Index
They are a series of chemical changes that occur in living cells through which energy is provided to the body to carry out vital processes and activities.
These physical and chemical processes that occur in the body that convert or use energy are mainly:
- The breathing.
- The circulatory process of the blood.
- Control of body temperature.
- Contraction of muscles.
- The digestion of food and nutrients.
- The elimination of waste through urine and feces.
- Functioning of the brain and nerves.
In metabolism, all the chemical reactions that take place within an organism cause complex molecules to break down to produce energy and through this process energy is also used to form new molecules.
An example of a metabolic reaction is one that takes place when a person eats a tablespoon of sugar.
Once inside the body, the sugar molecules break down into simpler molecules with the release of energy.
That energy is then used by the body for a variety of purposes, such as maintaining body temperature or creating new molecules within the body.
The digestion process
Metabolic processes start in the body once food is consumed.
In the metabolic process, the energy from the food that we eat daily is processed into the energy that is needed to carry out all the activities we do, including thinking and growing.
There are specific proteins in the body that control all the chemical reactions that occur during metabolism, and each chemical reaction that occurs is coordinated with other functions in the body.
The metabolism of all life forms is a constant process that begins at the moment of conception and culminates when the body dies.
If the metabolism stops, living things die.
One way to find out how the metabolic process works starts with plants.
First, a seed starts its metabolic processes to develop roots and stem.
This plant to develop its metabolic functions uses sunlight from which it absorbs energy.
This energy, together with the chlorophyll molecule, builds sugars from the water it absorbs and carbon dioxide.
This process is called photosynthesis.
When animals and humans eat, plants absorb this energy in the form of sugar, along with other chemicals vital to the formation of cells.
The body then breaks down the sugar so that the released energy can be distributed and used as fuel in the body’s cells.
During the digestive process, enzymes break down proteins and convert them into amino acids, in the same way they break down fats into fatty acids and carbohydrates into sugars.
Sugar, amino acids, and fatty acids can be used as energy sources by the body when needed.
These compounds are absorbed into the blood, which carries them into the cells.
Again other enzymes act in the chemical reactions of the cell by accelerating or regulating the chemical reactions that are involved in the metabolism of the compounds.
The energy produced by these compounds is released or stored in the body’s tissues, especially in the tissues of the liver, muscles, and body fat.
A nutrient is any substance that helps an organism stay alive, stay healthy, and grow.
Three major categories of nutrients are carbohydrates, proteins, and fats.
The path of a typical nutrient as it passes through the body is as follows:
The moment a person has just eaten a piece of bread.
An important nutrient in this bread is starch, which is a complex carbohydrate.
As soon as bread enters a person’s mouth, digestion begins to occur.
Enzymes in the mouth begin to break down starch molecules and turn them into smaller molecules of simpler substances – sugars.
This process can be easily observed, as anyone who holds a piece of bread in their mouth for a period of time begins to recognize a sweet taste, the taste of sugar formed from the breakdown of starch.
Digestion is a necessary first step for all foods.
The molecules in the food that are made are too large to pass through the lining of the digestive system.
In digestion, the formation of smaller molecules takes place that are able to pass through this lining and enter the bloodstream.
Sugar molecules formed by the digestion of starch enter the bloodstream.
They are then transported to individual cells throughout the body to carry out vital functions for the body.
In fact, thousands of metabolic reactions occur at the same time, all regulated by the body, to keep our cells healthy and functioning.
The smallest molecules into which nutrients are broken down form the metabolic group.
The metabolic group consists of the simplest substances formed by the breakdown of nutrients.
It includes simple sugars (formed by the breakdown of complex carbohydrates), glycerol and fatty acids (formed by the breakdown of lipids), and amino acids (formed by the breakdown of proteins.
Cell Metabolism
The substances that make up the metabolic complex are transported to individual cells by the bloodstream.
They pass through cell membranes and enter the interior of the cell.
Once inside a cell, a compound undergoes further metabolism, usually in a series of chemical reactions.
For example, a sugar molecule breaks down inside a cell into carbon dioxide and water, with the release of energy. But that process doesn’t happen in one step.
It takes about two dozen separate chemical reactions to convert the sugar molecule into the final products.
Each chemical reaction involves a relatively modest change in the sugar molecule, the removal of a single oxygen atom or a single hydrogen atom, for example.
The purpose of these reactions is to release energy stored in the sugar molecule.
To explain this process, one must know that a sugar molecule consists of carbon, hydrogen and oxygen atoms that are held together by chemical bonds.
A chemical bond is an attractive force between two atoms. That attractive force is a form of energy.
