An animal cell is a type of cell that is characteristic of animals and is present in all multicellular organisms that belong to the animal kingdom. Animal cells are eukaryotic, which means they have a true nucleus that holds their genetic material and is separated from the cytoplasm by a nuclear envelope.

  • Animal cells are typically smaller in size than plant cells and have a more irregular shape. Because they have cilia, flagella, or pseudopodia, they can move around more than plant cells.
  • Animal cells can be recognized by their cell membranes, which surround the cell and control what goes in and out of the cell. 
  • They also have different organelles, like the mitochondria, which make energy for the cell through a process called cellular respiration, and the endoplasmic reticulum and Golgi apparatus, which make proteins and change them.
  • Animal cells do not have a cell wall, which is a characteristic feature of plant cells. 
  • They also do not have chloroplasts, which are organelles that are responsible for photosynthesis in plant cells.

Animal cell size and shape

Plant cells are usually bigger than animal cells. The diameter of an animal cell is usually between 10 and 30 micrometers.

  • They can be any shape, and because they have cilia, flagella, or pseudopodia, they move around more than plant cells.
  • Cilia are small, hairlike protuberances that are found on the surface of some animal cells and are used for locomotion or for moving substances along the surface of the cell.
  • Flagella are longer and thicker than cilia and are used for propulsion.
  • Pseudopodia are temporary, bulging extensions of the cell membrane that are used for movement and for capturing food.
  • Animal cells are also characterized by the presence of cell membranes, which enclose the cell and regulate the movement of substances in and out of the cell.
  • The cell membrane is a thin, flexible barrier that surrounds the cell and separates the inside of the cell from the external environment.
  • It is made of lipids and proteins, and it is selectively permeable, which means that it lets some things through but not others.
  • Animal cells have organelles like the mitochondria, which make energy for the cell through a process called cellular respiration, and the endoplasmic reticulum and Golgi apparatus, which help make proteins and change them.
  • Animal cells do not have a cell wall, which is a characteristic feature of plant cells, nor do they have chloroplasts, which are organelles that are responsible for photosynthesis in plant cells.
animal cell

List of Animal cell organelles

The organelles found in animal cells include:

  1. Nucleus: This is the largest organelle in the cell and is responsible for storing and managing the cell’s genetic material. A nuclear envelope separates the nucleus from the cytoplasm. The nucleoli, which help make ribosomes, are in the nucleus.
  2. Endoplasmic reticulum (ER): This organelle is involved in the synthesis and modification of proteins and lipids. The rough endoplasmic reticulum (RER) is full of ribosomes, which help make proteins. The smooth endoplasmic reticulum (SER), on the other hand, helps make lipids and changes to them.
  3. Golgi apparatus: This organelle is involved in the modification, sorting, and distribution of proteins and lipids. It consists of flattened stacks of membrane-bound sacs called cisternae that are involved in the modification and sorting of proteins and lipids.
  4. Mitochondria: These organelles are involved in the production of energy for the cell through the process of cellular respiration. They have enzymes that help break down glucose to make ATP, which is the main source of energy for the cell.
  5. Lysosomes: These organelles contain enzymes that are involved in the breakdown of waste materials and the recycling of cellular components.
  6. Peroxisomes: These organelles are similar to lysosomes and contain enzymes that are involved in the breakdown of toxic substances.
  7. Vacuoles: These organelles are involved in the storage of water, nutrients, and waste materials.
  8. Cilia and flagella: These are small, hairlike protuberances that are found on the surface of some animal cells and are used for locomotion or for moving substances along the surface of the cell. Cilia are shorter and more numerous than flagella, which are longer and thicker.
  9. Centrioles: These parts of the cell help make the mitotic spindle when the cell divides.
  10. Microtubules: These are thin, rod-like structures that are involved in maintaining the shape of the cell and in cell division. They are made up of proteins called tubulin.
  11. Microfilaments: These are thin, thread-like structures that are involved in maintaining the shape of the cell and in cell division. They are made up of proteins called actin.
  12. Intermediate filaments: These are thicker than microfilaments and are involved in maintaining the shape of the cell and in cell division. They are made up of proteins such as vimentin and keratin.

