Structure of Animal Cells – Both plants and animals are composed of cells that have
differences. One of the differences between the two can be seen from their size, namely animal
cells are smaller than plant cells. Animal cell is the general name for the eukaryotic cells
that make up animal tissues.
The structure of animal cells differs from other eukaryotic cells, such as plant cells, in that they lack a
cell wall, and chloroplasts, and they usually have smaller, if not none, vacuoles. Lacking a
hard cell wall, animal cells vary in shape. The human cell itself is a type of animal
cell.
The structure of animal cells consists of mitochondria, centrioles, nucleus, nucleolus, chromatin,
ribosomes, endoplasmic reticulum, microtubules, plasma membrane, vacuoles, cytosol, nuclear envelope, golgi
bodies, cytoskeleton, lysosomes, and peroxisomes. To understand in more detail about animal
cells including the definition, characteristics, structure of animal cells, functions and so on, here is an
explanation that we can learn.
Definition of Animal Cell
Animal cells are the smallest organelles with a thin membrane in which there is a colloidal solution
containing chemical compounds. This cell has a number of advantages, one of which is being able
to duplicate itself independently through the process of division.
Inside the cell there are compounds that are important for the process of division and also photosynthesis,
namely carbohydrates and lipids. It is known, carbohydrates are very useful in the process of
photosynthesis. While lipids function as food reserves, such as fats and oils. In
addition, there are also proteins that play a role in the metabolic processes of animal and plant bodies, as
well as nucleic acids which are compounds with quite an important role in the process of protein
synthesis.
Functions, Parts, and Structure of Animal Cells
Broadly speaking, animal cells and plant cells are the same. Both based on animal cell
structure, enzyme type, and also genetic material. In fact, both have diverse cell
types.
So, here are some of the functions and structures of animal cells that we need to know, including:
1. Cell membranes
The cell membrane is a semipermeable membrane in a cell that surrounds and encloses the contents of the
cytoplasm and nucleoplasm. The cell membrane separates the cell from the interstitial fluid
(the main component of extracellular fluid) around it. The formation of cell membranes is
carried out with the basic ingredients in the form of lipoproteins which are formed by fats and proteins.
This membrane is composed of a lipid bilayer, including cholesterol (a component of the lipid)
which is sandwiched between phospholipids to maintain fluidity at various temperatures.
The cell membrane also contains membrane proteins, including integral membrane-crossing proteins (serving
as membrane transporters) and peripheral proteins loosely attached to the outer (peripheral) side of the
cell membrane, which act as enzymes that shape the cell. The cell membrane controls the
movement of substances in and out of cells and organelles. In this way, it is selectively
permeable to ions and organic molecules.
In addition, the cell membrane is involved in various cellular processes such as cell adhesion, ionic
conductivity, and cell signaling, and serves as a surface on which several extracellular structures attach,
including the cell wall, a carbohydrate layer called the glycocalyx, and an intracellular network of protein
fibers called the cytoskeleton. . In the field of synthetic biology, cell membranes can be
reassembled artificially.
The cell membrane is the outer covering of the cell and is composed of proteins (lipoproteins), fats
(lipids), and also cholesterol. This section has a fairly important role in regulating minerals
and nutrients that are inside or outside the cell.
2. Cytoplasm
The cytoplasm is the part of the cell that is enclosed by the plasma membrane. The cytoplasm
consists of water, proteins, carbohydrates, fats, minerals and vitamins. The cytoplasm serves
as a storage area for cell chemicals that are important for cell metabolism, such as enzymes, ions, sugars,
fats and proteins. In eukaryotic cells, the cytoplasm is the non-nuclear part of the
protoplasm. In the cytoplasm there is a cytoskeleton, various organelles and vesicles, as well
as a cytosol which is a liquid in which organelles float around in it.
The cytosol fills the cell space that is not occupied by organelles and vesicles and is the site for many
biochemical reactions as well as an intermediary for the transfer of materials from outside the cell to
organelles or the cell nucleus. The cytoplasm is colloidal. The dissolved particle
size is 0.001-0.1 micron and is transparent. The cytoplasm is inside the cell but outside the
nucleus and other cell organelles.