A sugar molecule with two dozen chemical bonds can be thought of as containing two dozen small units of energy.
Every time a chemical bond is broken, a unit of energy is released. Cells have developed remarkable methods to capture and store the energy released in catabolic reactions.
These methods make use of very special chemical compounds, known as energy carriers.
An example of such compounds is adenosine triphosphate, generally known as ATP.
Adenosine triphosphate is formed when a simpler compound, adenosine diphosphate (ADP), combines with a phosphate group.
Adenosine diphosphate will combine with a phosphate group, only if energy is added to it.
In cells, that energy comes from the catabolism of compounds in the metabolic group, such as sugars, glycerol, and fatty acids.
The adenosine triphosphate molecule formed in this way has then absorbed the energy previously stored in the sugar molecule.
When a cell needs energy for some process, it can obtain it from a molecule of adenosine triphosphate.
The energy of an adenosine triphosphate molecule can be used to put simpler molecules together to form more complex molecules. For example, suppose a cell needs to repair a break in its cell wall.
To do this, you will need to produce new protein molecules. Those protein molecules can be made up of amino acids in the metabolic group.
A protein molecule consists of hundreds or thousands of amino acid molecules linked together.
The energy required to form all the new chemical bonds necessary to hold the amino acid units together comes from adenosine triphosphate molecules.
The reactions by which a compound is metabolized differ in various nutrients. Also, energy carriers other than adenosine triphosphate may be involved.
For example, the compound known as nicotinamide adenine dinucleotide phosphate is also involved in the catabolism and anabolism of various substances.
Equilibrium law
The process of metabolism is really a balancing act that involves activities that occur at the same time: the accumulation of body tissues and the breakdown of body tissues.
The body’s metabolic reactions can be divided into two general categories, catabolic and anabolic reactions.
Anabolism or constructive metabolism: Anabolism is the process by which energy is used to form complex molecules that the body needs to maintain and develop.
This process is all about building and storing energy: it supports the growth of new cells, the maintenance of body tissues, and the storage of energy for future use.
During anabolism, small molecules transform into larger, more complex carbohydrate, protein, and fat molecules.
Catabolism or destructive metabolism: Catabolism is the process by which large molecules break down into smaller ones with the release of energy. This energy is required for all activities in cells.
In this process, cells break down large molecules (mainly carbohydrates and fats) to release energy. This release of energy provides fuel for anabolism, warms the body, and allows the muscles to contract and the body to move.
When complex chemical units are broken down into simpler units, waste products are released in the catabolism process that are eliminated from the body by sweat through the skin, by urine from the kidneys, by the daily breathing process that it is done in the lungs and in the stool.
Several of the hormones of the endocrine system are involved in controlling the speed and direction of metabolism.
Thyroxine, a hormone produced and released by the thyroid gland, plays a key role in determining how fast or slow the chemical reactions of metabolism are going to be.
Another gland, such as the pancreas, is responsible for secreting hormones that determine whether the metabolic activity is anabolic or catabolic at a given time.
For example, after eating, more anabolic activity generally occurs because eating increases the level of glucose, the body’s most important fuel, in the blood.
At this time the pancreas releases insulin, this hormone orders the cells to increase their anabolic activities.
Metabolism is a complicated chemical process, but for many people it is something as simple: as the process that influences weight gain and loss: as calories.
A calorie is a unit that measures how much energy a particular food provides to the body.
The amount of calories someone burns in a day is affected by the amount that person exercises, the amount of fat and muscle in their body, and the person’s basal metabolic rate.
The basal metabolic rate is the rate at which the body, while at rest, uses energy in the form of calories.
Metabolic rate plays a very important role in a person’s tendency to gain weight.
For example, someone with a low metabolic rate (who burns fewer calories while resting or sleeping) will tend to gain more pounds of body fat over time compared to a similarly sized person with an average metabolic rate who eats the same amount of food. and you get the same amount of exercise.
To some extent, the metabolic rate is inherited, passed down through genes. Sometimes health problems can affect someone’s metabolic rate.
But people can change their metabolic rate in some way.
For example, by exercising more, a person burns more calories during additional activity and becomes more physically fit, which increases their metabolic rate.
Metabolic rate is also influenced by body composition – people with more muscle and less fat generally have a higher metabolic rate.
Problems with metabolism
Most of the time the metabolic process works perfectly, but sometimes an individual’s metabolism can create great chaos, which is called: metabolic disorder.
A metabolic disorder is a disease that arises, because in the cells of the body, a chemical reaction develops abnormally.
Most metabolic disorders involve abnormal levels of enzymes or hormones or problems with the functioning of those enzymes or hormones.
