1 Comment
One mark Questions
1. Name the information source for making proteins. In what respect is the human male gamete different from the female gamete? 2. DNA copies generated will be similar, but may not be identical. Why is it so? 3. Plants like rose, banana and jasmine are grown by vegetative means. Why? 4. How does sexual reproduction help in maintaining the chromosome number of a species constant from generation to generation? (HOTS) 5. What is the function of stigma? Two marks Questions 6. Why are testes located outside the abdominal cavity? 7. How does a human foetus derive its nutrition? Three marks Questions 8. What is the role of the seminal vesicles and the prostate gland? 9. Give and advantage of vegetative propagation. Five marks Questions 10. Explain happens when: (a) Testosterone is released in males (b) Pollen grain falls on the stigma of the flower. (c) Egg fuses with sperm cell. (d) Planaria is cut into many pieces. (e) Buds are formed on the notches of the Bryophyllum leaf. 11. Differentiate between the following : (a) Pollen tube and Style (b) Fission in Amoeba and Plasmodium (c) Fragmentation and Regeneration (d) Bud of Hydra and bud of Bryophyllum (e) Vegetative propagation and Spore formation 12. Answer these Questions (a) Give one examples of each unisexual and bisexual flower (b) Mention the changes a flower under goes after fertilization (c) How does the amount of DNA remain constant though each new generation is combination of DNA copes of two individuals? 13. What is the main difference between sperms and eggs of humans? Write the importance of this difference. 14. Name the part where (i) eggs develop. (ii) Fertilisation takes place. (iii) Fertilised egg gets implanted. (b) Describe, in brief, the changes the uterus undergoes. (i) to receive the zygote. (ii) if zygote is not formed. 15. Name the following parts: (i) Part that produces pollen grain (ii) Part that transfers male gametes to the female gametes (iii) Part that is sticky to trap the pollen grain (iv) Part the develops into a fruit 16. There are a number of ways by which the genes enter a population. Explain briefly the three ways. Test yourself: Solution- Chapter - How Do Organisms Reproduce Class 10 Answer: 1. DNA . Male gametes (sperms) are mobile and smaller in size while female gamete (ovum) is immobile and bigger in size. 2. This is because the process of copying the DNA will have certain variations each time. 3. This is because they have lost the capacity to produce viable seeds. 4. Male & female gametes have only half the number of chromosomes & half the amount of DNA. The fusion of these germ cells during sexual reproduction results in re-establishment of the number of chromosomes. 5. Stigma receives pollen grains during pollination & provides the nutrients necessary for pollen germination. 6. This is because sperm formation requires a temperature lower than that of the normal body temperature. 7. The human foetus gets nutrition from the mother‘s blood through a special tissue called placenta. This is a disc which is embedded in the uterine wall. It contains villi on the embryo‘s side of the tissue. On mother‘s side are blood spaces which surround the villi. This provides a large surface area for nutrients to pass from the mother to the embryo. 8. Seminal Vesicle: Its secretion form a major part of the semen (60%). Its secretion is alkaline in nature which neutralizes the effect of acid in the female genital tract. It has fructose sugar which provides nutrition and energy to the sperm. Prostate gland: Its secretion form 13-33% of semen. It helps in sperm motility and viability(chances of striking the ovum). Cowper 's gland: Its secretion lubricates the end of male reproductive part during copulation. 9. (i) Propagation of plants which have lost the capacity to produce seeds (ii) Plants raised by this method can bear fruits earlier (iii) Produce genetically similar plants 10. (a) Secondary sexual characters (b) Pollen tube formed for fertilization (c) Fertilization (d) Each part grows into a new organism (e) Fall on the soil and forms new plants 11. (a) Pollen tube – Carries male germs cell Style – Carries pollen tube (b) Fission in Amoeba – Binary fission Plasmodium – Multiple fission (c) Fragmentation – Simple multicellular organisms Regeneration – Complex multicellular organisms (d) Budding Vegetative propagation (e) Vegetative propagation – Formation of new plants from leaves, root and stem Spore formation – reproduction by spores 12. (a) unisexual flowers : Papaya, Watermelon, Corn, etc. bisexual flowers : Mustard, rose, lily, hibiscus, etc. (b) After fertilization the petals,stamen and carpel fall off and only sepal,ovary and ovule remain. This