Lesson 5 Great biologist and their contribution to the science Translate the text into Uzbek. Abu Ali ibn Sino

The electron microscope
Electron microscopes use a beam of electrons instead of a beam of light. Electron beams have a much smaller wavelength than light rays, so electron microscopes have greater resolving powers and can produce much higher effective magnifications than light microscopes. There are two main types of electron microscopes: the transmission electron microscope (TEM), and the scanning electron microscope (SEM).
The transmission electron microscope
T

he TEM is used to study the details of the internal structure of cells. Extremely thin samples of the specimen are needed. To make these the specimen is supported in a resin block to prevent in collapsing during cutting, and is sliced with a diamond or glass knife. The section is then impregnated with a heavy-metal stain, such as osmium tetroxide.
As the beam passes through the specimen, electrons are absorbed by heavily stained parts but pass readily through the lightly stained parts. Electromagnets bend the electron beam to focus an image onto a fluorescent screen or photographic film. Photograph taken through an electron microscope is called an electron micrograph.
The most modern TEMs distinguish objects as small as 0.2nm. This means that they can produce clear images magnified up to 250 000 times. The magnification is varied by changing the strength of the electromagnets.


Glossary

№	English	Russian	Uzbek
1	existence	Существование	Mavjudlik
2	Fluid	Жидкость	Suyuqlik
3	grain	Зерно	Don
4	according to	Согласно	ga ko'ra
5	to fuse	сплавляться, сливаться	sug'urta qilmoq
6	Fertilization	оплодотворение, удобрение	Urug'lantirish
7	to damage	Повреждать	zarar etkazish uchun
8	Nucleus	Ядро	Yadro
9	Mitosis	митоз, непрямое деление ядра	Mitoz
10	Meiosis	мейоз, редукционное деление	Meozis
11	to provide	Обеспечивать	ta'minlash uchun
12	Continuity	непрерывность, неразрывность	Uzluksizlik
13	Stain	краситель, пятно	Lek
14	to wrap	Обертывать	o'rash
15	apart from	кроме, помимо	dan tashqari

Test

Cellular Structure and Function (16–17%)

1. 
   Biological compounds
   
   1. 
      Macromolecular structure and bonding
      
   2. 
      Abiotic origin of biological molecules
      
   3. 
      Nutrient, salt
      
   4. 
      water exchange
      
2. 
   Enzyme activity, receptor binding, and regulation
   
3. 
   Major metabolic pathways and regulation
   
   1. 
      Respiration, fermentation, and photosynthesis
      
   2. 
      Synthesis and degradation of macromolecules
      
   3. 
      Hormonal control and intracellular messengers
      
4. 
   Membrane dynamics and cell surfaces
   
   1. 
      Transport, endocytosis, and exocytosis
      
   2. 
      Electrical potentials and transmitter substances
      
   3. 
      Mechanisms of cell recognition, intercellular transport and communication
      
   4. 
      Cell wall and extracellular matrix
      
5. 
   Organelles: structure, function, synthesis, and targeting
   
   1. 
      Nucleus, mitochondria, and plastids
      
   2. 
      Endoplasmic reticulum and ribosomes
      
   3. 
      Golgi apparatus and secretory vesicles
      
   4. 
      Lysosomes, peroxisomes, and vacuoles
      
6. 
   Cytoskeleton: motility and shape
   
   1. 
      Actin-based systems
      
   2. 
      Microtubule-based systems
      
   3. 
      Intermediate filaments
      
   4. 
      Bacterial flagella and movement
      
7. 
   Cell cycle: growth, division, and regulation (including signal transduction)
   
8. 
   Methods
   
   1. 
      Microscopy (e.g., electron, light, fluorescence)
      
   2. 
      Separation