Essay on Genetics and Health: Top 6 Essays | Biology

Here is a compilation of essays on ‘Genetics and Health’ for class 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Genetics and Health’ especially written for school and college students.

Essay on Genetics and Health

Essay Contents:

1. Essay on the Meaning of Genes
2. Essay on Chromosomal Abnormalities
3. Essay on Chromosomal Disorders
4. Essay on Hereditary Disorders
5. Essay on Hazardous Effects of Exposure to Toxic Metals
6. Essay on the Effects of Noxious Gases

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1. Essay on the Meaning of Genes:

Genes are the units of heredity which transmit the hereditary information from one generation to next generation. These are basic structure of chromosomes.

Genes occurs in pairs.

If pairs are alike (AA)—known as Homozy­gous.

If pairs are different—known as Heterozy­gous.

Dominant Gene manifests its effect both in Heterozygous and Homozygous state.

Recessive Gene manifests its effect only in homozygous state.

Polygenes show their effect by combined action, e.g.,

In man muscular dystrophy occurs due to combined effect of 3 genes:

(i) Sex-linked recessive gene,

(ii) Autosomal recessive gene,

(iii) Autosomal dominant gene.

Multiple gene or polygene control various characteristics in human being like:

(i) Colour of skin

(ii) Height

(iii) Weight

(iv) Life-span.

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2. Essay on Chromosomal Abnormalities:

It refers to structural or numerical alteration due to the following reasons:

(i) Non-Dysfunction:

A pair of chromosomes may fail to separate and both are carried to one pole.

(ii) Deletion:

A piece of chromosome may become detached.

(iii) Translocation:

Part of chromosome breaks away and attaches to another homologous chromosome.

(iv) Duplication:

Same gene may appear twice in the same chromosome.

(v) Iso-Chromosomes:

Structurally abnormal chromosome.

(vi) Inversion:

Chromosomal segment inverted resulted into alteration of sequence of genes.

(vii) Mosacism:

Body contain cells of two or more genetically chromosomal types.

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3. Essay on Chromosomal Disorders:

About 300 numerical and structural types of chromosome observation have been described till date. It’s prevalent in about 0.4 to 0.5% in new­born. These abnormalities may be sex chromosomes related to autosomes.

(A) Sex Chromosomes Related:

1. Klinefelter’s Syndrome:

a. Abnormal males having two or more X chromosomes with one Y chromosome e.g., XXY, XXXY.

b. Eunuchoid males with non-functional testes.

c. Spermatozoa are absent in their ejaculation.

d. Growth of hair on face, axillae and pubis is scanty.

e. Incidence is 1:400 among males at birth.

2. XYY Syndrome:

a. Male with an extra Y chromosome.

b. Such males have anti-social tendency, aggressive and criminal behaviour.

3. Turner’s Syndrome:

a. They have 45 chromosomes instead of 46.

b. 46th chromosome constitute XO set, i.e., X with developed sex glands.

c. These are apparent females with under-developed sex glands.

d. Short stature, infertile, have primary amenorrhoea.

e. Incidence 1: 2,500 among females.

4. Super Females:

a. Females with 30r 4 X (XXXX) chromosome in spite of XX.

b. These show underdeveloped external genitalia, uterus and vagina.

(B) Autosomes:

1. Mongolism or Down’s syndrome or trisomy 21

2. Other are so many which are not very important in community health point of view.

1. Described by London Down first time in 1886.

2. It is due to extra chromosome which occurs at 21st pair.

3. Short stature, small round head, narrow, tilted eye slits and small formed ears. Short broad hands, mental retardation and internal congenital defects.

4. European confines birth of Mongolism reported 1 to 2 per thousand.

Preventive Measures:

A. Health Promotion:

1. Genetic Counselling:

a. Prospective Genetic Counselling:

Identification of Heterozygous individuals and explaining to them about risk of it to their children if they marry another homozygous, e.g., Sickle cell disease and Thalassaemia.

b. Retrospective Genetic Counselling:

Counselling to be conducted in connection with congenital mental retardation, psychiatric illness and inborn errors.

Methods which could be suggested under retrospective genetic counseling are:

1. Contraception

2. Pregnancy termination

3. Sterilisation

2. Eugenics:

Galton proposed the term eugenics for the science which aims to improve the genetic endowment of human population, it can be negative and positive.

i. Positive Eugenics:

It seeks to reform the genetic endowment of the human specially and to engineer the genetic foundation of new man.

ii. Negative Eugenics:

It is way of improving the health of human by destroying the weak and defective gene. People who are suffering from serious hereditary diseases are sterilised or debarred from producing children.

