Unit C Section 1.1 Flashcards
What are elements?
Elements are pure substances that cannot be broken down into other substances.
What do elements form?
They form chemical compounds that are used and
reused by living things.
Why is nitrogen important for living things.
plants require nitrogen to make substances necessary for life
How is nitrogen taken in plants?
plants can use nitrogen only when it is combined with other elements, such as hydrogen and oxygen
It has to be “fixed” in compounds with
other elements
How much nitrogen is in the air?
is about 78% nitrogen in the form of nitrogen gas (N2(g))
What is 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.
What does most of the nitrogen fixation in soil?
Certain types of bacteria do most of the nitrogen fixation in the soil.
How do bacteria do nitrogen fixation in the soil?
- Some of these bacteria are located in the root nodules of specific types of plants, such as beans, clover, and alfalfa
- The bacteria in these nodules are able to separate the two nitrogen atoms that form nitrogen gas (free nitrogen).
- Once separated, the nitrogen atoms can form compounds with other elements, such as hydrogen and oxygen.
What can also fixate nitrogen in the air?
Lightning also converts nitrogen in the air to nitrogen compounds that plants can use.
What are nodules?
The bumps on the roots of this alfalfa plant are called “nodules.”
What are steps in the nitrogen cycle?
- After nitrogen fixation occurs, plants use the nitrogen-containing compounds
- Animals then eat the plants.
- Their bodies use the nitrogen in the compounds to make more complex substances, such as proteins.
- Decomposers break down these large nitrogen-containing molecules in dead organisms and animal waste into simpler nitrogen compounds in the soil.
- The nitrogen can move from organisms and back to the soil several times.
- Eventually, some nitrogen-containing compounds are broken down further by other bacteria in the soil.
- This nitrogen is released back into the air as free nitrogen, and the cycle begins again.
Is the concentration of nitrogen the same everywhere?
-the concentration of usable nitrogen is not the same everywhere.
How is nitrogen removed from local environments in different ways?
-Conversion to free nitrogen by bacteria is one way
-by water carrying dissolved nitrogen compounds
away from or deep in to the soil so that they are unavailable to plants
-by water carrying dissolved nitrogen compounds
away from or deep into the soil so that they are unavailable to plants
What do farmers do if the soil lacks nitrogen?
If the soil lacks nitrogen, farmers plant nitrogen-fixing plants such as clover and alfalfa or add fertilizers to
increase the amount of nitrogen
The process of cellular respiration?
-You give it food as “fuel” and air rich in oxygen
-It uses the chemicals in the food and the oxygen in
the air in the process of cellular respiration to give you energy
-One of the products you release in this process is carbon dioxide
the vehicle burns fuel such as gasoline or
propane process?
- Oxygen from the air is required for that reaction.
- Along with the energy produced in this combustion reaction, gases such as water vapor, carbon dioxide, carbon monoxide, and nitrogen oxides are released into the atmosphere.
What is Pollution?
Pollution is any change in the environment that produces a condition that is harmful to living things.
For example, smog caused by vehicle exhaust emissions.
-Forest fires
What happens to the concentration of chemicals that is left in the environment through man-made activities:
- Many of these chemicals can be broken down through natural processes.
- Other chemicals cannot be broken down easily and can cause long-term problems
what is an issue?
An issue is any subject of importance about which people have strong, conflicting points of view
What is a fertilizer?
A fertilizer is a substance that enriches soil so that plants will grow better.
Fertilizers are described by the major nutrient elements they contain.
Which are:
These elements are nitrogen, phosphorus, and potassium.
15–30–15
What can be the fourth element in the fertilizer?
Some fertilizers have a fourth number and the letter “S” on the label to indicate that they contain sulfur as a major ingredient.