Plasma membrane

The plasma membrane, also known as the cell membrane or cytoplasmic membrane, is a thin, flexible barrier that surrounds the cell and separates the inside of the cell from the external environment. It is made up of a phospholipid bilayer, which is a double layer of phospholipid molecules arranged in a certain way, and proteins, which are either embedded in the phospholipid bilayer or attached to the surface of the membrane.

plasma membranes

The phospholipid bilayer is partially permeable, which means that it lets some things through but stops others. Proteins in the plasma membrane do a lot of different things, like move molecules across the membrane, let cells talk to each other, and recognize molecules.

The plasma membrane is important to the cell’s survival because it keeps the cell from breaking apart and controls what goes in and out of the cell. It also helps with important things like sending signals, making energy, and dividing cells. 

Structure of plasma membrane

The cell membrane, which is also called the plasma membrane, has the following structure:

  • The plasma membrane is a thin, flexible barrier that surrounds the cell and separates the inside of the cell from the external environment.
  • It is made up of a phospholipid bilayer, which is a double layer of phospholipid molecules arranged in a specific orientation.
  • The phospholipid bilayer is composed of two layers of phospholipid molecules, with their hydrophobic tails facing towards the center of the membrane and their hydrophilic heads facing outward.
  • The phospholipid bilayer is semi-permeable, meaning it allows certain substances to pass through while blocking others.
  • The plasma membrane also contains proteins, which are embedded in the phospholipid bilayer or attached to the surface of the membrane. These proteins serve a variety of functions, including transport of molecules across the membrane, communication between cells, and recognition of molecules.
  • The phospholipid bilayer and proteins of the plasma membrane are in constant motion, which helps to maintain the integrity of the membrane and allows it to respond to changes in the external environment.

Functions of Plasma membrane

The plasma membrane, which is also called the cell membrane or the cytoplasmic membrane, does the following:

  1. Regulating the movement of substances in and out of the cell: The plasma membrane is partially permeable, which means that it lets some things through but stops others. This helps keep the cell’s environment stable and keeps harmful substances from getting in.
  2. Maintaining the integrity of the cell: The plasma membrane helps to hold the cell together and maintain its shape.
  3. Communicating with other cells: The proteins of the plasma membrane, such as receptors, are involved in communication between cells.
  4. Participating in energy production: Enzymes and other proteins in the plasma membrane help the cell make energy.
  5. Participating in cell signaling: The proteins of the plasma membrane, such as receptors, are involved in signaling pathways that help to regulate the activities of the cell.
  6. Participating in cell adhesion: Adhesion molecules and other proteins in the plasma membrane help the cell stick to other cells or the extracellular matrix.
  7. Participating in cell recognition: Antibodies and other proteins in the plasma membrane help the body recognise other cells or molecules.
  8. Participating in cell defense: The proteins of the plasma membrane, such as antibodies, are involved in the defense of the cell against pathogens and other harmful substances.
  9. Participating in cell movement: Some of the proteins in the plasma membrane, like motor proteins, help move the cell or things inside the cell.
  10. Participating in the formation of the mitotic spindle: The proteins of the plasma membrane, such as motor proteins, are involved in the formation of the mitotic spindle during cell division.

Cilia and Flagella

Cilia and flagella are hair-like projections that are found on the surface of cells. They are composed of microtubules, which are structural proteins that help to give the cilia and flagella their shape and movement.

Both cilia and flagella help an animal move, but their structure and purpose are different.

Cilia are shorter, have more of them, and are found in large groups on the surface of cells. They are typically found on cells that line the respiratory and reproductive tracts, as well as on some types of cells in the brain and other organs. Cilia are responsible for moving mucus and other substances along the surface of the cell, and they work by beating in coordinated waves.

Flagella, on the other hand, are longer and fewer in number.

Most single-celled organisms, like bacteria, have them, and they use them to move. Flagella are composed of a single, long filament that extends from the surface of the cell and is driven by a motor protein called dynein. The dynein moves the filament in a whip-like motion, propelling the cell forward.

Both cilia and flagella are important for many cells and organisms to work right, and problems with their structure or function can lead to a number of health problems. 

For example, defects in the cilia of cells in the respiratory tract can lead to respiratory problems, while defects in the flagella of bacteria can affect their ability to move and cause infections.