is because after fertilization the ovary develops into fruit and protect the seeds, these seeds are actually fertilized ovule. But, carpels and petals do not have any role after fertilization so they fall off. After fertilization, the outer layers of the ovule become impervious, hard and function as a seed coat. An ovule with an embryo inside is called a seed . (c) In sexual reproduction the gametes usually contain half number of chromosomes compared to the chrome gametes and some numbers present in the body cells. These haploid gametes when fuse produce a new cell with double number of chromosomes than the gametes and same as the body cells. In this way organisms restrict doubling of DNA and maintain the chromosome number. 13. Sperm has Y chromosome as sex chromosome, while egg has X chromosome as sex chromosome. Human eggs are much larger than sperms and are highly metabolically active cells. They contain more amount of cytoplasm. Importance of the difference: The difference in the sperm and egg cells maintains the continuity of the species generation after generation by the process of reproduction. 14.(a) (i) The development of egg occurs in the ovary. (ii) Fertilisation takes place in the fallopian tubes. (iii) The fertilised egg gets implanted in the uterus. (b) (i) The uterus prepares itself every month to receive a fertilised egg/zygote. The inner uterus lining (endometrium) becomes thick and is supplied with blood to nourish the embryo. (ii) If the egg is not fertilised, then the uterus lining is not required. Hence, it breaks down and gets released in the form of blood and mucous through the vagina. This process lasts for 2–8 days. This cycle occurs every month and is known as menstruation. 15. (i) Part that produces pollen grain: anther (ii) Part that transfers male gamete to the female gamete: style (iii) sticky part to trap pollen grain: stigma (iv) Part that develops into fruit: Ovary (b) Pollination 16. Gene flow refers to the transfer of alleles from one population to another as a result of interbreeding between members of two populations. Mutation: Mutation are the sudden change that takes place in the DNA sequence of an organism. Migration: Migration will change gene frequencies by bringing in more copies of an allele already in the population or by bringing in a new allele that has arisen by mutation. 10th Biology Chapter - 8 How Do Organisms Reproduce Click Here Reproduction for class 10 solved question from Board Exam
1. Give and advantage of vegetative propagation. Ans: Any one: Propagation of plants which have lost the capacity to produce seeds OR Plants raised by this method can bear fruits earlier OR Produce genetically similar plants 2. Variation is useful for the survival of species over time. But the variants have unequal chances of survival. Explain this statements Ans: - If organisms are suited to a particular niche, drastic changes in the niche could wipe out that population If some variations are there, few individuals might survive Depending on whether the variations are useful to the change in the environment some variants survive whereas others do not 3. Explain happens when : (a) Testosterone is released in males (b) Pollen grain falls on the stigma of the flower. (c) Egg fuses with sperm cell. (d) Planaria is cut into many pieces. (e) Buds are formed on the notches of the Bryophyllum leaf. Ans: (a) Secondary sexual characters (b) Pollen tube formed for fertilization (c) Fertilization (d) Each part grows into a new organism (e) Fall on the soil and forms new plants 4. Some flowers contain either stamens or carpel’s whereas some flowers contain both categorise the two types of flowers and give one example of each. Ans: Either stamens/carpels – Unisexual, e.g. – papaya/watermelon Both – Bisexual, e.g. – Hibiscus/mustard 5. Compare the processes of binary fission and multiple fission using diagrams. Ans: Binary fission-division into two equal halves Multiple fission – division into many daughter cells Diagram [yourself] 6. Differentiate between the following : (a) Pollen tube and Style (b) Fission in Amoeba and Plasmodium (c) Fragmentation and Regeneration (d) Bud of Hydra and bud of Bryophyllum (e) Vegetative propagation and Spore formation Ans: (a) Pollen tube – Carries male germs cell Style – Carries pollen tube (b) Fission in Amoeba – Binary fission Plasmodium – Multiple fission (c) Fragmentation – Simple multicellular organisms Regeneration – Complex multicellular organisms (d) Budding Vegetative propagation (e) Vegetative propagation – Formation of new plants from leaves, root and stem Spore formation – reproduction by spores 7. What is the effect of DNA copying which is not perfectly accurate on the reproduction process? Ans. During the process of DNA copying, some mutations are produced which give rise to useful, harmful or neutral variations in the offspring. 