EXCRETION

Excretion is the removal of toxic materials and waste products of metabolism from the living organisms.

Excretion in plants

1. Respiration produces CO2 as a waste product.

2. Photosynthesis produces O2 as a by-product. Both gases are released through the stomata by diffusion.

3. Some deciduous plants excrete chemicals which may be left in the leaves in autumn. When the leaves fall, these substances are lost from the plants.

4.  Water is produced during respiration and also removed during transpiration.

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BIOTECHNOLOGY

BIOREACTORS

Biotechnology is the method of using biological process, organisms and systems in manufacturing and service industries. 

Examples:

  •  Cheese production
  •  Yoghurt production
  •   Bread making
  • Antibiotic production
  • alcohol production
  • Single cell protein production 
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SEED STRUCTURE AND GERMINATION

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STRUCTURE OF A DICOT SEED

 EXAMPLE FRENCH BEAN

The seed contains a small plant, the embryo which consists of a young root or radicle and a young shoot or plumule. The embryo is attached to two leaves called the cotyledons, which are swollen with stored food. This stored food mainly consists of starch, which is used by the embryo for growth. The embryo and the cotyledons are enclosed in a tough seed coat or testa. The micropyle, the hole through which the pollen tube entered the ovule, remains as a hole in the testa and is an important route for the entry of water during germination. The hilum is the scar left where the seed was attached to the pod.

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PARASITISM

The relationship between two organisms in which one organism is benefited and the other one is harmed is called parasitism.

 Anopheles_

Malarial parasite

Parasites are organisms that live in or on the body of another organism from which it obtains food and cause harm to the host.eg. Mosquitoes, round worm, tape worm,

Host:- the organism in which the parasite lives in and obtain its food.

Ectoparasite – The parasite which lives outside body of the host. E.g. Mosquitoes.

Endoparasite – The parasite which lives inside the body of the host.

Vector – Many endo parasites do not have locomot0ry organs to move from one host to another. They employ some medium to carry them from one host to another. These mediums are called vectors.

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TRANSPORT IN HUMAN

CIRCULATORY SYSTEM 

blood vessel

The term ‘transport system’ in human, refers to the circulatory system. After digestion, the digested food like amino acids, glucose, etc., are absorbed in the small intestine. These substances are needed in all living cells in the body such as the brain cells, leg muscle cells, liver cells and kidney cells. The substances are carried from the intestine to other parts of the body by the blood system. In a similar way, the oxygen taken in by the lungs is needed by all the cells and is carried round the body in the blood.

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RESPIRATION

The constant need for oxygen is one of the most essential features of animal life, because the energy for animal is provided by the oxidation of food. All organisms obtain their energy by respiration.

Respiration is a characteristic of all living organisms. It is the release (not ‘production’) of energy from food substances in all living cells. The food substance involved is usually glucose. However, lipids and proteins are also used for respiration during starvation. This energy released is available in the form of ATP (Adenosine Tri Phosphate).

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TRANSPORT IN FLOWERING PLANTS

Why do plants need a transport system? 

-      To provide a way of carrying water and ions from the root to the leaves.

-      To provide a way of carrying sugars and amino acids from the leaves to other parts of the plant.

-      If necessary, from storage organs to the leaves when it is not photosynthesizing.

Transp 1

What tissues of the plant make the transport system?

The two vascular tissues of flowering plants involved in transporting materials around the plant are:-

1.       Xylem – transports water and dissolved minerals from the roots up the stem and leaves. (Also xylem gives support to the plant).

2.      Phloem – transport food (mainly sugar and amino acids)

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SEXUAL REPRODUCTION IN PLANTS

Sexual reproduction is the process involving the fusion of haploid nuclei to form a diploid zygote and the production of genetically dissimilar offspring.

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There are two types of reproduction, sexual reproduction and asexual reproduction.

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Asexual reproduction:This is the production of genetically identical offspring from one parent. The parent cell divides by mitosis producing copies of it as new individuals. Since the offspring produced in this way are identical to the parent they are known as clones.

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NUTRITION

All living organisms need food. They require constant supply of essential nutrients.  Every living organism depends on nutrition, the taking in of food and the use of the food for survival.  Animals need a variety of nutrients to meet their basic needs. These nutrients include fat and carbohydrates that provide energy. Protein that furnish amino acids, vitamin that serve as co factors for enzymes and perform other functions.  To determine how nutrition can affect athletics performance, researchers alter the intake of specific nutrients and assess how athletes respond. For example, investigator have shown that athletes who ingest a high carbohydrate diet for three days out perform individuals who ingest a high fat, high protein diet. In all living organisms food is used as follows:-

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PHOTOSYNTHESIS

Photosynthesis

The process by which green plants make large organic molecules (glucose) from small inorganic molecules, carbon dioxide and water using light energy which is absorbed by chlorophyll. The by-product of photosynthesis is oxygen.

photosynthesis

How do green plants obtain raw materials for photosynthesis?                                              

  1. Carbon dioxide diffuse through the stomata

Plants obtain CO2 from the air. Only about 0.04% of the air is CO2. Therefore, the leaves must be very efficient in absorbing it. The leaf is held out into the air by the stem and leaf stalk and its large surface area helps to expose it to as much air as possible. CO2 diffuse into the air spaces through the stomata. It dissolves in the film of moisture around the cell wall of the mesophyll cells. It can then diffuse through the cell wall and cell membrane of each cell into the chloroplast down a concentration gradient.

  1. water is absorbed from the soil by the root hair cells

Water is absorbed from the soil by the root hair cell by osmosis

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