Types of Diseases and Pathogens for Class 5 Science
- Any type of disease or malfunctioning of the body or mind that leads to impaired mental and physical health is considered a disease.
- Diseases can be classified based on their mode of transmission, duration and causal organism.
- Disease-causing microbes are called pathogens, and the organism that spread disease from diseased to healthy persons is called a vector.
- Some diseases are caused due to deficiency of vitamins and minerals in our body. These are called deficiency diseases.
Meaning of Diseases and Pathogens
How Are Diseases Inherited From Parents to Offspring?
- The diseases are inherited from parents to offspring through the genetic material in our cells.
- Offsprings receive half their genetic material from each parent.
- During this transmission, the genes responsible for genetic diseases are also transferred.
- Such a transmission leads to the occurrence of genetic diseases in the offspring.
Why Are Viruses an Intermediate Between Living and Non-Living Organisms?
- Viruses are considered intermediate as they show the properties of a dead organism outside the host body, whereas they are living inside the host body.
- Viruses can multiply only when they are inside the host body. They remain in a dormant stage when they are not inside a host.
Fungi Are Often Called Saprophytes. State the Reason for the Same.
- Fungi are a group of microbes that have some similarities with the plant kingdom but lack chlorophyll.
- Fungi depend on dead and decaying matter for nourishment and absorb the nutrients from the same.
- Such a mode of nutrition is called saprophytic nutrition; hence, fungi are called saprophytes.
What Is a Microscope? Name the Parts of the Microscope.
- The microscope is a device used to observe microorganisms that are invisible to the naked eye.
- The different parts of a microscope are shown below—
Communicable Disease and Non-Communicable Diseases
Why Do Genetic Diseases Not Transfer From a Diseased Person to a Healthy Person by Sharing Food, Water or Clothes?
- Genetic diseases are not caused by any causal organism.
- They occur because of the alteration of the genes. So, genetic diseases do not get transferred by sharing food, water and clothes.
What Are Antibiotics? Why Are They Not Effective Against Viral Diseases?
- The medicines that are used to inhibit the growth of microorganisms are called antibiotics.
- Viruses do not have a mechanism to multiply. They multiply inside the host body and keep creating their own copies. Therefore, antibiotics are not effective against them.
What Is AIDS? Mention the Causal Organism of the Disease AIDS. Can AIDS Spread Through Sharing Food and Shaking Hands?
- AIDS stands for Acquired Immune Deficiency Syndrome. It is caused by the Human Immunodeficiency Virus (HIV).
- This disease does not get transmitted by sharing food or shaking hands.
- It gets transferred from an infected person to a healthy person only when bodily fluids like saliva or blood are exchanged.
You Must Have Heard of the Disease COVID-19. What Is Its Causal Organism, and How Does It Spread? Name Any Two Vaccines Developed To Provide Immunity Against This Disease.
- COVID-19 is caused by a virus.
- It spreads through the droplet infection.
- Two vaccines developed to provide immunity against the disease are Covishield and COVAXIN.
Why Is It Advised Not To Share Personal Items Like Razors, Toothbrushes, Tongue Cleaners, etc.?
- Sometimes our body is invaded by certain viruses, but we survive without showing any symptoms. This ability varies from person to person based on immunity.
- The personal items we use have the remains of our body fluids like saliva or sometimes blood.
- Hence, we should not share them as it may expose another person to a certain causal organism which may infect them.
- Also, by limiting personal things to ourselves, we ensure that we are not exposed to pathogens.
Vectors and Deficiency Diseases
How Can We Diagnose a Disease?
A disease can be diagnosed by laboratory tests and symptoms such as the FeNO test is used to diagnose asthma, and a blood test is used to diagnose typhoid, jaundice or malaria.
Apart from the tests, a few common symptoms may indicate a disease. For example—
- High fever with chills indicates malaria.
- Yellowish eyes, nails, or skin shows jaundice.
- Prolonged cough (around 3 weeks) indicates tuberculosis.
What Is Dehydration? Why Should We Prevent It?
- Dehydration stands for the excess loss of water from the body. It generally happens due to vomiting or diarrhoea.
- It should be prevented as water constitutes our major body weight and is required for all body functions.
- The removal of excess water from the body may lead to loss of strength and stamina, and long-term dehydration leads to the risks of kidney failure too.
What Is Cancer? How Is It Caused?
- Cancer is a genetic disease caused by the alteration of our genes.
- It is generally characterised by an uncontrolled division of cells in our body which leads to the development of tumours.It is generally characterised by an uncontrolled division of cells in our body which leads to the development of tumours.
- These genetic alterations may be caused due to exposure to certain chemicals or UV rays. A person with a family history of cancer may inherit specific mutated genes, which can lead to cancer development.
What Is Anaemia? How Does It Affect Our Body?
- Anaemia is a medical deficiency disease caused when the haemoglobin in a person’s body is below the required amount.
- Haemoglobin is the red pigment present in the red blood cells of our blood.
- The primary function of haemoglobin is to bind with the oxygen molecules we breathe in and transfer them to various organs of our body.
- Lower levels of haemoglobin in the body may lead to weakness, headache, dizziness, fatigue etc.
Why Is the Protein Requirement of a 12-Year Boy More Than an Older Adult?
- At the age of 12 years, our body undergoes growth and development. The body attains maximum height and starts developing muscles during this age.
- Therefore, a high protein diet is required to meet the nutritional requirements of body spurts.
Why Should We Avoid Eating Overcooked Food?
- Raw food contains vitamins and minerals.
- These vitamins and minerals may be destroyed or lost if cooked above the required temperature. Hence, food should not be overcooked.
What Is Autoimmune Disease?
- Autoimmune disease is a disorder related to our body's immune system.
- The essential function of the immune system is to prevent the invasion of foreign substances in the body and kill them.
- But when a body stops distinguishing between foreign substances and its own cells, the situation is considered an autoimmune disorder.
- Because of autoimmune disorders, the immune system starts attacking the body cells, leading to diseases like arthritis, lupus, etc.