Heredity and Development - Class 6

• The passing on of traits from the parents to their offsprings by reproduction (asexual or sexual) is called heredity.
  
• The life cycle of an organism can be defined as a sequence of life stages or events an organism undergoes from birth to reproduction.
• Reproduction is the process by which new organisms or offspring are produced by their parents
• The fusion of male and female gamete is called fertilization.
• So, the correct answer is 'i and ii only'.
  

The term germplasm was first used by the German biologist August Weismann. His germplasm theory states that multicellular organisms consist of germ cells that contain and transmit heritable information and somatic cells which carryout ordinary bodily functions. In the germplasm theory, inheritance in a muticellular organism only takes place by means of the germ cells: the gametes, such as egg cells and sperm cells. Other cells of the body do not function as agents of heredity.

Hammerling began growing acetabularia in laboratories in the 1930s. There he discovered that the plant had one cell and the nucleus was always located in the rhizoid. Then he began studying the roles of the nucleus and cytoplasm by experimenting with the acetabularia. He demonstrated that nucleus has the genetic material which regulates the inheritance of characters.

So, the correct answer is option C.

• Mendel is widely considered a pioneer in the field of genetics. Gregor Mendel, known as the "father of modern genetics," was born in Austria. A monk, Mendel discovered the basic principles of heredity through experiments in his monastery's garden. 
• His experiments showed that the inheritance of certain traits in pea plants follows particular patterns, subsequently becoming the foundation of modern genetics and leading to the study of heredity.

Heredity can be defined as the passing of traits from parents to their offspring, either through asexual reproduction or sexual reproduction. This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve through the natural selection of specific phenotype traits. The study of heredity in biology is called genetics, which includes the field of epigenetics. Study of heredity deals with resemblances and differences between the parents and offsprings. Thus, option A is correct and other options are wrong.

Cats produces cats. This statement indicates the inheritance of characters from the parents to offspring. Genes are the fundamental unit which carries the characters from one generation to the other. This tendency of inheritance of genotypic and phenotypic character is known as heredity.

During sexual reproduction, traits from parents are transmitted to offspring. These are combinations of male and female parent. This is called heredity.

Transfer of genetic makeup from one generation to another is called heredity. Genes are found on Chormation fibre i.e DNA. All living being have tendency to transfer DNA during sexual or asexual reproductions.

A sperm's function is to swim upwards the vaginal canal and deposit genetic material (DNA) within the egg. The midbody contains the vast stores of mitochondria needed for such an exhausting process, the tail allows for swimming, the head contains the genetic material and the acrosome, which uses enzymes to break through the egg's zona pellucida.

Eugenics is a social philosophy advocating the improvement of human genetic traits through the promotion of higher reproduction of people with desired traits and reduced reproduction of people with less-desired or undesired traits.

Genetically controlled traits are the one which is regulated by genes and are inherited from one generation to next via the process of reproduction. The overall appearance of an organism (phenotype) is the product of its genotype and environmental factors. The weight of an organism is determined in part by its genotype and in part by environmental factors like nutrition, lifestyle, physical activity etc. Thus, reduction in weight due to malnutrition is the environmental factor and is not determined genetically. Thus, the correct answer is option B 

In the process of sexual reproduction, the offsprings produced neither totally resemble (i.e., identical to) their parents nor are they totally different from their parents. Hence, heredity deals with the study of both resemblances and differences of offspring with their parents.

Mendel, during his hybridization experiments on pea plant, proposed presence of unit factors for each trait as heredity material that is faithfully transmitted from one generation to next. He called them “factors”. Sutton and Boveri recognized parallelism between inheritance of Mendel's factors and behavior of the chromosome in meiosis and fertilization. This led them to propose the chromosomal theory of inheritance states that genes are linearly arranged on chromosomes at specific loci. Darwin proposed the theory of natural selection to explain the process of evolution. Khorana extended the experiment of Nirenberg and Holley to reveal that polycytidylate encodes a polypeptide containing only proline and polyadenylate encodes polylysine. M. Nirenberg, Khorana, and Holley were awarded Nobel Prize for in vitro synthesis of polypeptides using artificially synthesized mRNA. Thus, the correct answer is option C.

Hereditary characters are physical or mental characteristics that pass from one generation to another in a family. Heredity is passing of that trait or certain features from parents to offspring.

Not everyone born with inherent skills or talent instead human beings learn and develop skills over the time to make their own survival better. Developing skills make a person confident and independent. One can earn and lead a healthy life by adopting their desired career line.

Our height grows till we are about eighteen years old. There are various factors that determine the height of any person. Like genetics, nutrition, lifestyle etc. Increases in height are primarily due to the lengthening of our bones and growth plates.

It is an old proverb that a healthy mind resides in a healthy body. Food rich in nutrition is a primary requirement for a healthy body but regular physical exercise along with nutritious food maintain the balance of minerals, protein etc in the body and keeps unnecessary diseases away from the body.