutrient elements found in fertilizers?
These elements are nitrogen, phosphorus, and potassium.
How are fertilizers labeled to indicate their nutrient content?
The three numbers on the fertilizer label indicate how much of the elements on the fertilizer contain (nitrogen,phosperous, and potassium)
Why might some fertilizers have a fourth number and the letter “S” on the label?
Some fertilizers have a fourth number and the letter “S” on the label to indicate that they contain sulfur as a major ingredient.
