LOGO 1 Biochemistry 2 Introduction of metabolism (1) Dr. Moeen Al Burch

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Biochemistry 2Introduction of metabolism (1)

Dr. Moeen Al Burch

www.themegallery.com2

Introduction of metabolism (1)

Metabolism Metabolism: is all the chemical & energy

transformation that occur in the body, it includes: - anabolism - catabolism

Anabolism: It's the formation of large organic molecules with uptake of energy.

Anabolic reaction are endergonic (they consume more energy than they produce).

Catabolism: Is break down of large organic molecules with release of energy, for maintaining body function.



Catabolism reaction are exergonic (they produce more energy than they consume) 75% appears as heat & 25% is stored as ATP. .

Note: The IC compartment of the BW accounts for about

40% of body weight & The EC compartment account for about 20% 25% of EC compartment is in the vascular system

(Plasma = 5% of BW), & 75% outside the BV (interstitial fluid = 15% of BW ) .

The total blood volume is about 8% of BW



Metabolism & the Basal Metabolic Rate Is the sum of total chemical reactions that occur in

the living cell. It contains two processes: Anabolism and catabolism. Anabolism is the sum of processes leading to

synthesis of complex molecules from simpler ones.

Catabolism is the sum of degradative processes leading to the cleavage of large molecules into smaller ones and is accompanied by release of energy.



The two phases occur during the life cycle During childhood anabolism exceeds catabolism,

during adulthood the two phases are equal but during aging catabolism exceeds anabolism.

Metabolism During the absorptive state: - Soon After a meal, nutrients as glucose, amino acids,

& triglycerides, & enter the blood. Two metabolism reactions occur:

Oxidation: of glucose & ATP production in most body cells.

- Storage of excess energy in liver, , & skeletal muscle.



- After 4 hours the last meal, blood glucose start to fall.- Thus, the metabolic challenge is to maintain the normal

blood glucose of 70-110 mg/100 ml of blood which is important for the normal function of nervous system & red blood cells.

Post absorptive state reactions :( to maintain the normal blood glucose )

1- break down of liver & muscle glycogen .2- lipolysi3- gluconeogenesis using lactic acid .4- gluconeogenesis .5- oxidation of fatty acids, lactic acid, amino acids, &

ketone bodies.



Energy balance: means that the energy input = energy output . Positive energy balance : anabolism exceeds catabolism e.g growth in

children . Negative energy balance : when energy output is greater than energy input as in

atrophy in old age, loss of weight in starvation & severe illness.

Calorie : is the amount of energy necessary to raise the temp. of 1gm of water 1C (from 15 – 16 C) It is the standard unit of heat energy. In medicine kilocalorie (Kcal) or (C) is used Kcal = 1000cal



The caloric value of food: is amount of heat energy (C) liberated when 1gm of a certain food is oxidized. It depends on:

a- type of food. b- whether food is oxidized outside the body ( physical caloric value ''CV'' ) or inside the body ( physiological caloric value ). E.G :

Type of Food physical CV physiological CV

1gm carbohydrate 4.1 C 4.1 C

1gm fat 9.3 C 9.3 C

1gm proteins 5.3 C 4.1 C



Respiratory quotient : Definition: The ratio of volume of Co2 produced to

volume of O2 consumed per unit time. RQ = Vol. of Co2 produced X unit time

Vol. of O2 consumed

Metabolic rate ( MR ) : is amount of energy production per unit time (hour). It's the energy needed for the work of vital organs i.e the heart, respiratory ms, liver & muscles



Determination of MR: 1- direct method by calorimetry . 2- indirect method as follow . MR = O2 (liters) consumed by hour x energy

equivalent of O2 of mixed food . MR = 250 x 60 x 4.8/1000 = 72.0 K Cal/hour .

the Basal metabolic Rate (BMR) is measured under the following 3 Basal condition.

1-Complete physical & mental rest: for at least 1/2 an hour but without sleep.



2- Post-absorptive state: 12-14hrs after the last meal to avoid specific dynamic action of food.

3- Comfortable temperature (21-22 C): neither cold nor hot (neither shivering nor sweating).

BMR can be expressed in Kcal / hour / m2 surface area) as heat exchange occurs at the body surface.

BMR is less in females by 7% due to more fats%.



