NaimExplain

Summarize digestive functions in terms of the hormones and neural systems that regulate it. (Hint: Cephalic, gastric, and intestinal phases) 1. The cephalic phase comprises those stimuli that originate from the head: sight, smell, taste, or thoughts of food, as well as emotional states. In response, the following reflexes are initiated: Neural response: Stimuli that arouse digestion are relayed to the hypothalamus, which in turn initiates nerve impulses in the parasympathetic vagus nerve. These impulses innervate nerve networks of the GI tract (enteric nervous system), which promote contraction of smooth muscle (which causes peristalsis) and secretion of gastric juice. Stimuli that repress digestion (emotions of fear or anxiety, for example) innervate sympathetic fibers that suppress muscle contraction and secretion. General effects: The stomach prepares for the digestion of proteins. 2. The gastric phase describes those stimuli that originate from the stomach. These stimuli in...

Explain the process of translation. 1. Processed mRNA leaves the nucleus, and binds to a ribosome. 2. once attached, the mRNA codons can be read 3. a codon (3 based sequence) matches with an anticodon found on tRNA 4. tRNA, (carrying amino acids on a seperate region of code), uses the 3 sequence anticodons to bind the codon 5. tRNA drops off their amino acid and leave the ribosome to be recharged by an enzyme 6. tRNA keep reading the code until you reach the stop codon. (you have no made a protein)

Explain the process of transcription and mRNA processing. 1. Transcription factors bind to the promoter regions of DNA. Promoter regions typically have repetitive sequences such as TATA, CAAT, or GC. When you look at sequences, they repeat themselves 2. The addition of Transcriptional factors will allow the binding to the RNA polymerase 3. RNA polymerase moves along DNA, and reads the gene. (adding in RNA nucleotide) 4. The template strand of DNA guiding the production of RNA 5. Complimentary RNA bases are attached to dna strands during a process called elongation. Making the strand longer 6. When the RNA polymerase reaches the stop codon Termination of production of RNA 7. If the newly formed RNA is mRNA it will go through mRNA processing. Leaves nucleus

Compare the processes of fermentation and cellular respiration. Fermentation is a catabolic process that makes a limited amount of ATP from glucose without an ETC and that produces a characteristic end product such as lactic acid. Cellular respiration is the catabolic pathways or aerobic and anaerobic respiration, which break down organic molecules and uses an ETC for the production of ATP.

Explain why fermentation is necessary. Fermentation is necessary because it regenerates NAD+ so that glycolysis can make 2 ATP.

Summarize the net ATP yield from the oxidation of a glucose molecule by constructing an ATP ledger. In eukaryotic cells, the theoretical maximum yield of ATP generated per glucose is 36 to 38, depending on how the 2 NADH generated in the cytoplasm during glycolysis enter the mitochondria and whether the resulting yield is 2 or 3 ATP per NADH.

Explain how membrane structure is related to membrane function in chemiosmosis. In order for chemiosmosis to work properly you need to build up a high concentration of H+ ions so they can cascade down the gradient to fuel the production of ATP. The double membrane allows a space to be created so these ions can be placed and accumulated for use in the process.

Describe the process of chemiosmosis. Chemiosmosis is the process in which energy stored in the form of a hydrogen ion gradient across a membrane is used to drive cellular work.

Explain how the exergonic "slide" of electrons down the electron transport chain is coupled to the endergonic production of ATP by chemiosmosis. As electrons slide down the ETC, energy is released. This energy is used by ATP synthase to create ATP. Energy is needed to produce ATP.

Describe the cellular regions where glycolysis, the krebs cycle, and the ETC occur. Glycolysis occurs in the cytosol, which begins the degradation process by breaking down glucose into two molecules of a compound called pyruvate. The Krebs cycle occurs in the matrix of the mitochondrion. The electron transport chain occurs in the inner membrane of the mitochondrion.

Describe the role of NAD+ and the electron transport chain during respiration. The role of NAD+ during respiration is to function as an oxidizing agent during respiration. The role of the electron transport chain is to break the fall of electrons to oxygen into several energy-releasing steps.

Explain why organic molecules that have an abundance of hydrogen are excellent cellular fuels. Organic molecules that have an abundance of hydrogen are excellent cellular fuels because their bonds are a source of "hilltop" electrons, whose energy may be released as these electrons "fall" down an energy gradient when they are transferred to oxygen.

Explain how redox reactions are involved in energy exchanges. Redox reactions are involved in energy exchanges by transferring electrons through oxidation and reduction.

Explain how ATP is recycled in cells. ATP is recycled in cells by releasing a phosphate (creating ADP- di phosphate) to release energy. Vice versa, ADP can pick up a phosphate and become ATP, storing the energy in the bond that locks the new phosphate on. When the cell needs energy, it takes the ATP, converts it to a ADP and phosphate and uses the energy. Rather than disregarding the ADP and phosphate, they travel back to the mitochondria where they are recycled in respiration to produce another ATP

Describe the summary equation for cellular respiration. The summary equation for cellular respiration is C6H12O6 + 6 O2 > 6 CO2 + 6 H2O. The glucose produces pyruvate, 2 ATP, and 2 NADH.

Explain how the location of enzymes in a cell influences metabolism. Explain why compartmentalization is important in eukaryotic cells. The location of enzymes in a cell influences metabolism because they have fixed locations within the cell and act as structural components of particular membranes. Compartmentalization is important in eukaryotic cells because they have organelles and these organelles need to carry out specific functions for the cell.

Explain how metabolic pathways are regulated. Metabolic pathways are regulated by controlling enzyme activity. The binding of an activator to a regulatory site keeps the shape that has functional active sites while the binding of an inhibitor keeps the inactive form. Cooperativity is the binding of one substrate increases the binding of subsequent substrates. Feedback inhibition is when the end product inhibits an early step in a biochemical pathway.

Explain how enzyme activity can be regulated or controlled by environmental factors, co-factors, and enzyme inhibitors. Enzyme activity can be regulated by temperature and pH. With temperature, the rate of an enzymatic reaction increases with increasing temperature. Each enzyme has an optimal temperature at which its reaction rate is greatest. With pH, enzymes also have an optimal pH at which it is most active. The optimal pH values for most enzymes are 6-8. For both factors, if it passes the optimal value, the protein will denature. Cofactors are required for catalytic activity. Cofactors are any nonprotein molecule or ion that is required for the proper functioning of an enzyme. There are two types of enzyme inhibitors, one which binds to the active site and blocks catalysis (competitive inhibitors) and one that binds at the allosteric site and causes a conformational change. (non-competitive inhibitors).

Explain how substrate concentration affects the rate of an enzyme-controlled reaction. Substrate concentration affects the rate of an enzyme-controlled reaction by the more substrate there is, the more frequently they can access the active sites of the enzyme. There is a limit to how fast the reaction can happen by adding more substrate. At one point, the concentration will be high enough that all the enzymes have their active sites occupied. This concentration is said to be saturated, and the rate of the reaction is determined by the speed at which the active site converts substrate to product.

Describe several mechanisms by which enzymes lower activation energy. Enzymes lower activation energy by orienting substrates correctly, straining substrate bonds, providing a favorable microenvironment, and covalently bonding to the substrate.