8. Why do testes lie outside the abdominal cavity? Ans. Testes are present inside a fibrous covering called scrotum or scrotal sac. The scrotum helps in maintaining 1–3 degree Centigrade lower temperature than the body temperature. This is necessary for the development of sperms. 9. The organisms formed by asexual reproduction are considered as clones. Why? Ans: This is because In asexual reproduction, the young ones formed are genetically identical to the parents. 10. Draw the diagrams to explain the process of regeneration in Planaria. Name any other organism in which a similar process occur. Ans: Regeneration in Planaria — Planaria have the ability to give rise to new individuals from their body parts. This process is called regeneration. If the body of Planaria is somehow cut or broken up into many pieces, each piece grows into a complete organism . Figure 8.3 Regeneration in Planaria NCERT Other organism in which a similar process occur are: Hydra, Lizard etc 11. List any four method of contraception used by humans? How does their use have direct effect on the health and prosperity of a family? Ans: Following are the four method of contraception used by humans :- Barriers: Here a mechanical barrier is created so that the sperms cannot penetrate the egg. It Include condoms, diaphragms, cervical caps and vaults. Intra uterine devices (IUDs) : They release hormones to cause phagocytosis of sperms, or they release copper ions to decrease sperm motility. Oral contraceptive pills: They contain hormones—either progesterone or progesterone- oestrogen combination, which causes hormonal imbalance of the body. Surgical methods : Include vasectomy (removal of a part of the vas deferens) in males and tubectomy (removal of a part of the fallopian tubes) in females. Use of these contraceptive devices helps in preventing unwanted pregnancies. They can prevent the chances of frequent pregnancies which otherwise affect the health of a mother. They help in family planning by controlling the number of children in a family. So, that proper care is provided to the children and that also reduces the chances of poverty. Use of contraceptive devices also reduces the chances of getting sexually transmitted diseases such As AIDS. In this way, the birth control methods play important roles in the health and prosperity of the family. 12. Answer these Questions (a) Give one examples of each unisexual and bisexual flower (b) Mention the changes a flower under goes after fertilization (c) How does the amount of DNA remain constant though each new generation is combination of DNA copes of two individuals? Ans: (a) The flowers in which either the male or the female reproducative organs are present only, are called unisexual flowers. They are called incomplete flowers. They undergo cross-pollination in order to reproduce. Example - Papaya, Watermelon, Corn, etc. The flowers in which both the male and female reproductive organs are present, are known as complete or bisexual flowers. They are capable of self-pollination. Example - Mustard, rose, lily, hibiscus, etc. (b) After fertilization the petals,stamen and carpel fall off and only sepal,ovary and ovule remain. This is because after fertilization the ovary develops into fruit and protect the seeds, these seeds are actually fertilized ovule. But, carpels and petals do not have any role after fertilization so they fall off. After fertilization, the outer layers of the ovule become impervious, hard and function as a seed coat. An ovule with an embryo inside is called a seed . (c) In sexual reproduction the gametes usually contain half number of chromosomes compared to the chrome gametes and some numbers present in the body cells. These haploid gametes when fuse produce a new cell with double number of chromosomes than the gametes and same as the body cells. In this way organisms restrict doubling of DNA and maintain the chromosome number. 