3- Comfortable temperature (21-22 Co): neither cold nor hot (neither shivering nor sweating).

BMR can be expressed in Kcal / hour / m2 surface area) as heat exchange occurs at the body surface.

BMR is less in females by 7% due to more fats%.



Decrease MR Increase MR

sleep muscular exercise

fasting Recent food ingestion

MR declines with age low environmental temperature.

Growth

Pregnancy & Lactation.

- Factors affective the metabolism rate:- (1) Physiological factors:


Biochemistry 2

-(2) Pathological factors that increase MR :

- Fever = increase body temperature. - Hyperthyroidism = increase thyroid hormones. - increase epinephrine & nor epinephrine. - Malignancy & polycythemia .


Biochemistry 2

Specific dynamic action (SDA) of blood: is the obligatory energy expenditure occurs during

assimilation of food into the body.

It varies according to the type of food : An amount of protein sufficient to provide 100 K

cal increase the MR by 30 K cal A similar amount of carbohydrates increase the MR

by 6.0 K cal . A similar amount of fat increase the MR by 4.0 K

cal.


Diseases of protein deficiency and energy

Diseases of protein deficiency and energy • diseases of protein deficiency and energy is a group of serious diseases that result from lack of calories and essential nutrients (micronutrients) and affects mainly young children (usually in the process of weaning), particularly in developing countries and poor



Marasmus is a form of emaciation and wasting in an infant

due to protein-energy malnutrition. It is characterized by growth retardation in weight

more than height so tha the head appears quite large relative to the

body.



There is a progressive wasting of subcutaneous fat and muscle so that the skin appears loose.

Severe prolonged marasmus may result in permanent retardation.

Marasmus is common in Third World countries in situations with poor access to protein-rich food sources or where unsanitary water is associated with severe infant diarrhea and a corollary inability to absorb nutrients



2- kwashiorkor a form of protein-energy malnutrition produced

by severe protein deficiency; caloric intake is usually also deficient. Symptoms include retarded growth, changes in skin and hair pigment, edema, immune deficiency, and pathologic changes in the liver.



3- marasmic kwashiorkor a condition in which there is a deficiency of both calories and protein, with severe tissue wasting, loss of subcutaneous fat, and usually dehydration

Is wasted as a serious global problem affecting about 50 million children under the age of five, according to the World Health Organization, 49% of deaths in children under five years of age-related diseases are the lack of protein and energy.



The result of wasting due to a negative balance of energy in the body, either because:

1 - lack of caloric intake.

2 - An increase in the calories lost or both



This usually happens in: The child begins to adapt and cope with the

shortage of energy to reduce the level of physical activity, inactivity and lack of metabolic rate and slow growth rate and with the continued lack of situation occurs in the body mass.



The changes are occurring in the body due to a lack of protein and energy

1 - Physical changes Lack of fat mass. A relative increase in the amount of water in the

body with an increase in the amount of water outside the cells (the tissue), which Cause edema (oedema) and be clear in Alkouachir than in wasting.



Lack of muscle mass as muscle fibers become thinner with atrophy of the muscle cells and loss of muscle plans

Are also affected by the other member of the body such as liver, heart, pancreas, gastrointestinal tract, while the remaining kidney, brain and skeletal unchanged



2- Physiological changes As a result of reduced metabolic rate

(metabolism) decline in body temperature as the body can not adapt to any external temperature can not raise the internal temperature (core body temperature)



in the case of cold weather due to the lack of metabolic rate and the inability to produce energy , also in the case of infectious disease might not raise the temperature of the body (fever does not occur), as happens in ordinary people

Low blood sugar.



3. Vitamins and minerals: Iron deficiency anemia and the occurrence of

iron deficiency . Lack of inventory and a lack of potassium

calcium, magnesium and phosphorus. A lack of fat soluble vitamins (a, d, k, e) and

vitamins dissolved in water (b 6, b 12, folic acid).



Changes in metabolic processes: Lack of affordable caloric shortfalls in physical activity and slow the rate of growth or stop growth altogether

The continuation of the situation begins with the lack of weight decrease of fat mass and then the lack of muscle mass

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LOGO 1 Biochemistry 2 Introduction of metabolism (1) Dr. Moeen Al Burch