Nucleus

Nucleus structure
  • Animal cells are typically smaller in size than plant cells, with diameters ranging from 10 to 30 micrometers.
  • They can be any shape, and because they have cilia, flagella, or pseudopodia, they move around more than plant cells.
  • Cilia are small, hairlike protuberances that are found on the surface of some animal cells and are used for locomotion or for moving substances along the surface of the cell.
  • Flagella are longer and thicker than cilia and are used for propulsion.
  • Pseudopodia are temporary, bulging extensions of the cell membrane that are used for movement and for capturing food.
  • Animal cells are also characterized by the presence of cell membranes, which enclose the cell and regulate the movement of substances in and out of the cell.
  • The cell membrane is a thin, flexible barrier that surrounds the cell and separates the inside of the cell from the external environment.
  • It is made of lipids and proteins, and it is selectively permeable, which means that it lets some things through but not others.
  • Animal cells have organelles like the mitochondria, which make energy for the cell through a process called cellular respiration, and the endoplasmic reticulum and Golgi apparatus, which help make proteins and change them.
  • Animal cells do not have a cell wall, which is a characteristic feature of plant cells, nor do they have chloroplasts, which are organelles that are responsible for photosynthesis in plant cells.

Structure of Nucleus:

The structure of the nucleus can be described as follows:

  • The nucleus is the largest organelle in the cell and is usually round or oval in shape.
  • It is separated from the cytoplasm by a nuclear envelope, which is a double membrane that surrounds the nucleus. The nuclear envelope is perforated with nuclear pores, which allow substances to pass in and out of the nucleus.
  • The nucleus contains chromatin, which is made up of DNA and proteins and is the genetic material of the cell. The chromatin is put together into chromosomes, which hold the genes that control how the cell looks and works.
  • During cell division, the chromosomes are visible as distinct structures within the nucleus.
  • The nucleus also has nucleoli, which are small, spherical bodies that help make ribosomes, which are organelles that are in charge of making proteins.
  • The nucleus is involved in many important processes, such as DNA replication, transcription, and controlling how genes are expressed.
  • The nucleus is also involved in the regulation of cell division and the maintenance of the cell’s genetic material.

Functions of Nucleus

The functions of the nucleus can be summarized as follows:

  1. Storing and managing the cell’s genetic material: The nucleus contains chromatin, which is made up of DNA and proteins and is the genetic material of the cell. The chromatin is organized into chromosomes, which contain the genes that control the characteristics and functions of the cell.
  2. Controlling the synthesis of proteins: Proteins are made in the nucleus through a process called transcription. During transcription, the genetic information in DNA is copied into RNA, which is then used to make proteins.
  3. Regulating gene expression: The nucleus is involved in the regulation of gene expression, which is the process by which the information in genes is used to produce proteins and other biomolecules.
  4. Regulating cell division: During mitosis and meiosis, the nucleus makes chromosomes and moves them around. This is how it controls cell division.
  5. Maintaining the integrity of the cell’s genetic material: The nucleus is involved in the process of DNA replication, which copies the genetic information in DNA in preparation for cell division. This keeps the cell’s genetic material in good shape.
  6. Participating in the synthesis of ribosomes: The nucleus has nucleoli, which are involved in making ribosomes, the organelles that are in charge of making proteins.

Cytoplasm

Cytoplasm is the substance inside a cell that is surrounded by the cell membrane. It is a gel-like substance that contains everything in a cell except the cell nucleus.

Cytoplasm is mostly made up of water and salts, and it also contains enzymes, hormones, and other small molecules that carry out the cell’s functions.

In addition to helping the cell make energy, the cytoplasm is a space where organelles can move and talk to each other.

It is an important part of every cell and plays a key role in keeping the cell healthy and working well. 

Structure of Cytoplasm

  • Cytoplasm is a semi-fluid substance that is located within the cell membrane but outside the cell nucleus.
  • It is mostly made up of water and ions that have been dissolved, as well as small organic molecules like enzymes, hormones, and other small molecules.
  • The cell’s organelles and structures, except for the cell nucleus, are all made of a gel-like substance called cytoplasm.
  • It is mostly made up of water and salts, and it also contains enzymes, hormones, and other small molecules that carry out the cell’s functions.
  • In addition to its role in cell metabolism, the cytoplasm also provides a medium in which organelles can move and interact with one another.
  • It is an important part of every cell and plays a key role in keeping the cell healthy and working well. 

