The Wonderful Natural Camera- Human Eyes

Kumari Omana

EyeIt is not difficult for even person blessed with normal vision to appreciate the value of vision. In terms of clarity of vision, as well as in terms of variety of shapes and range of colours preceived, man fares better than most animals. The excellence of the sense of sight has tempted man to rely almost exclusively on it for pursuit of food and safety. this is in contrast to animals who depend a lot more on smell and hearing for these activities. Perhaps through disuse, man has suffered a blunting of other sense, particularly that of smell. It is difficult for a man with his eyes closed to find his way around, and to steer himself safely on the road for even a short distance. In addition,much of our knowledge about the world comes through our eyes. Apart from these necessities, vision is also the means by which we can enjoy and appreciate beauty, colour and brightness of the world. 

                                 –Adapted From “The Human Machine”- by R L Bijlani & S K Manchanda”

Importance of Diet

Kumari Omana

              Junk food   Diet plays an important role in our day to day life for maintenance of our health, energy and various activities. It is now generally agreed that diet governs many situations favouring the onset of many diseases. All diseases require modified diet, but diet plays a variable role in their cure. To keep good health we must “eat to live and not live to eat”. Diet is an important factor in the cause of various diseases which are mainly the result of overeating and or wrong diet.

                        Healthy Food

               The Concept of diet has been given due importance in various texts of Ayurveda. Diet occupies a dominant place in the Ayurveda and Yoga System. It is said that ” As you eat, so you become”. This is because the kind and quality of food affects the physical as well as mental condition of the individual.

                       The dietetic habits vary from person to person and a study of an individual’s diet is essential before any modification is suggested for his ailments. Not only the selection of raw material is is important, but the processing of food, amount of each constituent, total amount of food, frequency of intake etc. are also very important.

Albert Einstein

Kumari Omana

Albert Einstein

 The main concern of a Teacher or Educator essentially consists in stimulating the mind to think rather than just answering.

The best method of transaction is one in which active participation of learner is involved and teacher’s role is restricted to a guide or facilitator. It should have participatory approach encouraging learner to achieve hand on experiences from variety of   activities he is involved.

Role Of Teachers

Albert Einstein said that the main concern of a teacher educator ( or facilitator ) essentially consists in stimulating the mind to think rather than just answering.

Gandhi’s Talisman

Kumari Omana
Gandhi14“I will give you a talisman. Whenever you are in doubt, or when the self becomes too much with you, apply the following test. Recall the face of the poorest and the weakest man [woman] whom you may have seen, and ask yourself, if the step you contemplate is going to be of any use to him [her]. Will he [she] gain anything by it? Will it restore him [her] to a control over his [her] own life and destiny? In other words, will it lead to swaraj [freedom] for the hungry and spiritually starving millions?
Then you will find your doubts and your self melt away.”
– One of the last notes left behind by Gandhi in 1948, expressing his deepest social thought.
             Source: Mahatma Gandhi [Last Phase, Vol. II (1958), P. 65]

Flip Contents: Chapter 5

Kumari Omana

PRINCIPLES OF INHERITANCE AND VARIATION
List of the lesson
 Mendelian experiments- Monohybrid and Dihybrid
 Mendelian Laws
 Dominance, co-dominance, incomplete-dominance, sex linked inheritance
 Linkage and crossing over
 Polygenic inheritance
 Pleiotropy
 Sex determination mechanisms
 Pedigree analysis
 Mendelian disorder: autosomal and sex-linked
 Chromosomal disorders-Aneuploidy

SEX DETERMINATION

XX X0 XX XY ZZ ZW
Female Male Female Male Male Female

Grass Hopper Man Birds
MLL
Know the terms
Terms Meaning
Locus Location of a gene in a chromosome
Allele Alternative form of a gene
Homozygous Both alleles of a gene at a locus similar
Heterozygous Both alleles of a gene at a locus dissimilar
Homozygous dominant Both alleles of a gene at a locus similar & dominant
Homozygous recessive Both alleles of a gene at a locus similar & recessive

