biology exam #3 Flashcards
what is metabolism?
the totality of organisms’ chemical reactions. (low = less reactions, high = more Reactions)
what is a metabolic pathway?
a series of chemical reactions in a cell that build and breakdown molecules for cellular processes.
what is required for a metabolic pathway to occur?
a substrate and enzymes must be present to form a product.
what is an anabolic reaction?
a chemical reaction that builds something up.
what is a catabolic reaction?
a chemical reaction that breaks something down to release energy?
what is an example of a catabolic reaction?
proteins being broken down to release usable energy.
what is an example of an anabolic reaction?
a protien being built in order to store energy.
what is the ultimate sorce of energy for most living things on earth?
the sun.
how do plant make ATP?
cellular respertation.
how do animals gain sugars to make ATP?
They eat plants and other animals.
what is energy?
the capacity to do work, cause change, or rearange molecules.
what are some types of kinetic energy?
Thermal energy: due to random movment of molecules.
Light Energy: can be harnessed by plants via photosynthesis.
what is heat produced from?
the transfer of thermal energy.
what are some types of Potential Energy?
chemical energy: energy found in chemical bonds.
- also a concentration gradient on one side of a cell membrane is a form.
what are two examples of molecules with high levels of chemical energy?
ATP and Glocuse
what is thermodynamics?
the study of energy (usually mesured in heat).
what is the first law of energy?
energy can not be created or destroyed just transferred.
what happens when energy is transfered?
some energy is lost and transforms to heat which is unusable energy.
what is the second law of thermodynamics?
energy transfer will always result in a greater amount of disorder in the universe. = ENTROPY
what does the second law of energy mean?
It means that the more energy is transferred the less useful it becomes because each time it is transferred some energy is converted to unusable energy heat.
why is order maintained in living things if the second law of thermodynamics is true?
living organisms require a constant flow of energy ito maintian order.
what is an exergonic reaction?
When a complex, energy rich molecule is broken down into smaller, less energy rich molecules
what happens when a exergonic reaction occures?
bonds are broken and energy is released to make ATP
heat is lost so the product holds less usable energy
what is an example of an exergonic reaction?
breaking glucose dow into co2 and h2o
what is required for an endergonic reaction?
Requires input of FREE energy to build more complex, energy-rich molecules from smaller, less energy rich molecules
give an exapmle of an endergonic reaction?
plants need an energy input from the sun in order to turn co2 and h2o into gloclose during photosynthesis.
wha tis energy coupling?
Energy coupling occurs when the energy produced by one reaction or system is used to drive another reaction or system.
what is an example of energy coupling?
exergonic and endergonic reactions
what are the three types of cellular work done by cells?
chemical work: endergonic reactions and anaobolic reations –building polymers from monomers
transport work: moving through membranes –pumps, endocytosis and exocytosis
Mechanical work: moving stuff – muscle contraction, cell division, cilia/flagella
what is Adenosine triphosphate?
ATP
why is ATP so important?
- it is the most important energy transfer molecule in our body.
- provided energy for everything your body dose.
- it is the final product of the energy harvesting process from food.
why is The triphosphate group in ATP unstable?
all three molecules are negativly charged are repelled by each other this men’s it required a lot of energy to put them together.and once broken the bonds will release lots of stored up energy contained in those bonds.
how is ATP broken apart?
Atp is broken apart by hydrolysis when water is added so, the ATP is hydrolisised into ATP+Pi