Transcript SC.912.L.18.9 - Welcome to G. Holmes Braddock

Photosynthesis
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Photosynthesis is a process used by plants and other autotrophic organisms to
convert light energy, normally from the sun, into chemical energy that can be
used to fuel the organisms' activities.
0 Carbohydrates, such as sugars, are synthesized from carbon dioxide and
water, "light," during this process. Oxygen is also released, mostly as a waste
product. Most plants, most algae, and cyanobacteria perform the process of
photosynthesis, and are called photoautotrophs.
0 Photosynthesis maintains atmospheric oxygen levels and supplies most of the
energy necessary for all life on Earth, except for chemotrophs, which gain
energy through oxidative chemical reactions.
Cellular respiration
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Cellular respiration is the set of the metabolic reactions and processes that
take place in the cells of organisms to convert biochemical energy from
nutrients into adenosine triphosphate (ATP), and then release waste products.
0 The reactions involved in respiration are catabolic reactions, which break
large molecules into smaller ones, releasing energy in the process as they
break high-energy bonds. Respiration is one of the key ways a cell gains useful
energy to fuel cellular activity. Cellular respiration is considered an exothermic
redox reaction.
0 The overall reaction is broken into many smaller ones when it occurs in the
body, most of which are redox reactions themselves. Although technically,
cellular respiration is a combustion reaction, it clearly does not resemble one
when it occurs in a living cell.