Consider the effects of the following 2 proposed enzyme. The first enzyme (A) ca
ID: 166369 • Letter: C
Question
Consider the effects of the following 2 proposed enzyme. The first enzyme (A) catalyzes the following reaction: ATP + GDP doubleheadarrow ADP + GTP and, the second enzyme (B) catalyzes the reaction: NADH + doubleheadarrow NAD++ NADPH (a) State whether enzyme (A) would be beneficial or detrimental to cells and explain why. (b) State whether enzyme (B) would be beneficial or detrimental to cells and explain why. (slightly enhance 3-18) Select the statements that are INCORRECT, and for each incorrect statement EXPLAIN why!! (slightly modified 12-10) a) The plasma membrane is highly impermeable to all charged molecules. b) Channels must first bind to solute molecules before they can select those that they allow to pass. c) Transporters allow solutes to cross a membrane at much faster rates than do channels. d) Certain H+ pumps are fueled by light energy. e) The plasma membrane of many animal cells contains open K+ channels, yet the K concentration in the is much higher than outside the cell. f) A would function as an if its orientation in the membrane were reversed (i.e., .f the portion of the molecule normally exposed to the faced the outside of the cell instead) g) the membrane potential of an axon temporarily becomes more negative when an action potential excites it. g) The membrane potential of an axon temporarily becomes more negative when an action potential excites it. Name (a) one similarity and (b) one difference between each of the following (slightly modified 12-12) a) b) Active transport & passive transport c) Membrane potential & electrochemical gradient d) Axon & telephone wire e) Solute & ionExplanation / Answer
A) Enzyme A is a nucleoside dipohosphate kinase which catalyses the transfer of the terminal phosphate Adenosine diphosphates (ADP) and triphosphates (NTP) in a reversible manner to produce triphosphates (GTP). This reaction is seen in Kreb's cycle and helps in the production of citric acid. Hence, it is beneficial to the cells.
The terminal Pi which is released from ATP (Adenosine triphosphate) is transferred and accepted by GDP (Guanosine diphosphate) to convert it into a triphosphate and reducing the ADP into a diphosphate. This phosphorylation results in the formation of GTP-bound G proteins, which is an active conformation of the signal-coupling proteins. This cause activation of G proteins, facilitated solely by a GDPGTP exchange reaction. Amongst the other benefical function consists of cell proliferation, differentiation and development, signal transduction, G protein-coupled receptor, endocytosis, and gene expression.
B) This enzyme B is Oxidoreductase - Dehydrogenase, which catalyses the transfer of electrons and causes oxidation of NADH molecule and thus reducing NADP forming NADPH. This is a reversible reaction and is beneficial to the cells. they plan an important role in aerobic and anaerobic reaction. Various biochemical cycles require them like glycolysis, TCA cycle, oxidative phosphorylation, and in amino acid metabolism.
8)A- true
B) False
Carrier or transporter proteins and channel proteins are the two major classes of membrane transport proteins. Carriers bind to solute to be transported, undergo a series of conformational changes to transfer the bound solute across the membrane in cotrast to channel proteins which form aqueous pores.
C) False.
Channel proteinstransport the solutes weakly in compared to transporters. They form aqueous pores extending across the lipid bilayer; as and when pores open, specific solutes like inorganic ions are allowed to pass through them and thereby cross the membrane Thus, transport through channel proteins occurs at a much faster rate than transport mediated by carrier proteins/transporters.
D) False
H+ pumps or proton pumps are not fueled by light energy. it works on the principle of the hydrolysis of ATP which generates electrochemical gradient/ embrane potential.
E) True
F) False
Symport causes one flow direction from outside to the inside of the cell. However, antiport causes exchange between the two side of the cell.
G) True
9.
A) Similarity- Symport and antiport is a part of cotransport where they help a molecule being transported across a membrane against their concentration potential. Both require proteins to function, electric potential to operate.
Difference-
Antiporter will move ions/slutes in opposite direction or which might seem like an exchange;
Symport will move ions in the same directions
B)Active and Passive transport-
Similarity-
Both allow the cell to maintain its homeostasis by maintaining an equilibrium of subtances moving in and out of the cell and involve moving material to pass throuh, like plasma membrane.
Differences- Active transport requires chemical energy because it is the movement of biochemicals from areas of lower concentration to areas of higher concentration. Passive trasport moves biochemicals from areas of high concentration to areas of low concentration; so it does not require energy.
C) Membrne potential and electrochemical potential
Similarity- Both determine the transport method by implying electic charge
Difference-Membrane potential is the difference in electric potential between the interior and the exterior of a biological cell. Electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane.
E)Solute and ion
Difference- The substance with no charge that dissolves or disperses is called the Solute. Ion always carries either positive or negative charge