NCERT Class 10 - Biology

• The main parts of a flower are: sepals, petals, stamens and carpels.
• Stamens and carpels are the reproductive parts of a flower which contain the part cells.
• The male organ of a flower called ‘stamen’ makes the male gamete which are present in the pollen grain.
• Flowers may be unisexual (e.g., papaya and watermelon) or bisexual (e.g., Hibiscus and mustard).
• Pollination is the transfer of pollen grains from the anther of a stamen to the stigma of a carpel.
• Pollination is of two types: Self pollination and cross pollination.
• Carpel: female reproductive organ of a flower.
• Pollination: transferring pollen grain from male anther to the female stigma.
• Fertilization: fusion of male gametes (pollen) with the female gametes (ovum) to form a diploid zygote.
• Cross-pollination introduces variations in plants because of the mixing of different genes.
• The transfer of pollens take place by agents like wind, water or animals.
• After pollination, a pollen tube grows out of pollen grains, through which male germ cell reaches the ovary and fuses with the female germ cell.
• Fertilisation is the process of fusion of male and female gamete to produce zygote.
• Other floral parts such as sepals, petals, stamens, styles and stigma may fall off, but in some cases, they persist in the fruit.
• In this process, out of the two male nuclei, one male nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and another fuses with the polar nuclei to form an endosperm (process is called triple fusion).
• Seed protects the future plant i.e., embryo.
• A seed consists of seed coat(s), cotyledon(s) and an embryonal axis.
• The process of development of seedling from the embryo under suitable conditions such as air, moisture etc., is known as germination.
• Ethylene is a gaseous hormone which helps in artificial ripening of fruits and promotes senescence (Ageing) and abscission of leaves.
• The nervous system is the system of conducting tissues that receives the stimulus and transmits it to other parts of the body forming a network of nerves.
• The nervous system is involved in receiving information (sensation) and generating responses to that information (motor response).
• A typical neuron consists of following parts: Cyton or Cell body, Dendrite, Axon, Myelin sheath, and Synapse.
• The units which make up the nervous system are called nerve cells or neurons.
• The receptors pass the information to the brain through a type of nerve cells called sensory neurons.
• Motor neurons transmit the information from the brain to the effector organs, mainly muscles and glands.
• Nerve Impulse is the information in the form of chemical and electrical signals passing through neurons.
• The point of contact between the terminal branches of axon of one neuron with the dendrite of another neuron is called synapse.
• Voluntary Action are the actions which need thinking and are performed knowingly, these are controlled by conscious thought.
• Phloem transports product of photosynthesis from leaves to the non-photosynthesising parts of the plants such as root & stem.
• Involuntary Action are not under the control of the will of an individual and are automatic response to a stimulus which is not under the voluntary control of the brain.
• Xylem does not use energy for transport.
• Reflex action is a quick, sudden and immediate response of the body to a stimulus.
• Phloem uses energy from ATP for transport.
• On maturity, the xylem becomes dead tissue and gives mechanical support to the plant.
• Phloem exists as living soft tissue.
• Transpiration is the process of loss of water as vapours from aerial parts of the plant.
• Excretion in human beings involves the removal of harmful metabolic wastes like urea and uric acid.
• The excretory system of human beings includes a pair of Kidney, a Urinary Bladder, a pair of Ureter and a Urethra.
• Nephrons are the basic filtration units of kidneys.
• Nephrons carry out filtration, selective reabsorption and tubular secretion to form urine in kidney, which is then passed out through the urethra, via the ureters and urinary bladder.