Functions of Cytoplasm:

  • Organelles and other parts of a cell can move around and talk to each other through the cytoplasm.
  • It plays a key role in the cell’s metabolic processes, such as the synthesis and degradation of proteins, carbohydrates, and lipids.
  • Cytoplasm helps move things around inside the cell. This includes moving things from the cell membrane to the cell nucleus and moving organelles around inside the cell.
  • It helps keep the cell’s shape and integrity by giving the cell membrane support and keeping organelles in their right places.
  • The structure and functions of the cytoplasm are essential for the proper functioning and survival of the cell.

Mitochondria

Mitochondria are small organelles that make energy and are found in the cells of all eukaryotic organisms, such as plants and animals.

structure of mitochondria

They are sometimes referred to as the “powerhouses” of the cell because they generate most of the cell’s supply of ATP, a molecule that cells use for energy.

Mitochondria are unique in that they have their own DNA and can replicate and divide independently of the cell.

They are thought to have come from endosymbiotic bacteria that were taken in by larger cells and became part of the metabolism of those cells.

Several diseases, like neurodegenerative disorders, heart disease, and diabetes, are linked to mitochondria that don’t work right.

Structure of mitochondria:

  • Mitochondria are small, rod-shaped organelles found within the cytoplasm of eukaryotic cells.
  • They have a double membrane structure, with an outer membrane and an inner membrane.
  • The outer membrane is smooth and partially permeable, while the inner membrane is highly folded into cristae, which increases its surface area.
  • The space between the two membranes is called the intermembrane space, while the space within the inner membrane is called the matrix.
  • The inner membrane has proteins that help make ATP, which is the main source of energy for the cell.
  • The citric acid cycle, also called the Krebs cycle, makes energy in the form of ATP. This cycle is made up of enzymes.
  • Mitochondria also contain their own DNA, ribosomes, and tRNA, which are used to synthesize proteins needed for their own functions.
  • Mitochondria can copy themselves and divide without help from the cell. This lets them adapt to changes in the amount of energy they need.

Functions of Mitochondria:

  • Energy production: Mitochondria are the main site of ATP production in the cell. They generate ATP through the process of cellular respiration, which involves the breakdown of glucose and other nutrients to produce energy.
  • Calcium storage: Mitochondria play a role in regulating the levels of calcium ions within the cell. They can store calcium ions in their matrix and release them when they are needed. This lets them act as a buffer to keep the calcium level in the body at a stable level.
  • Apoptosis: Mitochondria are involved in programmed cell death, or apoptosis. When a cell undergoes apoptosis, mitochondria release molecules that trigger the cell’s death pathway.
  • Regulation of ROS: Mitochondria produce reactive oxygen species (ROS) as a byproduct of ATP production. These ROS can cause damage to DNA, proteins, and other cellular components if their levels become too high. Mitochondria have mechanisms in place to regulate ROS levels and prevent oxidative stress.
  • Steroid hormone synthesis: Some steroid hormones, such as testosterone and estrogen, are synthesized within the mitochondria.
  • Metabolic regulation: Mitochondria play a role in regulating the metabolism of the cell. They can adjust their activity based on the energy needs of the cell and can also influence the activity of other organelles and pathways involved in metabolism.

Ribosomes

ribosome structure

Ribosomes are cellular organelles that are small, spherical or ellipsoidal in shape.They are composed of two subunits, called the small subunit and the large subunit, which are made up of proteins and ribosomal RNA (rRNA). The small subunit is responsible for decoding the genetic information contained in messenger RNA (mRNA) into a sequence of amino acids, while the large subunit is responsible for synthesizing a polypeptide chain using the amino acids provided by the small subunit.

