The Fundamental Unit of Life Test - 13

Lysosmes are popularly known as 'suicidal bags'. They contain enzymes for hydrolysis of all cell components in case of damage. They play a role in cell death. 
Centrioles are a very important part of centrosomes or spindle pole bodies which act as the microtubule organizing centers in animal cells. 
Golgi apparatus consists of a system of membrane-bound vesicles. The proteins manufactured by the ribosomes are packed inside the vesicles. 
Smooth endoplasmic reticulum (SER) helps in the manufacture of fat molecules or lipids. Some of these lipids help in building the cell membrane (known as membrane biogenesis).

The energy required for various chemical activities is released by mitochondria. They contain enzymes for cellular respiration. During cellular respiration, energy is released in the form of ATP (Adenosine triphosphate). The body uses energy stored in ATP. Hence, ATP is called the energy currency of the cell. 
Chloroplasts are found in leaves of plants. They make use of sunlight to perform a process called photosynthesis. Chloroplasts are involved in the process of photosynthesis during which oxygen is produced and the net amount is given off. 
Red Blood Cells in mammals anucleate when mature i.e. they do not contain a nucleus. This is so that the cell has maximum space for haemoglobin. 
Ribosomes are associated with the synthesis of proteins from amino acids. Proteins are required by a cell for functions such as repair or directing chemical processes.

There are two types of Endoplasmic Reticulum (ER). The rough Endoplasmic Reticulum (RER) has particles called ribosomes attached to its surface. Ribosomes are the sites of protein manufacture. The smooth endoplasmic reticulum (SER) helps in the manufacture of fat molecules or lipids. Some of these proteins and lipids help in building the cell membrane (known as membrane biogenesis). Processing and packaging is done by Golgi apparatus.

In animals cells, centriole is present in the centrosome. Centrioles are a very important part of centrosomes. Centrosomes or spindle pole bodies act as the microtubule organising centers in animal cells. They help in the movement of chromatids towards the opposite pole.

Nucleolus is present in the nucleus of the cell. It is called as little nucleus of the cell.

Centrioles are a very important part of centrosomes. Centrosomes or spindle pole bodies act as the microtubule organising centers in animal cells. During cell division in animal cells, spindle formation takes place from the centriole. The spindle help in movement of chromatids towards the opposite poles.

Chromosomes are composed of DNA and protein. Functional segments of DNA are called genes. Genes are functional units of heredity that determines the characters of organisms. In a cell which is not dividing, the DNA material is present as part of chromatin material. When a cell is about to divide, the chromatin material gets organised into chromosomes.

Nucleus is a double membranous structure. It is surrounded by a double membrane - the inner nuclear membrane and the outer nuclear membrane. A liver cell contain about 500-1000 mitochondria. Large amount of cellulose is present in the wood of a plant.

Eukaryotic cells have a distinct nucleus. a nucleolus and a nuclear membrane. The presence of a nucleus gives eukaryotes their name. 

Nucleoid is present in prokaryotic cells. It is the area of the cytoplasm that contains the prokaryote's single DNA molecule.

The passage of water from a region of higher water concentration to a region of lower concentration through a semi-permeable membrane is called osmosis. The movement of water across the plasma membrane is affected by the amount of substance dissolved in water.