The Class 10 is an important year in a student’s life and Maharashtra State Board Science 2 is one of the subjects that require dedication, hard work, and practice. It’s a subject where you can score well if you are well-versed with the concepts, remember the important formulas and solving methods, and have done an ample amount of practice. Worry not! Home Revise is here to make your Class 10 journey even easier. It’s essential for students to have the right study material and notes to prepare for their board examinations, and through Home Revise, you can cover all the fundamental topics in the subject and the complete Maharashtra State Board Class 10 Science 2 Book syllabus.
1. Which are the important life processes in living organisms? Which life processes help to maintain the continuity of the species?
Answer: All those life processes such as nutrition, respiration, excretion, sensation and response (control and coordination) and so on are crucial for each living organism in order to remain alive. Aside from these life processes, one more life process that takes place in living organisms is reproduction. However, reproduction does not help the organism to remain alive but it helps to maintain the continuity of the species of that organism.
2. What are the types of asexal reproduction in unicellular organisms? Explain Binary fission with example.
Answer: There are three types of asexual reproduction. They are binary fission, multiple fission, budding, vegetative propagation and spore formation. Take the example below to understand binary fission in unicellular organisms:
Binary fission: Collect the water in a conical flask from a pond having stagnant water and aquatic plants. Then, put some wheat grains and aquatic plants to it and keep it for three to four days, allowing the wheat grains and the plants to decompose. On the early morning of the fourth day, pour a drop of that water over a glass slide and put a cover-slip on that drop carefully. Now, view under the compound microscope and you will get to see many paramecia performing the binary fission. Some other organisms that perform asexual reproduction using binary fission are Prokaryotes (Bacteria), Protists (Amoeba, Paramoecium, Euglena, etc.) and eukaryotic cell-organelle like mitochondria and chloroplasts. During the process of binary fission, the parent cell is divided to produce two daughter cells that are similar. Binary fission takes place via either mitosis or amitosis. Meanwhile, the axis of fission/division is different in different protists, that is Amoeba divides in any plane as it lacks specific shape and so is known as ‘ simple binary fission’. Paramoecium divides by ‘transverse binary fission’ whereas Euglena uses ‘longitudinal binary fission’. Binary fission is normally performed by living organisms under favorable conditions, that is there will be abundant food material available.
3. Explain the concept of IVF.
Answer: During IVF, fertilization is brought about in the test-tube and the embryo created is implanted in the uterus of the woman at an appropriate time. This fertilization technique is used to have children by childless couples with problems such as less sperm count, obstacles in oviduct and so on. Also, some of the women may have problems in implantation of embryo in the uterus. Such women can adopt a modern remedial technique known as surrogacy. In this technique, oocyte collected from the ovary of the woman having problems in implantation in the uterus is fertilized in a test-tube with the help of sperms collected from her husband. The embryo resulting from such fertilization is implanted in the uterus of some other woman having a normal uterus. Such a woman, in whose uterus the embryo is implanted, is called a surrogate mother.
4. What is a menstrual cycle? Describe it in brief.
Answer: The repetitive changes that a female reproductive system undergoes at puberty and repeats every 28 – 30 days are menstrual cycles. It is a natural process, controlled by four hormones, which are follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogen and progesterone. Know more about menstrual cycle
5. Sketch the labelled diagram of a flower with its sexual reproductive organs.
Answer:
6. Gender of the child is determined by the male partner of the couple. Explain with reasons whether this statement is true or false.
Answer: Gender of the child is totally determined by the man. He is responsible, if the couple will have a girl child or a boy. During the zygote creation, it is the man who transfers either X or Y chromosome to the next generation, while the female contributes only X chromosome. Now, at the time of fertilization, if X chromosome comes from male, the child will be a girl and if Y chromosome is transferred then the child will be a boy. Hence, the women have no role in the determination of the gender of a child.
7. How are newborns with down syndrome produced?
Answer: Oocytes that are released from ovaries during the last few months nearing the age of menopause at 40 – 50 years old have lesser ability of division as it has diminished till now. Owing to this, they could not complete proper meiotic division. Now, if these oocytes are fertilized, the newborns created from them may have some abnormalities such as Down’s syndrome.
8. What are monozygotic twins and dizygotic twins?
Answer: Offsprings delivered from two embryos that have developed simultaneously in the same uterus are known as twins. Twins are of two kinds, monozygotic and dizygotic twins. Twins formed from a single embryo are known as Monozygotic twins. During early times of the embryonic development, that is within eight days of zygote formation, the cells of the embryo are divided into two groups, which develop as two separate embryos and this results in formation of monozygotic twins. These twins are genetically exactly similar to each other, that they are exactly similar in appearance and their gender is the same, both will either be girls or boys. If the embryonic cells are divided into two groups eight days after the zygote formation, there is possibility of conjoined twins (Siamese twins). These twins have some parts of the body joined to each other. They may also have some common organs. Meanwhile, sometimes two
oocytes are released from the ovary of a woman and these oocytes are fertilized by two separate sperms and form two zygotes. These two embryos are formed from those two zygotes and both of those embryos are separately implanted in the uterus and thus dizygotic twins are delivered after complete development. Such twins are genetically different and may be the same or different by gender.
9. Explain sexual reproduction in Flower.
Answer: Sexual reproduction always occurs with the help of two germ cells, the female gamete and male gamete. Learn more about sexual reproduction of flowering plants from this.