Name: Measuring Cells
Uploaded: 2019-07-19
Duration: 5 min 50 s
Description: This interesting video discusses the basics, such as using a stage micrometer to calibrate eyepiece graticule, magnification and resolution, in a simple and easy manner.

Question

List ten structures that could find in an electron micrograph of an animal cell which would be absent from the cells of a bacterium.

Accepted Answer

Bacteria consist of prokaryotic cells that devoid of a definite nucleus and membrane-bound organelles. Animal cells are the examples of eukaryotic cells that possess the following structures which are absent in a bacterium:

i) Nucleus: It is a double-membrane enclosed organelle found in most eukaryotic cells. It contains most of the genetic materials.

ii) Nuclear membrane: The nucleus consists of an outer double-layered nuclear envelope that encloses the nuclear sap, called nuclear membrane. It has many pores called nuclear pores.

iii) Nucleolus: It is located inside the nucleus. Its function is to make ribosomes.

iv) Mitochondria: These are the membrane-enclosed organelle found in the cytoplasm of all eukaryotic cells. These are generally described as the powerhouse of the cell or cellular power plants as they generate most of the cell's supply of ATP. It is the site of cellular respiration.

v) Endoplasmic reticulum: ER is the double membrane-bound organelle which is the largest internal membrane system in the cytoplasm of the cell. It is of two types on the basis of the presence of ribosomes. Endoplasmic reticulum which possesses ribosome called as rough endoplasmic reticulum (RER) and without ribosome is called smoth endoplasmic reticulum (SER). The RER is responsible for the manufacturing and transport of membrane-bound and secretory proteins. The SER engaged in producing a lot of lipids, vitamins, carbohydrates, steroid hormones and also in the process of detoxification of the cell.

vi) Golgi complex: It refers to stacks of single membrane-bound vesicle that is composed of sacs known as cisternae or saccules, tubules and vesicles. It is important in packaging macromolecules for transport to elsewhere in the cell and out of the cell.

vii) Lysosomes: These are the single membrane-bound cell organelles that are is responsible for the controlled intracellular digestion of macromolecules. It is the principal site of cholesterol assimilation.

viii) Vacuoles: These are the non-cytoplasmic areas bounded by a single membrane bilayer present in the cytoplasm. It contains digestive enzymes and various dissolved minerals.

ix) Centrosome: It is present only in animal cell which contains two centrioles. It acts as microtubule organising centre. These constitute the mitotic spindle responsible for the movement of chromosomes during cell division.

x) Peroxisomes: These are a kind of microbodies present in almost all eukaryotic cells. It is a single membrane-bound vesicle. It is a major site of oxygen utilisation.

List ten structures that could find in an electron micrograph of an animal cell which would be absent from the cells of a bacterium.

Important Questions on Cell Structure

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