Chapter 8 An Introduction to Metabolism Flashcards
Sugars can be converted to amino acids that are linked together into
proteins
when food is digested, proteins are dismantled into amino acids that can be converted to
sugars
drives this cellular economy by extracting the energy stored in sugars and other fuels. Cells apply this energy to perform various types of work, such as the transport of solutes across the plasma membrane,
cellular respiration
the ocean waves are brightly illuminated from within by free-floating, single-celled marine organisms called
dinoflagellates.
dinoflagellates convert the energy stored in certain organic molecules to light, a process called
bioluminescence
bioluminescent organisms are found in the oceans, but some exist on land, such as the
bioluminescent firefly
Bioluminescence and other metabolic activities carried out by a cell are precisely
coordinated and controlled
is an emergent property of life that arises from orderly interactions between molecules.
Metabolism
We can picture a cell’s metabolism as an elaborate road map of the thousands of chemical reactions that occur in a cell, arranged as .
intersecting metabolic pathways
begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product
metabolic pathway
Each step of the pathway is catalyzed by a
specific enzyme
Metabolism as a whole manages the
material and energy resources of the cell.
Some metabolic pathways release energy by breaking down complex molecules to simpler compounds. These degradative processes are called
catabolic pathways, or breakdown pathways
A major pathway of catabolism is
cellular respiration, in which the sugar glucose and other organic fuels are broken down in the presence of oxygen to carbon dioxide and water.
Pathways can have more than one starting
molecule and/or product
consume energy to build complicated molecules from simpler ones;
Anabolic pathways, sometimes called biosynthetic pathways
Examples of anabolism are the
synthesis of an amino acid from simpler molecules and the synthesis of a protein from amino acids.
Catabolic and anabolic pathways are the
“downhill” and “uphill” avenues of the metabolic landscape.
Energy released from the downhill reactions of catabolic pathways can be stored and then used to drive the uphill reactions of
anabolic pathways.
the study of how energy flows through living organisms.
bioenergetics
is the capacity to cause change
Energy
energy is the ability to rearrange a
collection of matter
Energy can be associated with the relative motion of objects; this energy is called
kinetic energy
is kinetic energy associated with the random movement of atoms or molecules;
Thermal energy
thermal energy in transfer from one object to another is called
heat
is also a type of energy that can be harnessed to perform work, such as powering photosynthesis in green plants.
Light
it is energy that matter possesses because of its location or structure
potential energy
possess energy because of the arrangement of electrons in the bonds between their atoms
Molecules
is a term used by biologists to refer to the potential energy available for release in a chemical reaction
Chemical energy
release energy by breaking down complex molecules
catabolic pathways
During a catabolic reaction, some bonds are broken and others are formed, releasing
energy and resulting in lower-energy breakdown products.
transformation also occurs in the engine of a car when the hydrocarbons of gasoline react explosively with oxygen, releasing the
energy that pushes the pistons and producing exhaust
a similar reaction of food molecules with oxygen provides chemical energy in biological systems, producing
carbon dioxide and water as waste products
woman climbing the ladder to the diving platform is releasing
chemical energy from the food she ate for lunch and using some of that energy to perform the work of climbing
