Szószedet: homeostasis (önbévület*)

homeostasis: The maintenance of a dynamic steady state by regulatory mechanisms that compensate for changes in external circumstances.
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*) V.ö.: extasis = önkívület.
... http://forum.vectrix.hu/?f=13&t=99

Natessék: itt van feketén-fehéren, hogy ez építészet !

There Are Four Levels of Architecture in Proteins

... Lehninger-Nelson-Cox: Principles of Biochemistry, 161.o.

Szószedet: exciting (izgalmas)

... familiarity with them is a prerequisite for understanding more advanced topics covered in this book, as well as the rapidly growing and exciting literature of biochemistry.

Lehninger-Nelson-Cox: Principles of Biochemistry, 109.o.

... Játsszunk biokémiát ! ... :)

Vannak akik azt mondják, hogy az egysejtűektől a többsejtűekhez evolúciós ugrás kellett - pedig nem: sima átmenet !

At some later stage of evolution, unicellular organisms found it advantageous to cluster together, thereby acquiring greater motility, efficiency, or reproductive success than their free-living single-celled competitors. Further evolution of such clustered organisms led to permanent associations among individual cells and eventually to specialization within the colony – to cellular differentiation.


The advantages of cellular specialization led to the evolution of ever more complex and highly differentiated organisms, in which some cells carried out the sensory functions, others the digestive, photosynthetic, or reproductive functions. Many modern multicellular organisms contain hundreds of different cell types, each specialized for some function that supports the entire organism. Fundamental mechanisms that evolved early have been further refined and embellished through evolution. The simple mechanism responsible for the motion of myosin along actin filaments in slime molds has been conserved and elaborated in vertebrate muscle cells, which are literally filled with actin, myosin, and associated proteins that regulate muscle contraction. The same basic structure and mechanism that underlie the beating motion of cilia in Paramecium and flagella in Chlamydomonas are employed by the highly differentiated vertebrate sperm cell. Figure 2–25 illustrates the range of cellular specializations encountered in multicellular organisms.


Figure 2–26 Three types of junctions between cells.
(a) Tight junctions produce a seal between adjacent cells. (b) Desmosomes, typical of plant cells, weld adjacent cells together and are reinforced by various cytoskeletal elements. (c) Gap junctions allow ions and electric currents to flow between adjacent cells.

Lehninger-Nelson-Cox: Principles of Biochemistry, 49.o.

Van egy rossz (vagy jó) hírem: a testünk alacsony hőmérsékleten működő gőzgép !

"Living cells are chemical engines that function at   constant temperature."

Lehninger-Nelson-Cox: Principles of Biochemistry, 9.o.

Eddig azt hittem, hogy a Lehninger-könyv 4. oldalán van az első utalás a biokémia és az informatika összefüggésére - de nem: már a 3. oldalon, az első fejezet címében is ott van !

Chapter 1

The Molecular Logic of Life

 

Lehninger-Nelson-Cox: Principles of Biochemistry, 3.o.

Ötlet: a "growth factor" mintájára, amit mi keresünk, azt nevezzük el "aging factor"-nak !

Figure 22-15 (a) Location of the hypothalamus and pituitary gland. (b) Details of the hypothalamus-pituitary system. Signals arriving from connecting neurons stimulate the hypothalamus to secrete hormones destined for the anterior pituitary into a special blood vessel, which carries the hormones directly to a capillary network in the anterior pituitary. In response to each hypothalamic hormone, the anterior pituitary releases its appropriate hormone into the general circulation. Posterior pituitary hormones are made in neurons arising in the hypothalamus, transported in axons to nerve endings in the posterior pituitary, and stored there until released into the blood in response to a neuronal signal.

