All Living organisms irrespective of size are made up of cells. Cells can be called the ground level workers of our body as they carry out all the functions of our body ranging from breathing to digestion of food. They are the smallest units of life and cannot be viewed by the naked eye. A microscope must be used if we want to have a look at a cell. The Cell generally consists of a cytoplasm and a nucleus which is protected from the outer environment by a thin layer of phospholipids known as the plasma membrane. Cells can be categorised into 2 types namely eukaryotic and prokaryotic.
Animal Cell Basics
As mentioned earlier, the cell is the smallest unit of life in an animal’s body. It was discovered by Robert Hooke in 1665 with the help of a microscope. The animal cell is eukaryotic in nature as they have a proper defined nucleus that is enclosed within a nucleus membrane. The largest known animal cell is the ostrich egg.
Animal Cell Structure
- Animal cells can be from micron to millimetre in size.
- The animal cell is protected by a semi-permeable plasma membrane but does not have a cell wall like the plant cell.
- Animal cells can be of different shapes like rod, oval, flat, etc.
- The animal cell has a nucleus that is enclosed by a membrane.
- The cell also has organelles that are membrane bound.
- The organelles can be made up of 2 layers of membrane or just a single membrane.
- The cell has organelles like the mitochondria, peroxisome, endoplasmic reticulum, ribosome, Golgi apparatus, etc.
- The fluid part in the cell is known as Cytoplasm.
Cell Organelles
- Plasma Membrane – It is a thin semi permeable layer of lipids and proteins surrounding the cell. The lipids are arranged in a bilayer and the proteins are either attached to the bilayer or are penetrating the bilayer. It protects the cell from the environment. Also, it regulates the entry and exit of organic compounds like amino acids, fats, etc and other microscopic substances into the cell. It also plays a major role in signal transduction of the cells.
- Mitochondria – It is a double membrane bound organelle and is regarded as the “PowerHouse of the Cell” as it is the prime organelle involved with ATP production. ATP is the energy currency of the cell. ATP is used by cells for every kind of activity.
- Nucleus– It is double membraned organelle present almost in the central position of the cell. It contains DNA which is the genetic material and contains the information about the human body. Various processes like DNA replication, transcription take place in the nucleus. It is also regarded as the information centre of the body.
- Golgi Apparatus– It is a single membrane bound organelle which is divided into 3 regions; Cis, medial and trans. Its role in the cell is to transfer protein from one area to its desired region with some modifications like addition or removal of sugar moieties, phosphorylation, etc.
- Endoplasmic Reticulum- It is a single membraned organelle which performs the function of protein formation, transformation, processing and transportation. The endoplasmic reticulum is divided into 2 types Rough Endoplasmic reticulum (RER) and Smooth Endoplasmic Reticulum (SER). RER is known for protein synthesis whereas SER is known for lipid synthesis and detoxification.
- Ribosome– these are small single membrane organelle which contains RNA. It is the prime site for protein synthesis. It can be free in the cytoplasm or remain attached to the endoplasmic reticulum. Both the types of ribosomes perform different types of function but still both are involved in protein synthesis.
- Cytoskeleton– These are the fibrous network of proteins present in the cytoplasm. There are 3 types of cytoskeleton; Microfilament, Microtubule and intermediate Filaments. The cytoskeleton creates a mesh to organise the components of the cell and also to maintain the cell shape. It also provides an even movement of the cell and also the other organelles. It plays a very important role in the movement of the cell and cell organelles.
- Peroxisome– It is small, spherically and bound by a single membrane. It is involved in lipid synthesis and detoxification of the body by reacting with Reactive Oxygen Species.
- Lysosome– it is known as the suicide bag of the cell as it can digest or degrade organic compounds as well as other cell organelles. It used to destroy toxic materials present in the cell in order to protect the cell from harmful effects. The organelle is single membraned organelle containing acidic pH due to the presence of acidic enzymes. The acidic pH is maintained in the lysosome with the help of a proton pump.
- Centrioles– it can replicate and plays a very important role in the formation of spindle fibre during mitosis or meiosis. It contains 9 sets of microtubules in a triplet arrangement.
Animal Cell Function
- An animal cell performs all the processes of the body like producing energy and storing it, manufacturing proteins which plays an important role in metabolism as enzymes and substrates, Etc.
- Different types of cells combine to form tissues and perform the same type of function. The same type of tissues combine to form organs which carry out major functions of our body. Like the heart which carries out the circulatory system in our body, stomach which performs a major role in the digestive process, etc.
Conclusion
In conclusion Animal cell is a type of eukaryotic cell having a lipid bilayer around it. This lipid bilayer is known as the plasma membrane which acts as a protective layer as it is semi-permeable in nature and allows only selective specific substances to pass through it. The animal cell contains a number of organelles present in the fluid portion of the cell known as the cytoplasm. The organelles present can be either single membrane or double membraned. The different organelles of an animal cell are Mitochondria, Endoplasmic Reticulum, Golgi Apparatus, Nucleus, Etc. The organelles are known for their specific functions. The animal cells play a very important role in the maintenance of the body as all the metabolic processes take place in the cells. The cells combine to form tissues and similar types of tissues combine to form an organ which can perform a specific function for proper functioning of the human body.