Учебно-методический комплекс дисциплины " Basis of biochemistry " Для специальности

List of Hormones

List of vertebrate hormones and the secretory organs is as follows:

S. No.	Secretory Organ	Hormone
1.	Ovary  Testes	Estrogens   ß-estradiol   Estriol   Estrone Androgens   Testosterone   Androsterone   DHEA
2.	Adrenal Cortex Medulla	Corticosteroids   Aldosterone   Cortisone   Cortisol   Corticosterone Epinephrine Norepinephrine
3.	Corpus Leuteum	Progesterone Relaxin
4.	Islets of Langerhans ß-cells α- cells	Insulin Glucagon
5.	Pars distalis Pars inermedia Pars nervosa	Thyrotropin Corticotropin Gonadotropins FSH LH LTH Somatotropin Intermedins Oxytocin Vasopressin
6.	Gastrointestinal Tract	Secretin Pancreozymin Gastrin
7.	Parathyroid	Parathormone
8.	Thyroid	T3,  Thyroxine, T4

Hormone Regulation

Controlling how much hormones are secreted and released from the cells is hormones regulation. This regulatory activity is done in two mechanisms - the negative feedback mechanism and positive feedback mechanism and also by counter regulatory hormones.

Negative Feedback Mechanism - Mostly hormones regulation is done by negative feedback mechanism. In this mechanism hormone causes an effect, the cells that make hormones detect this effect and the production of hormones is ceased.

Example of negative feedback mechanism is with the hormone insulin. Insulin hormone is produced by ß-cells of pancreas. The release of insulin by the pancreas is the response to the consumption of glucose. Rise in the glucose levels in blood, is detected by the pancreas and secretes insulin into the blood. Insulin increase the uptake of glucose in the target cells. Some of the glucose is used by the cells and the other is converted and stored in the form of glycogen. The uptake of glucose by the cells decreases glucose levels, this decrease is detected by the pancreas and as a response to the decrease in glucose levels,it stops secreting insulin into the bloodstream. Decrease in insulin levels in the blood decreases glucose uptake by the cells. This negative feedback mechanism helps to maintain normal blood  glucose levels and prevents extremities. 

Positive Feedback Mechanism - A few hormones are regulated through positive feedback mechanism. In the positive feedback mechanism the effect of hormones, make the gland secrete more hormones. This is the opposite of negative feedback mechanism.

Example of positive feedback mechanism is the hormone that causes childbirth. The hormones is oxytocin which is made by the pituitary gland. The onset of labor stretches the muscles in the cervix, the nerves here sends signals to the pituitary. This signal makes the pituitary release more oxytocin. The oxytocin hormone causes the muscles of the uterus to contract which causes more stretching in the cervix. This stretching causes even more secretion of oxytocin. The levels of oxytocin keeps rising until the contractions leads to childbirth. 

Counter regulatory hormones - Activities in the body is sometimes controlled by two or more hormones.

Example of counter regulatory hormones - Glucose levels in blood is very important to an organism. This is just not controlled by one hormone, other hormones also make  glucose levels to increase or decrease. If the levels of glucose is too low, the body release hormones that function opposite to the activity of insulin. These hormones do not let the cells uptake of glucose from the blood. They make the cells put back glucose into the blood. These hormones that work opposite to other hormones are called counter regulatory hormones. Counter regulatory hormones for insulin are glucagon and epinephrine.


Modul 9. Nucleicacids

Biological value of nucleic acids. Deoxyribonucleicand ribonucleic acids. Nucleotides. A constitution and functions in alive organisms. Transfer of ancestral features. Biosynthesis of protein. Processes of replication, a transcriptional and translation. A mutagenesis and hereditary diseases. Biotechnology and gene engineering.

Modul 10. Metabolism

Concept about a metabolism and metabolic paths: the katabolism and anabolism.

A metabolism and reception of biochemical energy.

Role of АТР in an energy exchange.

Proteins metabolism.

Carbohydrates metabolism.

Metabolism: chemical reactions in cells

Countless chemical reactions take place in cells and are responsible for all the actions of organisms. Together, these reactions make up an organism's metabolism. The chemicals taking part in these reactions are called metabolites.

In all reactions:

• 
  chemical bonds in the reacting molecules are broken; this takes in energy
  
• 
  new chemical bonds form to make the products; this gives out energy
  

When a chemical reaction takes place energy is either taken in or released. This depends on the relative strengths of bonds being broken and bonds being formed.

In an exergonic reaction, energy is released to the surroundings. The bonds being formed are stronger than the bonds being broken.

In an endergonic reaction, energy is absorbed from the surroundings. The bonds being formed are weaker than the bonds being broken.

