bio test 3
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What is energy?
The ability to do work or bring about a change
What are the two major types of energy?
Kinetic and potential
the energy of motion (like water flowing over a waterfall
stored energy whose capacity to do work is not being used at the moment
What do the laws of thermodynamics explain?
Why energy flows thru ecosystems and thru cells
What are the Laws of Thermodynamics?
- 1st Law of Thermodynamics (Conservation) - Energy cannot be created or destroyed, but may be changed in form
- 2nd Law of Thermodynamics (Entropy) - Nature tends toward greater randomness or disorder (greater entropy)
- * Living systems maintain the order only through the constant intake of energy
What is Energy of Activation?
The energy that must be added to cause molecules to react with one another
What is Entropy?
Disorganization in the universe. Usable energy is lost when there is a changeLost energy increases disorder. When things are more organized they are less stable.
What happens when energy is converted from one form to another?
Usable energy is lost in the form of heat
How can enzymes be turned on or off?
An inhibitor can temporarily turn an enzyme off and denaturing an enzyme will turn it off forever
organic catalysts, usually proteins, that speed up chemical reactions
the reactant in the enzymatic reaction
the region of contact between the substrate and enzyme where the reaction occurs
enzymes are not
used up in a reaction
factors that effect enzyme activity
- substrate concentration
cold temperatures tend to
slow chemical reactions
warm temperatures tend to
speed chemical reactions
energy of activation
the energy that must be added to cause molecules to react with one another
how do enzymes speed the rate of chemical reactions?
they lower the amount of energy of activation
require you to put energy in (cellular respiration)
yields energy ATP ---> ADP + P
Free energy -
available to perform work
Induced fit model:
Enzyme is induced to undergo a slight alteration to achieve optimum fit for the substrates. Change shape to fit a 2nd substrate, to allow the 2 substrates to bind together (dehydration reaction)
Competitive inhibition –
either substrate or inhibitor can bind to active site (substrate and inhibitor are competing for active site)
Noncompetitive inhibition –
inhibitor binds at allosteric site. (location other than active site)
reversal or stopping of a metabolic pathway due to non-competitive inhibition by a product
starting the metabolic pathway
loss of an electron; removal of hydrogens; release energy
gain of an electron (gain a negative charge); store energy
reduction (redox) reactions: Electrons pass from one molecule to another
anabolic reactions -
tend to store energy, form larger molecules (ants build stuff up)
- tend to release energy, break molecules (cats break down mice)
- membrane-bound carrier proteins in mitochondria and chloroplasts accept hydrogens from one another so they can be released as energy to do work.
- Starts with high-energy electrons. Electrons are passed from carrier to carrier.
- Ends with low-energy electrons and high-energy ATP
The formation of ATP by hydrogen ions moving thru the membrane
Raw materials used for photosynthesis
carbon dioxide and water
equation for photosynthesis
6CO2 + 6H2O + solar energy → C6H12O6 + 6O2
equation for respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy
photosynthesis stores energy in the
chemical bonds of organic molecules like glucose
photosynthesis takes place in the
_______ are stacked in the chloroplasts
the two processes of photosynthesis
- light reactions
- Calvin cycle
- light is converted from solar energy into a temporary form of chemical energy (red and blue light are absorbed; NOT green)
- takes place in the thylakoids
- a series of chemical reactions that take the molecules from light reactions and convert them into molecules better suited to the long term storage of energy
- takes place in the stroma
- light is NOT necessary for these reactions
3 parts to calvin cycle
- Fixation of carbon dioxide (fixing it into a carbohydrate)
- Reduction of carbon dioxide (adding hydrogens to it) makes PGAL
- Regeneration of RuBP
different pigments in plants
- chlorophyll a
- chlorophyll b
- Noncyclic pathway: high energy electrons go thru electron transport chain and are not recycled. yeilds ATP + NADPH
- Cyclic pathway: high energy electrons go thru electron transport chain and then is re-energized and is recycled yields ATP (only)
plants do not need light for photosynthesis because carbon fixation and calvin cycle occur at different times in different places
live in hot environments. Fix carbon at night. Keep from drying out by dividing when they bring in carbon dioxide from when they release it to the calvin cycle
Enzyme in photosynthesis
Enzyme in aerobic respiration
what color do chlorophylls absorb best?
Cellular respiration definition
is the process cells use to obtain energy from the food molecules that have been brought into the cell, this energy is then stored in the form of the molecule ATP.
simple explanation of what happens in cellular respiration
Electrons are removed from substrates and received by oxygen, which combines with H+ to become water. Glucose is oxidized and O2 is reduced . Occurs around and in the mitochondria
Cellular respiration occurs in three stages
- 1. Glycolysis
- 2. Kreb's Cycle
- 3. Electron transport chain
glucose (a 6-carbon compound) is broken down into two molecules of pyruvic acid (a 3-carbon compound). This process occurs in the cytoplasm of the cell.
- acetyl coenzyme A (produced from pyruvic acid) is further broken down, and the hydrogen is removed from the carbon skeleton.
- The hydrogens are picked up by the hydrogen carriers NAD and FAD and taken to the electron transport chain.
- Kreb's cycle occurs in the mitochondrion.
Electron Transport Chain -
the hydrogen proton and electron are separated to form a chemical gradient. This provides the energy for the formation of ATP. Electron transport occurs in the mitochondrion.
Net Production of ATP
- Glycolysis - 2 ATP molecules
- Kreb's Cycle - 2 ATP molecules
- Electron Transport Chain - 32 ATP molecules
- total: 36 molecules of ATP from the respiration of 1 glucose
- Occurs in cytoplasm outside the mitochondria; anaerobic
- Advantage: quick burst of ATP for muscular activity
- Disadvantages:Lactate and alcohol are toxic to cells. Yeast die from the alcohol they produce by fermentation
which organelle in plants carries out photosynthesis
which organelle in plants and animals is involved in carrying out cellular respiration
C6H12O6 + 6O2 -------> 6CO2 + 6H2O + energy
the energy in the equation for cellular respiration becomes chemical bond energy in what molecule
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