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Academia - Collins Scientific Pocket Dictionaries - Biology
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platelets
plaquettes fpl

Platelets. The smallest cells in mammalian blood, related to blood clotting.


pleural membranes
Membrane mpl pleuraux

Pleural membranes. A double lining covers the lungs from the outside and the thorax in mammals, and secretes pleural fluid between them, which facilitates breathing movements. See breathing.


plumule
plumule f

plumule. The leafy part of the embryonic shoot
For seed plants. See seed and germination.


poikilothermic
poikilotherme

Temperature variable. A description of animals whose body temperatures change with changes in the temperature of the environment. All animals, with the exception of birds and mammals, are endothermic, although they are often described as cold-blooded.
Compare with homoiothermic.


pollen
pollen m

It turned out. Vaccine. Reproductive spores of flowering plants each containing a male gamete. Pollen grains adapt to the way they are transported, whether by insects or by wind.

Pollinated by wind
Soft and light
Pollination by insects
Prickly and sticky
Air bladders.

stamen and pollination fertilization in plants see


pollination
pollinisation f

vaccination. pollination. Transfer of pollen grains from stamens to carpels in flowering plants. Pollination within a flower or between the flowers of a single plant is called self-pollination. As for cross-pollination between two separate plants, it is called cross-pollination. The male and female parts of a plant do not usually mature at the same time, which encourages cross-breeding, which leads to mixing of chromosomes that can lead to variation. Pollen is transported by insect bodies or by wind. Flowers adapt to preferring one of two methods of transportation.

(a) Insect pollination: Insects visit flowers to drink or collect nectar, attracted by the color or scent of the flower. The insects' bodies change with the pollen, some of which sticks to the stigmas of the flowers they visit later. (b) Wind pollination: Pollen grains carried by the wind must be produced in very large numbers to compensate for loss during transportation.
See fertilization in plants, flowers and pollen


pollution
pollution f

pollution. Adding any substance that disturbs the natural balance of the environment. Pollution results mainly from industrialization, which depends largely on the burning of fossil fuels. (a) Air pollution results specifically from the combustion of fossil fuels:

Coal - combustion - smoke + carbon dioxide
+ Sulfur dioxide

Gasoline - combustion - smoke + carbon monoxide
+ Nitrogen oxides + Lead.

Air pollutants, such as smoke and sulfur dioxide, cause irritation in the human respiratory system and may accelerate the development of diseases such as bronchitis and lung cancer.

(b) Water pollution: It results from the intentional or unintentional addition of certain substances to fresh water or sea water. Pollutants result from industrial and agricultural practices as well as from residential homes. Examples of this include: mine and stone quarry wash water, acids and pesticides, oil, radioactive waste, fertilizers, detergents, sewage and hot water (from power plants).
electricity) .

Some pollutants, such as pesticides, may poison aquatic organisms, while organic pollutants such as sewage may cause an increase in the population of microorganisms in the water, which leads to a decrease in dissolved oxygen levels and makes the water unsuitable for many organisms.
See the following drawing:

Solution oxygen
Germs
Remote cathode
Sewage disposal


polysaccharides
polysaccharides mpl

Polysaccharides are carbohydrates consisting of long chains of monosaccharides linked together by bonds. For example, glucose units can be linked in different ways to form various polysaccharides, such as starch, glycogen, and cellulose.