Here is a point-wise summary of the structure of ribosomes:

  • Ribosomes are composed of two subunits: the small subunit and the large subunit.
  • The small subunit is in charge of turning the genetic information in mRNA into a sequence of amino acids.
  • The small subunit provides the amino acids that the large subunit needs to make a chain of polypeptides.
  • Both the small and large subunits are made up of proteins and rRNA.
  • The small subunit has several molecules of rRNA, including the 16S rRNA, which is in charge of decoding the genetic information in mRNA.
  • The 23S rRNA and the 5S rRNA are two of the rRNA molecules found in the large subunit. These molecules help make the polypeptide chain.
  • Ribosomes are found in the cytoplasm of cells and are involved in the synthesis of proteins.
  • Ribosomes can be found in both prokaryotic and eukaryotic cells.

Functions of ribosomes

Ribosomes are small, spherical or ellipsoidal organelles found in cells that are in charge of protein synthesis. Here is a point-by-point summary of the functions of ribosomes:

  • Ribosomes are in charge of making proteins. They do this by decoding the genetic information in mRNA and putting amino acids together in the right order.
  • They are very important in the making of enzymes, hormones, and other proteins that are needed for cells to work properly.
  • Ribosomes are also needed to make structural proteins like collagen and keratin, which give cells and tissues their shape and support.
  • Ribosomes are found in the cytoplasm of cells. They are important for making proteins, which are needed for cells to work properly.
  • Ribosomes can be found in both prokaryotic and eukaryotic cells. In prokaryotes, ribosomes are responsible for synthesizing proteins that are required for the proper functioning of the cell. In eukaryotes, ribosomes are found in the cytoplasm and in the endoplasmic reticulum, where they are involved in the synthesis of proteins that are destined for export from the cell or for incorporation into the cell membrane.
  • Ribosomes are also involved in making proteins that are needed for organelles like mitochondria and chloroplasts to work properly.
  • Ribosomes not only make proteins, but they also help control how genes are expressed by controlling how certain proteins are made in response to different stimuli.
  • Ribosomes are important to the way cells work and take part in many important biological processes, such as growth, development, and repair.

Endoplasmic Reticulum

Endoplasmic reticulum organelle

The endoplasmic reticulum (ER) is an organelle found in eukaryotic cells that is involved in the synthesis, folding, and transport of proteins and lipids. Here is a point-wise summary of the endoplasmic reticulum:

  • The endoplasmic reticulum is an organelle found in eukaryotic cells that is involved in the synthesis, folding, and transport of proteins and lipids.
  • The endoplasmic reticulum is made up of a network of flattened sacs and tubes that are connected to the nuclear envelope and the Golgi apparatus.
  • The endoplasmic reticulum is divided into two types: the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER).
  • The rough endoplasmic reticulum (RER) has ribosomes on its surface. Ribosomes are parts of cells that help make proteins.
  • The smooth endoplasmic reticulum (SER) doesn’t have ribosomes on its surface. It helps make lipids like cholesterol and steroid hormones and changes them.
  • The endoplasmic reticulum is part of the process of making proteins that will either leave the cell or be added to the cell membrane.
  • When a protein is made on the RER, it is sent to the Golgi apparatus, where it is changed and sorted before being sent to its final destination.
  • The endoplasmic reticulum also plays a role in the synthesis of lipids and the detoxification of drugs and other harmful substances.
  • The endoplasmic reticulum is a key organelle that is involved in making proteins and lipids and moving them around in eukaryotic cells.

Types of endoplasmic reticulum:

The endoplasmic reticulum (ER) is an organelle found in eukaryotic cells that is involved in the synthesis, folding, and transport of proteins and lipids.

It is made up of a network of flattened sacs and tubes that are connected to the nuclear envelope and the Golgi apparatus.

types of endoplasmic reticulum

The endoplasmic reticulum is divided into two types: the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER).

  1. Rough endoplasmic reticulum (RER): The rough endoplasmic reticulum (RER) is characterized by the presence of ribosomes on its surface, which are involved in the synthesis of proteins. Proteins synthesized on the RER are transported to the Golgi apparatus, where they are further modified and sorted for delivery to their final destination. The RER is also involved in how proteins fold and change, like when carbohydrate or lipid groups are added.
  2. Smooth endoplasmic reticulum (SER): The smooth endoplasmic reticulum (SER) lacks ribosomes on its surface and is involved in the synthesis and modification of lipids, such as cholesterol and steroid hormones. The SER also helps get rid of drugs and other harmful substances and makes signaling molecules like cyclic AMP.