13. Answer these Questions (a) Name the reproductive part of humane female reproductive system: (i) That produce egg (ii) where fussion of egg and sperm takes place (iii) where zygot get implanted (b) Describe what happen to the zygote after it get implanted Ans: (a) (i) ovaries (ii) oviduct[Fallopian tube] (iii) In the lining of the uterus (b) The fertilised egg, the zygote, gets implanted in the lining of the uterus, and starts dividing . The lining thickens and is richly supplied with blood to nourish the growing embryo 14. Q. Name the information sources making protein in the cell? What is the basic event in reproduction? Ans: The information source for making proteins in the cells: gene specific for that protein Basic event of reproduction: replication of DNA 15. (a)Write the name of those parts of a flower which serve the same functional as the following do in the animals: (i) Testis (ii) sperm (iii) ovary (iv) egg (b) State the function of flower in the flowering plants Ans: (a) (i) Testis : Anther In animals, testis is the male reproductive organ that produces sperms. Similarly, in plants, anther is the male reproductive part that produces pollen grains. (ii) Sperm : Pollen grains Sperm is a male gamete in animals. In plants, pollens are male gametes. The generative cell of pollen divides to produce two nuclei called male gametes. (iii) Ovary : Ovary In animals, ovary is the female reproductive organ that produces eggs. Similarly, in plants, ovary is the female reproductive organ that contains ovules. (iv) Egg : Ova/Ovum Eggs in animals are also called ova. In plants, eggs are present inside the female gametophyte, i.e., ovule. (b) The function of flowers in flowering plants is to assist in sexual reproduction. Flower is the most important part in angiosperms because the reproductive parts are located inside it. 16. What is the main difference between sperms and eggs of humans? Write the importance of this difference. Ans:Difference between sperms and eggs of humans: The major genetic differences lies in the difference in sex chromosome of sperm (male gamete) and egg( female gamete). Sperm has Y chromosome as sex chromosome, while egg has X chromosome as sex chromosome. There is a marked difference in size, shape, metabolic activity, cytoplasm content, motility, etc in the sperms and eggs. Human eggs are much larger than sperms and are highly metabolically active cells. They contain more amount of cytoplasm. Importance of the difference: The difference in the sperm and egg cells maintains the continuity of the species generation after generation by the process of reproduction. 17. How is the process of regeneration in Planaria different from reproduction? Ans: Different from asexual reproduction: The reproduction in planaria is different from the asexual reproduction because in the asexual reproduction, a complete individual is formed while in planariathe body parts are regenerated. Different from sexual reproduction: It is entirely different from the sexual reproduction because in sexual reproduction male and female gamete fuses and zygote is formed. 18. What is placenta? State its function in human female. Ans: Placenta is a special umbilical cord develops in the fourth week which establishes an intimate connection between the foetal membrane and he uterine wall. Function of Placenta: The exchange of materials between the mother’s blood and the blood of foetus takes place through placenta. It serves as a nutritive, respiratory and excretory organ of the foetus. 19.Name the part where (i) eggs develop. (ii) fertilisation take place. (iii) fertilised egg gets implanted. (b) Describe, in brief, the changes the uterus undergoes. (i) to receive the zygote. (ii) if zygote is not formed. Ans: (a) (i) The development of egg occurs in the ovary. (ii) Fertilisation takes place in the fallopian tubes. (iii) The fertilised egg gets implanted in the uterus. (b) (i) The uterus prepares itself every month to receive a fertilised egg/zygote. The inner uterus lining (endometrium) becomes thick and is supplied with blood to nourish the embryo. (ii) If the egg is not fertilised, then the uterus lining is not required. Hence, it breaks down and gets released in the form of blood and mucous through the vagina. This process lasts for 2–8 days. This cycle occurs every month and is known as menstruation. 20. (a) What is pollination? State its significance. (b) How does fertilisation occur in flowers? Name the parts of the flower that develop into (i) seed, and (ii) fruit after fertilisation. Ans: (a) The transfer of pollen grains from the anther to the stigma of a flower is known as pollination. It is of two types: (i) Self-pollination It is the transfer of pollen grains from the anther to the stigma of the same flower or another flower on the same plant. (ii) Cross-pollination It is the transfer of pollen grains from the anther to the stigma of the flower present on two different plants. Significance of pollination: (i) It is a significant event because it precedes fertilisation. (ii) It brings the male and female gametes closer for the process of fertilisation. (iii) Cross-pollination introduces variations in plants because of the mixing of different genes. These variations further increase the adaptability of plants towards the environment or surroundings. (b) Double fertilisation is a characteristic