The hypothalamic hormones pass directly to the nearby pituitary gland through special blood vessels and neurons that connect the two glands (Fig. 22-15b). The pituitary gland has two functionally distinct parts. The anterior pituitary responds to hypothalamic hormones carried in the blood, by producing six tropic hormones or tropins (from the Greek tropos, meaning "turn"), relatively long polypeptides that activate the next rank of endocrine glands (Fig. 22-14). Adrenocorticotropic hormone (ACTH, also called corticotropin; Mr 4,500) stimulates the adrenal cortex; thyroid-stimulating hormone (TSH, also called thyrotropin; Mr 28,000) acts on the thyroid gland; follicle-stimulating hormone (FSH; Mr 34,000) and luteinizing hormone (LH; Mr 20,500) act on the gonads; and growth hormone (GH, also called somatotropin; Mr 21,500) stimulates the liver to produce several growth factors.

Lehninger-Nelson-Cox: Principles of Biochemistry, 752.o.

Megvan, hogy az orvosok és az elméleti tudósok miért utasítják el a projektjavaslatomat ... Mert ez mérnöki feladat !

... These are only some of the more straightforward examples. Release of genetically engineered organisms into the environment carries with it a level of risk that is sometimes difficult to evaluate. Human gene therapy (Box 28-2), with all of its promise, doubtless will present society with ethical dilemmas not yet anticipated. Issues of this kind must in the end foster a closer and more productive collaboration between science and the society it serves, as well as higher levels of scientific literacy in the general public, as we move toward the twenty-first century.

Lehninger-Nelson-Cox: Principles of Biochemistry, 1010.o.

Ezt informatikus ne lássa: két kódszegmens ugyanazon a memóriaterületen, eltolt értelmezési kezdőcímmel ! ... ez hajmeresztően pimasz trükk !

Ha egy humán programozó ilyen kódot gyártana, azt a szoftver-igazgató azonnal, páros lábbal kirúgja !
:))

Lehninger-Nelson-Cox: Principles of Biochemistry, 904.o.

Megáll az ész és ácsorog - DNS polimeráz: kész űrtechnika !

Lehninger-Nelson-Cox: Principles of Biochemistry, 823.o.

Nem azért mondom, de ez elképesztő: az élet-technológia !

Ez nem csak úgy magától pöndörödik, ezt pöndöríteni kell ! ... Ez komplett gyártási folyamat:

In every cell, DNA supercoiling is a precisely regulated process that influences many aspects of DNA metabolism. Not surprisingly, there are enzymes in every cell whose sole purpose is to underwind and/or relax DNA. The enzymes that increase or decrease the extent of DNA underwinding are called topoisomerases, and the property of DNA they affect is the linking number. These enzymes play an especially important role in processes such as replication and DNA packaging. There are two classes of topoisomerases. Type 1 topoisomerases act by transiently breaking one of the two DNA strands, rotating one of the ends about the unbroken strand, and rejoining the broken ends; they change Lk in increments of 1. Type 2 topoisomerases break both DNA strands and change Lk in increments of 2.

Lehninger-Nelson-Cox: Principles of Biochemistry, 805.o.

Az élet-információ drága !

Forming specific bonds and preventing sequence errors in these polymers has an enormous impact on the thermodynamics, chemistry, and enzymology of the synthetic processes. For example, formation of a peptide bond should require an input of only about 21 kJ, and relatively simple enzymes that catalyze comparable reactions are known. To synthesize the correct peptide bond between two specific amino acids at a given point in a protein, however, the cell invests about 125 kJ in chemical energy and makes use of the combined activities of over 200 RNA molecules, enzymes, and specialized proteins. Information is expensive.

Lehninger-Nelson-Cox: Principles of Biochemistry, 790.o.

A "supercoil" ("pödört söndör" ?) ... Hogyan fogjuk ezt az unokáinknak elmagyarázni ?

Figure 23-9 Supercoils. A typical phone cord is a coil. A phone cord twisted as shown is a supercoil. The illustration is especially appropriate, because an examination of the twisting of phone cords helped lead Jerome Vinograd and colleagues to the insight that many properties of small, circular DNAs could be explained by supercoiling. They first detected DNA supercoiling in small, circular viral DNAs in 1965.

Lehninger-Nelson-Cox: Principles of Biochemistry, 799.o.