In summary, the endoplasmic reticulum is divided into two types: the RER, which is involved in the synthesis and modification of proteins, and the SER, which is involved in the synthesis and modification of lipids. Both the RER and SER play important roles in the synthesis and transport of proteins and lipids in eukaryotic cells.

Functions of the Endoplasmic Reticulum (ER)

The endoplasmic reticulum (ER) is an organelle found in eukaryotic cells that is involved in the synthesis, folding, and transport of proteins and lipids. Here is a point-by-point summary of the functions of the endoplasmic reticulum:

  • The endoplasmic reticulum is part of the process of making proteins that will either leave the cell or be added to the cell membrane.
  • When proteins are made on the rough endoplasmic reticulum (RER), they are sent to the Golgi apparatus, where they are changed and sorted before being sent to their final location.
  • The endoplasmic reticulum also helps fold and change proteins by adding carbohydrate or lipid groups, for example.
  • The smooth endoplasmic reticulum (SER) helps make lipids like cholesterol and steroid hormones and changes them as well.
  • The SER also helps get rid of drugs and other harmful substances and makes signaling molecules like cyclic AMP.
  • In eukaryotic cells, the endoplasmic reticulum is very important for making proteins and lipids and moving them around.
  • It is needed for cells to work properly and is a part of many important biological processes, such as growth, development, and repair.
  • The endoplasmic reticulum also controls the production of certain proteins in response to different stimuli. This is another way that it controls gene expression.

Golgi Apparatus

The Golgi apparatus, also known as the Golgi complex or Golgi body, is an organelle found in eukaryotic cells that is involved in the sorting, modification, and transport of proteins and lipids.

Golgi apparatus structure
  • It is a stack of flattened membranous sacs that are arranged in a single row or in multiple rows, synthesized depending on the cell type.
  • There are three main parts to the Golgi apparatus. These are the cis face, the medial region, and the trans face.
  • The cis face of the Golgi apparatus is the entry point for proteins and lipids that are  on the rough endoplasmic reticulum (RER) and are transported to the Golgi apparatus for further modification and sorting.
  • In the middle of the Golgi apparatus, in the medial region, proteins and lipids are changed and put in the right place. The trans face is where proteins and lipids leave the cell after the Golgi apparatus has changed them and put them in the right place.
  • The Golgi apparatus helps change proteins by adding carbohydrate or lipid groups to them. It also helps fold and sort proteins so they can be sent to their final destination.
  • It also plays a role in making lipids and changing them, such as sphingolipids and glycolipids.
  • The Golgi apparatus is a key part of how eukaryotic cells make proteins and lipids and move them around. It is also essential for how cells work. 

Functions of the Golgi apparatus:

  1. Modification of proteins: The Golgi apparatus modifies newly synthesized proteins by adding carbohydrate or lipid groups to them, a process called glycosylation or lipid modification. This change can change how the protein works, how stable it is, and where it goes inside the cell or in the environment outside the cell.
  2. Sorting and transport of proteins: The Golgi apparatus sorts and directs proteins to their proper destination within the cell or outside the cell. This includes sending proteins to lysosomes to be broken down, to the plasma membrane to be sent out of the cell, or to other organelles to be changed or stored.
  3. Synthesis of complex carbohydrates: The Golgi apparatus also helps make complex carbohydrates like glycolipids and proteoglycans, which are important for cell-to-cell communication and the organization of the extracellular matrix.
  4. Packaging and secretion of proteins: The Golgi apparatus packages proteins into vesicles for secretion outside the cell or for transport to other organelles within the cell. This process is important for many tissues and organs, like the liver, pancreas, and immune system, to work well.
  5. Maintenance of cellular architecture: The Golgi apparatus helps maintain the overall architecture of the cell by providing structural support and organization to the cytoskeleton and cell membrane. This is important for maintaining the shape and function of the cell.