feature of flowering plants. In this process, out of the two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and another fuses with the polar nucleus to form an endosperm (process is called triple fusion). Because two kinds of fusion—syngamy and triple fusion—take place, the process is known as double fertilisation. After fertilisation, (i) the ovule develops into a seed (ii) the ovary develops into a fruit More you need to study 10th CBSE NCERT Question Banks 10th CBSE NCERT Board Questions 10th Reproduction Study material for slow learner 10th Reproduction solved Question Bank term-ii Download Files CBSE TEST PAPER-01 SCIENCE and TECHNOLOGY (Class-10) Chapter 7 : Control and Coordination Ch. 7 - Control and Coordination class 10 Trend setter solved CBSE Test paper-03 VERY VERY SHORT ANSWER QUESTIONS (1 Mark) 1. Mention one example of chemotropism. [2010 (T-I)] Ans: Growth of pollen tube towards the ovule 2. Mention the function of hind brain in humans. [2010 (T-I)] Ans: Main function of hind brain in humans is to maintain the posture and balance of the body. It is responsible for the precision of voluntary actions like walking in straight line, riding a bicycle. 3. Name and explain the function of the hormone secreted by the pituitary gland in humans.[2010 (T-I)] Ans: Growth hormone is secreted by the pituitary gland. This hormone regulates growth and development of the body. If there is a deficiency of this hormone in childhood, it leads to dwarfism and excess of this hormone leads to giant body size 4. State the main function of abscisic acid in plants.[2010 (T-I)] Ans: Abscieic acid is the plant hormones which stop plant growth Abscieic acid also perform following functions in plants: · It promotes seed dormancy by inhibiting cell growth. · It is involved in the opening and closing of stomata. · It is also responsible for the shedding of leaves. 5. Name the hormone the secretion of which is responsible for dramatic change in appearance in girls when they approach 10-12 years of age. [2008] Ans: Oestrogen from ovaries 5. Name the hormone that helps in regulating level of sugar in our blood. Name the gland that secrets it. Ans: Hormone : Insulin Gland : Pancreas VERY SHORT ANSWER QUESTIONS (2 Mark) 6. What are the end products formed during fermentation in yeast. Under what condition a similar process takes place in our body that leads to muscle cramps? [2010 (T-I)] Ans: Yeast breakdown glucose (food) into ethyl alcohol and carbon dioxide and release energy during fermentation. Under anaerobic (no oxygen) a similar process takes place in our body that leads to muscle cramps. 7. Differentiate between tropic and nastic movements in plants. Give one example of each. [2009] Ans: Nastic movements are non directional responses to stimuli such as temperature and heat. These are kind of movements do not depend on direction of stimulus such as seismonastic, chemonastic, etc. Example of seismonastic movement is movement of Venus fly trap. Tropic movement is the response to stimuli that comes from one direction. It is a directional movement. If the movement of the plant part is towards the stimulus, then it is known as positive tropism. If the movement of the plant part is away from the stimulus, then it is known as negative tropism. For example phototropism, Geotropism etc. 8. Name the hormone secreted by human testes. State its functions. Ans. Hormone secreted by human testes. Testosterone function of testosterone is the development of secondary sexual characters in males like growth of hair, hoarse voice, moustaches etc. 9. Write the name and the functions of any two parts of the hind brain. Ans: Hindbrain: It consists of three regions, namely, a) Cerebellum: It is present at the posterior part of the brain. It is responsible for precise and accurate voluntary actions as well as for maintaining the posture and balance of the body. It is considered as the seat of equilibrium of the body. b) Pons : It lies above the medulla oblongata and acts as a bridge carrying sensory and motor impulses between the brain and the spinal cord. c) Medulla oblongata : It is the posterior most part of the brain and is called the brain stem. It has reflex centres to control involuntary actions like heart beat, blood pressure, breathing movements, coughing, sneezing, salivation, vomiting, etc. 10. How does our body maintain blood sugar level? [2010 (T-I) Ans: Pancreas is just below the stomach. They secrete insulin which helps to regulate blood sugar levels when there is deficiency of sugar in blood the cells send information to the pancreas then it secretes more enzymes which regulates it.When insulin is not secreted properly we get diabetes and we take injections of insulin.
