Importance Topics
Difference between Self-pollination and Cross-pollination
Ans.
Self-pollination & Cross-pollination
S - Definition Transfer of pollen from anther to stigma of the same flower or same plant
C - Transfer of pollen from anther of one plant to stigma of a different plant of same species
S - Generally no external agents required
C - Requires agents like wind, water, insects, animals
S - Produces little or no variation
C - Produces greater genetic variation
S - Flowers usually small, less attractive, less nectar
C - Flowers often large, colourful, scented and nectar-producing
S - Offspring are genetically similar (pure line) but may be weaker
C - Offspring are genetically diverse and usually healthier (hybrid vigour ताकत)
(i) Write the functions of the following parts of human female reproductive system:
(1) Ovary
(2) Fallopian tube
(3) Uterus
(ii) State briefly two contraceptive methods used by human males.
Ans.
(i) Functions of parts of human female reproductive system
1. Ovary
- Produces female gametes (ova/eggs).
- Secretes female hormones oestrogen and progesterone which control menstrual cycle and others sexual characters.
2. Fallopian Tube (Oviduct)
- Receives the ovum released from ovary.
- Site of fertilization (fusion of sperm and egg).
- Transports the fertilized egg (zygote) to the uterus.
3. Uterus
- Site of implantation of the embryo.
- Nourishes and protects the developing foetus.
- Muscular walls help in childbirth (delivery).
(ii) Two contraceptive methods used by human males
1. Condom – A barrier method worn on the penis that prevents sperm from entering the female reproductive tract; also protects from STDs.
2. Vasectomy – A surgical method in which the vas deferens is cut and tied to prevent sperms from mixing with semen.
(a) What are chromosomes?
(b) How is stability of DNA content ensured in sexually reproducing organisms?
Chromosomes are thread-like structures present in the nucleus of a cell. They are made of DNA and proteins and carry genes that control heredity and characteristics from parents to offspring.
In sexual reproduction, the chromosome number remains constant generation after generation because of two processes:
1. Meiosis (reduction division):
Gametes (sperm and egg) are formed with half the number of chromosomes (haploid, n).
Example: Humans → Body cells = 46 chromosomes, Gametes = 23 chromosomes.
2. Fertilization:
When male and female gametes fuse, the diploid number is restored.
23 (sperm) + 23 (egg) = 46 (zygote)
1 Watt
When the power consumed in an electric circuit is 1 joule of electrical energy is used in 1 second is called 1 watt.
1 W = 1J / 1s
Besides minimising the loss of blood, why is it essential to plug any leak in a blood vessel? Name the component of blood which helps in this process and state how this component perform this function.
Ans. Besides minimizing the loss of blood, it is essential to plug any leak in a blood vessel to prevent the entry of germs (microorganisms) into the body. If germs enter the bloodstream, they can cause infection and diseases.
Platelets and White blood cells.
- When a blood vessel is injured, platelets reach the damaged area.
- They stick to the injured surface and to each other.
- Platelets release chemicals that help in blood clotting.
- A clot is formed, which seals the leak in the blood vessel and prevents bleeding and infection.
- This process is called blood coagulation.
Q. The transport system in plants is relatively slower than in animals. Give reasons
Ans.
The transport system in plants is slower than in animals due to the following reasons:
1. Plants do not have a pumping organ like the heart to push substances quickly.
2. Plants have lower energy requirements compared to animals.
3. Water and minerals move through xylem mainly by root pressure and transpiration pull, which is slower than blood circulation.
4. Food is transported through phloem, which is also a slow process.
Most Important Questions for Class 10th
Q: What helps making the acidic food alkaline that is coming from the stomach?
A: Bile Juice
Q: What helps making the acidic food alkaline that is coming from the stomach? Explain?
Bile juice is secreted by the liver and stored in the gallbladder. It is released into the small intestine when food enters. Bile neutralizes the acid in chyme, raising its pH and making the intestinal environment more alkaline. This is critical step, as the enzymes in the small intestine that further digest food work optimally in an alkaline condition. Along with neutralizing the acid, bile aids in the emulsification of dietary fat, which helps in its digestion.
Q: What do you mean by Gastric Juice?
A: Gastric juice, a combination of pepsin, hydrochloric acid, and other enzymes, is secreted into the stomach to aid in the digestion of food. It is acidic in nature, with a pH ranging from 1.5 to 3.5, which is essential for pepsin's protein digestion process. The acidity of gastric juice also kills many bacteria that enter the stomach, providing a protective function against infection.
Q: What do you mean by Hydrochloric Acid?
A: Hydrochloric acid (HCL) is one of the main components of gastric juice. It creates the acidic environment in the stomach needed to activate pepsin and other enzymes. HCL helps to break down food and kill ingested pathogens.
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