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


Download 266.37 Kb.
bet3/3
Sana20.12.2022
Hajmi266.37 Kb.
#1038303
1   2   3
Bog'liq
LESSON 5 (lar)

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

Download 266.37 Kb.

Do'stlaringiz bilan baham:
1   2   3




Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2024
ma'muriyatiga murojaat qiling