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Showing posts with label Class 10 Science (Biology). Show all posts
Showing posts with label Class 10 Science (Biology). Show all posts

Saturday, July 23, 2016

July 23, 2016

Vegetables Which Will Help You To Loose Weight Faster

Vegetable which are rich in proteins, minerals, vitamins, dietary fibers and metabolites, can be yours strongest ally in the fight for faster loosing weigh.

Vegetables Which Will Help You To Loose Weight Faster

Find out which are the 10 vegetables, which will help you the most in the fight for loosing weight.

Onions
It contains very few calories, which make the onion ideal for those people who want to lose weight. For best effect, always consume the onions fresh.
Green Peppers
Green pepper and vegetables which is related to it, helps in speeding up metabolism. This may result in significant degradation of the fatty tissue of the abdomen.
Chili Peppers
One Canadian study proved that chili peppers help in lowering your appetite, but also they are helping our bodies ability to burn fat faster then before.







Cucumbers
Cucumber contains a lot of water, and is rich in fiber. Because of that it’s great for reducing our hunger. When you feel an irresistible desire to have a snack, eat a fresh cucumber and a glass of water. You will feel full, and in the same time you would have enter very few calories. In addition, all water that you will enter through the cucumber and the cup of water will help in removing the toxins from the body.
Carrots
The orange fruit is ideal for a snack, because it’s full of beta carotene and fiber. When you are consuming carrots, especially fresh carrots, you are making your body big favor because of the fibers and beta carotene.

Pumpkins
Pumpkin are rich in vitamin C and gives the body energy. That is why, after consuming you will feel ready for exercise. With pumpkin consumption, gaining weight is impossible!


Tomatoes
Tomatoes are full with vitamin C and calcium. When consumed together, these two elements are the best ally in the fight against fat in the abdomen area.
Legumes
They are full with fibers, proteins and in some cases iron. The best way to consume legumes is by adding them in salads.
Green Leafy Vegetables
Spinach, cabbage and broccoli, will also successfully keep you full. These foods will not only provides you with dietary fiber which will fill your stomach, but will also give you essential vitamins and minerals.
Celery
Just like fresh cucumber, big part of the celery consists of water and the number of calories is just to low. This combination makes the celery the perfect for loosing weight.
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Wednesday, June 29, 2016

June 29, 2016

NCERT Solutions for Class 10th Science: Chapter 8 How do Organisms Reproduce

NCERT Solutions for Class 10th Science: Chapter 8 How do Organisms Reproduce
Class 10th ,Science: ,Chapter 8, How do Organisms Reproduce
Class 10th Science: Chapter 8 How do Organisms Reproduce

