How do Organisms Reproduce?: Class 10 Science Q&A
112 free answers on How do Organisms Reproduce? (Science) for Class 10 students, across CBSE, ICSE and State boards. Includes questions such as “Describe sexually transmitted diseases and mention the ways to prevent them.”, “How does fertilisation take place? Fertilisation occurs once in a month. Comment.”, “What is placenta? Mention its role during pregnancy?”
Question & Answer
Questions
- ScienceClass 10CBSE
1. Describe sexually transmitted diseases and mention the ways to prevent them.
Disease that gets spread from person to person through sexual means are called sexually transmitted diseases. These include bacterial infections such as gonorrhoea and syphilis, and viral infections such as warts and HIV- AIDS. Below are the ways to prevent sexually transmitted diseases Use of condoms or other physical Avoiding sexual contacts with unknown Avoid sharing towels or Get a vaccination for hepatitis
- ScienceClass 10CBSE
1. Reproduction is essentially a phenomenon that is not for survival of an individual but for the stability of a species. Justify.
Competition for food, predation are common in nature. If there is no reproduction species would have become extinct. Hence reproduction linked to population if a species. New individuals carries lineage of their parents. More number of organisms produces counterbalances the mortality that arises due to various factors. Like this reproduction helps in maintain stability of a species.
- ScienceClass 10CBSE
1. How does fertilisation take place? Fertilisation occurs once in a month. Comment.
Once in a month one egg is released from either of the ovaries. The egg gets transferred to fallopian tube from the ovaries. Sperms swims towards fallopian tube and only one sperm can penetrate the egg at a time. This process is called fertilization. A menstrual cycle is composed of about 28 days. This means only one egg is available for fertilization in one menstrual cycle. Hence, it can be said that fertilization can occur only once in a month.
- ScienceClass 10CBSE
1. What are various ways to avoid pregnancy? Elaborate any one method. Various ways to avoid pregnancy are given below a) Physical barrier b) Copper-T c) Hormone Pills d) Surgical procedure
Barrier method: In the barrier methods of preventing preganancy, the physical devices such as diaphragm (or cap) and condoms are used. Diaphragm (or Cap) is used by human females which is put over the cervix. Condoms are used by males.
- ScienceClass 10CBSE
1. What is placenta? Mention its role during pregnancy?
Placenta is a disc which is embedded in the uterine wall. It contains villi on the embryo’s side of the tissue. On the mother’s side are blood spaces, which surround the villi. This provides a large surface area for glucose and oxygen to pass from the mother to the embryo. The embryo gets nutrition from the mother’s blood with the help of placenta. The developing embryo will also generate waste substances which can be removed by transferring them into the mother&rsqu
- ScienceClass 10CBSE
1. Write two points of difference between asexual and sexual types of reproduction. Describe why variations are observed in the offspring formed by sexual reproduction.
Soln: Sexual reproduction Asexual reproduction Two parents are involved Single parent is involved Gametes are formed Gametes are not formed In sexual reproduction we can find more variations when c
- ScienceClass 10CBSE
1. What would be the ratio of chromosome number between an egg and its zygote? How is the sperm genetically different from the egg?
The ratio of chromosome number between an egg and its zygote is 1:2. Sperm contains the genetic material from the father while egg contains the genetic material from the mother. Sperm can either have X chromosome or Y chromosome but egg always have an X chromosome.
- ScienceClass 10CBSE
1. What are the benefits of using mechanical barriers during sexual act?
Mechanical barriers prevents unwanted pregnancy Mechanical barriers prevent sexually transmitted
- ScienceClass 10CBSE
1. What changes are observed in the uterus subsequent to implantation of young embryo?
Following changes are observed in the uterus subsequent to implantation of young embryo. Uterine lining thickens to support to developing (PLACENTA) Uterine lining is richly supplied with blood vessels so that nutrition and oxygen could be supplied to the developing foetus.
- ScienceClass 10CBSE
1. What changes are observed in the uterus if fertilisation does not occur?
Following changes occur in the uterus if fertilization does not occur Extra lining of Uterus degenerates Uterus lining fragments gets discharged through vagina Unfertilized egg gets discharged Menstruation takes place
- ScienceClass 10CBSE
1. Trace the path of sperm during ejaculation and mention the gland and their functions associated with the male reproductive system.
Soln: Sequence of organs in the male reproductive system for transport of sperms is testis → epididymis → vasdeferens → prostate→ urethra . Glands associated with male reproductive system Function Testes Secretion of testosterone Prostate gland
- ScienceClass 10CBSE
1. How are general growth and sexual maturation different from each other?
General growth is all about growth of size. Sexual maturation is about achieving the ability to reproduce. General growth begins with growth of an organism whereas sexual maturity is attained at certain stage of life called as adolescence.
- ScienceClass 10CBSE
1. Reproduction is linked to stability of population of a species. Justify the statement.
Soln: Soln: Competition for food, predation are common in nature. If there is no reproduction species would have become extinct. Hence reproduction linked to population of the species.
- ScienceClass 10CBSE
1. Where is the zygote located in the flower after fertilization?
After fertilization zygote will be located in the ovary.
- ScienceClass 10CBSE
1. Is the chromosome number of zygote, embryonal cells and adult of a particular organism always constant? How is the constancy maintained in these three stages?
Meiosis is a way of cell division in which number of chromosomes get halved. After fertilization chromosomes become equal to that of somatic cells. After fertilization Mitosis takes place for the rest of the stages of life. Hence chromosomes remain constant.
- ScienceClass 10CBSE
1. Why cannot fertilisation take place in flowers if pollination does not occur?
Pollination is a process in which transfer of pollen grains from anthers to stigma takes place. If there is no pollination then there will be no fusion of gametes and fertilization do not take place.
- ScienceClass 10CBSE
1. In tobacco plant, the male gametes have twenty four chromosomes. What is the number of chromosomes in the female gamete? What is the number of chromosomes in the zygote?
Number of chromosomes in both the gametes are equal hence number of chromosomes in a female gamete of tobacco plant is 24. Combining both number of chromosomes in a zygote is 48.
- ScienceClass 10CBSE
1. From the internet, gather information about the chromosome numbers of five animals and five plants. Correlate the number with the size of organism and answer the following questions. (a) Do larger organisms have more number of chromosomes/cells? (b) Can organism with fewer chromosomes reproduce more easily than organisms with more number of chromosomes? (c) More the number of chromosomes/cells greater is the DNA content. Justify.
Soln: Animals Chromosome numbers Plants Chromosome numbers Man 46 Corn 20 <
- ScienceClass 10CBSE
1. Give two reasons for the appearance of variations among the progeny formed by sexual reproduction.
Gametes are contributed by two individuals of the same Crossing over occur during
- ScienceClass 10CBSE
1. Why does bread mould grow profusely on a moist slice of bread rather than on a dry slice of bread?
Spores of bread mould needs moisture to germinate and grow. Hence mould grow profusely on a moist slice of bread.