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SSC CPO General Science Biology Quick Guide

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SSC CPO General Science Biology Quick Guide

General Science Biology Quick Guide

shape Introduction

Biology is the study of life and living organism, including their structure, function, evolution, distribution, identification and Taxonomy. General Science Biology is an important section in the various competitive exams primarily the recruitment exams (Banking, SSC, Railways, RRB ALP, RRB Group D,etc.) in India. This General Science Biology Quick Guide presents the basics and key points of various Biology topics.

  • Aristotle is often called “the father of biology”.

  • Leeuwenhoek invented a simple microscope and studied living cells.

  • Alexander Flemming discovered Penicillin.

  • Gregor Johann Mendel discovered principles of inheritance.

  • Louis Pasteur proposed ‘Germ theory of disease. He also proposed pasteurization for sterilization.

  • Robert Hooke assembled a compound microscope and discovered cells in cork.

  • Charles Darwin is famous for the theory of Natural selection.

  • Hippocrates is considered to be the “father of western medicine”.

  • Edward Jenner is famous for creating the first effective vaccine for smallpox- (father of immunology)

  • William Watson (1909) introduced the term Genetics.

  • Watson and Crick gave the model of DNA.

  • In 1866 Ernst Haeckel coined word “ecology”

  • Camillo golgi discovered golgi body.

  • Salim Ali known as the “birdman of India”

  • Har Gobind Khorana is a biochemist who won the Nobel Prize in 1968 for demonstrating how the nucleotides in nucleic acids control the synthesis of proteins.

shape Concepts


  • All living organism are constituted of structural and functional units called cells.

  • Robert Hook coined the term ‘cell’ in 1665.

  • Cells are grouped into tissues, tissues into organ and organs into organ system.

  • Smallest cells- Mycoplasmas.

  • Largest isolated single cell- egg of an ostrich

  • Prokaryotic is without nucleus.

  • It is found in bacteria, blue green algae, mycoplasma.

  • The eukaryotic cells with nucleus occur in all protists, fungi, plants and the animals.

  • Cell wall is present in plants cell.

  • Cell membrane is composed of lipids.

  • The function of plasma membrane is the transport of the molecules across it.

  • Ribosomes were first observed by Palade.

  • Ribosomes are present only in grandular endoplasmic reticulum.

  • Except mammalian RBC all living cells have ribosomes.

  • Nucleus is centrally located spherical and largest component of all eukaryotic cell. Nucleolus is present in nucleus.

  • Mitochondria are also called “Powerhouse of cells”. They are involved in energy generation

  • Most acceptable classification was given by R. H. Whittaker (1969). These are Monera, protista, Fungi, Plantae, Animalia.

  • Study of genes is known as genetics.

  • Gene is a segment of DNA and basic unit of heredity. These are located on chromosomes.

  • DNA is found in nucleus, and also found in mitochondria and chloroplast.

  • It stands for deoxyribonucleic acid (DNA).

  • It is double stranded.

  • It consists of Nitrogenous bases-Adenine, Thymine, Cytosine or Guanine, 5-carbon sugar and a phosphate molecule

  • RNA is single stranded. It consists of phosphate, ribose sugar, nitrogenous bases Adinine, Uracil, Cytosine, and Guanine.

  • Mendel conducted cross hybridization experiments on green pea plant (Pisum sativum).


  • Sudden change in the sequence of DNA is known as mutation.

Sex Determination:

  • X and Y are the sex chromosomes which are responsible for the determination of sex. 46 chromosomes are present in human body cell. In which 22 pairs of these are autosomes & 23rd is sex chromosomes, i.e. x & y

Digestion of Food:

Name of the Digestive Juice Name of the Enzymes Substrate End product
Saliva Ptyalin (Salivary amylase) Starch Maltose
Pancreatic juice Amylopsin (pancreatic amylase) Starch, Glycogen Maltose and Glucose
Intestinal juice Sucrase (invertase), Maltase, Lactase Sucrose; Maltose, Lactose Glucose and fructose, Glucose, and galactose
Gastric Juice Pepsin, Rennin Proteins, Casein Proteoses and peptones, Calcium caseinate
Pancreatic Juice Trypsin, Chymotrypsin, Carboxyl peptidases Proteins, Peptides Proteoses and Peptides Amino acid.
Intestinal juice Amino peptidase, Dipeptidase Peptides Amino acids

Vitamin Required by the Body:

