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43 Cards in this Set

  • Front
  • Back
Define metabolism
defines all the biochemical reactions happening in a living cell.
Define catabolism
metabolic event
involves the breakdown of larger molecules to produce energy.
Define anabolism
metabolic events
synthesis of large molecules, using energy.
Describe the first law of thermodynamics
energy is conserved
it can never be created or destroyed, only converted from one form to another.
Second law of thermodynamics
energy flows from a more ordered state to disorder (or entropy), so long as no energy enters or leaves the system.
Exergonic
define and identify the ΔG0’ values
A chemical reaction that releases energy, as energy flows into a less ordered state.

Relative ΔG0’ of an exergonic reaction is negative as energy is being released.
Endergonic
define and identify the ΔG0’ values
Uses energy in the reaction, and its relative ΔG0’ value is positive.
How do enzymes enhance reaction rates
Enzymes enhance reaction rates by lowering the activation energy of the reaction.

Typically occurs when the enzyme binds to the substrate and modifies its structure to make it easier for the reaction to go to completion
define activation energy
the amount of energy required to break and rearrange bonds in a reaction.
define cofactors and their roles in enzymatic reactions
cofactors are small chemicals that assist enzymes in their reactions by transferring functional groups.
Define coenzymes and its role in enzymatic reactions
coenzymes are organic cofactors
Role of ATP in a cell?
ATP supplies the cell with chemical energy that helps drive the endergonic biochemical reactions in the cell.

Has two high-energy phosphoanhydride bonds that can be broken to release energy.
similarities between phosphorylation, oxidative phosphorylation, and photophosphorylation
substrate level phosphorylation, oxidative phosphorylation, and photophosphorylation rely on highly exergonic reactions to provide the energy for ATP production via the phosphorylation of ADP.
explain ATP generation by substrate-level phosphorylation
harnesses the high energy in the phosphate group of a phosphorylated molecule to make ATP by a direction chemical reaction.
explain ATP generation by oxidative phosphorylation
Couples ATP production to the flow of protons across a membrane.
The enzyme ATP synthase catalyzes the phosphorylation of ADP by harnessing the energy of proton movement back across the membrane.
The energy needed to form the proton gradient is generate by the transfer of electrons through a set of membrane carrier molecules.
The electrons originate from the oxidation of chemical substrates take up by the cell
Explain ATP generation by photophosphorylation
Relies on a proton gradient and ATP synthase to generate ATP, but the electron transfer begins with absorption of light energy, rather than oxidation of chemical substrates.
similarity between oxidation and reduction
reduction and oxidation are chemical processes that involve the transfer of electrons between molecules.
Reduction definition
the process of gaining an electron by a molecule, which is then called "reduced".
Definition of oxidation
the process of losing an electron by a molecule to become oxidized
The mathematical relationship between ΔE0 ‘ and ΔG0’.
ΔE0 ‘ is invesely related to free energy ΔG0’.
Higher ΔE0 ‘ results in a more negative ΔG0’; therefore, more free energy.
The amount of free energy ΔG0’ fora particular ΔE0 ‘ is determined by the number of electrons transferred and Faraday's constant.
glycolysis, TCA cycle, and ETC and ATP generation in a cell
-glycolysis catabolizes glucose into two molecules of pyruvate, producing two ATP by substrate level phosphorylation.
-The pyruvates are then completely catabolized by the TCA cycle reactions producing two more ATP by substrate-level phosphorylation.
-Glycolysis and TCA cycle allow electrons to be transferred to carrier molecules, such as NAD, that subsequently pass the electrons to the ETC in the membrane.
-A proton gradient is formed and a further 34 ATP are produce through oxidative phosphorylation using ATP synthase.
chemotroph
chemicals found in nature as their source of energy
phototrophs
obtain energy from light
organotrophs
remove electrons from organic molecules
lithotrophs
remove electrons from inorganic molecules.
hetertrophs
obtain carbon from organic molecules
autotrophs
use inorganic sources of carbon, like CO2
embden-meyerhof-parnas (EMP) pathway
glucose is initially phosphorylated to glucose 6-phosphate, using ATP. The EMP pathway converts glucose to pyruvate through successive oxidation steps using electrons supplied by NADH. The pathway results in two molecules of ATP formed by substrate-level phosphorylation for each molecule of glucose broken down.
The Entner-Doudoroff pathway
The Entner-Doudoroff pathway oxidizes the glucose 6-phosphate intermediate produced in the EMP pathway, producing pyruvate and glyceraldehyde 3-phosphate. The glyceraldehyde 3-phosphate can be used in the EMP to produce more pyruvate and ATP. However, only one molecule of ATP is produced per molecule of glucose. The oxidizing agent in the Entner-Doudoroff pathway is NADP+ rather than NAD+ used in the EMP pathway, and so this pathway is useful for making NADPH, which is a common electron donor for various biosynthetic reactions. The Entner-Doudoroff pathway is also used for the breakdown of other carbohydrates that contain aldehyde groups that can’t be catabolized by the EMP pathway
The pentose phosphate pathway
The pentose phosphate pathway works in conjunction with the EMP pathway. Like the Entner-Doudoroff pathway, it primarily produces NADPH. It also produces a number of five carbon intermediate products, which are useful in biosynthetic processes.
what are the three glycolytic pathways
EMP
Entner-Doudroff Pathway
Pentose Phosphate Pathway
the function of all three glycolytic pathways
Catalyze the breakdown of glucose to produce organic molecules such as pyruvate, as well as NADH and NADPH needed for biosynthetic pathways in cells.
In all three, glucose initially phosphorylated to glucose 6-phosphate, using ATP.
purpose of fermentation and cellular respiration
fermentation and cellular respiration are pathways used in cells to reset the levels of NAD+ so that catabolic pathways such as glycolysis can continue, ensuring ATP is made.
NAD+ is made when NADH donates its electrons
Fermentation
NADH donates its electrons to an organic molecule, like pyruvate, bypassing the TCA cycle and the electron transport system.
Cellular respiration
occurs when NADH donates its electrons to the electron transport system, producing energy ad NAD+
lactic acid fermentation
electrons donated to pyruvate by NADH are used by the enzyme lactate dehydorgenase to produce lactic acid, ATP, and sometimes ethanol.
examples of lactic acid fermentation bacteria
Streptococcus, Lactobacillus, and Bifidobacterium

