Functions of animal cell Cell Nucleus - Cell nucleus is referred to as the control center of the cell. The genetic material of the organism is present in the cell. The replication of DNA, and synthesis of RNA occurs in the nucleus of the cell. It also regulates the activities of the other cellular organelles. Mitochondria - The mitochondria is referred to as the power house of the cell. Its main function if to produce energy for cell by the process of cellular respiration. The energy produced is ATP. Endoplasmic Reticulum - It is a network for transportation of certain substances in and out of the nucleus. Golgi Apparatus - It is involved with processing and packaging of the molecules that are synthesized by the cells. The crude proteins that are passed on by the ER to the apparatus are developed by the golgi apparatus into primary, secondary, and tertiary proteins. Ribosomes - The function of ribosomes is protein synthesis. Lysosomes - They are referred to as the suicide bags of the cell. They have digestive enzymes and are involved in clearing the in wanted waste materials from the cell. They also engulf damaged materials like the damaged cells,and invading microorganisms and digest food particles. Vacuole - They are large storage organelles. They store excess food or water. Structure of animal cell Cell membrane • It is a semi-permeable barrier, allowing only a few molecules to move across it. • Electron microscopic studies of cell membrane shows the lipid bi-layer model of the plasma membrane, it also known as the fluid mosaic model. • The cell membrane is made up of phospholipids which has polar(hydrophillic) heads and non-polar (hydrophobic) tails. Cytoplasm • The fluid matrix that fills the cell is the cytoplasm. • The cellular organelles are suspended in this matrix of the cytoplasm. • This matrix maintains the pressure of the cell, ensures the cell doesnt shrink or burst. Nucleus • Nucleus is the house for most of the cells genetic material- the DNA and RNA. • The nucleus is surrounded by a porous membrane known as the nuclear membrane. • The RNA moves in/out of the nucleus through these pores. • Proteins needed by the nucleus enter through the nuclear pores. • The RNA helps in protein synthesis through transcription process. • The nucleus controls the activity of the cell and is known as the control center. • The nucleolus is the dark spot in the nucleus, and it is the location for ribosome formation. Ribosomes • Ribosomes is the site for protein synthesis where the translation of the RNA takes place. • As protein synthesis is very important to the cell, ribosomes are found in large number in all cells. • Ribosomes are found freely suspended in the cytoplasm and also are attached to the endoplasmic reticulum. Endoplasmic reticulum • ER is the transport system of the cell. It transports molecules that need certain changes and also molecules to their destination. • ER is of two types, rough and smooth. • ER bound to the ribosomes appear rough and is the rough endoplasmic reticulum; while the smooth ER do not have the ribosomes. Lysosomes • It is the digestive system of the cell. • They have digestive enzymes helps in breakdown the waste moelcules and also help in detoxification of the cell. • If the lysosomes were not membrane bound the cell could not have used the destructive enzymes. Centrosomes • It is located near the nucleus of the cell and is known as the microtubule organizing center of the cell. • Microtubules are made in the centrosome. • During mitosis the centrosome aids in dividing of the cell and moving of the chromosome to the opposite sides of the cell. Vacuoles • They are bound by single membrane and small organelles. • In many organisms vacuoles are storage organelles. Vesicles are smaller vacuoles which function for transport in/out of the cell. Golgi bodies • Golgi bodies are the packaging center of the cell. • The Golgi bodies modify the molecules from the rough ER by dividing them into smaller units with membrane known as vesicles. • They are flattened stacks of membrane-bound sacs. Mitochondria • Mitochondria is the main energy source of the cell. • They are called the power house of the cell because energy(ATP) is created here. • Mitochondria consists of inner and outer membrane. • It is spherical or rod shaped organelle. • It is an organelle which is independent as it has its own hereditary material. Peroxisomes • Peroxisomes are single membrane bound organelle that contain oxidative enzymes that are digestive in function. • They help in digesting long chains of fatty acids and amino acids and help in synthesis of cholesterol. Cytoskeleton • It is the network of microtubules and microfilament fibres. • They give structural support and maintain the shape of the cell. Cilia and Flagella • Cilia and flagella are structurally identical structures. • They are different based on the function they perform and their length. • Cilia are short and are in large number per cell while flagella are longer and are fewer in number. • They are organelles of movement. • The flagella motion is undulating and wave-like whereas the ciliary movement is power stroke and recovery stroke. Parts of animal cell Cell membrane - forms the outer covering of the cell, and is semi-permeable. Cytoplasm - is a gel-like matrix where all the other cell organelles are suspended inside the cell. Nucleus - contains the hereditary material DNA and directs the activities of the cell. Centrioles - organize the microtubules assembly during cell division. Endoplasmic Reticulum - are a network of membranes composed of rough and smooth endoplasmic reticulum. Golgi complex - is responsible for storing, packaging of cellular products. Lysosomes - are enzyme sacs, that digest cellular wastes. Microtubules - are hollow rods, function primarily as support and shape to the cell. Mitochondria - is the site for cellular respiration and producers of energy. Ribosomes - are