SHORT ANSWER QUESTIONS (3 Marks) 11. A compound of iodine is compulsorily added to common salt in small quantity. (a) Why is it important for us to have iodised salt in our diet. (b) Name the disease caused by its deficiency. (c) Write symptom of the disease. [2010 (T-I)] Ans: (a) It is important to have iodized salt in our diet because iodine is required for the synthesis of a hormone called thyroxin. Thyroxin is a very important hormone required metabolism, growth and development of body and brain. Iodine deficiency can result in various disorders like goitre, so it is necessary to consume iodized salt. (b)Goitor is caused by its deficiency (c) The neck of person appear to be swellen. 12. What is reflex action? Describe the steps involved in reflex action. [2009] Ans: Reflex Action is defined as an unconscious, automatic and involuntary response of efforts, i.e., muscles and glands, to a stimulus, which is monitored through the spinal cord. Mechanism of Reflex Action: It involves the following steps: (i)Receptor organ like skin perceives the stimulus and activates a sensory nerve impulse. (ii)Sensory organ carries message in the form of sensory impulse to the spinal cord. (iii)The spinal cord acts as modulator. The neurons of spinal cord transmit the sensory nerve impulse to motor neuron. (iv) Motor nerve conducts these impulses to the effectors like leg muscles which responds by pulling back the organ away from the harmful stimulus. 13. What is âhydrotropismâ? Describe an experiment to demonstrate âhydrotropismâ? [2009] Ans: The growth of the root of plant in response to water or moisture Experiment: 1. Take two plastic troughs say A and B Fill each one of them with two-thirds of soil 3. Place the seedling in the soil in trough A 4 Place the similar seedling in trough B, place a small clay pot inside the soil. 5. Water the soil in the trough A daily and uniformly 6. Do not water the soil in trough B, but put some water in the clay pot placed in the soil. 7. Leave both the troughs for a few days. On examining the roots later, it will be found that the root in trough B has bent towards the clay pot that is source of water. Roots in trough A grew normally straight. Thus roots show the hydrotropism. 14. What is âphototropismâ? How does it occur in plants? Describe an activity to demonstrate phototropism. [2009] Ans: The growth movements in plants in response to light as stimulus is said to be phototropism Activity: To demonstrate phototropism in plants. Requirements: A potted plant, Procedure: Take a potted plant and keep it in the sunlight in a horizontal position and observe the growth of roots and shoots. Observation: The shoots of the plant grow towards sunlight and roots away from sunlight Conclusion: Roots are negatively phototropic and shoots are positively phototropic 15. Name a hormone secreted by :a) pancreas b)pituitary c)thyroid. state one function of each of the hormone. Ans: Thyroxin (secreted by thyroid gland) The hormone called thyroxin helps in coordinated growth. It regulates carbohydrate, fat, and protein metabolism in our body. The deficiency of this hormone results in the enlargement of the thyroid gland or goitre. Growth hormone (GH) (secreted by the pituitary gland) Growth hormone (GH) is involved in the growth and development of the human body. The secretion of this hormone should be properly maintained in the body. Over secretion of this hormone results in abnormal growth of the body known as gigantism. On the other hand, its low secretion results in dwarfism. Insulin (secreted by pancreas) The pancreas secretes a hormone called insulin, which regulates the blood sugar level in the human body. It increases the permeability of the cell membrane for glucose and accelerates the passage of glucose into the cells from the bloodstream. LONG ANSWER QUESTIONS (5 Marks) 16. (a) Name two hormones secreted by pancreas. Write one function of each hormone. (b) How does our body respond when adrenalin is secreted into the blood. (c) Write an example to explain feedback mechanism for regulation of hormonal secretion. [2010 (T-I)] Ans: (a) Two hormones secreted by pancreas are insulin and glucagon. Both regulate the levels of glucose in our body.Glucagon helps in elevating the amount of glucose in the blood while insulin decreases the level of glucose in the blood stream. (b) When someone is in danger or in emergency then adrenal