Module 2 Flashcards
(67 cards)
What is Cellular Metabolism?
A controlled set of biochemical reactions that occur in living organisms in order to maintain life
What is the primary function of enzymes, and how are they regulated?
Enzymes speed up chemical reactions by lowering the activation energy. The enzyme is not consumed during the reaction and can be used repeatedly by a cofactor. Cofactors can regualte enzymes, there are times when cofactors must be present for the enzyme to work.
What is Catabolism?
The process of breaking down larger molecules into useful energy sources
What is Anabolism?
The building up or biosynthesis of macromolecules from smaller molecular units into larger complexes, most often associated with cellular growth and repair
ATP has the energy to ___ energy
Donate
ADP has the capacity to ___ energy
Accept
Chemotrophs can be subdivided into what 2 additional subgroups?
Chemotrophs acquire energy from preformed chemicals found in the environment such as organotrophs or lithotrophs
What are Organotrophs?
A chemical that removes electrons from organic molecules such as glucose
What are Lithotrophs?
A chemical that removes electrons from inorganic molecules
Chemotrophs utilize which form of phosphorylation?
- Oxidative phosphorylation; utilizes the energy released by the chemical oxidation of nutrients to reform ATP
- May also accept substrate level phosphorylation
What are the 3 distinct stages in the catabolism of glucose?
- Glycolysis : yields 2 molecules of ATP
- Fermentation (or respiration) : 2 additional molecules of ATP produced (resp.)
- Electron Transport Chain (ETC) : produces 34 ATP via an oxidative phosphorylation event at mitochondrial membrane
What are the Reactants of Glycolysis?
- Glucose
- 2 NAD+
- ATP
What are Reactants?
Any molecules present and involved at the beginning of a specific chemical reaction, located to the left of the arrow
What are the 2 main strategies for replenishing cellular concentrations of NAD+, and when these strategies be utilized?
- Fermentation and Respiration are the 2 strategies used by the cell to convert NADH back to NAD+
- Fermentation occurs in the absence of oxygen (anaerobic conditions) while Respiration occurs under aerobic conditions (presence of oxygen)
- Respiration is more efficient than fermentation
How are the TCA and ETC related?
The end products of the Kreb’s (TCA) are used to fuel the ETC. The Kreb’s cycle produces an abundance of reduced electron carriers (NADH and FADH2), it fuels the ETC. As the electrons are transferred from NADH/FADH2 to terminal electron acceptors a proton motor force is generated, ATP synthase is activated and up to 34 molecules of ATP can be produced.
In the absence of sugars, are entirely different metabolic pathways used to process alternative sugar sources (fructose or lactose)?
No. Additional enzymatic steps are simply required at the beginning of catabolism to convert complex sugars into usable forms of either glucose or a glucose intermediate (glucose-6-phosphate).
Proteases are used to catabolize what?
Proteases are used to breakdown proteins
Lipases are used to catabolize what?
Lipases are used to breakdown lipids
Excluding sugars, what are the other sources of energy? Which is highest in energy?
Carbohydrates, proteins, and lipids can all serve as potential energy sources in the absence of sugar. Lipids are rich in energy, often having several reduced carbon molecules (high in hydrogen content) that can be used in both the TCA and ETC cycles.
In what organelle does photosynthesis take place?
Occurs in the chloroplasts. Chloroplasts are double-membrane enclosed organelles. Each chloroplast contains the green photosynthetic pigment chlorophyll.
What is Photosynthesis?
Where does it occur?
The process of capturing sunlight and converting it into usable energy source, occurring in the chloroplasts
In phosphorylation, the light reactions always occur where?
(what is the main function)
The process of converting light energy into chemical energy (photophosphorylation) always occurs in the membrane. Similar to the ETC, one of its main functions is to generate a proton concentration gradient to generate ATP.
What are the byproducts of light reactions used for in dark reactions?
The ATP and NADPH produced via light reactions are used in dark reactions to convert carbon dioxide and water into organic carbon compounds as well as useful carbohydrates (a process called carbon fixation)
What determines the specificity of an enzyme?
(what is the structure influenced by)
Heavily influenced by its active site; a unique chemical structure bound only by select target molecules. The structure is influenced by the amino acid composition of the protein as this in turn influences the fold, shape, and ‘appearance’ of the enzyme. The active site provides a specificity (like a lock) that only specific target proteins can bind
