Online Notes on Chapter=9 ( Heredity and Evolution) Part 2

This is Online Notes on Chapter=9 ( Heredity and Evolution)  Part 2 for preparation of CBSE BOARD Examination, NTSE etc.





Dihybrid Cross:
A cross between two plants having two pairs of contrasting characters is

called dihybrid cross.

Conclusion:
No genetic change has occurred in the population of beetle. The population
gets affected for a short duration only due to environmental changes.

ACQUIRED AND INHERITED TRAITS:

Online Notes on Chapter=9 ( Heredity and Evolution) Part 1

This is Online Notes on Chapter=9 ( Heredity and Evolution)  Part 1 for preparation of CBSE BOARD Examination, NTSE etc.

Accumulation of Variation during Reproduction :

Importance of Variation :

(i) Depending upon the nature of variations different individuals would
have different kinds of advantage.
Example: Bacteria that can withstand heat will survive better in a heat
wave.

(ii) Main advantage of variation to species is that it increases the chances of
its survival in a changing environment.
Free ear lobes and attached ear lobes are two variants found in human
populations.

Mendel and His Work on Inheritance:
• Gregor Johann Mendel (1822 & 1884) : Started his experiments on
plant breeding and hybridisation. He proposed the laws of inheritance in
living organisms.

Mendel was known as Father of Genetics.
• Plant selected by Mendel : Pisum sativum (garden pea). Mendel used a
number of contrasting characters for garden pea.

Medel’s Experimental Material : He chose Garden Pea (Pisum sativum) as
his experiment material because of :

(i) Availability of detectable contrasting traits of several characters.
(ii) Short life span of the plant.
(iii) Normally allows self-fertilisation but cross-fertilisation can also be
carried out.
(iv) Large no. of seeds produced.

• Mendel’s Experiments : Mendel conducted a series of experiments in
which he crossed the pollinated plants to study one character (at a time).

Monohybrid Cross:
Cross between two pea plants with one pair of contrasting characters is called
a monohybrid cross.

Example : Cross between a tall and a dwarf plant (short).

Observations of Monohybrid Cross:

(i) All F1 progeny were tall, no medium height plant. (Half way
characteristic)

(ii) F2 progeny ¼ were short, ¾ were tall.

(iii) Phenotypic ratio F2 – 3 : 1 (3 tall : 1 short)

Genotypic ratio F2 – 1 : 2 : 1

TT : Tt : tt = 1 : 2 : 1

Conclusions:

1. TT and Tt both are tall plants while tt is a short plant.

2. A single copy of T is enough to make the plant tall, while both copies have
to be ‘t’ for the plant to be short.

3. Characters/traits like ‘T’ are called dominant trait (because it express
itself) and ‘t’ are recessive trait (because it remains suppressed).

Online Practice Q_ANS on CHAPTER => 8 (How do Organisms Reproduce )

This is Online Practice Q_ANS on CHAPTER => 8 (How do Organisms Reproduce )for preparation of CBSE BOARD Examination, NTSE etc.

VERY SHORT ANSWER TYPE QUESTIONS (1 Mark)

1. Name the two types of reproduction.

2. What type of reproduction takes place in plasmodium ?

3. Define vegetative propagation.

4. Where is DNA present in a cell ?

5. Name the glands associated with male reproductive system.

6. What is menstruation ?

7. Name two contraceptive methods.

8. Where are the reproductive parts located in a plant ?

SHORT ANSWER TYPE QUESTIONS (2 Marks)

1. Write two important functions of testosterone.

2. What is placenta ? Also write its functions.

3. Why do we see different types of organisms around us ?

4. What is the importance of variation ?

5. Why is vegetative propagation practiced for growing some types of plants ?

6. Write names of male and female sex hormones.

7. Mention the parts of a flower.

8. Differentiate between bisexual and unisexual flowers.

SHORT ANSWER TYPE QUESTIONS (3 Marks)

1. What is tissue culture ?

2. Explain the process of fertilisation in flowering plants.

3. Name the different constituents of semen.

4. Draw a well-labelled diagram of male reproductive system.

5. What is pre-natal sex determination ? Why is it banned ?

6. Draw a labelled diagram of the longitudinal section of a flower.

LONG ANSWER TYPE QUESTIONS (5 Marks)

1. What are the different modes of asexual reproduction ?

2. Draw a labelled diagram of female reproductive system and write the function

of its different parts.

