NOTES

NOTES ON GENETICS

Q.SHORT NOTE:-                                                                                                           5 Marks

Q.1    KARYOTYPING

ANS.1   

                     1.         It is a Basic tool of Cytogeneticist

                     2.         Karyotype is a photographic representation in which chromosomes are arranged in order of decreasing length

                     3.         Giemsa stain (G banding) technique—each chromosome can be seen to possess a distinctive pattern of alternating light and dark bands of variable widths

                     4.         Shorthand of Cytogenetics:

                     5.         Short arm denoted as p, long arm denoted q.

                     6.         Each arm divided into numbered regions from the centromere onwards.

                     7.          Each region numerically arranged into bands.

                     8.         For e.g., 5p24 would denote chromosome 5, short arm, region 2 and band 4.

                     9.         Cytogenetic disorders may result from structural or numeric abnormalities of chromosomes.

                   10.       It may affect autosomes or sex chromosomes.

                   11.       Applied ;-Cytogenetic Disorders involving Autosomes

a)      Trisomy 21/Down’s syndrome most common chromosomal disorder.

b)      Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on the 21^st chromosome

c)      Trisomy 21 is caused by a meiotic nondisjunction event.

d)     With nondisjunction, a gamete (i.e., a sperm or egg cell) is produced with an extra copy of chromosome 21; the gamete thus has 24 chromosomes

e)      When combined with a normal gamete from the other parent, the embryo now has 47 chromosomes, with three copies of chromosome 21.

f)       About 4% of cases are due to Robertsonian translocations.

g)      Maternal age has a strong influence.

h)      Karyotype for trisomy Down syndrome. Notice the three copies of chromosome 21

g:\anatomy pdf\notes\short notes karyotyping notes .docx

ONE OR TWO SENTENCES.                                                                                2 MARKS.

Q1.WHAT IS GENETICS?

ANS. A BRANCH OF BIOLOGICAL SCIENCE CONCERNED WITH THE STUDY OF THE CAUSE & NATURE OF SIMILARITY & DISSIMILARITY OF THE INDIVIDUALS RELATED BY COMMON ANCESTRY(HEREDITARY).

My Third Blog Post

History

1857 painting by Alexander Beydeman, showing historical figures and personifications of homeopathy observing the brutality of medicine of the 19th century

Historical context

Homeopaths claim that Hippocrates may have originated homeopathy around 400 BC, when he prescribed a small dose of mandrake root to treat mania, knowing it produces mania in much larger doses.^[28] In the 16th century, the pioneer of pharmacology Paracelsus declared that small doses of "what makes a man ill also cures him".^[29] Samuel Hahnemann (1755–1843) gave homeopathy its name and expanded its principles in the late 18th century.

In the late 18th and 19th centuries, mainstream medicine used methods likebloodletting and purging, and administered complex mixtures, such as Venice treacle, which was made from 64 substances including opium, myrrh, and viper's flesh.^[30] These treatments often worsened symptoms and sometimes proved fatal.^[31][32] Hahnemann rejected these practices – which had been extolled for centuries^[33] – as irrational and inadvisable;^[34] instead, he advocated the use of single drugs at lower doses and promoted an immaterial, vitalistic view of how living organisms function, believing that diseases have spiritual, as well as physical causes.^[35]

My Second Blog Post

Hahnemann believed the underlying causes of disease were phenomena that he termed miasms, and that homeopathic preparations addressed these. The preparations are manufactured using a process of homeopathic dilution, in which a chosen substance is repeatedly diluted in alcohol or distilled water, each time with the containing vessel being bashed against an elastic material, (commonly a leather-bound book).^[9] Dilution typically continues well past the point where no molecules of the original substance remain.^[10] Homeopaths select homeopathics^[11] by consulting reference books known as repertories, and by considering the totality of the patient's symptoms, personal traits, physical and psychological state, and life history.^[12]

Homeopathy is not a plausible system of treatment, as its dogmas about how drugs, illness, the human body, liquids and solutions operate are contradicted by a wide range of discoveries across biology, psychology, physics and chemistry made in the two centuries since its invention.^{[7][13][14][15][16]} Although some clinical trials produce positive results,^[17][18] multiple systematic reviewshave indicated that this is because of chance, flawed research methods, andreporting bias. Continued homeopathic practice, despite the evidence that it does not work, has been criticized as unethical because it discourages the use of effective treatments,^[19] with the World Health Organisation warning against using homeopathy to try to treat severe diseases such as HIV and malaria.^[20]The continued practice of homeopathy, despite a lack of evidence of efficacy,^[6][7][21] has led to it being characterized within the scientific and medical communities as nonsense,^[22]quackery,^[4][23][24] and a sham.^[25]

My First Blog Post

Homeopathy (ⁱ/ˌhoʊmiˈɒpəθi/) is a system of alternative medicine created in 1796 by Samuel Hahnemann, based on his doctrine of like cures like (similia similibus curentur), a claim that a substance that causes the symptoms of a disease in healthy people would cure similar symptoms in sick people.^[1]Homeopathy is a pseudoscience – a belief that is incorrectly presented as scientific. Homeopathic preparations are not effective for treating any condition;^[2][3][4][5] large-scale studies have found homeopathy to be no more effective than a placebo, suggesting that any positive feelings that follow treatment are only due to the placebo effect and normal recovery from illness.^[6][7][8]