Question 1:
What is the importance of DNA copying in reproduction? Answer:
DNA (Deoxyribonucleic acid) is the genetic material found in the chromosomes, which are present in the nucleus of a cell. The DNA is the information site for making proteins and each specific type of protein leads to a specific type of body design.
Thus, it is the DNA molecule that determines the body design of an individual. Therefore, it can be concluded that it is the DNA that gets transferred from parents to offsprings and makes them look similar.
Question 2:
Why is variation beneficial to the species but not necessarily for the individual? Answer:
Variations are beneficial to the species than individual because sometimes for a species, the environmental conditions change so drastically that their survival becomes difficult. For example, if the temperature of water increases suddenly, then most of the bacteria living in that water would die. Only few variants that are resistant to heat would be able to survive. However, if these variants were not there, then the entire species of bacteria would have been destroyed. Thus, these variants help in the survival of the species. However, all variations are not necessarily beneficial for the individual organisms.
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Question 1:
How does binary fission differ from multiple fission? Answer:
In binary fission, a single cell divides into two equal halves. Amoeba and Bacteria divide by binary fission.
Question 2:
How will an organism be benefited if it reproduces through spores? Answer:
There are many advantages, if an organism reproduces through spores.
Advantages of spore formation:
  • Large numbers of spores are produced in one sporangium.
  • Spores are distributed easily by air to far-off places to avoid competition at one place.
  • Spores are covered by thick walls to prevent dehydration under unfavourable conditions.
Question 3:
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration? Answer:
Simple organisms such as Hydra and Planaria are capable of producing new individuals through the process of regeneration. The process of regeneration involves the formation of new organisms from its body parts. Simple organisms can utilize this method of reproduction as their entire body is made of similar kind of cells in which any part of their body can be formed by growth and development. However, complex organisms have organ-system level of organization. All the organ systems of their body work together as an interconnected unit. They can regenerate their lost body parts such as skin, muscles, blood, etc. However, they cannot give rise to new individuals through regeneration.
Question 4:
Which of the following is a plant hormone? (a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin
Answer:
(d) Cytokinin is a plant hormone.
Question 5:
Why is DNA copying an essential part of the process of reproduction? Answer:
DNA (Deoxyribonucleic acid) copying is an essential part of reproduction as it passes genetic information from parents to offspring. It determines the body design of an individual. The reproducing cells produce a copy of their DNA through some chemical reactions and result in two copies of DNA. The copying of DNA always takes place along with the creation of additional cellular structure. This process is then followed by division of a cell to form two cells.
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Question 1:
How is the process of pollination different from fertilization? Answer:
Pollination is the process of transfer of pollens from anther to stigma. It occurs with the help of certain pollinators such as air, water, birds, or some insects.
Fertilization, on the other hand, is the fusion of the male and female gametes. It occurs inside the ovule and leads to the formation of zygote.
Question 2:
What is the role of the seminal vesicles and the prostate gland? Answer:
The secretions from seminal vesicles and prostate glands lubricate the sperms and provide a fluid medium for easy transport of sperms. Their secretion also provides nutrient in the form of fructose, calcium, and some enzymes.
Question 3:
What are the changes seen in girls at the time of puberty? Answer:
Secondary sexual characteristics in girls:
  • Increase in breast size and darkening of skin of the nipples present at the tips of the breasts.
  • Appearance of hair in the genital area.
  • Appearance of hair in other areas of skin like underarms, face, hands, and legs.
  • Increase in the size of uterus and ovary.
  • Beginning of menstrual cycle.
  • More secretion of oil from the skin, which results in the appearance of pimples.
Question 4:
How does the embryo get nourishment inside the mother’s body? Answer:
The embryo develops inside the mother’s body for about nine months. Inside the uterus, the outer tissue surrounding the embryo develops finger-like projections called villi. These villi are surrounded by uterine tissue and maternal blood. They provide a large surface area for exchange of oxygen and nutrients. Also, there is a special tissue called placenta, which is embedded in the uterine wall. The embryo receives the oxygen and nutrients from the mother’s blood via the placenta. The waste materials produced by the embryo are also removed through the placenta.