És, micsoda jelerősítés: 1 adrenalin-jelből 10 000 szőlőcukor-molekula !

Lehninger-Nelson-Cox: Principles of Biochemistry, 762.o.

És, az üzenetküldögetés: idegek és mirigyek - és ez a kettő = egy !

... Except for this anatomical difference, the chemical signaling in the neural and endocrine systems is remarkably similar in mechanism. Even some of the chemical messengers are common to both systems. Epinephrine and norepinephrine, for example, serve as neurotransmitters in certain synapses of the brain and smooth muscle and also as hormones regulating fuel metabolism in the liver and in muscle. Although the neural and endocrine systems were traditionally treated as separate entities, it has become clear that in the regulation of metabolism they merge into a single neuroendocrine system.

Lehninger-Nelson-Cox: Principles of Biochemistry, 746.o.

És, azért hogy semmiből se legyen több, mint amennyi kell belőle: a vese !

The ions and low molecular weight solutes in the blood plasma are not fixed components, but are in constant flux between blood and various tissues. Dietary uptake of inorganic ions is, in general, counterbalanced by their excretion in the urine. For many of the components of blood, something near a dynamic steady state is achieved; the concentration of the component changes little, although a continual flux occurs from the digestive tract, through the blood, and to the urine. For example, almost regardless of the dietary intake of Na+, K+, and Ca²⁺, the plasma levels of these ions remain close to 140, 5, and 2.5 mM, respectively. Any significant departure from these values can result in serious illness or death. The kidneys play an especially important role in maintaining the ion balance, serving as a selective filter that allows waste products and excess ions to pass from the blood to the urine while preventing the loss of essential nutrients and ions.

Lehninger-Nelson-Cox: Principles of Biochemistry, 745.o.

És a vér, a csoda: elszállít mindent (anyagot és információt) mindenhonnan, mindenhova !

The blood flows through and connects all of the tissues, mediating the metabolic interactions among them. It transports nutrients from the small intestine to the liver, and from the liver and adipose tissue to other organs; it also transports waste products from the tissues to the kidneys for excretion. Oxygen moves in the blood from the lungs to the tissues, and CO₂ generated by tissue respiration returns in the blood to the lungs for exhalation. Blood also carries hormonal signals from one tissue to another. In its role as signal carrier, the circulatory system resembles the nervous system; both serve to regulate and integrate the activities of different organs.
The average adult human has 5 to 6 L of blood. Almost half of this volume is occupied by three types of blood cells (Fig. 22-9): erythrocytes (red cells), filled with hemoglobin and specialized for carrying O₂ and CO₂; much smaller numbers of leukocytes (white cells) of several types, central to the immune system that defends against infections; and platelets, which help to mediate the blood clotting that prevents loss of blood after injury. The liquid portion is the blood plasma, which is 90% water and 10% solutes. The plasma is very complex in chemical composition; in it are dissolved or suspended a large variety of proteins, lipoproteins, nutrients, metabolites, waste products, inorganic ions, and hormones. Over 70% of the plasma solids are plasma proteins (Fig. 22-9). Major plasma proteins include immunoglobulins (circulating antibodies), serum albumin, apolipoproteins involved in the transport of lipids (as VLDL, LDL, HDL), transferrin (for iron transport), and blood-clotting proteins such as fibrinogen and prothrombin.

Lehninger-Nelson-Cox: Principles of Biochemistry, 744.o.

A rák gyógyításához is közelebb visz, ha megértjük az enzimek működését

És, az öregedés gyógyításához is !

Cancer cells grow more rapidly than the cells of most normal tissues, and thus they have greater requirements for nucleotides as precursors to DNA and RNA synthesis. Consequently, cancer cells are generally more sensitive to inhibitors of nucleotide biosynthesis than are normal cells. A growing array of important chemotherapeutic agents act by inhibiting one or more enzymes in these pathways. We will examine several well-studied examples that both illustrate productive approaches to treatment of cancer and facilitate an understanding of how these enzymes work.

Lehninger-Nelson-Cox: Principles of Biochemistry, 730.o.