You may also come across the terms exothermic and endothermic reactions. These describe exergonic and endergonic reactions when the energy released or absorbed is heat energy. In an exothermic reaction the temperature of the surroundings increases. In an endothermic reaction the temperature of the surroundings decreases.


Anabolism and catabolism

Two types of metabolic reactions take place in the cell: 'building up' (anabolism) and 'breaking down' (catabolism).

Anabolic reactions use up energy. They are endergonic. In an anabolic reaction small molecules join to make larger ones. For example, the following condensation reactions that occur in cells are anabolic:

• 
  amino acids join together to make dipeptides:

  e.g. NH₂CHRCOOH + NH₂CHRCOOH    NH₂CHRCONHCHRCOOH + H₂O 

  and the process continues as large protein molecules are built up
  

• 
  small sugar molecules join together to make dissacharides: 

  e.g. C₆H₁₂O₆ + C₆H₁₂O₆     C₁₂H₂₂O₁₁ + H₂O

  and the process continues as large polysaccharide molecules are built up
  

• 
  glycerol reacts with fatty acids to make lipids:

  e.g. CH₂OHCH(OH)CH₂OH + C₁₇H₃₅COOH    CH₂OHCH(OH)CH₂OOCC₁₇H₃₅ 

  and the process continues as the trigyleride is produced via similar reactions with the other two hydroxyl groups of the glycerol molecule
  

• 
  during photosynthesis carbon dioxide and water are used to produce glucose and oxygen:

  e.g. 6CO₂ + 6H₂O    C₆H₁₂O₆ + 6O₂

  
  

Catabolic reactions give out energy. They are exergonic. In a catabolic reaction large molecules are broken down into smaller ones. For example, the reverse of the condensation reactions described above, i.e. hydrolysis reactions, are catabolic.

• 
  A simple example of a catabolic reaction that occurs in cells is the decomposition of hydrogen peroxide into water and oxygen:
  

2H₂O₂    2H₂O + O₂

• 
  The conversion of glucose during respiration to produce carbon dioxide and water is another common example:

  C₆H₁₂O₆ + 6O₂    6CO₂ + 6H₂O

  
  

How chemical reactions occur

Chemical reactions that occur during metabolism are affected by temperature. Many animals maintain a constant temperature which results in relatively stable rates of metabolic reactions. Cold-blooded animals are particularly influenced by the temperature of their environment - they are livelier when warm. In the cold their metabolism slows dramatically, and this is why some cold-blooded animals hibernate. Surgery is sometimes carried at low temperatures to slow the patient's metabolic rate, for example, during operations on the heart or brain.

Molecules move and collide

Molecules are constantly moving. Their bonds vibrate and rotate. In gases, liquids and solutions molecules move around, bumping into one another. When molecules collide there is the possibility of a reaction taking place, but only if the colliding molecules:

• 
  Have enough energy
  
• 
  Are aligned correctly
  

The more collisions there are between molecules with sufficient energy and correct alignment, the faster the reaction takes place. This is called collision theory.

• 
  The more molecules present, the faster the reaction. Therefore reactions take place faster in concentrated solutions than in solutions that are more dilute.
  
• 
  At high temperatures molecules have more energy than at lower temperatures. Therefore collisions are more frequent and the likelihood of the molecules having enough energy is greater. Consequently the rate of chemical reactions increases with increasing temperature.
  

Activated complexes and activation energy

Some reactions take place in a single step. We can represent this using an energy profile. An activated complex (or transition state) forms between reactant and product. This is not a 'real' substance in the sense that it can be isolated and put in a test tube. But based on various pieces of experimental evidence it is the chemist's model of how the reaction occurs. The energy 'hump' shows how much energy reacting molecules must have for a 'successful' collision, i.e. one that leads to reaction. The formation of an activated complex requires energy to bring molecules together in the correct orientation. Therefore, it is always an endergonic reaction. The energy required is called the activation energy (E_a).

It is more common for reactions between molecules to take place in a series of consecutive steps. After each step a reaction intermediate forms. Unlike an activated complex this has a real existence. For each step an activated complex is formed and there is an associated activation energy. The step with the highest activation energy is the rate-determining step in the reaction and controls how fast the overall reaction is.
3. Practical work
Practical work № 1

Topic: Biochemistry subject

Qualitative analysis of fat-soluble vitamins

The purpose of the work: Consider the qualitative reactions tofat-soluble vitamins.
Qualitative reactions to vitamin A

Reaction with sulfuric acid

Principle of the method. Vitamin A gives color reaction with sulphuric acid. The received bond is painted in blue-violet color. Chemism of reaction it is final on examinations.

Devices: Rack with test tubes(test tubes must be dry).

Reactants: Vitamin A solution in oil (industrial medicine). Сoncentrated sulfuric

acid.