Mendel‘s first law (Law of dominance): characters are controlled by discrete units called genes (allele) which occur in pair. In heterozygous condition only one gene that is dominant can express itself (Can be explained by monohybrid cross)
Mendel‘s second law (Law of segregation): The two alleles received, one from each parent, segregate independently in gamete formation, so that each gamete receives one or the other with equal probability. (Can be explained by monohybrid cross)
Mendel‘s third law (Law of Independent assortment): The law states that when two pairs of traits are combined in a hybrid, segregation of on pair of characters is independent of the other pair of characters.
Basic outline of Mendels cross
1. Pure breeding parents for a pair of contrasting character (allelic pair) is taken Eg. Tall pure bred pea plants (TT) & short pure-bred pea plants (tt)
2. Gamete formation Meiosis)
3. Hybridization (crossing is done)
4. F1 generation the product of the above cross (are called hybrids)
5. Selfing (allowed to self fertilize/ self breeding)
6. Gamete formation (Meiosis)
7. F2 generation their product of the above selfing
8. Analysis of result (Phenotype and Genotype)

Linkage
Tendency of genes on same chromosome to remain together
Such genes are called linked genes.
Linked genes present only parental types
Co Dominance and multiple allelism
Blood Group Possible genotype
A |A|A OR |Ai
B |B|B OR |Bi
AB |A|B
O ii
Example for co-dominance: AB blood group in humans
Polygenic lnheritance
More than one gene responsible for a character. Shows cumulative phenotypic effect
Eg. Polygenic inheritance- skin colour in man
Controlled by three genes A, B &C
AABBCC X aabbcc
(Very dark) (Very light)
ABC X abc

F1 AaBbCc
On Selling F1
F2 generation shows 64 combinations

Pleiotropy
Phenomenon when single gene may produce more than one effect
i.e., the multiple effect of a gene
Eg. In Drosophila, white eye mutation leads to depigmentation In many other parts of the body-this Is pleiotropic effect

Sex determination and sex chromosome
Organism Male Female
Human beings XY XX
Birds ZZ ZW
Insects XO XX
Sex Determination In Honey Bee
Male Female
16 32
16 16 16
32 16
Female Male
Female would lay infertile eggs, but it hatches into normal fertile haploid male.
Pedigree Analysis
Pedigreeis a chart of graphic representation of record of inheritance of a trait through several generations in a family.
Genetic Disorders- Two types
1. Mendelian
a) Determined by alteration or mutation in single gene
b) Transmitted to offspring on the same line of principle of inheritance
c) May be dominant or recessive
d) Some trait linked to sex, such X-linked recessive traits transmitted from carrier female to male.
Eg.Haemophilia, Sickle Cell Anaemia, Phenyl Ketonuria
2. Chromosomal
a) Is due to aneuploidy or polyploidy conditions
b) It may be due to trisomy or monosomy conditions
Eg. Downs Syndrome, Klinefelter’s Syndrome, Turner’s Syndrome
Colour Blindness
i) It is a recessive sex linked trail
ii) Here eye fails to distinguish red and green colours
iii) Gene for normal vision dominant
iv) Male has one X-chromosome. So if diseased X-chromosome is present, they directly express it.
v) Female in heterozygous condition have normal vision
XCXc X XCY
Carrier female Normal male
F1 XCXC XCY XCXc XcY
N N CarrierAffected
Thalassemia
i) Genetic defect occurs due to mutation or deletion
ii) Affected person produce very few globins
iii) Group of disorders-Caused in synthesis of globin. Absence or reduced synthesis of one globin chain results’ In excess of another. This leaves free globin chains which are insoluble and accumulate inside the RBC, forms precipitate which damages the cell. This cause Lysis and Anaemia.
Two types:
i) Alpha Thalassemia
ii) Beta Thalassemia
There is third type-Delta Thalassemia where about 3% of adult haemoglobin is made of alpha and chains.

