Structure of a typical plant cell

Plants, animals, fungi, slime moulds, protozoa, and 1 … are all eukaryotic. These cells are about fifteen times 2 … than a typical prokaryote and can be as much as a thousand times greater in volume. The main 3 … feature of eukaryotes as compared to prokaryotes is compartmentalization: the presence of membrane-bound compartments in which specific metabolic activities 4 … place. Most important among these is a cell nucleus, a membrane-delineated compartment that houses the eukaryotic cell's DNA. This 5 … gives the eukaryote its name, which means "true nucleus". Other differences include:

• The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell 6 … may or may not be present.

• The eukaryotic DNA is organized in 7 … or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the 8 … nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles such as mitochondria also 9 … some DNA.

• Many eukaryotic cells are ciliated with 10 … cilia. Primary cilia play important roles in chemosensation, 11 …, and thermosensation. Cilia may thus be "viewed as a sensory cellular antennae that coordinates a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation."

• Eukaryotes can move using motile cilia or flagella. Eukaryotic flagella are less 12 … than those of prokaryotes.

1. – primary

2. – walls

3. – distinguishing

4. – contain

5. – take

6. – one

7. – algae

8. – mechanosensation

9. – cell

10. – wider

11. – complex

12. – nucleus

Exercise 4. Read the text above once again and decide if the following statement true or false:

1. Eukaryotic and prokaryote are two different types of cells.

2. Compartmentalization is the distinguishing feature of eukaryotes from prokaryotes.

3. A cell nucleus houses the prokaryotes cell's DNA.

4. The eukaryote means "true nucleus".

5. Cell walls are never present in prokaryotes.

6. All chromosomal DNA is stored in the membrane.

Exercise 5. Read the following text “Structure of Animal Cell” and match the following expressions:

1. biological a. acids

2. living b. information

3. building c. unit

4. cell d. cell

5. nucleic e. monks

6. single f. organisms

7. hereditary g. years

8. Christian h. functions

9. vital i. blocks

10. billion k. biology

Structure of Animal cell

The cell (from Latin cella, meaning "small room") is the basic structural, functional, and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently, and are often called the "building blocks of life". The study of cells is called cell biology.

Cells consist of a protoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids. Organisms can be classified as unicellular (consisting of a single cell; including most bacteria) or multicellular (including plants and animals). While the number of cells in plants and animals varies from species to species, humans contain about 100 trillion (10¹⁴) cells. Most plant and animal cells are visible only under the microscope, with dimensions between 1 and 100 micrometres.

The cell was discovered by Robert Hooke in 1665, who named the biological unit for its resemblance to cells inhabited by Christian monks in a monastery. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells. Cells emerged on Earth at least 3.5 billion years ago.

Exercise 6. Read the text “Structure of Animal Cell” and decide true or false are the following statements:

1. Cells can’t replicate independently.

2. Cell is enclosed within a membrane.

3. Protoplasm contains many biomolecules such as proteins and nucleic acids.

4. Multicellular organisms consist of one cell.

5. Most cells are invisible for unaided eye.

6. Robert Hooke developed the cell theory in 1665.

7. All cells come from preexisting atoms.

8. The hereditary information is transmitted to the next generation of cells.

Exercise 7. Separate the following text into words and sentences and then read and translate it into Russian: