Saturday, 17 January 2015


The breakdown of  complex compound of food into simple substance is called ?
Digestion(The digestive system of humans is well developed. It consists of the gut or alimentary canal, along with many associated digestive glands. The alimentary canal is divided into mouth, oesophagus, stomach, small intestine, large intestine and rectum.

Mouth: The food is ingested through the mouth. The mouth contains tongue, teeth and salivary glands. Teeth break the food into smaller particles. This process is called mastication. The chewed food is mixed with saliva. Saliva is a watery fluid secreted by the salivary glands. Saliva contains a type of enzyme called the salivary amylase, which converts starch into sugar.
Tongue – The tongue is a muscular organ. Tongue helps to mix saliva in the food. It also helps to push the food down the food-pipe or oesophagus. Taste receptors are present in tongue and give us the sense of taste.

Oesophagus – It is a tube-like structure connecting the mouth and the stomach. It is about 30 cm. long. Oesophagus has powerful muscles which gently push the food down to the stomach. The oseophagus contracts and relaxes in a rhythmic fashion to facilitate the forward movement of food. This movement happens in other parts of the alimentary canal as well and is called peristalsis. There is no digestion takes place in oesophagus.

Stomach –It is a muscular J- shaped thick walled bag. Stomach is the widest part of alimentary canal. It receives food at one end from food pipe and open into the small intestine from other end.

Stomach churns the food to mix digestive juices. The food in the stomach is churned into semi solid. The churned semi-solid food is called chime. Gastric juice is secreted from the wall of stomach and mixed with food. Gastric juice contains some enzymes and hydrochloric acid. The enzymes present in the gastric juices break down protein from food. The hydrochloric acid kills the harmful bacteria present if any in the food and helps the gastric enzymes to work.

Small intestine – The food leaves the stomach at certain intervals of time and enters into the small intestine.
The small intestine is the longest part of the digestive system. It is about 20 feet or seven meters long in an adult human. Small intestine is a highly coiled tube. It consists of three parts: duodenum, jejunum and Ileum.

In the duodenum, the liver and pancreas pour their secretions. Liver secretes bile juice and pancreas secretes the pancreatic juice. The bile juice contains the bile which carries out emulsification(emulsification (in digestion) The breakdown of fat globules in the duodenum into tiny droplets, which provides a larger surface area on which the enzyme pancreatic lipase(lipase is an enzyme secreted by the pancreas that catalyses the breakdown of fats into fatty acids and glycerol in the small intestine.) can act to digest the fats into fatty acids and glycerol. Emulsification is assisted by the action of the bile salts) of fat. In this process, the fat is broken into tiny droplets. The pancreatic juice contains several enzymes. The enzymes of the pancreatic juice break down starch into simple sugars and proteins into amino acids.

Minerals and vitamins do not need to be changed because cells are able to absorb them easily.

From duodenum the food goes to the lower part of the intestine. There are numerous finger-like projections on the wall of the small intestine. These projections are called villi. They have fine blood capillaries to absorb the food. After absorption; food mixes in the blood stream and is carried to all the cells of the body. The cells utilize this food to release energy.

Large intestine: The digested food enters into large intestine after small intestine. The large intestine is wider and shorter than small intestine. It is about 1.5 metre in length.
In large intestine excess of water from the materials is absorbed. The semi solid residue is stored in the last part of the large intestine called rectum and finally throw out of the body through the anus time to time. The throwing out of waste of digested food from rectum is called egestion.) Source - www.excellup.com

Photosynthesis generally takes place in which part of the plant?
Leaf and other chloroplast bearing parts.

Plant absorb dissolved nitrates from soil and convert them into?
Free nitrogen

Ordinary table salt is sodium chloride, what is baking soda?
Sodium bicarbonate( NaHCO3)

Ozone hole refers to ?
Decrease in thickness of ozone layer in stratosphere 

Pine, fir , spruce, cedar, larch and cypress are the famous timber-yielding plants of which several also occur widely in the hilly regions of India. All these belong to?
Gymnosperms.(Angiosperms, also called flowering plants, have seeds that are enclosed within an ovary (usually a fruit), while gymnosperms have no flowers or fruits, and have unenclosed or “naked” seeds on the surface of scales or leaves. Gymnosperm seeds are often configured as cones. The characteristics that differentiate angiosperms from gymnosperms include flowers, fruits, and endosperm in the seeds.)

what defines pollination?
Transfer of pollen from anther(male part) to stigma(female part) of the plant.

Plants receive their nutrients mainly from?

Movement of cell against concentration gradient is called?
Active transport

Most fish do not sink in water because of the presence of ?
swim bladder and air bladder

Plants synthesis protein from which of the following?
Amino acids

Nucleus, the genetic material containing rounded body in each cell, was first discovered in 1831 by
Robert Brown

Primary phloem develops from which of the following?
Provascular tissue

Other than spreading malaria, anopheles mosquitoes are also causes

Plants absorb most part of water needed by them through their?
Root hairs

Which one of the following defines photo-oxidation?
Photorespiration, Photolysis,light and oxygen induced breakdown

Cell division can takes place by which of the following process?

which is the most highly intelligent mammal?

Plant development is influenced by which of the following?
Quality, quantity,and duration of light

Phloem is a tissue found which of the following?
Plants(In vascular plants, phloem is the living tissue that carries organic nutrients (known as photosynthate), in particular, sucrose, a sugar, to all parts of the plant where needed. In trees, the phloem is the innermost layer of the bark. The phloem is concerned mainly with the transport of soluble organic material made during photosynthesis. This is called translocation.
Xylem is one of the two types of transport tissue in vascular plants, phloem being the other. The best-known xylem tissue is wood, though it is found throughout the plant.
The basic function of xylem is to transport water, but it also transports some nutrients.)
Source - www.wikipedia.org

Nitrogen content is kept constant in the biosphere due to which of the following?
Nitrogen cycle
In agriculture,  leaching refers to the loss of water-soluble plant nutrients from the soil, due to rain and irrigation.

Photosynthesis takes place faster in which colour light?
White light

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