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This illustration shows the molecular structure of NAD^{+} and NADH. Both compounds are composed of an adenine nucleotide and a nicotinamide nucleotide, which bond together to form a dinucleotide. The nicotinamide nucleotide is at the 5' end, and the adenine nucleotide is at the 3’ end. Nicotinamide is a nitrogenous base, meaning it has nitrogen in a six-membered carbon ring. In NADH, one extra hydrogen is associated with this ring, which is not found in NAD^{+}.
The oxidized form of the electron carrier (NAD + ) is shown on the left and the reduced form (NADH) is shown on the right. The nitrogenous base in NADH has one more hydrogen ion and two more electrons than in NAD + .

Atp in living systems

A living cell cannot store significant amounts of free energy. Excess free energy would result in an increase of heat in the cell, which would result in excessive thermal motion that could damage and then destroy the cell. Rather, a cell must be able to handle that energy in a way that enables the cell to store energy safely and release it for use only as needed. Living cells accomplish this by using the compound adenosine triphosphate (ATP). ATP is often called the “energy currency” of the cell, and, like currency, this versatile compound can be used to fill any energy need of the cell. How? It functions similarly to a rechargeable battery.

When ATP is broken down, usually by the removal of its terminal phosphate group, energy is released. The energy is used to do work by the cell, usually by the released phosphate binding to another molecule, activating it. For example, in the mechanical work of muscle contraction, ATP supplies the energy to move the contractile muscle proteins. Recall the active transport work of the sodium-potassium pump in cell membranes. ATP alters the structure of the integral protein that functions as the pump, changing its affinity for sodium and potassium. In this way, the cell performs work, pumping ions against their electrochemical gradients.

Atp structure and function

At the heart of ATP is a molecule of adenosine monophosphate (AMP), which is composed of an adenine molecule bonded to a ribose molecule and to a single phosphate group ( [link] ). Ribose is a five-carbon sugar found in RNA, and AMP is one of the nucleotides in RNA. The addition of a second phosphate group to this core molecule results in the formation of adenosine di phosphate (ADP); the addition of a third phosphate group forms adenosine tri phosphate (ATP).

This illustration shows the molecular structure of ATP. This molecule is an adenine nucleotide with a string of three phosphate groups attached to it. The phosphate groups are named alpha, beta, and gamma in order of increasing distance from the ribose sugar to which they are attached.
ATP (adenosine triphosphate) has three phosphate groups that can be removed by hydrolysis to form ADP (adenosine diphosphate) or AMP (adenosine monophosphate).The negative charges on the phosphate group naturally repel each other, requiring energy to bond them together and releasing energy when these bonds are broken.

The addition of a phosphate group to a molecule requires energy. Phosphate groups are negatively charged and thus repel one another when they are arranged in series, as they are in ADP and ATP. This repulsion makes the ADP and ATP molecules inherently unstable. The release of one or two phosphate groups from ATP, a process called dephosphorylation    , releases energy.

Energy from atp

Hydrolysis is the process of breaking complex macromolecules apart. During hydrolysis, water is split, or lysed, and the resulting hydrogen atom (H + ) and a hydroxyl group (OH - ) are added to the larger molecule. The hydrolysis of ATP produces ADP, together with an inorganic phosphate ion (P i ), and the release of free energy. To carry out life processes, ATP is continuously broken down into ADP, and like a rechargeable battery, ADP is continuously regenerated into ATP by the reattachment of a third phosphate group. Water, which was broken down into its hydrogen atom and hydroxyl group during ATP hydrolysis, is regenerated when a third phosphate is added to the ADP molecule, reforming ATP.

Questions & Answers

what is ecology
volex Reply
ecology is the study of living organisms in interaction to the environment
Mwansa
show the diagram of sponge
Favour Reply
explain the processes found in a carbon cycle
Elvas Reply
photosynthesis;this is the process by which grean plants make there own food by using carbon,oxygen, sunlight in the precess of chlorophyll combusion ;this is the process by which fossil fuels are converted in form of a gas of carbon dioxide by an enzyme called a foillitrrion respiration;a proces
Mwansa
Respiration;this is a process by which living organism release energy from food there eat
Mwansa
decoposition;this process is carried by dead matters or decomposes such as bacteria and fungi where dead matters decay buried for thousand of years excretions the remove of toxic metabolism waste product from the body through excretory or gain such as anus and skin etc
Mwansa
also tarnspiratiom where by a plant losses water inform of water vapour into the at mosphere by rhisombium ezyme
Mwansa
so not enzyme but bacteria
Mwansa
sorry not enzyme but bacteria
Mwansa
what is a base?
Alice Reply
base can be define as the anatomy of structure
Ogundipe
what are somatic cells
KAKU Reply
Somatic cells responsible for making the body
Ahsan
vegetative cells, they divide by mitosis.
Ishitha
what is angiosperms
Papillon Reply
what is the function of bile
Papillon
what is neurologist
Benjamin Reply
A neurologist is a brain doctor,a physician who diagnose and treat all categories of conditions and disease involving the central and peripheral nervous system eg.covering, blood vessels and all effector tissue such as muscle
Favour
what is a cell
God Reply
is a basic unit of living organism
Mwansa
or a basic building blocks of all living things
Mwansa
explain cell biology
Grace Reply
cell biology is a biology branch which study about function,size,definition ,....of cells.
fitsum
what are endotherms
angelina Reply
pls can someone elaborate more on biomagnification
angelina
Hey,what?
Peter
Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain.
chance
An endotherm (from Greek ἔνδον endon "within" and θέρμη thermē "heat") is an organism that maintains its body at a metabolically favorable temperature, largely by the use of heat set free by its internal bodily functions instead of relying almost purely on ambient heat.
chance
these are substances that absorbs heat energy
Alice
What diffusion
Oseres Reply
it is the movement of water molecules from the region of higher concentretion to a region of lower concentration
Lukas
is the movement of anything from region of higher concentration to a region of lower concentration.
chance
is a movemnt of H2O molecule from a region of higher concentration to the legion of lower Concentration.
Benjamin
diffusion is the movement of particles from a region of higher concentration to a region of lower concentration resulting into an even distribution
Alice
is the movement of water molecules,ions from the region of higher concentration to the region of lower concentration in a semi permeable membrane.
Favour
pls I don't know how to read very well so how can I understand all this
Mercy Reply
But you wrote all this ur self so please continue till you become perfect thanks
Favour
What's succession
Talabi Reply
an acid is a substance that produces hydrogen ions in an aqueous solution
angelina Reply
how? give a reason to support ur answer
SSEJJO
Types of acids and there definitions
SSEJJO
what is acid
asaa Reply
An acid is a substance which gives Hydrogen ions in aqueous solutions.
Ahsan
food poison
asaa
an acid is a chemical substance that produces or gives out hydrogen ions as the only positively charged ion when dissolved in water
Alice
what is salt?
Basit
a sait is a substance formed when hydrogen ions in an acid are partially or fully replaced by a metal or ammonium ions
Alice
When an acid and base react chemically, a salt is form.
Ahsan
what is nervous system
kumkum
nervous system is rensposible of homeostasis
Mwansa
a sait is a compound which tests beta
Mwansa

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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