3. What is contraception ? Give different methods of contraception.

4. What happens in human female :

(a) when egg is fertilised ?

(b) when egg is not fertilised ?

5. Trace and explain the steps involved in the formation of seed.

VALUE BASED QUESTIONS

A pregnant woman, who is a mother of one daughter, requests the doctor of

an ultrasound clinic to test and determine the sex of the baby in her womb.

The doctor, very politely, refused and explained the legal and ethical point of

view of the situation. On the basis of arguments and counseling, the doctor

prepared the woman to happily accept the baby.

(a) Why is pre-natal sex determination ethically wrong ?

(b) Had you been in place of the doctor, what argument you would have

placed to counsel the mother ?

(c) State the values exhibited by the doctor.

Hints to Long Answer Type Questions

1. Methods of asexual reproduction :

(a) Fission

(b) Fragmentation

(c) Regeneration

(d) Budding

(e) Vegetative propagation

(f) Spore formation

2. Labelled diagram of female reproductive system.

Functions :

Ovary : Production of eggs.

Oviduct : Site for fertilization.

Uterus : Place of development of embryo.

3. Contraception : Barrier for fertilisation.

• Physical barrier

• Chemical methods

• Surgical methods

• Intrautrine contraceptive device (IUCD)

4. (a) (i) Zygote is formed → Implanted in uterus

(ii) Onset of pregnanacy

(b) Menstruation

5. Labelled diagram of germination of pollen grain on stigma of flower.

Online Notes on Chapter=8 ( How do Organisms Reproduce) Part 2

This is Online Notes on Chapter=8 (How do Organisms Reproduce)  Part 2 for preparation of CBSE BOARD Examination, NTSE etc.

Sexual Reproduction:

When reproduction takes place as a result of the fusion of male and female
gametes is called sexual reproduction.
Fusion of gametes is called fertilization which results in variation.

Sexual Reproduction in Plants:

• Flowers are the reproductive organs of plants.
• A typical flower consists of four main whorls namely sepals, petals,
stamen and pistil.

Types of Flowers:

• Bisexual flower : Both male and female reproductive parts are present.
E.g., Hibiscus, mustard.

• Unisexual flower : Either male or female reproductive part is present.
E.g., Papaya, watermelon.

Structure of Flower :

Process of Seed Formation:

• Pollen grains, produced in the anther, are transferred to the stigma of
same flower (self pollination) or stigma of another flower (cross
pollination) through agents like air, water or animals.

• Pollen grains germinate and form pollen tubes which pass through style
to reach upto the ovules present in ovary.

• The fusion of male and female gametes is called fertilization. Zygote is
produced inside the ovary.

• Zygote divides to form embryo. Ovule develops thick coat and changes
into seed gradually.

• Ovary changes into fruit and other parts of flower fall off.

• The seed germinates to form a plant under suitable conditions such as air,
moisture etc.

Reproduction in Human Beings:

• Humans use sexual mode of reproduction.

• Sexual maturation : The period of life when production of germ cells
i.e., ova (female) and sperm (male) start in the body. This period of

sexual maturation is called puberty.

Changes at Puberty:

(a) Common in male and female

• Thick hair growth in armpits and genital area.
• Skin becomes oily, may result in pimples.

(b) In girls

• Breast size begin to increase.
• Girls begin to menstruate.

(c) In boys

• Thick hair growth on face.
• Voice begin to crack.

These changes signals that sexual maturity is taking place.

Male Reproductive System:

(a) Testes : A pair of testes are located inside scrotum which is present
outside the abdominal cavity. Scrotum has a relatively lower temperature needed
for the production of sperms.
• Male germ cell i.e., sperms are formed here.
• Testes release male sex hormone (testosterone). Its function is :

(i) Regulate production of sperms.
(ii) Bring changes at puberty.

