Unit 3: Topic 4 - Cellular Energy Flashcards
Where does the majority of energy originate from, and what type of energy is it?
From the sun, this energy is called light energy (which consists of energy bound to photons). This constant input of energy is necessary for all living things.
What is the final form light energy will end up in?
Light energy is converted to cellular energy through photosynthesis and then converted (through many steps) into ATP and used for cellular processes.
What is the first law of thermodynamics?
Energy cannot be created or destroyed and can only change its form or be transferred.
What is the second law of thermodynamics?
The overall entropy/randomness of the universe is increased with every energy transfer. This is partly due to every energy transfer yielding some amount of unusable energy (in the form of heat). Most energy is lost as heat.
Why does a living system need a greater input of energy than its total energy loss, and what is the biggest consequence of not doing so?
To counter the energy loss as heat from maintaining order and powering cellular processes. If a living system loses its order or energy flow, this results in the death of cells and the living organism.
What are anabolic and catabolic reactions?
An anabolic reaction requires energy to build a complex molecule from a simpler one. In contrast, a catabolic reaction releases energy when breaking a complex molecule into simpler ones.
How and why does coupling cellular processes and reactions contribute to a sequential energy-related pathway?
The coupling of anabolic and catabolic reactions increases efficiency and reduces energy lost as heat.
In these scenarios (of processes that release energy coupled with processes that require energy),
the product of a reaction is used as the reactant for the next step in the metabolic pathway.
What are endothermic and exothermic reactions?
An endothermic reaction (anabolic) absorbs heat in the process, while an exothermic reaction (catabolic) releases heat during a chemical reaction.
