أكاديميا - كولنز معاجم الجيب العلمية - البيولوجيا انكليزي - فرنسي - عربي الحرف ٢_ m

Academia - Collins Scientific Pocket Dictionaries - Biology
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metamorphosis
metamorphose f

A physical transformation. A period in the life history of some animals during which the juvenile stage turns into adulthood, for example: in amphibians:

Adult frog
Transformation
Eggs
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Incomplete metamorphosis: A type of development in which relatively few changes occur from youth to adulthood. This transformation occurs in insects such as the dragonfly, the locust, and the cockroach, where the nymph form resembles the adult stage except that it is smaller, wingless, and sexually immature. For example:

The cockroach.
Adult
Several months
Egg wallet
virgin

Complete metamorphosis: It includes major changes between the larval stage and adulthood, and occurs in insects such as the butterfly, moth, and housefly. . Etc., and the larvae at these life dates are called worms, maggots, grubs, or caterpillars (depending on the species, and they differ greatly from the adult form. A series of molts (ecdysis) produces the pupa, or pupa. Its organization changes completely later and it develops into an adult insect, which is the only stage in which it is sexually mature, for example: a butterfly.


microorganisms
microorganisms mpl

Microorganisms. Very small living organisms that can usually only be seen with a microscope. Microorganisms include the phylum Protozoa, viruses, algae, protozoans, fungi, and bacteria.


micropile
micropyle m

skylight. Hole (a) a tiny hole in the seed through which water is absorbed at the beginning of germination.

(b) A minute hole in the flower’s egg (flower ovule), through which the pollen tube gives the male the gamete.

(c) A tiny hole in the insect egg through which the spermatozoon enters.

microscope
microscope m

microscope. microscope. A tool used to magnify structures, such as cells or organelles, that are not visible to the naked eye.

(a) Light microscope: Light illuminates the sample, which is magnified by glass lenses.

The magnification power of the microscope is obtained by multiplying the magnification of the objective lens (40 x, ​​for example) by the magnification of the eyepiece lens (10 x, for example), which gives the total magnification of 400 x in our example. The maximum magnification possible using an optical microscope is 1500×. Thin samples are placed on a glass slide and may be stained with dyes to reveal specific structures.


b) Phase-contrast microscope: allows transparent and unstained structures to be seen.
(c) Electron microscope: the most advanced microscope. Provides magnification up to x 500 000.


milk teeth (or deciduous teeth)
dents fpl de lait

Baby teeth or deciduous teeth). The first two sets of teeth that appear in most mammals. For example: A person has twenty baby teeth, which are replaced during childhood by larger, permanent teeth.


mineral salts
Sels mpl mineraux

Mineral salts . Soil components formed by the disintegration (weathering of rocks and mineralization of humus) are found dissolved in soil water. Plant roots absorb mineral salts and transport them through the plant in the transpiration stream. Mineral salts, such as vitamins, are required in very small quantities, but they are Animals. The absence of a certain mineral salt can lead to mineral deficiency disease and death. Plants need at least twelve mineral salts that are vital for healthy growth.

(a) The essential elements needed in relatively large quantities: nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium.

(b) Trace elements needed in very small quantities: manganese, copper, zinc, iron, boron, and molybdenum.

Plants need some mineral salts, animals need others, and both need some. The following table summarizes the properties of some important mineral salts:

Mineral salt
Function
Some effects of deficiency

Phosphorus
One of the components of adenosine trihydrate
Phosphate ATP and nucleic acids
Cell membranes and animal bones
Impaired plant growth

calcium
Components of cell walls
Plant and animal bones
Rickets in humans

Nitrogen
Components of proteins and nucleic acids
Poor reproductive development in plants

Iron
A component of hemoglobin
Anemia in humans

Magnesium
Components of chlorophyll
Pale yellow leaves (chlorosis larvae)


mitochondrion
mitochondrie f

Filamentous granule. Organelle Cell Microscopic cell in cytoplasm Aerobic cells in which some respiration occurs The inner membrane of the wall of the nematode granule contains many folds that form a series of divisions called cristae that greatly increase the surface area for the attachment of respiratory enzymes.

Norms
1 micron