HOTS
1. In a monohybrid cross the monotypic and phenotypic ratio is 1:2:1. What type of inheritance is it example of? Give one example.
2. If a human zygote has XXY sex chromosomes along with 22 pairs of autosomes. What sex will the individual be? Name the syndrome.
3. A mother with blood group ‘B’ has a fetus with a blood group ‘A’ father is ‘A’. Explain the situations.
4. The genes for hemophilia are located on sex chromosome of humans. It Is normally impossible for a hemophilic father to pass the gene to his son. Why?
5. Justify the situation that in human beings sex of the child is determined by father and not by mother?
6. Distinguish between Complete and Incomplete linkage.
7. A man with AB blood group marries a woman with AB blood group.
i) Work out all possible genotypes& phenotypes of the progeny.
ii) Discuss the kind of domination in the parents & progeny.
8. A dihybrid heterozygous round, yellow seeded garden pea was crossed with arecessive plant.
i) What type of cross is this?
ii) Work out the genotype & phenotype of the progeny.
iii) What principle of Mendel is illustrated by it?

Diagram-Based Questions

1. Identify the traits shown in pedigree chart. Give one example each.

Flip Content:Chapter 4

Kumari Omana

Reproductive Health

–Refers to healthy reproductive organs with normal function.

It also includes emotional and social aspects.

WHO – Total well-being in all aspects of reproduction in physical , emotional , and social.

Reproductive Health – Problems and strategies

India initiated family planning programs in 1951.

Currently modified to

Reproductive and Child Health Care(RCH)

  • Creating Awareness for building up a reproductively healthy society.
  • Introduction of Sex Education in school prevented children from believing in myths and misconceptions.
  • Proper Knowledge of : *Reproductive organs

*Adolescence and related changes

*Safe and hygienic sexual practices

*Sexually transmitted diseases

  • Educating fertile couples and marriageable age groups.
  • Birth control options
  • Care of pregnant mothers
  • Post-natal care of mother and child
  • Breast feeding
  • Equality in sex
  • Statutory Ban on amniocentesis .

 

 

A test for karyotyping where the foetal sex is determined and leads to foeticide.

  • Research on various reproduction related areas are encouraged.

* Saheli – A new oral contraceptive for females developed by scientists of CDRI.

Population Explosion and Birth control

World Population which was around 2 billion in 1900 rocketed to about 6 billion by 2000.

In India 350 million during independence reached 1 billion by May 2000, due to

  • Rapid decline in death rate
  • Maternal mortality rate (MMR)
  • Infant mortality rate (IMR)
  • Increase in number of people in reproductive age.
 
   

To overcome the problem of population explosion;

  • Motivate smaller families.
  • Statutory rising of marriageable age.
  • Incentives for couples with smaller families.
  • Wide range of contraceptive methods are presently available, broadly grouped into:-

Natural Methods

– Periodic abstinence

– Withdrawal /

– Lactational amenorrhea

(No side effects)

Barrier method: – Preventing ovum and sperms from

physically meeting.

Condoms: –Available for both male and female.

-Protection from STD’s and RTI’s.

-These are disposable.

Diaphragms, Caps & Vaults:-

  • Barriers used in female
  • Covers cervix
  • Blocks entry of sperms through cervix
  • Reusable
  • Spermicidal cream, jellies and foam used along with these barriers to increase contraceptive efficiency

 

 

Progestogen/Progestogent Estrogen

Used as injections/ implants

  • Action is just as pills
  • Effective periods are much longer

Or IUD`s within 72 hours of certes very effective emergency contraceptive used to avoid possible pregnancy due to rape/casual unprotected intercourse. Or breast cancer should not be totally ignored.