Vitamin Chemical Name Function in Body Deficiency Disease Sources
\(B_1\) Thiamine pyrophosphate Part of coenzyme for respiration Beri-beri: nerve and heart disorders Found in whole grain cereals, etc.
\(B_2\) Riboflavin Part of coenzyme FAD needed for respiration Ariboflavinosis: skin and eye disorders Milk, yogurt, etc
\(B_{12}\) Cyanocobalamin Coenzyme needed for making red blood cells, etc. Pernicious anaemia Animal products etc
\(B_5\) Nicotinic acid (‘niacin’) Part of coenzymes NAD, NADP used in respiration Pellagra: skin, gut and nerve disorders Widespread in foods.
C Ascorbic acid Not precisely known Scurvy: degeneration of skin teeth and blood vessels. Lemon, orange, etc.
A Retinol Visual pigment, rhodopsin Xeropthalmia: ‘dry eyes Milk, eggs, etc.
D Cholecalciferol Stimulates calcium absorption by small intestine, needed for proper bone growth Rickets: bone deformity Found in dairy products, etc.
E Tocopherol Not precisely known Infertility Found primarily in plant oils, green, leafy vegetables, etc
K Phylloquinone Involved in blood clotting Possible haemorrage Green, leafy vegetables, etc.

Minerals Required by the Body:

Minerals Source Function
Sodium (Na) Table salt large amounts is present in processed foods, etc. for proper fluid balance, etc
Chloride Table salt, large amounts is present in processed foods, etc. for proper fluid balance, etc.
Potassium Meats, milk, etc for proper fluid balance, etc
Calcium Milk and milk products, etc Important for healthy bones and teeth, etc
Phosphorus Meat, fish, poultry, eggs, milk, processed foods Important for healthy bones and teeth, etc.
Magnesium Nuts and seeds; etc. Found in bones, etc
Sulfur Occurs in foods as part of protein, meats, etc. Found in protein molecules.
Iron Organ meats; etc. found in red blood cells.
Iodine Seafood, foods grown in iodine-rich soil, etc. Found in thyroid hormone.

  • Marasmus is produced by a simultaneous deficiency of proteins and calories.

  • Kwashiorkar is produced by protein deficiency

Respiratory System:
The organ system which aids in the process of respiration is called the Respiratory system.

Organs of Respiration in Animals:

Respiratory Organ Animals
Lungs Mammals, Birds, Reptiles and Amphibians
Gills Fish, Crabs, Tadpole larva of Frog
Skin Earthworm, Leech, Amphibians
Trachea Insects

Human Respiratory System:

  • Human respiratory system consists of external nostrils, nasal cavity, nasopharynx, larynx, trachea, bronchiole and lungs.

Circulatory System:

  • These are of two types open circulatory system and closed circulatory system.

  • Generally present in arthopods and molluscs.

  • Annelids and chordates have a closed circulatory.

  • The human heart beats at the rate of about 72-80 per minute in the resting condition.

  • ECG stands for Electrocardiogram. It is the graphic record of electronic current produced by the excitation of cardiac muscles.

  • It is process of removal of undigested wastes from the body.

  • Kidney plays a major role in the elimination of water waste in the form of urine.

  • Urine contains ammonia, urea, uric acid, etc.

Endocrine System: Hormones and their Action:

S.No. Endocrine gland Hormone Action
1 Pituitary (Master gland) Growth hormones, Anti-diuretic hormone Adeno – Corticotrophic hormone Regulates the growth of bone and tissue. Controls the amount of water reabsorbed by the water. Defending the body against physiological stress e.g. exposure to cold. Follicle stimulating hormone stimulates ovary to produce female hormone.
2 Pineal Melatonin Regulates, circadian and sexual cycle
3 Thyroid Thyroxine Regulates rate of growth and metabolism. Too little-over weight and sluggishness. Too much-thin and over active.
4 Thymus Thymosin Helps in production of lymphocytes
5 Adrenal Cortisone Aids in conversion of proteins to sugar, cortex of this gland produces the hormone.
6 Pancreas Insulin Regulates sugar metabolism. Too little insulin leads to high sugar level in blood and weakness (a condition called diabetes)
7 Ovary Estrogen Development of secondary sexual characters e.g. development of breasts in female.
8 Testis Testosterone Development of many masculine features such as growth of moustaches and beard.

Common Heart Diseases:

  • Coronary artery disease or Arthrosclerosis

  • Angina (angina pectoris)

  • Heart Failure (congestive heart failure)

Common Lung Diseases:

  • Asthma

  • Bronchitis (Inflammation of the Bronchi)

Common Brain Diseases:

  • Epilepsy: Epilepsy is a condition where a person has recurrent seizures, abnormal discharge of electrical activity in the brain cells.