(b) Vas deferens : It passes sperms from testes upto urethera.

(c) Urethera : It is a common passage for both sperms and urine. Its outer
covering is called penis.

(d) Associated glands : Seminal vesicles and prostate gland add their
secretion to the sperms. This fluid provide nourishment to sperms and make their
transport easy.

Sperm alongwith secretion of glands form semen.

Female Reproductive System:

(a) Ovary : A pair of ovary is located in both sides of abdomen.

• Female germ cells i.e., eggs are produced here.
• At the time of birth of a girl, thousands of immature eggs are present
in the ovary.
• At the onset of puberty, some of these eggs start maturing.
• One egg is produced every month by one of the ovaries.

(b) Oviduct or Fallopian tube:

• Receives the egg produced by the ovary and transfer it to the uterus.
• Fertilisation i.e., fusion of gametes takes place here.

(c) Uterus : It is a bag-like structure where development of the baby takes
place.

• Uterus opens into vagina through cervix.

When egg is fertilised :

• The fertilized egg called zygote is planted in uterus and develops into an
embryo.

• The embryo gets nutrition from the mother’s blood with the help of a
special tissue called placenta. It provides a large surface area for the
exchange of glucose, oxygen and waste material.

• The time period from fertilization upto the birth of the baby is called
gestation period. It is about 9 months.

When egg is not fertilised :

• The uterus prepares itself every month to receive fertilized egg.

• The lining of the uterus becomes thick and spongy, required to support
the embryo.

• When fertilisation had not taken place, this lining is not needed any
longer.

• This lining breaks and comes out through vagina as blood and mucus.
This cycle takes around 28 days every month and called menstruation.

Reproductive Health:

Reproductive health means a total well-being in all aspects of reproduction
i.e., physical, emotional, social and behavioural.

Sexually Transmitted Diseases (STDs):

• Many diseases can be sexually transmitted such as :
Bacterial : Gonorrhoea and syphilis.

Viral : Warts and HIV-AIDS
• Use of condom prevents these infections to some extent.

Contraception:

It is the avoidance of pregnancy, can be achieved by preventing the
fertilisation of ova.

Methods of contraception:

(a) Physical barrier:

• To prevent union of egg and sperm.
• Use of condoms, cervical caps and diaphragm.

(b) Chemical methods:

• Use of oral pills
• These change hormonal balance of body so that eggs are not released.
• May have side effects.

(c) Intrauterine contraceptive device (IUCD):

• Copper-T or loop is placed in uterus to prevent pregnancy

(d) Surgical methods:

• In males the vas deferens is blocked to prevent sperm transfer called
vasectomy.

• In females, the fallopian tube is blocked to prevent egg transfer called
tubectomy.

Female Foeticide:

• The practice of killing a female child inside the womb is called female
foeticide.

• For a healthy society, a balanced sex ratio is needed that can be achieved
by educating people to avoid malpractices like female foeticide and
prenatal sex determination.

• Prenatal sex determination is a legal offence in our country so as to
maintain a balanced sex ratio.

Online Notes on Chapter=8 ( How do Organisms Reproduce) Part 1

This is Online Notes on Chapter=8 (How do Organisms Reproduce)  Part 1 for preparation of CBSE BOARD Examination, NTSE etc.

• Reproduction is the process by which living organisms produce new
individuals similar to themselves. It ensures continuity of life on
earth.

• Nucleus of the cell contains DNA (Deoxyribose Nucleic Acid) which
is the heredity material.

• DNA replicates and forms new cells causing variation. So, these new
cells will be similar but may not be identical to original cell.

• Variations are useful for the survival of the individual and species
over time as well as basis for evolution.

Types of Reproduction :

(a) Asexual Reproduction

• A single individual give rise to new individual.
• Gametes are not formed.
• New individual is identical to parent.
• It is extremely useful as a means of rapid multiplication.
• Adopted by lower organisms.

(b) Sexual Reproduction

• Two individuals i.e., one male and one female are needed to give rise
to new individual.
• Gametes are formed.
• New individual is genetically similar but not identical to parents.
• It is useful to generate more variations in species.
• Adopted by higher organisms.

