What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.
HIV stands for Human Immunodeficiency Virus.
Yes, AIDS is an infectious disease.
Four modes of spreading AIDS are as follows:
(i) By having sexual contact with an infected person.
(ii) By the transfusion of blood from an infected person.
(iii) Through infected needles used for injection.
(iv) Through the placenta from the mother to child during pregnancy.
What is the effect of DNA copying which is not perfectly accurate on the reproduction process?
How are the modes for reproduction different in unicellular and multicellular organisms ?
State one genetically different feature between sperms and eggs of humans. What is its consequence?
Which of the following is not a pan Of the female reproductive system in human beings ?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube
List any four reasons for vegetative propagation being practised in the growth of some type of plants.
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.
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
“DNA copies generated during reproduction will be similar but may not be identical to the original.” Justify this statement.
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?
Name one sexually transmitted disease each caused due to bacterial infection and viral infection. How can these be prevented?
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?
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?
(a) Draw a diagram showing germination of pollen on stigma of a flower.
(b) Label pollen grain, male germ- cells, pollen tube and female germ-cell in the above diagram.
(c) How is zygote formed?
What are sexually transmitted diseases?
Name four such diseases. Which one of them damages the immune system of human body?
What is reproduction? What are its two types? Which one of the two confers new characteristics on the offsprings and how?
“Variations that confer an advantage to an individual organism only will survive in a population.” Justify.
(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.
Illustrate the following with the help of suitable diagrams:
(i) Regeneration in Planaria.
(ii) Budding in Hydra.
Draw a longitudinal section of a flower and label 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 that develops into a fruit.
Name an organism which reproduces by spore formation. List three conditions favourable for spores to germinate and grow.
Differentiate between ‘self-pollination’ and ‘cross-pollination’. Describe double fertilisation in plants.
(a) Name the parts labelled A, B, C, D and E.
(b) Where do the following functions occur?
(i) Production of an egg
(ii) Fertilisation
(iii) Implantation of zygote.
(c) What happens to the lining of uterus:
(i) before release of a fertilised egg?
(ii) if no fertilisation occurs?