3. Euthenics:

The environmental manipulation to adopt his environment to his gene environment is called euthenics.

4. Consanguineous Marriages:

Blood relatives marry each other, increases risk in the off-springs to traits controlled by recessive genes and those determined by polygenous, e.g., phenylketonuria and albinism. Lowering of consanguineous marriages would be advantageous to the health of the community.

5. Heterozygous Marriages:

Heterozygous marriages of any particular defect can be prevented, e.g., thalassaemia-minor and sickle-cell anaemia.

B. Specific Protection:

(i) X-ray exposures to be avoided.

(ii) X-ray exposures, of foetus to be avoided.

C. Early Diagnosis and Management:

1. Detection of Genetic Carriers.

2. Amniocentesis.

3. Detection of preclinical cases.

D. Rehabilitation:

1. Mental Rehabilitation for mentally retarded people.

2. Physical Rehabilitation for physically retarded people.

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4. Essay on Hereditary Disorders:

I. Chromosomal Disorders:

Origin:

Originate from dysfunction of chromosomes, which occurs when a pair of chromosomes fails to separate. As a result a particular pair of chromosomes may have three instead of two chromosomes (trisomy) and another pair may have only one (monosomy).

Outcome:

Monosomy is a lethal disorder which usually terminates in intrauterine death. Trisomy is associated with multiple deformities involving both autosomes and sex chromosomes and giving rise to various syndromes.

Examples:

Down’s syndrome, Turner’s syndrome Klinefelter’s syndrome Meta female syndrome.

II. Autosomal Disorders:

Origin:

Autosomal dominant disorders originate in a heterozygous state when one of the alleles of a pair of autosomes carriers an abnormal dominant trait. Autosomal recessive disorders originate only in homozygous state when both alleles of a part of autosomes are mutant carrying a recessive trait.

Outcome:

In autosomal dominant disorders 50% of the offspring of a parent having a mutant dominant trait develop the disorder. In autosomal recessive disorders in which both the parents possess a mutant recessive trait only 25% offsprings are affected.

Examples:

i. Achondroplasia

ii. Marfan’s syndrome

iii. Neurofibromatosis

iv. Osteogenesis imperfecta

v. Phenylketonuria

vi. Galactosaemia

vii. Ataxia telangiectasia

viii. Cystic fibrosis

ix. Mucopolysaccharidosis

III. X-Linked Disorders:

Origin:

X-linked dominant disorders originate when mutant gene carrying a dominant trait is borne on the X chromosome X-linked recessive disorders originate when mutant gene carrying the recessive disorder is likewise borne on the X chromosome. Y chromosome plays a passive role in X-linked disorders.

Outcome:

In the event of father having X-linked dominant trait, all the daughters are affected. In the event of mother possessing the dominant trait, half of the sons and half of the daughters are affected. In the event of the mother possessing the recessive trait only half of the sons are affected. In the event of both the parents possessing the X-linked recessive trait half of the sons and half of the daughters are affected.

Examples:

i. Haemophilia

ii. Muscular dystrophy

iii. Hunter’s syndrome

IV. Polygenic Disorders:

Origin:

Polygenic disorders are multifactorial in origin appearing under the influence of a variety of genetic and environmental factors. Once the synergistic effect of multiple genes reaches threshold point, the environmental factors comes into play and bring about a multifactorial disorder.

Outcome:

The first-degree relations are at the highest risk of polygenic disorder, the second degree relations are at a lesser risk, and the third degree relations are at the lowest risk.

Examples:

Ischaemic heart disease Hypertension Diabetes mellitus Schizophrenia

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5. Essay on Hazardous Effects of Exposure to Toxic Metals:

I. Lead:

Occupational Exposure:

Occurs in workers engaged in the manufacturing of batteries, welding and flame cutting of lead, soldering, and lead- grinding and blasting of lead alloys.

Site of a Lesion:

Mainly nervous system.

Nature of Lesion:

Lead encephalo­pathy, lead palsy, lead anaemia, lead colic, lead line and lead ophthalmopathy.

II. Mercrury:

Occupational Exposure:

Occurs among worker manufacturing ther­mometers, mano­meters, fluorescent tubelights and various other electric goods.

Site of a Lesion:

Central nervous system.

Nature of Lesion:

Mercurial tremors, mercurial erethism and mercury poison­ing, if ingested.

III. Manganese:

Occupational Exposure:

Occurs in workers dealing with managanese and manga­nese containing alloys, and also in miners and other workers dealing with iron ore.

Site of a Lesion:

Central nervous system and respi­ratory system.