Lysosomes

Lysosomes are small, spherical organelles found in the cytoplasm of eukaryotic cells. They are composed of a single membrane and contain hydrolytic enzymes that are capable of breaking down a variety of biomolecules, including proteins, lipids, and polysaccharides.

lysosomes

Lysosomes are involved in several important cellular processes, including the degradation of waste materials and the recycling of cellular components. They also take part in the process of autophagy, which is how cells break down and reuse their own broken or extra parts.

Lysosomes are formed in the Golgi apparatus and are transported to their final destination by vesicles.

Structure of lysosomes:

  • Membrane: Lysosomes are spherical organelles that are surrounded by a single membrane. This membrane is similar to the cell’s plasma membrane and is composed of lipids and proteins.
  • Enzymes: Lysosomes have many different types of hydrolytic enzymes that can break down many different types of biomolecules, such as proteins, carbohydrates, lipids, and nucleic acids. The rough endoplasmic reticulum makes these enzymes and sends them to the Golgi apparatus, where they are put into vesicles and sent to the lysosomes.
  • pH: The pH inside lysosomes is lower than the pH of the rest of the cell, which helps to activate the enzymes and increase their efficiency.
  • Size: Lysosomes range in size from 0.1 to 1.2 micrometers in diameter.
  • Function: Lysosomes function as the cell’s waste disposal system, breaking down and recycling old or damaged organelles and other cellular components. They also play a role in the immune system, where they can engulf and digest foreign substances such as bacteria and viruses.

Functions of Lysosome

  • Degradation of waste materials: Lysosomes contain a variety of hydrolytic enzymes that can break down waste materials and foreign substances that enter the cell. This helps to keep the cell clean and free of debris. 
  • Recycling of cellular components: When organelles or other parts of a cell are broken or no longer needed, lysosomes can help break them down and recycle the molecules that are left over for use in the cell. 
  • Autophagy: Lysosomes are involved in the process of autophagy, in which cells break down and recycle their own damaged or unnecessary components. This helps to maintain the overall health and function of the cell. 
  • Defense against pathogens: Lysosomes can also play a role in the immune system by helping to destroy pathogens that enter the cell. 
  • Disposal of excess materials: If a cell produces too much of a particular molecule, lysosomes can help break it down and dispose of it. This helps prevent the buildup of harmful substances within the cell.

Cytoskeleton

The cytoskeleton is a network of protein filaments that is found within the cytoplasm of eukaryotic cells.

cytoskeleton
  • It is composed of three main types of filaments: microtubules, microfilaments, and intermediate filaments.
  • The cytoskeleton provides structural support to the cell and helps to maintain its shape.
  • It also plays a role in cell division, cell movement, and the transport of materials within the cell.
  • The cytoskeleton is dynamic, meaning that it is constantly undergoing changes in response to the needs of the cell.
  • It is composed of various proteins, including tubulin, actin, and intermediate filament proteins.
  • The cytoskeleton is an important part of how cells work, and it can be found in all eukaryotic cells. 

Functions of Cytoskeleton

  • Maintaining cell shape: The cytoskeleton helps give cells their shape and prevents them from becoming too round or too elongated.
  • Supporting the cell’s structure: The cytoskeleton helps hold up the cell and its organelles, giving the cell a framework to work within.
  • Facilitating cell movement: The cytoskeleton helps cells move, like when the cilia and flagella move. It also helps cells move during processes like wound healing and immune response.
  • Involved in cell division: The cytoskeleton is important for cell division, like when the duplicated chromosomes separate during mitosis and the mitotic spindle forms.
  • Transporting materials within the cell: The cytoskeleton also helps move organelles and vesicles around inside the cell.
  • Regulating gene expression: The cytoskeleton can also help control gene expression by putting the nucleus and other parts of the cell in the right place.

Peroxisomes

Peroxisomes are small, spherical organelles that are found in the cytoplasm of eukaryotic cells. They are similar in size and shape to lysosomes, but they have a different function. There are many different enzymes in peroxisomes. These enzymes are involved in many different metabolic processes, such as breaking down fatty acids and getting rid of harmful substances.

Structure:

Peroxisomes are made up of a single membrane that surrounds enzymes and other molecules inside. The membrane is made up of phospholipid bilayers, similar to the cell membrane and other organelles. The endoplasmic reticulum makes peroxisomes, and vesicles carry them to their final destination.