Question 5:
If a woman is using a copper−T, will it help in protecting her from sexually transmitted diseases? Answer:
No. Using a copper-T will not provide a protection from sexually transmitted diseases, as it does not prevent the entry of semen. It only prevents the implantation of the embryo in the uterus.
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Question 1:
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania. Answer:
(b) Asexual reproduction takes place through budding in yeast.
Question 2:
Which of the following is not a part of the female reproductive system in human beings?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube Answer:
(c) Vas deferens is not a part of the female reproductive system in human beings.
Question 3:
The anther contains
(a) sepals.
(b) ovules.
(c) carpel.
(d) pollen grains. Answer:
(d) The anther contains pollen grains.
Question 4:
What are the advantages of sexual reproduction over asexual reproduction? Answer:
Advantages of sexual reproduction:
  • In sexual reproduction, more variations are produced. Thus, it ensures survival of species in a population.
  • The new formed individual has characteristics of both the parents.
  • Variations are more viable in sexual mode than in asexual one. This is because in asexual reproduction, DNA has to function inside the inherited cellular apparatus.
Question 5:
What are the functions performed by the testis in human beings? Answer:
The testes are the male reproductive organs that are located outside the abdominal cavity within a pouch called scrotum.
Functions of testes:
  • Produce sperms
  • Produce a hormone called testosterone, which brings about secondary sexual characters in boys.
Question 6:
Why does menstruation occur? Answer:
Menstruation is a process in which blood and mucous flows out every month through the vagina. This process occurs every month because one egg is released from the ovary every month and at the same time, the uterus (womb) prepares itself to receive the fertilized egg. Thus, the inner lining of the uterus gets thickened and is supplied with blood to nourish the embryo. If the egg does not get fertilised, then the lining of the uterus breaks down slowly and gets released in the form of blood and mucous from the vagina.
Question 7:
Draw a labelled diagram of the longitudinal section of a flower. Answer:
Question 8:
What are the different methods of contraception? Answer:
The contraceptive methods can be broadly divided into the following types:
  • Natural method→ It involves avoiding the chances of meeting of sperms and ovum. In this method, the sexual act is avoided from day 10th to 17th of the menstrual cycle because during this period, ovulation is expected and therefore, the chances of fertilization are very high.
  • Barrier method → In this method, the fertilization of ovum and sperm is prevented with the help of barriers. Barriers are available for both males and females. Condoms are barriers made of thin rubber that are used to cover penis in males and vagina in females.
  • Oral contraceptives →In this method, tablets or drugs are taken orally. These contain small doses of hormones that prevent the release of eggs and thus fertilization cannot occur.
  • Implants and surgical methods →Contraceptive devices such as the loop or Copper-T are placed in uterus to prevent pregnancy. Some surgical methods can also be used to block the gamete transfer. It includes the blocking of vas deferens to prevent the transfer of sperms known as vasectomy. Similarly, fallopian tubes of the female can be blocked so that the egg will not reach the uterus known as tubectomy.
Question 9:
How are the modes for reproduction different in unicellular and multicellular organisms? Answer:
In unicellular organisms, reproduction occurs by the division of the entire cell. The modes of reproduction in unicellular organisms can be fission, budding, etc. whereas in multicellular organisms, specialised reproductive organs are present. Therefore, they can reproduce by complex reproductive methods such as vegetative propagation, spore formation, etc. In more complex multicellular organisms such as human beings and plants, the mode of reproduction is sexual reproduction.
Question 10:
How does reproduction help in providing stability to populations of species? Answer:
Living organisms reproduce for the continuation of a particular species. It helps in providing stability to the population of species by producing a new individual that resembles the parents. This is the reason why cats give birth to only cats or dogs give birth to only dogs. Therefore, reproduction provides stability to populations of dogs or cats or any other species.
Question 11:
What could be the reasons for adopting contraceptive methods? Answer:
Contraceptive methods are mainly adopted because of the following reasons:
(i) To prevent unwanted pregnancies.
(ii) To control population rise or birth rate.
(iii) To prevent the transfer of sexually transmitted diseases.
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Tuesday, June 5, 2012

