Section 9-1 Review Key Ideas

1. Identify the primary source of energy that flows through most living systems The sunlight. Autotrophs use sunlight to make their own food. Organisms that can’t make their own food consumed the food molecules made by autotrophs, eat autotrophs or eat organisms that consumed autotrophs. 2. Explain how an organism’s metabolism is related to Earth’s carbon cycle. An organism’s metabolism is related to using energy to build organic molecules which contain carbon or breaking down organic molecules in which energy is stored. Because of this, an organism’s metabolism is a part of the Earth’s carbon cycle. This cycle make carbon compounds continuously available in an ecosystem and deliver chemical energy to organism living within that ecosystem

3. Describe how energy is released from ATP. ATP is made up of an unstable chain of 3 phosphate group because they are all negatively charged and thus repel each other. The energy that was stored is released during the breaking of the 3rd bond. This energy can be released as heat or power in cell in order to help perform chemical activities. ATP can be used to contract muscle cell, actively transport a protein or help make more ATP. Critical Thinking

4. Analyzing Patterns Explain how life involves a continuous flow of energy. The law of conservation of energy states that the total amount of energy is an isolated system remains constant. The consequence of this law is that energy cannot be created nor destroyed. Energy can be converted or transformed into another form of energy. We can’t create more energy. A certain amount of energy will always be lost, usually as heat, to the environment.

Therefore, when we use glucose and other products to maintain our bodies, we generate heatas a “waste product”. Heat is also lost at each step as we go up the food chain, until all the energy trapped by plant is liberated as heat. Thus, energy does flow through life, or a system. At one point it was sunlight, at another point glucose, another point biomass consumed, and as heat finally.

5. Inferring Relationships How can the energy in the food that a fox eats be traced back to the sun? Fox in general or red fox may consume birds or small mammals like squirrels, rabbits and mice.

And as we know, squirrels eat fruits, nuts and seeds. These are products of plants, or autotrophs. Autotrophs make their own food through photosynthesis. However, it would be impossible for them to produce organic compounds from CO2 and H2O without sunlight. Therefore, the energy in the food that the squirrels eat, which the fox eats, came from the sun.

6. Summarizing Information What is the difference between cellular respiration and the process by which energy is released from a burning log?

When the log burns the chemical energy stored in wood molecules is released in a burst of heat and light. While during a cellular respiration, stored chemical energy is released gradually in a series of enzyme-assisted reactions. Cellular respiration takes place in the mitochondria. This process is the breaking down C6H12O6 and burning it with O2 in a combustion or water yielding reaction to form CO2 and H2O while burning a log is an exothermic reaction which is caused by the burning of Hydrocarbon in the presence of O2.