Nature of Lesion:

Magnism (a disease resembling Par­kinsonism) and chemical pneu­monitis.

IV. Chromium:

Occupational Exposure:

Occurs in workers dealing with chromium plating of metals, stain­less steel items and various types of metal alloys.

Site of a Lesion:

Skin and lungs.

Nature of Lesion:

Chronic der­matitis of exposed areas leading to chronic ulcers, Perforations of nasal septum and lung cancer.

V. Beryllium:

Occupational Exposure:

Occurs in workers dealing with the manufacture of fluorescent lamps, electrical goods and spacecrafts and aircraft.

Site of a Lesion:

Skin and lungs.

Nature of Lesion:

Papulovesicular eruption on exposed areas of skin. Chemi­cal pneumonitis and pulmonary granu­lomatosis.

VI. Nickel:

Occupational Exposure:

Occurs in workers engaged in industries using nickel for alloys, for surface treatment of metals and for stainless steel weilding. Occurs also among workers in electronic industries.

Site of a Lesion:

Skin and lungs.

Nature of Lesion:

Respiratory and skin lesion. Airway irri­tation, nasal cancer and pulmonary cancer.

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6. Essay on the Effects of Noxious Gases:

I. Carbon:

Mechanism of Action:

Causes asphyxia by combining with haemoglobin and producing carboxyhaemoglobin anaemic anoxia.

Principal Clinical Manifestations:

Headache, dizziness and occasional nausea which may be followed by nervous disturbance of psychological, motor or sensory kind.

Occupational Exposure:

Occurs among workers attending to electric furnaces, blast furnaces, oil furnaces, gas manufacturing plants, oven, kilns and mines— wherever carbonaceous material is subjected to combustion.

II. Hydrogen:

Mechanism of Action:

Causes irritation of mucous membranes of eyes, nose and respiratory passages; and produces asphyxia by paralysing the respiratory centre.

Principal Clinical Manifestations:

Salivation, lacrimation, photophobia, bronchopneumonia,pulmonary oedema, respiratory failure and death.

Occupational Exposure:

Occurs in workers attending to sewers, mines, breweries, tanneries, laboratories, etc.

III. Hydrogen Cyanide:

Mechanism of Action:

Causes asphyxia by interfering with respiratory enzymes leading to histotoxic anoxia.

Principal Clinical Manifestations:

Constriction of chest associated with hyperpnoea and palpitation followed by convulsions and unconsciousness leading to death.

Occupational Exposure:

Occurs in foundry workes, blast furnace workers, cellulose workers, dye makers, melters, vulcanisers etc.

IV. Ammonia:

Mechanism of Action:

Produces irritation of mucous membranes of eyes, nose, throat, respiratory passages and lung parenchyma which may lead to pulmonary oedema.

Principal Clinical Manifestations:

Burning sensation of mucous membrane followed by lacrimation, salivation, chemosis, conjunctivitis, rhinitis, coughing, choking and occasionally irritation of skin.

Occupational Exposure:

Occurs in workers engaged in refrigeration, cold storage and ice manufacturing plants.

V. Sulphur Dioxide:

Mechanism of Action:

Produces irritation of mucous membranes of eyes, nose, throat, respiratory passages and lung parenchyma which may lead to pulmonary oedema.

Principal Clinical Manifestations:

Burning sensation of mucous membranes and their associated manifestation. May also cause irritation of the alimentary tract.

Occupational Exposure:

Occurs in bleachers, dye-makers, petroleum refiners, vulcanisers and disinfectors.

VI. Chlorine:

Mechanism of Action:

Produces irritation of mucous membranes of eyes, nose, throat, respiratory passages and lung parenchyma which may lead to pulmonary oedema.

Principal Clinical Manifestations:

All the manifestations associated with irritation of mucous membranes. May also induce nausea and vomiting.

Occupational Exposure:

Occurs in disinfectors and bleachers in paper, chemical, dye and textile industries and workers engaged in petroleum refineries.

VII. Arsine:

Mechanism of Action:

Causes haemolysis, haemolytic anaemia and haemoglobinuria.

Principal Clinical Manifestations:

Increasing weakness, severe low back pain, dark coloured urine and characteristic odour to breath.

Occupational Exposure:

Occurs in workers engaged in smelting and refining of arsenic-containing ores.

VIII. Stibine:

Mechanism of Action:

Causes haemolysis and its complication invade central nervous system causing cerebral oedema and depression of the respiratory system.

Principal Clinical Manifestations:

Haemoglobinuria, nausea, vomiting, severe abdominal pain, headache, backache and marked weakness.

Occupational Exposure:

Occurs inadvertently during the processing antimony and its salts.