Science

 

Cell membrane

• The cell membrane separates cells from one another and also the internal contents from the surrounding medium.
• It is porous and allows the movement of substances or materials both inward and outward.

Cytoplasm

• It is the jelly-like substance present between the cell membrane and the nucleus.
• Various other components, or organelles of cells, are present in the cytoplasm.

Cell walls in plants

• A cell wall is an additional covering over the cell membrane in plant cells.
• It gives shape and rigidity to these cells.
• It gives a rigid structure to plant cells, and that is why they can withstand the stress of high-velocity wind, rain, high temperature etc.

Cell Factory

Organelles

• The various components present within the cell are known as cell organelles.
• All these components are special and specific to their functions.
• For example, mitochondria, lysosomes etc.

Nucleus

• It is generally spherical and located in the centre of the cell.
• The nucleus is separated from the cytoplasm by a membrane called the nuclear membrane.
• It uses information in the chromosomes to decide what each organelle should do and the functions of the cell.
• The nucleus contains an even smaller concentrated material called nucleolus.

Chromosomes

• The nucleus contains thread-like structures called chromosomes.
• These carry genes and help in the inheritance or transfer of characters from the parents to the offspring.
• Chromosomes are composed of DNA in the form of Chromatin and protein.
• Chromosomes contain information for the inheritance of features from parents to next generation in the form of DNA molecules.

DNA

• DNA molecules contain the information necessary for constructing and organising cells.

Functional segments of DNA are called genes.

Vacuoles, Endoplasmic Reticulum and Golgi Apparatus

Vacuoles

• Vacuoles are storage bubbles of irregular shapes which are found in cells.
• The vacuole stores the food, a variety of nutrients that a cell might need to survive or waste.
• In plant cells, vacuoles are much larger than in animal cells, and they provide rigidity to the plant cells.

Golgi Apparatus

• Golgi Apparatus, also termed as Golgi Complex, is a membrane-bound nucleus.
• Its main function is to modify proteins.
• These modified proteins are placed in Golgi so that they can transport elsewhere in the cell when required.

Endoplasmic Reticulum

• It is a membranous organelle.
• It is found in all eukaryotic cells.
• The ER is divided into two types based on their physical and functional properties viz. Smooth and Rough ER.