Bacteria Diseases:

Disease Pathogen Affected Organ Symptom
Anthrax Bacillus anthracis Skin and intestine Skinulcer, sore throat, nausea, fever, breathlessness
Cholera Vibrio cholerae Intestine Vomiting, acute diarrhoea, muscular cramps, dehydration etc.
Diphtheria Corynebacterium diphtheriae Respiratory tract Difficulty in respiration (mainly in child of age 2-5 yrs).
Leprosy or Hansen’s disease Mycobacterium leprae Chronic infection of skin and nerve Ulcers, nodules, scaly scabs (the infected part of the body becomes senseless).
(i) Bubonic plague
(ii) Pneumonic plaque
Pasteurella, Yersinia pestis Blood disease
High fever, weakness and haemorrhage which turn black.
Haemorrhage of bronchi, lungs
Tetanus (lock jaw) Clostridium tetani Central nervous system Painful contraction of neck and jaw muscles followed by paralysis of thoracic muscles.
Tuberculosis Mycobacterium tuberculosis Lungs Repeated coughing, high fever.
Whooping cough or Pertussis Bacillus pertussis Respiratory system Continuous coughing
Pneumonia Diplococcus pneumoniae Lungs Sudden chill, chest pain, cough, high fever.
Typhoid Salmonella typhi intestine High fever, diarrhoea and headache

Viral Diseases:

Disease Pathogen Affected Part Symptom
AIDS (Acquired Immuno Deficiency Syndrome) Bacillus anthracisHIV (Human Immuno Deficiency Virus) White blood cells Weak immune system.
Chicken pox Vericella virus Whole body High fever, reddish eruption on body
Small pox Variola virus Whole body Difficulty in respiration (mainly in child of age 2-5 yrs).Light fever, eruption of blood on body
Dengue fever RNA containing dengue virus Whole body, particularly head, eyes and joints High fever, backache, headache, retro-orbital pain behind the eye ball.
(Epidemic Jaundice)
(i) Hepatitis – A
(ii) Hepatitis – B
Hepatitis virus
Hepatitis – A virus
Hepatitis – B virus
Liver Loss of appetite, nausea, whitish stool and jaundice. Not fatal Fatal
Herpes Herpes virus Skin Swelling of skin.
Influenza (flu) Influenza virus Whole body Inflammation of upper respiratory tract, nose throat and eyes.
Measles German Rubella virus Whole body Loss of appetite, reddish eruption on the body
Polio or poliomyelitis Polio virus Throat, backbone and nerve Fever, backbone and intestine wall cells are destroyed. It leads to paralysis.
Rabies (hydrophobia) RNA virus called rabies virus Nervous system Encephalitis, fear of water, high fever, headache, spasm of throat and chest leading to death
Swine influenza (flu) \(H_1N_1\) flu virus Whole body (muscles) Headache, tiredness, sore throat, vomiting, breathing problems.

Protozoan Diseases:

Disease Pathogen (Causative agent) Vector Parts Affected and Symptoms
African trypanosomiasis Trypanosoma gambienes Tsetse fly (Glossina palpalis) Blood and nervous tissue. Man feels sleepy, may cause death.
Amoebic dysentery (Amoebiasis) Entamoeba histolytica None, Infection by contamination Colon (intestine). Develop loose motion with blood, pain in abdomen
Diarrhoea Giardia None, infection by contamination Digestive system causes loose motions, vomitting
Filaria or elephantiasis Wuchereria bancrofti Culex mosquito Swelling of legs, testes and other body parts
Kala azar or dumdum fever Leishmania donovani Sand flies (Phlebotomus) Spleen and liver enlarge and high fever develops.
Malaria Plasmodium sp. Female Anopheles mosquito Periodical attacks of high fever, pain in joints accompanied by chill, heavy perspiration and fast pulse.

Fungal Diseases in Human Beings:

Disease Pathogen (fungi) Symptoms
Asthma or aspergillosis Aspergillus fumigatus Obstruction in the functioning of lungs.
Baldness Tinea capitis Hair fall
Athlete’s foot Tinea pedis Skin disease, cracking of feet.
Ringworm Tricophyton Verrucosum Round red spot on skin
Scabies Acarus scabiei Skin itching and white spot on the skin.

  • Blood is a liquid connective tissue.

  • Blood has a fluid matrix called plasma.

  • Plasma is a pale coloured fluid which contributes 55% of blood volume. Plasma contains 90 to 92% of water.

  • Blood corpuscles are of three types: Red blood corpuscles (RBCs), white blood corpuscles(WBCs) and Blood platelets.

  • RBC’s are formed in the red bone-marrow, and lack nucleus.