Surgical Methods:

Called sterialisation

  • Done for males or female as terminal method
  • Prevent any more pregnancies.
  • Block gamete transport therefore conception

Sterilization in females-vasectomy

In females tubectomy            Small part of vasdeferences removed or tied up through small incessin in scrotum.

A small part of fallopian tube removed or tied through a small incessin in abdomna/through ‘vagina’

NOTE highly effective but partially

  • Contraceptive methods and its use should be under qualified medical professionals
  • It is actually practiced against the natural events
  • possible ill effects – nausea, abdominal pain, break through bleedings, irregular meastruatal bleeding

 

Medical Termination of Pregnancy (MTP)

  • 45-50 millions performed every year
  • Majority done illegally by unqualified quacks
  • Whether to accept/ legalise MTP- a major debate in many countries- due to emotional, social, ethical and religious issues

NOTE- Indian govt legalized in 1971 with strict conditions to avoid misuse

  • To prevent unwanted pregnancy due to rape
  • To prevent harmfulfatalsituationeither to mother / foetus
  • It is safe only during first

Sexually transmitted diseases(STD’s)

Transmitted through sexual intercourse

STD’s / VD (venereal disease)/RTI (reproductive tract infection)

Eg: gonorrhea                                  with infected persons

Syphilis                                   transfusion of blood

Genital herps                         infected mother to foetus

Chlanydiasis

Genital warts                transmitted by sharing of injection needles

Trichomoniasis             surgical instruments etc.

Hepatitis-B

AIDS (caused by HIV) àmost dangerous

Except these

Others are completely cureable if detected early and treated

Symptoms: itching, fluid discharge, sliqut pain, swelling etc.

  • Infected female asymptomatic-undetcted for cong
  • Social stigma attached to STD`s-prevents timely detection
  • Leads to complication later
  • Pelvic inflammatory diseases (PID)
  • Abortions
  • Still birth
  • Ectopic pregnancies
  • Infutitity/even cancer rep. tract
  • All persons are vulnerable to these infection
  • Vulnerable among age group 15-24 years
  • Prevention is possible if you follow simple principles
  1. Avoid sex with unknown partners or multiple partners
  2. Always use condoms during coites
  3. Incase of doubt go to a qualified doctor for early detection and complete treatment if diagnosed

 

 Infertility

many couples with no children may be due to

physical

congenital

diseases

drugs

immunological

psychological

-corrections not possible – but they could be assisted-assisted reproductive technology (ART)

Invitro fertilization (IVF)

 
   

Fertilization outside the body

Similar to the body conditions

Followed by embryo transfer (ET)

Popularly known as test tube baby

Ova from wife or donar

&

Sperm from husband /donar

Collected and induced from zygote under

simulated conditions

IUI-intra-uterine-              zygote / early embryo (splastomeres)

insemination

semen intr. artificially from

husband/healthy donor into

vagina or uterus                       transferred to fallopian tube

 ZIFT– zygote intra fallopian transfer if embryo with mere tra&blestomere-

Transferred directly to uterus

 IUT– intra utrine transfer

Embryo formed by in-vivo fertilization also could be used for transfer to anist the female who cannot conceive

GIFT – gamete intra fallopian

Is transferred from donor to another female who can not

ICSI- intra cytoplasmic sperm injection

Directly injected into ovum

AI – artificial inscrimination if male unable to incriminate

  • Due to low sperm count

Introduction

Kumari Omana

FrogBiology is the natural science that involves the study of life  and living organisms, including their physical and chemical structure, function, development and evolution. Modern biology is a vast field, composed of many branches. Despite the broad scope and the complexity of the science, there are certain unifying concepts that consolidate it into a single, coherent field. In general, biology recognizes the cell as the basic unit of life, genes as the basic unit of hereditary, and evolution as the engine that propels the creation of new species. It is also understood that all organisms survive by consuming and transforming energy and by regulating  their internal environment.