Modes of Asexual Reproduction:

(i) Fission : The parent cell divides into daughter cells.

• Binary fission : 2 cells are formed. E.g., amoeba.

• Multiple fission : Many cells are formed. E.g., Plasmodium.

(ii) Fragmentation : The organism breaks-up into smaller pieces upon
maturation, each piece develops into new individual. E.g., Spirogyra

(iii) Regeneration : If organism is somehow cut or broken into many pieces,
each piece grows into a complete organism. E.g., Planaria, Hydra.

(iv) Budding : A bud is formed which develops into tiny individual. It
detaches from parent

(v) Vegetative Propagation : In many plants, new plants develops from
vegetative parts such as :

• By roots : E.g., dahlias, sweet potato.
• By stem : E.g., potato, ginger.
• By leaves : E.g., bryophyllum (leaf notches bear buds which develop
into plants).

• Artificial methods :

(a) Grafting : E.g., Mango
(b) Cutting : E.g., Rose
(c) Layering : E.g., Jasmine
(d) Tissue culture : New plants are grown by using growing tip of a plant.
These growing cells are kept in a culture medium leads to the formation of
callus. Callus is then transferred to hormone medium which causes growth and
differentiation. E.g., ornamental plants, orchid.

Benefits of tissue culture :

• We can grow plants like banana, rose, jasmine etc. that have lost the
capacity to produce seeds.
• New plants are genetically similar to parents.
• Helps in growing seedless fruits.

(v) Spore Formation : Spores are small bulb like structures which are
covered by thick walls. Under favourable conditions, they germinate and
produce new organism.

Introduction to BIOMEDICAL ENGINEERING

Here, Get introduction to Biomedical Engineering for having basic understanding of Biomedical Engineering. 
Biomedical engineering (BME) is the application of engineering principles and design concepts to medicine and biology for healthcare purposes (e.g. diagnostic or therapeutic).

=> Definition of Biomedical Engineering:

Biomedical engineering is a discipline that advances knowledge in engineering, biology and medicine, and improves human health through cross-disciplinary activities that integrate the engineering sciences with the biomedical sciences and clinical practice. It includes:

1. The acquisition of new knowledge and understanding of living systems through the innovative and substantive application of experimental and analytical techniques based on the engineering sciences.

2. The development of new devices, algorithms, processes and systems that advance biology and medicine and improve medical practice and health care delivery.

The term "biomedical engineering research" is thus defined in a broad sense: It includes not only the relevant applications of engineering to medicine but also to the basic life sciences.

=> Development of Bioengineering:

Over the last few years there has been a major paradigm shift in both Europe and the United States away from traditional schemes of health care towards health care systems which are much more dependent on technology. This is true in terms of diagnosis (eg body scanners); treatment (radiation therapy and minimal access surgery); and health care system integration (via information technology).

In parallel with these changes, there has been a progressive increase in the proportion of the national Gross Domestic Product spent in the medical sector. For example, in the United Kingdom it is currently between 6 and 7%, in Germany about 9%, and in the United States about 14%. This has resulted partly from demographic changes and additionally from increasing public demand for better health care.

 As medical practice becomes more technologically based, a progressive shift is occurring in industry to meet the demand. Developments in science and engineering are increasingly being directed away from traditional technologies towards those required for health care in its widest sense. Although in many countries there is a problem with escalating costs in the medical sector, technology can contribute to economies because of falling costs of electronic/physics based components relative to those for personnel, and because of technologically based screening programmes.

=> What are the Specialty Areas?

Some of the well established specialty areas within the field of biomedical engineering are bioinstrumentation, biomechanics, biomaterials, systems physiology, clinical engineering, and rehabilitation engineering.

Bioinstrumentation is the application of electronics and measurement principles and techniques to develop devices used in diagnosis and treatment of disease. Computers are becoming increasingly important in bioinstrumentation, from the microprocessor used to do a variety of small tasks in a single purpose instrument to the extensive computing power needed to process the large amount of information in a medical imaging system.