- use EMP pathway to produce pyruvate, which is directly reduced to lactic acid.
- Lactic acid is then lost from the cell as waste.
- Some lactic acid bacteria, like Leuconostoc, produce a mix of lactic acid and ethanol.
Alcoholic fermentation
results in the production of ethanol and carbon dioxide by catabolizing pyruvate into carbon dioxide and acetaldehyde.
Acetaldehyde is then reduced to ethanol, which leaves the cell as waste.
example of microbes that carry out alcoholic fermentation
yeast
pyruvates role in the TCA cycle
TCA cycle allows pyruvate produced by glycolysis to be further oxidized and therefore produce more ATP and electron carriers that can donate electrons to the electron transport chain.
Pyruvate is oxidized to a two-carbon acetyl group, to which coenzyme A (CoA) is linked.
CO2 role in the TCA cycle
acetyl-CoA enters the TCA and gets further oxidized and decarboxylated to produce CO2
NADH and FADH2 role in the TCA cycle
oxidation of acetyl-CoA is facilitated by NAD+ and FADH+, oxidized electron carriers that take electrons from ther carbon intermediates in the TCA and become reduced to NADH and FADH2.
Large amounts of NADH and FADH2 produced in the TCA cycle will go on to supply electrons to the electron trasnport chain.
ATP and its role in the TCA cycle
The TCA cycle includes substrate-level phosphorylation step, when the loss of the CoA factor from succinyl-CoA produces energy to convert GDP to GTP. GTP, which is a molecule related to ATP, is converted to ATP