What is the role of the acid in our stomach?
Hydrochloric acid is present in the gastric juice secreted by the gastric gland which helps in the breakdown of the food. When the food enters in the stomach, contraction and expansion of muscles of the wall of stomach brings churning movement which leads to the mixing of the food with the help of gastric juice (mixture of hydrochloric acid, pepsinogen, prorennin, lipase and mucus) secreted by gastric glands.
Hydrochloric acid helps in to disinfect the food by killing of bacteria, stops the action of the salivary amylase. It converts the pepsinogen to pepsin in the active form and convert prorenin with the addition of HCL gives the end product Rennin. It produces appropriate, i.e, low hydrogen ion concentration for about 1- 2 acidic pH for the protein digestion and the food digestion. It moistens the food and helps in the breakdown of the larger food molecules; also denatures the many food proteins which increases the exposure of the peptide bond to the pepsin.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
How is the amount of urine produced regulated?
What criteria do we use to decide whether something is alive?
What are the different ways in which glucose is oxidised to provide energy in various organisms?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
What are the differences between autotrophic nutrition and heterotrophic nutrition?
What are outside raw materials used for by an organism?
What would be the consequences of a deficiency of haemoglobin in our bodies?
What are the components of the transport system in highly organised plants?
What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.
How are the modes for reproduction different in unicellular and multicellular organisms?
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
Oil and fat containing food items are flushed with nitrogen. Why?
Why is sodium kept immersed in kerosene oil?
Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
What is the need for a system of control and coordination in an organism?
How many structural isomers can you draw for pentane?
Explain different ways to induce current in a coil.
An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.