gland secrete adrenaline hormone. It is secreted directly into the blood and is transported to different parts of the body. It speeds up the heartbeat and hence supplies more oxygen to the muscles. This results in increasing breathing rate and blood pressure which enable them to fight with such urgent situation. (c) Feedback means that some element in the physiological response to a hormone feeds back to the endocrine gland either directly or indirectly and affects its secretion rate. The feedback may be negative or positive. For example insulin regulates the amount of blood glucose. When the level of blood glucose is high, insulin secretion is turned on by the pancreas which acts on target tissues like liver to convert excess sugar into glycogen. When the blood glucose concentration is normal the insulin secretion is stopped. 17. (a) Draw the structure of a neuron and label the following on it.Nucleus, Dendrite, Cell body and Axon (b) Name the part of neuron: (i) where information is acquired. (ii) through which information travels as an electrical impulse. [2008] Ans: (b) The information that is acquired is received by the neuron at the dendrites and then the information travels in the form of impulse to cell body and then to Axon. Later when it reaches to synapse it is converted to chemical form. 18. Name the two main organs of our central nervous system. Which one of them plays a major role in sending command to muscles to act without involving thinking process? Name the phenomenon involved. Ans. Two main organs of our central nervous system are: Brain and spinal cord. Spinal cord sends the command to muscles to act without involving thinking process. This phenomenon is known as reflex action. 19. Name the hormone secreted by human testes. State its functions. Ans. Hormone secreted by human testes. Testosterone function of testosterone is the development of secondary sexual characters in males like growth of hair, hoarse voice, moustaches etc. 20. Name the plant growth hormone which is synthesised at the shoot tip.Explain breifly why does a plant bend towards light during its growth. Ans: The plant growth hormone that is synthesized is the shoot tip is Auxin. The growth of a plant towards the light source is known as phototropism. It occurs in plants due to the hormone auxin which is highly light sensitive. As sunlight falls on one side of the shoot, auxin gets stimulated and generally it diffuses to the shaded portion of the plant. It starts elongating the cells of the shaded portion. Thus the shaded portion grows and elongates more than the illuminated part. As a result the curvature of the plant stem tip bends towards the light. Ch. 7 - Control and Coordination class 10 Trendsetter solved CBSE Test paper-01 Ch. 7 - Control and Coordination class 10 Trendsetter solved CBSE Test paper-02 Ch. 7 - Control and Coordination class 10 Trendsetter solved CBSE Test paper-03 ![]() Control: is the power of restrain and regulation by which something can be started, slowed down, expedited or stopped. Coordination: (L. co-joint, ordinates-regulated) is orderly or harmonious working of different but inter-related parts so as to perform one or more activities very smoothly. Need for control and coordination in an organism: The body of a multicellular organism consists of a number of components and sub-components; each specialized to perform a particular function. However, all the components are not required to function all the time at the same speed. A system of controls is required to function all the time at the same speed. A system of controls is required to allow them to perform or not to perform, slow down or speed up their working. Further, most activities require the simultaneous or sequential functioning of a number of parts, stopping some and stimulation others. During feeding, eyes locate the food, nose registers its smell, hands pick up the food and take it to mouth, mouth opens to receive the food, teeth and muscles take part in its mastication and saliva moistens it. Tongue perceives its taste. It moves the food below the teeth. Later it pushes the crushed food into pharynx. All this is possible only through a system of coordination. CBSE_NCERT Chapter 7 Control and Coordination Biology X Control and Co-ordination Study Notes Download File X Control and Co-ordination Solve Questions Download File |
Blog SeaRCH Link
All
Join Us For Update |