  • Life span of RBCs (Erythrocytes) is about 120 days.

  • WBCs (Leueocytes) are responsible for immunity.

  • WBCs are manufactured in bone marrow.

  • Neutrophils and monocytes are phagocytic cells (destroy foreign bodies)

  • Basophils are involved in inflammatory reactions.

  • Eosinophils are associated with allergic reactions.

  • Lymphocytes are responsible for immune response.

  • Platelets (thrombocytes) are responsible for clotting of blood during accidents.

  • For a healthy adult person the average systolic/diastolic pressure is 120/80 mm of Hg in arteries near heart.

  • The Rh factor is a type of protein on the surface of red blood cells. Most people who have the Rh factor are Rh-positive. Those who do not have the Rh factor are Rh-negative.

  • Karl Landsteiner (1900) discovered the blood group in human.

  • There are four groups of blood A, B, AB and O.

  • Universal Donor: ‘O’ blood group person can give blood to all the four blood groups (O, A, B, and AB).

  • Universal Recipient: ‘AB’ blood group person can take blood from all the four groups (AB, A, B, O).

Vaccines and their Doses:

Age Vaccination Dose
Birth to 12 months
  • DPT (triple vaccine, against diptheria, whooping cough/pertussis and tetanus)
  • Polio (Sabin’s oral, previously Salk’s injectible)
  • BCG (Bacillus Calmette Guerin)
  • Three doses (commonly oral) at intervals of 4-6 weeks.
  • Three doses at intervals of 4-6 weeks.
  • Intradermal and one vaccine
8-24 months
  • DPT
  • Polio (oral)
  • Cholera vaccine (can be repeated every year before summer)
  • Booster dose
  • Booster dose
  • One
9-15 months
  • Measles vaccine (MMR or Measles, Mumps and Rubella)
  • one dose
5-6 years
  • DT (Bivalent vaccine against diphtheria and tetanus)
  • TAB (vaccine against Salmonella typhi, S. paratyphi A and S paratyphi B) or Typhoid Paratyphoid vaccine
  • Booster dose
  • Two doses at intervals of 1-2 months
10 years
  • Tetanus, TAB (typhoid)
  • Booster dose
16 years
  • Tetanus, TAB
  • Booster dose

shape Inventions

Vaccines and Inventors:

Vaccine Developed by Country Year
Small Pox Edward Jenner England 1796
Cholera Louis Pasteur France 1880
Diphtheria and Tetanus Emil Adolf Von Behring and Shibasaburo Kitasato Germany/Japan 1891
TB Vaccine Albert Calmette and Camille Guerin France 1922
Polio Vaccine Jonas E. Salk US 1952
Oral Polio Vaccine Albert Bruce Sabin US 1955
Measles Vaccine John F. Enders, Thomas peeble US 1953
Rabies Vaccine Louis Pasteur France 1885
Typhus Vaccine Charles Nicolle France 1909
Rubella Vaccine Paul D.Parkman & Harry M. Meyer jr 1966
Scurvy vaccine James Lind 1753

Medical Science Discoveries:

Invention Inventor Year
Penicillin Alexander Fleming (scotland) 1928
Anesthetic William Morton 1846
Anthrax vaccine Louis Pasteur 1881
Antiseptic Joseph Lister (Scotland) 1867
Artificial heart Denton Cooley 1969
Bacteria (discovered) Anton van Leeuwenhoek 1674
Cholera and T.B. Germs Robert Koch (Germany) 1883
Cholera vaccine Louis Pasteur 1880
Contact lenses (glass) Adolf Fick 1887
Corneal transplants Eduard Zirm 1905
Cough drops James Smith and sons 1847
Dental drill (motor-driven) George Fellows Harrington 1864
Disposable syringe Colin Murdoch 1956
DNA (structure discovered) Frances Crick, James Watson and Rosalind Franklin 1953
Electrocardiograph Willem Einthoven 1903
Gas mask Garrett Augustus Morgan 1912
Genetics Johann Gregor Mendel 1865
Insulin (discovery) Frederick Banting and Charles Best 1921
Iron lung Philip Drinker 1929
Microscope (compound) Hans Janssen 1590
Morphine Friedrich Wilhelm Adam Serturner 1803
Pacemaker (human) Wilson Greatbatch 1960 (first use)
Pasteurisation Louis Pasteur 1864
Pathology Giovanni Battista Morgagni 1761
Penicillin Alexander Fleming 1928
Stethoscope René Laënnec 1819
Thermometer (medical) Thomas Allbutt 1866
X-rays Wilhelm Roentgen 1895