Work description. In a test tube pour 3 drops of Solutio oleosa of vitamin A and add 1 drop of sulphuric acid. In a test tube the blue-violet staining appears.
Qualitative reactions to vitamin D

Reaction with aniline

Principle of the method. Vitamin D at interaction with an aniline reactant when warming is painted in red color.

Devices: Rack with test tubes.

Reactants: Aniline reactant (mix 15 parts of aniline and 1 part of the concentrated hydrochloric acid).

Work description. In a dry test tube pour 1 ml of working fat, 1 ml of an admixture of aniline with the hydrochloric acid, mix, carefully heat at constant stirring of a dokipeniya and boil half-minute. In the presence of vitamin D turning yellow emulsions gains green, and then red color in the beginning.
Qualitative reactions to vitamin Е

Reaction with nitric acid.

Work description: In 2 test tubes pour 2-3 drops of Solutio oleosa of vitamin E. To the first test tube add 1-2 ml of water, to the second – the same amount of the concentrated nitric acid. Both test tubes heat on the boiling water bath of 10 min. In a test tube with nitric acid the oil layer of vitamin is painted in orange-red color.
To make out results of works in table 1.

Table 1

№	The name of vitamin	Reactants	The observed coloration	Note	Conclusions
1.	А
2.	D
3.	Е

Questions for self-preparation of students:

1. 
   Subject of biological chemistry.
   
2. 
   Use of achievements of biochemistry in livestock production and other fields of agriculture.
   
3. 
   General characteristic of vitamins. The mechanism of their action on a metabolism.
   
4. 
   Classification of vitamins, their nomenclature.
   
5. 
   Chemical nature of vitamins.
   
6. 
   A concept about hypo, hyper, poly-avitaminoses. Reasons of their emergence.
   
7. 
   Characteristic of vitamins of the A,D,E,K group.
   

Practical work № 2

Topic: Amino acids: classification, structure, stereochemistry, physical and chemical properties and classification amino acids forming proteins.

Qualitative analysis of water-soluble vitamins

The purpose of the work: Consider the qualitative reactions to water-soluble vitamins.
Qualitative reaction to vitaminВ₁

Principle of the method.In an alkaline environment thiazole cycle ofthiamine becomes unstable and easily cleaved to form reactive compounds - Thiamine-thiol.

Thiamine - thiol is reacted with p-diazobenzenesulfonic acid (diazoreagent) to form a compound which colored to yellow- pink color.

Devices: Rack with test tubes.

Reactants: Fresh whole milk. Vitamin В₁, 0,001%-aqueous solution.Sodium hydroxide, 5% solution.

Solution A (0.9 g a phenyl-sulfo acid dissolved in 9 ml of conc. HCl acid in a volumetric flask of 100 ml, and after some time is adjusted to the mark with water. In a dark bottle solution is stored for a long time).

Solution B (sodium nitrite), 5% solution, freshly prepared).A freshly prepared diazo reagent (in a volumetric flask of 50 ml which immersed in a container with ice, metered 1,5 ml of solution A and added in small portions to 7.5 mL of solution B. Volume of the solution adjusted to the mark with cold water; after 15 minutes the reagent is ready for use).

Work description. In test tube mixed 2 ml of sodium hydroxide solution and 3 ml of a diazo reagent. Half of the resulting mixture is cast into another tube. Added to the tube 1-2ml milk. In the tube develops yellow-pink color.
Qualitative reaction to vitamin В₂

Principle of the method.Vitamin B₂reduced by hydrogen, which is released by reacting metallic zinc with hydrochloric acid.

Devices: Rack with test tubes. Pipettes. Rubber stoppers for tubes.

Reactants: Vitamin B₂, 0,005%-aqueous solution; hydrochloric acid, diluted (1:1), metallic zinc (granular).

Work description. Pour intothe test tube 2 ml solution of vitamin B2, 1 ml of hydrochloric acid and stirred, and cast into an equal volume of another tube. In one of the tubes cast piece of zinc metal and both tubes are stoppered. In the tube with zinc discoloration of solution occurs within 5-10 min.
Qualitative reaction to vitamin В₆(РР)

Principle of the method. Under the action of sodium hydrosulfite is restored nicotinamide (nicotinic acid) to give 1,4 - dihydro pyridine derivative, a yellow colored.

Devices: Rack with test tubes.

Reactants: Nicotinic acid or nicotinic acid amide (powder). Sodium bicarbonate, 10% solution.Sodium hydrosulfite (Na₂S₂O₄ * 2H₂O), a 5% solution, freshly prepared.

Work description. Inthe test tube is placed a little vitamin B5 powder (nicotinic acid or nicotinamide), add 1.2 ml of sodium carbonate solution and after stirring, 2.1 ml of a solution of sodium hydrosulfite. The liquid in the tube becomes yellow.
Qualitative reaction to vitamin С.

