What are the different methods of contraception?
There are three main methods of contraception :
1. Barrier methods: In barrier methods, physical devices such as condom, diaphragm and cervical caps are used. They prevent the entry Of sperms in the female genital tract during copulation.
2. Chemical methods: The chemical methods make use of specific drugs by females. There are two types of such drugs, Oral pills and vaginal pills. Oral pills are mainly hormonal preparation, and are called oral contraceptives (OCS).
3. Surgical methods: In the surgical methods, a small portion of vas deferens in male, and the fallopian tube in female, in surgically removed or ligated (tied). It is called vasectomy in males and tubectomy in females.
Apart from these three methods the intrauterine contraceptive devices are used to prevent pregnancies. The use of Intra Uterine Contraceptive Devices (IUCDs) is also very effective and popular. A copper-T is placed safely inside the uterus by a practising doctor or a skilled nurse. IUCDs prevent implantation in the uterus.
How are the modes for reproduction different in unicellular and multicellular organisms ?
What is the effect of DNA copying which is not perfectly accurate on the reproduction process?
State one genetically different feature between sperms and eggs of humans. What is its consequence?
List two advantages of practising vegetative propagation in plants. Select two plants raised by this method from the list given below:
Banana, Gram, Pea, Rose, Tomato, Wheat.
What is reproduction? What are its two types? Which one of the two confers new characteristics on the offsprings and how?
Name the information source of making proteins in the cell. State two basic events in reproduction.
What is AIDS? Which microbe is responsible for AIDS infection? State one mode of transmission of this disease. Explain in brief one measure for the prevention of AIDS.
List the parts of human male reproductive system which contribute fluid to the semen. State two advantages semen offers to the sperms.
If a woman is using a copper-T will it help in protecting her from sexually transmitted diseases?
Differentiate between ‘self-pollination’ and ‘cross-pollination’. Describe double fertilisation in plants.
(a) Explain the role of placenta in the development of human embryo.
(b) Give example of two bacterial and two viral sexually transmitted diseases. Name the most effective contraceptive which prevents spread of such diseases.
State in brief the changes that take place in a fertilised egg (zygote) till birth of the child in the human female reproductive system. What happens to the egg when it is not fertilised?
What are sexually transmitted diseases?
Name four such diseases. Which one of them damages the immune system of human body?
Draw a diagram of a human female reproductive system and label the part
(i) that produces egg
(ii) where fusion of egg and sperm take place
(iii) where zygote is implanted
What happens to human egg when it is not fertilised?
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
a) List any four reasons for adopting contraceptive methods.
(b) If a woman is using Copper-T, will it help in protecting her from sexually transmitted diseases? Why?
Name the two types of germ-cells present in human beings. How do they structurally differ from each other? Give two differences.
Describe in brief the role of (i) testis (ii) seminal vesicle, (iii) vas deferens, (iv) ureter and (v) prostate gland in human male reproductive system.
Name one sexually transmitted disease each caused due to bacterial infection and viral infection. How can these be prevented?
(a) Explain the terms:
(i) Implantation (ii) Placenta
(b) What is the average duration of human pregnancy?
List any four reasons for vegetative propagation being practised in the growth of some type of plants.
What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.
Explain the following methods of contraception giving one example of each:
(i) Barrier method
(ii) Hormonal imbalance method
(iii) Surgical method.
(a) What is fragmentation in organism?
Name a multicell-ular organism which reproduces by this method.
(b) What is regeneration in organism? Describe regeneration in Planaria with the help of a suitable diagram.