Lecture 7 - The balance of anabolic and catabolic reactions Flashcards

Question

ATP is an...

Answer 1

energy rich molecule (high energy phosphate bond)

Answer 2

Energy from phosphate hydrolysis powers other reactions Covalent reactions/intermediates Produced by oxidative phosphorylation Produce ATP by the oxidative phosphorylation process and then it is used as one of the energy currencies in anabolism for building up these reduced biosynthetic products (polymer etc.)

Answer 3

electron rich molecule

Answer 4

Allows redox chemistry Produced during central carbon metabolism (the citric acid cycle/glycolysis) Powers oxidative phosphorylation and many central metabolic reactions Use the high energy electrons in NADH to drive the oxidative phosphorylation process and catabolism is really all about producing molecules like NADH or NADH itself, electron rich molecules are used in many processes but we are specifically going to talk about its involvement with oxidative phosphorylation

Answer 5

metabolically active and primed for regrowth

Answer 6

another electron rich molecule

Answer 7

NADH with an extra phosphate on it Phosphorylated form of NADH Enzymatic produced from NAD+ or NADH Powers reduction reactions that form polymers Distinct molecule, separates its redox chemistry away from NADH and essentially it is maintained at a differed ratio of oxidised and reduced and we instead use it to power reactions that create the reduced macromolecules

Answer 8

A redox cofactor Being reversible, easier to reroute certain reactions backwards than with ATP Phosphorylation = a simple solution to create two separate redox pools Pools maintained at different rations The two enzymes allows the addition of further level of regulation in terms of these 2 redox cofactors The balance of all such ratios is known as redox reactions - messing up redox balance, really messes up the system so a lot of the antibiotics are aimed at messing up the redox balance NAD(P)H or related molecules = reducing power/equivalents

Answer 9

NAD+/NADH - Normally high, more NAD+ to promote catabolism - drive these reactions forward, wanna break down molecules and receive the energy from them in terms of electrons, accept the electron and acquires the extra proton in the process therefore the NADH is in its reduced form

Answer 10

NADP+/NADPH - normally low, more NADPH to promote anabolism - trying to feed electrons in to create these reduced biosynthetic products, making more electrons available to allow for the production of more complicated molecules by reducing these bonds and basically adding phosphate is a very simple adaptation to create these 2 different pools of very similar molecules for different reasons

Answer 11

When the organic energy source is oxidized, the electrons released are accepted by electron carriers such as NAD+ and FAD. When these reduced electron carriers (e.g., NADH, FADH2) in turn donate the electrons to an electron transport chain, the metabolic process is called respiration and may be divided into two different types. In aerobic respiration, the final electron acceptor is oxygen, whereas the terminal acceptor in anaerobic respiration is a different oxidized molecule such as NO3- , SO42- , CO2, Fe3+ , or SeO42- . Organic acceptors such as fumarate and humic acids also may be used. As just noted, respiration involves the activity of an electron transport chain. As electrons pass through the chain to the final electron acceptor, a type of potential energy called the proton motive force (PMF) is generated and used to synthesize ATP from ADP and phosphate (Pi). In contrast, fermentation uses an electron acceptor that is endogenous (from within the cell) and does not involve an electron transport chain. The endogenous electron acceptor is usually an intermediate (e.g., pyruvate) of the catabolic pathway used to degrade and oxidize the organic energy source. During fermentation, ATP is synthesized almost exclusively by substrate-level phosphorylation, a process in which a phosphate is transferred to ADP from a high-energy molecule (e.g., phosphoenolpyruvate) generated by catabolism of the energy source.

Answer 12

Transporters are integral transmembrane proteins - enzymes are sitting inside a cell membrane, transports molecules into the cell’s cytoplasm Transporters can either be importers (e.g. nutrient uptake), or exporters (e.g. drug efflux). Some are reversible

Answer 13

ATP-binding cassette (ABC) family Major facilitator superfamily (MFS) Group translocation e.g. phosphotransferase system (PTS)

Answer 14

active or passive

Answer 15

molecules diffuse according to concentration gradient (molecules move from a region of higher concentration to a region of lower concentration)

Answer 16

an energy source is used to rapidly accumulate against a concentration gradient (move solute molecules to higher concentrations)

Answer 17

ATP or similar is hydrolysed for energy

Answer 18

co-transport of another molecule is the energy source (cotransport = the ion whose gradient powers transport and the substance being moved across the membrane)

Answer 19

High affinity: more competitive for scarce, low concentration resources Rapidly responds to a fluctuating environment Allows cells to accumulate against a concentration gradient - keeps intracellular enzymes saturated with substrate

Answer 20

Energy cost and more complex proteins required

Answer 21

Facilitated diffusion is where substances move across the plasma membrane with the assistance of transport proteins that are either channels or carriers.

Answer 22

Know how to draw Performs primary active transport using ATP as the energy source Can be exporters (drug pumps) or importers (solute uptake) (exporters tend to not have the binding protein) Multi-subunit. 7 different subtypes exist with varying transport mechanisms Periplasmic binding protein - solutes/molecules can be bound by these binding proteins in the periplasm that can either be physically attached or diffused and then interact with the complexes and then transport ultimately the molecules after ATP has been hydrolysed

Answer 23

ATP binding cassette superfamily

Answer 24

Facilitated diffusion of ions/solutes that do not otherwise cross the cell membrane Either passive or secondary active (aka cotransport) Transport is power by concentration gradients Uniport, antiport or symport

Answer 25

Major facilitator superfamily

Answer 26

Passive for MFS. Driven by the concentration gradient of the main solute Unidirectional import or export which is concentration gradient based

Answer 27

Uniport Antiport Symport

Answer 28

MFS Active. Concentration of another molecule moving in the opposite direction is used Something being exported across its concentration gradient and this can drive the import in the opposite direction of another molecule Secondary active transport - using the concentration gradient of another molecule and the movement of it drives conformational/energy changes that allow movement of another molecule

Answer 29

MFS Active. Concentration gradient of another molecule moving in same direction is used Both molecules are moving in the same direction Secondary active transport

Answer 30

Cascade of phosphate transfer used to trap substrate inside the cell Energy atom phosphate used to power transport Substrate is modified during transport. Its own class of active transport - not primary or secondary transport A lot of these systems are taking up primary carbohydrates such as glucose, fructose Gradually the cascade gets more specific as you go along Use an energy source driven by phosphates to bring the glucose in, the phosphate that is released from these high energy molecules gets attached to the glucose and comes into the ell and what this phosphate does is that it changes the glucose and now it cannot diffuse back out of the cell (trapped) which helps to accumulate glucose

Answer 31

redox balance