How does the process of fertilisation take place in flowers?
The process of fusion of gametes of male and female (egg) to form the diploid zygote in the embryo sac is called fertilization.
Fertilization takes place as follows: The pollen generally germinates on the stigma. When a pollen grains falls on the stigma of the pistil then the pollen grains grows a pollen tube into downward direction through the style towards the female gametes in the ovary. A male gamete are carried to the egg by the pollen tube and enters the ovule in the ovary. The tip of pollen tube bursts out and male gametes comes out of pollen tube or gets spreads out. In ovary, the male gametes of pollen fuses with the female gamete present in ovule to form the ‘zygote’ then zygote develops into the embryo sac; this process is known as siphonogamy. Embryo is that part of a seed that develops into the new plant.
Sketch the reproductive parts of a flower.
Match items in Column I with those in Column II:
Column I Column II
(a) Bud (i) Maple
(b) Eyes (ii) Spirogyra
(c) Fragmentation (iii) Yeast
(d) Wings (iv) Bread mould
(e) Spores (v) Potato
(vi) Rose
Describe the various ways by which seeds are dispersed.
Describe the different methods of asexual reproduction. Give examples.
Explain the difference between self-pollination and cross-pollination.
Explain what you understand by sexual reproduction.
State the main difference between asexual and sexual reproduction.
Tick the correct answer:
(a) The reproductive part of a plant is the
(i) leaf (ii) stem (iii) root (iv) flower
(b) The process of fusion of the male and the female gametes is called
(i) fertilisation (ii) pollination
(iii) reproduction (iv) seed formation
(c) Mature ovary forms the
(i) seed (ii) stamen
(iii) pistil (iv) fruit
(d) A spore producing plant is
(i) rose (ii) bread mould
(iii) potato (iv) ginger
(e) Bryophyllum can reproduce by its
(i) stem (ii) leaves
(iii) roots (iv) flower
Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called_____________.
(b) A flower may have either male or female reproductive parts. Such a flower is called_____________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
(d) The fusion of male and female gametes is termed as _____________.
(e) Seed dispersal takes place by means of _____________, _____________ and _____________.
State similarities and differences between the laboratory thermometer and the clinical thermometer.
State differences between acids and bases.
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food
Name the elements that determine the weather of a place.
Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———.
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants
Why does an athlete breathe faster and deeper than usual after finishing the race?
Match structures given in Column I with functions given in Column II.
Column I Column II
(i) Stomata (a) Absorption of water
(ii) Xylem (b) Transpiration
(iii) Root hairs (c) Transport of food
(iv) Phloem (d) Transport of water
(e) Synthesis of carbohydrates
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.
Why do organisms need to take food?
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.
Will the compass needle show deflection when the switch in the circuit shown by Fig.14.24 is closed?
Why is blood needed by all the parts of a body?
What is meant by the following terms?
(i) Rearing (ii) Shearing (iii) Sericulture
When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.
A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:
(i) 100 km (ii) 25 km
(iii) 15 km (iv) 10 km
Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, __________, sorting, __________, __________, _________.
Draw a diagram of the human excretory system and label the various parts.
Fill in the blanks:
(a) Cleaning of water is a process of removing ____________.
(b) Wastewater released by houses is called ____________.
(c) Dried ____________ is used as manure.
(d) Drains get blocked by ____________ and ____________.
Study the following statements about ozone:
(a) It is essential for breathing of living organisms.
(b) It is used to disinfect water.
(c) It absorbs ultraviolet rays.
(d) Its proportion in air is about 3%.
Which of these statements are correct?
(i) (a), (b) and (c)
(ii) (b) and (c)
(iii) (a) and (d)
(iv) All four