Biomechanics is mechanics applied to biological or medical problems. It includes the study of motion, of material deformation, of flow within the body and in devices, and transport of chemical constituents across biological and synthetic media and membranes. Efforts in biomechanics have developed the artificial heart and replacement heart valves, the artificial kidney, the artificial hip, as well as built a better understanding of the function of organs and musculoskeletal systems.

Biomaterials describes both living tissue and materials used for implantation. Understanding the properties of the living material is vital in the design of implant materials. The selection of an appropriate material to place in the human body may be one of the most difficult tasks faced by the biomedical engineer. Certain metal alloys, ceramics, polymers, and composites have been used as implantable materials. Biomaterials must be nontoxic, noncarcinogenic, chemically inert, stable, and mechanically strong enough to withstand the repeated forces of a lifetime.

Systems physiology is the term used to describe that aspect of biomedical engineering in which engineering strategies, techniques and tools are used to gain a comprehensive and integrated understanding of the function of living organisms ranging from bacteria to humans. Modeling is used in the analysis of experimental data and in formulating mathematical descriptions of physiological events. In research, models are used in designing new experiments to refine our knowledge. Living systems have highly regulated feedback control systems which can be examined in this way. Examples are the biochemistry of metabolism and the control of limb movements.

Clinical engineering is the application of technology for health care in hospitals. The clinical engineer is a member of the health care team along with physicians, nurses and other hospital staff. Clinical engineers are responsible for developing and maintaining computer databases of medical instrumentation and equipment records and for the purchase and use of sophisticated medical instruments. They may also work with physicians on projects to adapt instrumentation to the specific needs of the physician and the hospital. This often involves the interface of instruments with computer systems and customized software for instrument control and data analysis. Clinical engineers feel the excitement of applying the latest technology to health care.

Rehabilitation engineering is a new and growing specialty area of biomedical engineering. Rehabilitation engineers expand capabilities and improve the quality of life for individuals with physical impairments. Because the products of their labor are so personal, often developed for particular individuals or small groups, the rehabilitation engineer often works directly with the disabled individual.

These specialty areas frequently depend on each other. Often the biomedical engineer who works in an applied field will use knowledge gathered by biomedical engineers working in more basic areas. For example, the design of an artificial hip is greatly aided by a biomechanical study of the hip. The forces which are applied to the hip can be considered in the design and material selection for the prosthesis. Similarly, the design of systems to electrically stimulate paralyzed muscle to move in a controlled way uses knowledge of the behavior of the human musculoskeletal system. The selection of appropriate materials used in these devices falls within the realm of the biomaterials engineer. These are examples of the interactions among the specialty areas of biomedical engineering.

=> Where do they Work?

Biomedical engineers are employed in industry, in hospitals, in research facilities of educational and medical institutions, in teaching, and in government regulatory agencies. They often serve a coordinating or interfacing function, using their background in both the engineering and medical fields. In industry, they may create designs where an indepth understanding of living systems and of technology is essential. They may be involved in performance testing of new or proposed products. Government positions often involve product testing and safety, as well as establishing safety standards for devices. In the hospital, the biomedical engineer may provide advice on the selection and use of medical equipment, as well as supervising its performance testing and maintenance. They may also build customized devices for special health care or research needs. In research institutions, biomedical engineers supervise laboratories and equipment, and participate in or direct research activities in collaboration with other researchers with such backgrounds as medicine, physiology, and nursing.

Some biomedical engineers are technical advisors for marketing departments of companies and some are in management positions. Some biomedical engineers also have advanced training in other fields. For example, many biomedical engineers also have an M.D. degree, thereby combining an understanding of advanced technology with direct patient care or clinical research.

=> Career Preparation:

The biomedical engineer should plan first and foremost to be a good engineer. Beyond this, he or she should have a working understanding of life science systems and terminology. Good communications skills are also important, because the biomedical engineer provides a link among professionals with medical, technical, and other backgrounds.

From our experience, a top-quality biomedical engineer must have an excellent knowledge of physiology so that he/she can make sound judgments in solving biomedical problems. When working in a specific area of biomedicine, it is also necessary to know how disease alters functions, this is the field of pathophysiology. With such knowledge, the biomedical engineer does not have to rely on others for information about living organisms.