June 05, 2012

NCERT Answers for Class 10th Science: Chapter 7 Control and Coordination

Class 10th Science: Chapter 7 Control and Coordination

class 10 , ncert solutions , control and coordination , ncerthelp,meritnation,studyrankers

 

Question 1:
What is the difference between a reflex action and walking?
Answer:
A reflex action is a rapid, automatic response to a stimulus. It does not involve any thinking. For example, we close our eyes immediately when the bright light is focused. Walking, on the other hand, is a voluntary action. It is under our conscious control.
Question 2:
What happens at the synapse between two neurons?
Answer:
A very small gap that occurs between the last portion of axon of one neuron and the dendron of the other neuron is known as a synapse. It acts as a one way valve to transmit impulses in one direction only. This uni-direction transfer of impulses occurs as the chemicals are produced in only one side of the neuron i.e., the axon’s side. From axon, the impulses travel across the synapse to the dendron of the other neuron.
NCERT Solutions for Class 10th Science Chapter 7 Control and Coordination
Question 3:
Which part of the brain maintains posture and equilibrium of the body?
Answer:
Cerebellum, a part of hindbrain is responsible for maintaining posture and equilibrium of the body.
Question 4:
How do we detect the smell of an agarbatti (incense stick)?
Answer:
The thinking part of our brain is the forebrain. It has separate areas that are specialized for hearing, smelling, sight, taste, touch, etc. The forebrain also has regions that collect information or impulses from the various receptors. When the smell of an incense stick reaches us, our forebrain detects it. Then, the forebrain interprets it by putting it together with the information received from other receptors and also with the information already stored in the brain.
Question 5:
What is the role of the brain in reflex action?
Answer:
Reflex actions are sudden responses, which do not involve any thinking. For example, when we touch a hot object, we withdraw our hand immediately without thinking as thinking may take time which would be enough to get us burnt.
The sensory nerves that detect the heat are connected to the nerves that move the muscles of the hand. Such a connection of detecting the signal from the nerves (input) and responding to it quickly (output) is called a reflex arc. The reflex arcs −connections present between the input and output nerves − meet in a bundle in the spinal cord.
NCERT Solutions for Class 10th Science Chapter 7 Control and Coordination
Reflex arcs are formed in the spinal cord and the information (input) reaches the brain. The brain is only aware of the signal and the response that has taken place. However,
the brain has no role to play in the creation of the response.
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Question 1:
What are plant hormones?
Answer:
Plant hormones or phytohormones arenaturally-occurring organic substances. These are synthesized in one part of the plant body (in minute quantities) and are translocated to other parts when required. The five major types of phytohormones are auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
Question 2:
How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
Answer:
The movement of leaves of the sensitive plant, Mimosa pudica or “touch me not”, occurs in response to touch or contact stimuli. This movement is independent of growth. The movement of shoot towards light is known as phototropism. This type of movement is directional and is growth dependent.
Question 3:
Give an example of a plant hormone that promotes growth.
Answer:
Auxin is an example of growth-promoting plant hormone.
Question 4:
How do auxins promote the growth of a tendril around a support?
Answer:
Auxin is synthesized at the shoot tip. It helps the cell grow longer. When a tendril comes in contact with a support, auxin stimulates faster growth of the cells on the opposite side, so that the tendril forms a coil around the support. This makes the tendrils appear as a watch spring.
Question 5:
Design an experiment to demonstrate hydrotropism.
Answer:
Take two small beakers and label them as A and B. Fill beaker A with water. Now make a cylindrical-shaped roll from a filter paper and keep it as a bridge between beaker A and beaker B, as shown in the figure. Attach few germinating seeds in the middle of the filter paper bridge. Now, cover the entire set-up with a transparent plastic container so that the moisture is retained.
NCERT Solutions for Class 10th Science Chapter 7 Control and Coordination
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Question 1:
How does chemical coordination take place in animals?
Answer:
Chemical coordination takes place in animals with the help of hormones.Hormone is the chemical messenger that regulates the physiological processes in living organisms. It is secreted by glands. The regulation of physiological processes, and control and coordination by hormones comes under the endocrine system. The nervous system along with the endocrine system in our body controls and coordinates the physiological processes.
Question 2:
Why is the use of iodised salt advisable?
Answer:
Iodine stimulates the thyroid gland to produce thyroxin hormone. It regulates carbohydrate, fat, and protein metabolism in our body. Deficiency of this hormone results in the enlargement of the thyroid gland. This can lead to goitre, a disease characterized by swollen neck. Therefore, iodised salt is advised for normal functioning of the thyroid gland.
Question 3:
How does our body respond when adrenaline is secreted into the blood?
Answer:
Adrenalin is a hormone secreted by the adrenal glands in case of any danger or emergency or any kinds of stress. It is secreted directly into the blood and is transported to different parts of the body.
