Cell Structure And Functions Test - 3

P. Rough endoplasmic reticulum is specialised to synthesise proteins. Q. Mitochondria is the site of cellular respiration leading to production of ATPR. Chloroplast stroma contains enzymes for conversion of carbon dioxide into carbohydrate. Lysosomes help in intracellular digestion of food particles.

The longest cells are neurons (nerve cells) with a length of 90cm-100cm linking the central nervous system (brain and spinal cord) to other parts of the body.

Durjarden used the term 'sarcode' for the cellular fluid, which was later on, named as "Protoplasm" by Purkinje and Von Mohl.

The Golgi apparatus, first described by Camillo Golgi, consists of a system of membrane bound vesicles arranged approximately parallel to each other in stacks called cisterns. These membranes often have connections with the membranes of ER and therefore constitute another portion of a complex cellular membrane system.
Ribosomes are submicroscopic dense granules about 150 to 2500 Angstrom in diameter and have been seen by Palade in 1955 under electron microscope.
The term 'nucleolus' was coined by Bowman in 1840.

Endoplasmic reticulum was discovered and named so by Porter. Endoplasmic reticulum is an interconnected system of membrane-lined channels that runs through the cytoplasm.

The term 'mitochondria' was coined by Carl Benda in 1898. It is double membrane organelle of the cell. The functions of mitochondria are:

1. Mitochondria are described as the power house of a cell, and therefore is directed to the processes that evolve energy, mainly TCA, ETS, oxidative phosphorylation. All these three processes occur in mitochondria and result in the formation of energy compound called ATP.

2. Some of the enzymes have been located in mitochondria, which help in the synthesis of lipids like Lecithin from fatty acids and glycerol.

3. Mitochondria help in the transport of ATP. They collect at sites where energy requirement is high.

4. Due to the presence of RNA, DNA and ribosomes, proteins can be manufactured in mitochondria.

5. Mitochondria possess some of the enzymes of glyoxylate cycle. This cycle is modification of Kreb's cycle in which fatty acids are converted into the carbohydrates. Endoplasmic reticulum was discovered and named so by Porter.

Purkinje coined the term 'protoplasm' for the fluid substance of the cell in 1839.

A. Cells are enclosed by a plasma membrane composed of lipids and proteins.B. In plant cells, a cell wall composed mainly of cellulose is located outside the cell membrane. In animal cell the cell wall is mainly composed of phospholipids and proteins.C. The nucleus in eukaryotes is separated from the cytoplasm by double-layered membrane and it directs the life processes of the cell.D. Chloroplasts contain the pigment chlorophyll and are responsible for photosynthesis

Leucoplasts are primarily organelles in which materials such as starch, oils and protein granules are stored.
Lysosomes help in removing dead and worn out cellular organelles (cell debris) by digesting them.