Principle of the method. Ascorbic acid reduces iron in the complex ion - ferrocyanide, turning it into a hexacyanoferrate, painted in blue color (Prussian Blue).

Devices: Rack with test tubes.

Reactants: Potassium hexacyanoferrate (6К₃[Fe(CN)₆]), 1% solution; ferric chloride, 1% solution; Vitamin C, 0.5% solution.

Work description. Into the test tube pour 2.3 ml of water, poured into another test tube 3.2 ml of a solution of vitamin C. In both tubes add a few drops of a potassium hexacyanoferrate solution and ferric chloride. In the tube with Vitamin C solution appears blue color.
The results write to the table 2.

Table 2

№	The name of vitamin	Reactants	Theobservedcoloration	Note	Conclusions
1.	В1
2.	В2
3.	В5
4.	С

Questions for self-preparation of students:

1. Characteristicsof vitamins B:

-B₂/ riboflavin/ - В₁₂/ cobalamin/

-В₃/ pantothenic acid/ - В_с/ folic acid/

-В₅/ РР, nicotinamide/ - В₁₅/ pangamic acid/

2. Characteristicsof vitamins С:

- С / ascorbic acid/

- Р/ flavone/
Practical work № 3

Topic: Primary structure of proteins. Secondary, tertiary and quaternary structures.

The general properties of enzymes – thermolability, specificity and influence рН on activity of enzymes.

The purpose of the work: To study properties of enzymes.
А. Thermolability of enzymes.

Principle of the method. Influence of change of temperature of the external environment on activity of enzyme of amylase of saliva is investigated.

Devices: Support with test tubes; glass (50 ml); spirit-lamp; thermostat (37 ͦC); a glass with ice.

Reactants: The diluted saliva (rinse a mouth with the distilled water, and then, having gained 20-25 ml of water in a mouth, bring together her in a glass); sodium chloride; 0,3% solution of chloride of sodium; the Lugol reactant (приготовление:в 100 ml of water dissolve 20 g of iodide of potassium and 101 g of iodine. For reaction with starch the received solution is dissolved with the distilled water 1:5).

Work description. In three test tubes pour 2-3 ml of the diluted saliva (amylase). Saliva in a test tube 1 is boiled within 1-2 min. Then add 4-5 ml of starch to all test tubes. Test tubes 1 and 3 put in the thermostat / 37 ͦ For 10 min. The test tube 3 is immersed for 10 min. in ice. After the specified time add to all test tubes on 1 drop of a reactant of Lugol. Results of experience enter 3 thermolabilities of enzymes in the table and draw conclusions.
Thermolability of enzymes

Table 3

№	Enzyme	Experimental conditions	Substrate	Incubation	Coloring with iodine
1.	Amylase	The denatured enzyme	Starch	10 min
2.	Amylase	Enzymatic	Starch	10 min 37ͦ с
3.	Amylase	Enzymatic	Starch	10 min 0ͦ с

B. Influence of рН on activity of enzymes.

Principle of a method. Activity of enzyme of amylase of saliva at various values of the environment is investigated.

Devices: A support with test tubes. Pipettes. Thermostat /37ͦ С/.

Reactants: Disubstituted format of sodium, 0,2 M solution/B/; buffer solutions (рН 5,0: To mix 515 ml of solution A from 485 ml of solution B; рН 6,8: To mix 772,5 ml of solution A from 27,5 ml of solution B). The diluted saliva (Starch, 1% solution. Lugol reactant).

Work description. In three test tubes flow 2-3 ml of buffer solutions with various rn/5,0; 6,8; 8,0/. Add to all test tubes on 2-3 ml of the diluted saliva / amylase(s) on 4-5 ml of solution of starch, 10 min. in the thermostat / 37 ͦ With / mix and incubate. Then add to each test tube on 1 drop of a reactant of Lugol. Results of observation enter in table 4 showing influence рН to activity of amylase of saliva.
Table 4

№ of test tubes	Enzyme	рН	Substrate	Incubation	Coloring with iodine
1.	Amylase	5,0	Starch	10 min. 37ͦ С
2.	Amylase	6,8	Starch	10 min. 37ͦ С
3.	Amylase	8,0	Starch	10 min. 37ͦ С

C. Specificity of enzymes.

Principle of a method. It is investigated impacts of enzymes of amylase and sucrose on various substrata - starch and sucrose.

Devices: A support with test tubes. Pipettes. Thermostat (37 ͦ C). Spirit-lamp.

Reactants: Starch, 1% solution. Sucrose, 2% solution, the diluted saliva/. Sakharaza, solution / 10 g of yeast homogenize in 100 ml vody./. Lugol reactant/. Reactant of Felinga/preparation: