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What is metabolism?
all of the chemical reactions within each cell of an organism
What does metabolism do?
provide energy for life’s processes and creates key molecules
What are chemical reactions?
the breaking and forming of bonds between different substances during chemcial
What do reactions do with energy?
they either absorb it or release it
What does breaking a bond require?
energy to be absorbed
What does forming a bond require?
energy to be released
Is energy lost in a system?
no due to the law of conservation of energy, it just changes forms (may be released as heat, light, etc)
What is catabolic?
the breaking down of larger molecules into simpler compounds causing a release in energy
What can catabolic reactions be classified as because they release energy?
exergonic
What is anabolic?
the building of larger molecules from smaller ones, requiring the consumption of energy
What can anabolic reactions be classified as because they consume energy?
endergonic
What do all reactions need to happen?
energy
What is activation energy?
the amount of energy needed to make a chemical reaction start
What are reactants/substrates?
substances that are changed during a chemical reaction
What are products?
substances that are made by a chemical reaction
What are the two types of reactions?
endothermic and exothermic
What is an endothermic reaction?
absorbs energy in the form of heat or light (example: photosynthesis)
What is an exothermic reaction?
releases energy in the form of heat or light (example: cellular respiration)
What is the equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
Why is photosynthesis an endothermic reaction?
light energy is stored as chemical energy in sugar
What is the equation for cellular respiration?
C6H12O6 + 6O2 → 6CO2 + 6H2O
Why is cellular respiration an exothermic reaction?
chemical energy in sugar is converted to chemical energy released as ATP
What controls metabolic reactions?
enzymes
What are enzymes?
mostly proteins that speed up biochemical reactions by lowering activation energy
What are enzymes called?
catalysts because they speed up reactions
What are catalysts?
substances that speed up reactions without being permanently altered
How do enzymes work?
they are very specialized molecules that bind to reactants (aka substrates) and help to break or form bonds releasing a newly created product
Are enzymes used up in reactions?
no, they aren’t changed and can be used over and over again
What are enzymes critical for?
the regulation of life’s processes in all organisms
What is the structure of an enzyme?
they have an active site (the part of the enzyme where the substrate binds) that fits only one substrate
After the substrate connects to an enzyme what occurs?
the bind tights producing an induced fit
What can enzymes do to produce two products?
break bonds in a substrate
What is denaturation?
an enzyme’s active site gets deformed and loses its specific shape resulting in a loss of biological activity
What are some causes of denaturation?
changes in environment like extreme changes in pH, temperature, ion strength, and solubility
Can some enzymes be “renatured?”
yes, they can return to their original shape, but not always
What are 5 ways to change the rate of a chemical reaction?
temperature
pH
substrate concentration
catalysts
competitive inhibitors
How does temperature change the rate of a chemical reaction?
increasing temperature increases the rate of reaction as molecules are moving faster and colliding more with each other; if the temperature gets outside a certain range, it can cause an enzyme to denaturate
How does pH change the rate of a chemical reaction?
most enzymes only work at very specific pH so if the pH changes it can affect the speed of reaction (outside of a certain pH range, enzymes denature)
How does substrate concentration change the rate of a chemical reaction?
the higher the amount of substrate, the faster the reaction due to more particle collisions
How do catalysts change the rate of a chemical reaction?
like enzymes speed up reactions by lowering activation energy for the reaction to start; there are co-enzymes that also help speed up reactions
How do competitive inhibitors change the rate of a chemical reaction?
they slow down reactions by competing with substrates for the active site on the enzyme
What does ATP stand for?
adenosine triphosphate
What does our body need to run our cells?
energy
Do our bodies directly use food for energy?
no, you can only use the energy in the food you eat stored in its chemical bonds
How do our bodies convert energy into a form it can directly use?
it breaks bonds and forms new ones
What happens once energy is converted into a more usable form?
ATP carries it to be used for cell functions
What is ATP?
an energy carrying molecule that carries/stores energy for cell functions; it is the main energy currency for the cell
What is the structure of ATP?
a nitrogen base (adenine), sugar ring (ribose), and 3 phosphate groups held together with high energy bonds, and it isn’t a stable molecule meaning it is easy to break the bond between the 2nd and 3rd phosphate
What does ADP stand for?
adenosine diphosphate
When is energy released during the ATP-ADP cycle?
when a phosphate group is removed (and added to another molecule)
When does ADP become ATP?
when a phosphate group is added
Where is the most energy stored in ATP?
in the bond between the last two phosphates
What is recycled in the ATP-ADP cycle?
ADP
What kind of process is the ATP-ADP cycle?
chemiosmotic
What is chemiosmosis?
the movement of ions down a concentration gradient
What is used to add the third phosphate to ADP to make ATP using energy from the food we eat?
ATP synthase
When ATP is broken down is energy for the cell to use (and becomes ADP and a phosphate) released or taken in?
released
Is the breaking down of ATP endothermic or exothermic?
exothermic (because more energy is given off than required)
What do cells need to do to make ATP?
they must join together ADP and a phosphate using energy from food
Is the formation of ATP exothermic or endothermic?
endothermic (because energy is taken in)
What is the most common carbon based molecule broken down for ATP?
carbohydrates (can get around 36 ATP from 1 glucose molecule and stores around 4 cal/g of energy)
What is broken down after carbs for energy?
lipids/fats (store 9 cal/g of energy)
What is least likely to be broken down for energy?
proteins (store 4 cal/g of energy)
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