Functions:

  1. Breakdown of fatty acids: Peroxisomes contain enzymes that are involved in the breakdown of fatty acids, a process known as beta-oxidation. This helps generate energy for the cell.
  2. Detoxification of harmful substances: Peroxisomes also contain enzymes that are involved in the detoxification of harmful substances, such as alcohol and certain drugs. These enzymes change the harmful substances into safer byproducts that can be released from the cell.
  3. Synthesis of certain amino acids: Peroxisomes also have enzymes that help make ornithine and arginine.
  4. Oxidation of certain molecules: Peroxisomes contain enzymes that can oxidize certain molecules, such as hydrogen peroxide. This helps prevent the buildup of harmful substances within the cell.
  5. Metabolic reactions: Peroxisomes are involved in a variety of metabolic reactions, including the synthesis and degradation of certain molecules. They play a vital role in the overall functioning of the cell.

Vacuoles

Vacuoles are large, fluid-filled organelles that are found in the cytoplasm of eukaryotic cells. They vary in size and shape depending on the type of cell in which they are found. The tonoplast, a single membrane that surrounds vacuoles and divides them from the rest of the cell, is what separates the contents of the vacuole from the rest of the cell..

what are vacuoles

Structure:

Vacuoles are made in the Golgi apparatus, and vesicles take them to where they need to go. They are made up of a single membrane called the tonoplast. This membrane surrounds the fluid inside the vacuole. The tonoplast is made up of phospholipid bilayers, similar to the cell membrane and other organelles.

Functions:

  • Storage: Vacuoles are involved in the storage of a variety of substances, including water, ions, and organic molecules. This helps to maintain the balance of substances within the cell.
  • Waste disposal: Vacuoles can also be used to get rid of waste and extra substances inside the cell.
  • Support for cell structure: Vacuoles are flexible compartments inside the cell that can help keep the cell’s shape.
  • Plant cell growth: In plant cells, vacuoles are involved in the growth and expansion of the cell. As the vacuole fills with water, it helps to increase the turgor pressure within the cell, which helps to maintain the cell’s shape and support its structure.
  • Defense against pathogens: Vacuoles can also help keep pathogens that get into a cell from spreading by isolating and killing them.

Frequently Asked Questions (FAQs)

What is the structure of an animal cell?

The parts of an animal cell are the cell membrane, the cytoplasm, and the DNA, which is the genetic material. They also have organelles and structures like the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and the cytoskeleton. These organelles and structures do the different jobs that are necessary for the cell to work as a whole.

What are the functions of the organelles in an animal cell?

Each organelle in an animal cell has a specific job that is important for the cell to work as a whole. The cell’s DNA is stored in the nucleus, which also helps control how genes are expressed. The mitochondria are the cell’s energy-producing organelles, generating ATP through cellular respiration. Proteins and lipids are made and moved around by the endoplasmic reticulum and the Golgi apparatus. Lysosomes have hydrolytic enzymes that help break down waste and recycle cellular parts. There are enzymes in peroxisomes that help break down fatty acids and get rid of harmful substances. The cytoskeleton is made up of a network of protein filaments that hold the cell together and help it keep its shape.

How do animal cells differ from plant cells?

Some parts of animal and plant cells are the same, like having a cell membrane, cytoplasm, and organelles. However, there are also several key differences between the two types of cells. Plant cells have a cell wall that provides additional support and protection, while animal cells do not. Plant cells also have chloroplasts, which are involved in photosynthesis, while animal cells do not. Plant cells have a big central vacuole that stores water and other things. Animal cells, on the other hand, usually have smaller vacuoles or none at all. Finally, plant cells have cell plates, which are involved in cell division, while animal cells do not.

Summary of Animal cell

Animal cells are the basic building blocks of life in animals. They have a cell membrane, cytoplasm, and DNA, which is the genetic material. Animal cells are diverse and can vary in size, shape, and function depending on the type of tissue or organ in which they are found.

They are made up of different organelles and structures, such as the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and the cytoskeleton. These organelles and structures do the different jobs that are important for the cell and the organism as a whole to work.

Animal cells take part in things like metabolism, growth, reproduction, and reacting to things that happen around them. Overall, animal cells are complex structures that are well put together and play a key role in keeping life going.

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