When secreted in large amounts, it speeds up the heartbeat and hence supplies more oxygen to the muscles. The breathing rate also increases due to contractions of diaphragm and rib muscles. It also increases the blood pressure. All these responses enable the body to deal with any stress or emergency.
Question 4:
Why are some patients of diabetes treated by giving injections of insulin?
Answer:
Diabetes is a disease in which the level of sugar in the blood is too high. Insulin, a hormone secreted by the pancreas, helps in regulating the blood sugar levels. This is the reason why diabetic patients are treated by giving injections of insulin.
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Question 1:
Which of the following is a plant hormone?
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin
Answer:
(d) Cytokinin is a plant hormone.
Question 2:
The gap between two neurons is called a
(a) dendrite.
(b) synapse.
(c) axon.
(d) impulse.
Answer:
(b) The gap between two neurons is called a synapse.
Question 3:
The brain is responsible for
(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.
Answer:
(d) The brain is responsible for thinking, regulating the heart beat and balancing the body.
Question 4:
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Answer:
Receptors are sensory structures (organs/tissues or cells) present all over the body. The receptors are either grouped in case of eye or ear, or scattered in case of skin.
Functions of receptors:
(i) They sense the external stimuli such as heat or pain.
(ii) They also trigger an impulse in the sensory neuron which sends message to the spinal cord.
When the receptors are damaged, the external stimuli transferring signals to the brain are not felt. For example, in the case of damaged receptors, if we accidentally touch any hot object, then our hands might get burnt as damaged receptors cannot perceive the external stimuli of heat and pain.
Question 5:
Draw the structure of a neuron and explain its function.
Answer:
Neurons are the functional units of the nervous system. The three main parts of a neuron are axon, dendrite, and cell body.
NCERT Solutions for Class 10th Science Chapter 7 Control and Coordination
Functions of the three parts of a neuron:
Axon: It conducts messages away from the cell body.
Dendrite: It receives information from axon of another cell and conducts the messages towards the cell body.
Cell body: It contains nucleus, mitochondria, and other organelles. It is mainly concerned with the maintenance and growth.
Question 6:
What are the changes seen in girls at the time of puberty?
Answer:
Secondary sexual characteristics in girls:
  • Increase in breast size and darkening of skin of the nipples present at the tips of the breasts.
  • Appearance of hair in the genital area.
  • Appearance of hair in other areas of skin like underarms, face, hands, and legs.
  • Increase in the size of uterus and ovary.
  • Beginning of menstrual cycle.
  • More secretion of oil from the skin, which results in the appearance of pimples.
Question 7:
Which signals will get disrupted in case of a spinal cord injury?
Answer:
The reflex arc connections between the input and output nerves meet in a bundle in the spinal cord. In fact, nerves from all over the body meet in a bundle in the spinal cord on their way to the brain. In case of any injury to the spinal cord, the signals coming from the nerves as well as the signals coming to the receptors will be disrupted.
Question 8:
How does chemical coordination occur in plants?
Answer:
In animals, control and coordination occur with the help of nervous system. However, plants do not have a nervous system.
Plants respond to stimuli by showing movements. The growth, development, and responses to the environment in plants is controlled and coordinated by a special class of chemical substances known as hormones. These hormones are produced in one part of the plant body and are translocated to other needy parts. For example, a hormone produced in roots is translocated to other parts when required. The five major types of phytohormone are auxins, gibberellins, cytokinins, abscisic acid, and ethylene. These phytohormones are either growth promoters (such as auxins, gibberellins, cytokinins, and ethylene) or growth inhibitors such as abscisic acid.
Question 9:
What is the need for a system of control and coordination in an organism?
Answer:
The maintenance of the body functions in response to changes in the body by working together of various integrated body systems is known as coordination. All the movements that occur in response to stimuli are carefully coordinated and controlled. In animals, the control and coordination movements are provided by nervous and muscular systems. The nervous system sends messages to and away from the brain. The spinal cord plays an important role in the relay of messages. In the absence of this system of control and coordination, our body will not be able to function properly. For example, when we accidentally touch a hot utensil, we immediately withdraw our hand. In the absence of nerve transmission, we will not withdraw our hand and may get burnt.
Question 10:
How are involuntary actions and reflex actions different from each other?
Answer:
Involuntary actions cannot be consciously controlled. For example, we cannot consciously control the movement of food in the alimentary canal. These actions are however directly under the control of the brain. On the other hand, the reflex actions such as closing of eyes immediately when bright light is focused show sudden response and do not involve any thinking. This means that unlike involuntary actions, the reflex actions are not under the control of brain.
Question 11:
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Answer:
NCERT Solutions for Class 10th Science Chapter 7 Control and Coordination
Question 12:
What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
NCERT Solutions for Class 10th Science Chapter 7 Control and Coordination

 

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