made of RNA and proteins, and are sites for protein synthesis. Nucleolus - is the structure within the nucleus and helps in synthesis of ribosomes. Nucleopore - is the tiny hole in the nuclear membrane, allows the movement of nucleic acids and proteins in/out of the cell. Parts of plant cell Cell wall is the outermost rigid covering of the plant cell. It is a salient feature of plant cell. Cell membrane or the plasma membrane is the outer lining of the cell inside the cell wall. Cytosol or cytoplasm is the gel-like matrix inside the cell membrane which constitutes all other cell organelles. Nucleus is the control center of the cell. It is a membrane bound structure which contains the hereditary material of the cell - the DNA Chloroplast is a plastid with green pigment chlorophyll. It traps light energy and converts it to chemical energy by the process of photosynthesis. Mitochondria carries out cellular respiration and provides energy to the cells. Vacuoles are the temporary storage center of the cell. Golgi body is the unit where proteins are sorted and packed. Ribosomes are structures that assemble proteins. Endoplasmic reticulum are membrane covered organelles that transport materials. Structures and function of plant cell Cell wall: The cell wall is a rigid layer that surrounds the plant cells. It is made up of cellulose. Cell wall is a characteristic feature to cells of plants. Plant cell walls are primarily made up of cellulose. Plant cell wall consists of three layers: the primary cell wall, secondary cell wall and the middle lamella. It is located outside the cell membrane whose main function is to provide rigidity, strength, protection against mechanical stress and infection. Cell wall is made up of cellulose, pectins,glycoproteins, hemicellulose and lignin. Cell membrane: It is the outer boundary of the cell, it encloses the cytoplasm and the organelles of the cells. In plants cells it is inside the cell wall. The cell membrane is semi permeable, allowing only specific substances to pass through and blocking others. Chloroplasts: It is an elongated or disc-shaped organelle containing chlorophyll. They have two membranes and have structures that look like stack of coins. They are flattened structures which contain chemical chlorophyll. The process of photosynthesis occurs in this region of the plant cell. The chlorophyll is a green pigment that absorbs energy from sunlight to make food for the plants by converting light energy into chemical energy. Cytoskeleton: It is a network of fibers made up of micro-tubule and micro-filament. They maintain the shape and gives support to the cell. Microtubules: They are hollow cylinder like structures found in the cytoplasm of the cells. Its function is transport and structural support. Microfilaments: Microfialments are solid rod like structures whose primary function is structural support. Plasmodesmata: They are microscopic channels which traverse the cell walls of plant cells and enables transport and communication between them. Vacuole: Vacuoles are known as cells storage center. Plant cells have large membrane bound chamber called vacuole. Its main function is storage. Vacuoles are found in the cytoplasm of most plant cells. They are membrane bound organelles, they perform functions of secretion, excretion and storage. Tonoplast: A vacuole that is surrounded by a membrane is called tonoplast. Plastids: Plastids are storage organelles. They store products like starch for synthesis of fatty acids and terpenes. Leucoplast: They are a type of plastid which are non-pigmented. Chromoplast: They are plastids responsible for pigment synthesis and storage. They are found in photosynthetic eukaryotic species. They are found in colored organs of plants like fruits and flowers. Golgi complex: The Golgi bodies look like the endoplasmic reticulum and are situated near the nucleus. They are found in almost all eukaryotic cells. Their main function is to process and package macromolecules synthesized from other parts of the cell. The Golgi apparatus is referred to as the cells packaging center. Ribosomes: Ribosomes are smallest and the most abundant cell organelle. It comprises of RNA and protein. Ribosomes are sites for protein synthesis. They are found in all cells because protein are necessary for the survival of the cell. The ribososomes are known as the protein factories of the cell. Endoplasmic reticulum: Endoplasmic reticulum is a membrane bound compartment, which look like flattened sacs lined side by side. It is a large network of interconnecting membrane tunnels. It is composed of both rough endoplasmic reticulum and smooth endoplasmic reticulum. They are responsible for protein translation, and protein transport to be used in the cell membrane. They also aid in sequestration of calcium, and production and storage of glycogen and other macromolecules. Mitochondria: Mitochondria are surrounded by two membranes. They are described as the power plants of the cell as they convert glucose to energy molecules (ATP). They possess their own hereditary material which help in self duplication and multiplication. Lysosome: Lysosome contain digestive enzymes. They digest excess or worn out organelles, food particles and any foreign bodies. Microbody: It is a single membrane bound organelle that comprises of degradative enzymes Cytoplasm: It is a gel-like matrix inside enclosed by the cell membrane. The cytoplasm supports cell organelles and also prevents the cell from bursting or shrinking. Nucleus: It is the control center of the cell. It is bound by a double membrane known as the nuclear envelope. It is a porous membrane, it allows passage of substances and is a distinctive characteristic of the eukaryotic cell. Most of the genetic material is organized as multiple long linear DNA molecules. The nucleus directs all the activities of the cell and also help in protein formation.
Posted on: Tue, 22 Jul 2014 11:22:07 +0000