In cases where the metabolism of chemical substances present in the human body are blocked or defective, the accumulation of toxic substances in the body can be caused.
Or a deficiency of the substances necessary for the normal functioning of the body, and these situations can give rise to symptoms of serious diseases.
These metabolic diseases and conditions include:
Thyroidism
The thyroid is often referred to as the “master gland.”
This gland controls important processes, such as the creation of proteins, energy levels in the body, and metabolism.
Metabolic processes often affect body mass, and normal function is very important when it comes to regulating body weight.
Thyroid problems can lead to weight gain or conditions such as hypothyroidism and hyperthyroidism .
The thyroid gland produces two very important hormones, T3 and T4, which are essential for controlling the body’s metabolic rate .
The component that activates these hormones is iodine.
When there is a variation in iodine levels, the production of these hormones varies, metabolism is blocked.
Hyperthyroidism: Hyperthyroidism is caused by an overactive thyroid gland. The thyroid releases too much thyroxine hormone, so the metabolic rate of a person’s body is high.
Hyperthyroidism causes symptoms such as weight loss, an increase in heart rate and blood pressure, signs such as bulging eyes, and neck swelling caused by an enlarged thyroid, commonly called a goiter. This disease can be controlled with medications or by surgery or radiation treatments.
Hypothyroidism: Hypothyroidism is caused by the missing or underactive thyroid gland. The thyroid releases too little thyroxine, so the body’s metabolic rate is low. When hypothyroidism is not treated it can induce growth and brain problems in babies and children.
Hypothyroidism slows down the body’s processes and causes tiredness, slow heart rate, weight gain, and constipation. Adolescents with it can be treated with an oral thyroid hormone.
Inborn errors of metabolism
Inherited metabolic diseases are called inborn errors of metabolism.
Congenital metabolism problems include:
Galactosemia: Babies born with galactosemia do not have enough of the enzyme responsible for breaking down the sugar in milk, called galactose.
Phenylketonuria: This is caused by a defect in the enzyme that is responsible for breaking down the amino acid phenylalanine. Phenylalanine is necessary for normal growth and protein production.
Inborn errors of metabolism can lead to serious problems in some cases if medications or special diets are not prescribed from an early age.
Diabetes
The metabolism of people with diabetes is almost identical to the metabolism of people without diabetes.
The only difference is the volume or effectiveness of the insulin produced by the human body.
The pancreas responds to the presence of food by releasing stored insulin.
Insulin allows glucose present in the blood to enter the cells of the body, where glucose is normally used for fuel.
Insulin also allows glucose to be stored by the muscles and the liver as glycogen.
If necessary, the stored glycogen can later be returned to the blood as glucose.
When glucose remains in the bloodstream, insulin converts this glucose into saturated fat.
Protein in food also breaks down into glucose to some extent, however this is a much slower process than with carbohydrates.
After the initial release of insulin from the body, the beta cells of the pancreas begin to develop new insulin that can also be released. This is known as the insulin response.
When glucose is used up from the blood to the point where sugar levels begin to drop, the body releases glucagon.
Glucagon works to transform stored glycogen into glucose that is released into the bloodstream.
There are two types of diabetes:
Type 1 diabetes : Type 1 diabetes occurs when the pancreas cannot make and secrete insulin in sufficient amounts. Symptoms of this disease include excessive thirst, frequent urination, hunger, and weight loss.
This disease over time can cause kidney problems, pain caused by nerve damage, loss of vision, vascular and heart disease.
Type 1 diabetes patients need regular insulin injections and must control their blood sugar levels to reduce the risk of developing problems from diabetes.
Type 2 diabetes : Type 2 diabetes occurs when the body cannot respond normally to insulin. The symptoms are similar to those of type 1 diabetes.
Many children and adolescents who develop type 2 diabetes are overweight, and this is believed to play a role in their decreased ability to respond to insulin. Some teens can be successfully treated with changes in diet, exercise, and oral medications, others will need insulin injections.
Controlling blood sugar levels reduces the risk of developing long-term health problems similar to those with type 1 diabetes.
Overweight people, with either prediabetes or type 2 diabetes, generally produce significantly more insulin than non-diabetic people as a result of a higher ratio of body fat to muscle.
The reason for this is insulin resistance, which means that the body cannot use its insulin effectively enough.
So it makes sense for the body to produce more insulin to compensate.
However, the stress of producing all this extra insulin means that the beta cells become overworked and will eventually begin to fail.
Also, the increasing amounts of insulin in the body cause the body to gradually become more resistant to it.
It can be seen as something similar to how drug addicts can increase drug tolerances.