Please note, the cytoplasm is the liquid part of the cell in the form of a gel. This organelle
has two form phase processes, namely the sol phase (solid) and the gel phase (liquid).
Cytoplasmic fluid can be found in the nucleus and is called the nucleoplasm.
This cytoplasm is a complex colloid which means it is not liquid, but also not solid.
Cytoplasm can change shape depending on the concentration of water contained in it.
Basically, when the water concentration is low, the cytoplasm will turn into a mushy solid.
Meanwhile, when it contains water with a high concentration, the gel will turn out to be more
dilute, so it is called sol. Cytoplasmic organelles serve as a source of cell chemicals and
also the place where animal cell metabolism takes place.
3. Endoplasmic Reticulum
Next is the endoplasmic reticulum which is a thread-shaped organelle in the cell nucleus. The
endoplasmic reticulum is an organelle that can be found in all eukaryotic cells. The
endoplasmic reticulum is part of the endomembrane system. The endoplasmic reticulum is such a
large membranous labyrinth that it comprises more than half of the total membrane in eukaryotic
cells.
The endoplasmic reticulum consists of a network of tubules and membranous sacs called
cisternae ( Latin cisterna , meaning “box” or
“chest”). The endoplasmic reticulum membrane separates the internal spaces, namely the
sternal space and the cytosol. This membrane is in direct contact with the nuclear envelope
or nuclear envelope, so that the space between the two envelope membranes is connected to the
endoplasmic reticulum sternal space.
The endoplasmic reticulum is divided into two, namely rough endoplasmic reticulum and smooth endoplasmic
reticulum. The rough endoplasmic reticulum has the ability to attach to ribosomes, while the
smooth endoplasmic reticulum is not attached to ribosomes.
The function of the endoplasmic reticulum organelles is as a protein synthesis and also as a transport site
for the synthesis of steroids and fats. In addition, the endoplasmic reticulum also plays a
role in helping detoxify harmful cells in cells and as a place to store phospholipids, steroids, and
glycolipids.
4. Mitochondria
The next part of animal cells is the mitochondria which is the largest organelle as a machine in cells.
This organelle has two layers of indented membranes called cristae. Inside the
mitochondria, glucose and oxygen work together to form the energy needed.
Of course, this process is part of the body’s metabolic processes and cellular activities so that mitochondria
are also referred to as The Power House . Single mitochondria are called mitochondrions
which are capable of converting chemical energy into other forms of energy. In conclusion,
these mitochondria function as a means of cellular respiration and produce energy in the form of
Adenosine Triphosphate (ATP).
5. Microfilaments
Microfilaments or actin filaments are part of the cell framework (cytoskeleton) in the form of solid rods
about 7 nm in diameter and composed of actin protein, which is a globular protein.
Microfilaments are present in eukaryotic cells. In contrast to the stress-resisting
(compressive) role of microtubules, the structural role of microfilaments in the cytoskeleton is to resist
tension (tensile forces).
By joining with other proteins, microfilaments often form three-dimensional strands just inside the plasma
membrane, which help support the shape of the cell. These strands give the cortex (outer
cytoplasmic layer) of the cell its semisolid, gel-like consistency, as opposed to the more fluid state of
the inner cytoplasm (sol).
In animal cells specialized for transporting materials across the plasma membrane, bundles of
microfilaments form the core of microvilli, fine projections that increase the surface area of the cell.
Microfilaments are well known for their role in cell movement, especially as part of the muscle
cell contraction apparatus. Thousands of actin filaments arranged parallel to each other
throughout the muscle cell are interspersed with thicker filaments made of a protein called myosin.
Muscle contraction occurs due to microfilaments and myosin sliding past each other, which shortens
the cell.
Microfilament activity causes movements such as cytoplasmic flow and ameboid movement (movement of single cells
of protists, fungi, and animals that use their protoplasm flowing out of the cell to form a kind of pseudopod or
pseudopod, then the remaining part of the cell advances towards the pseudopod to produce cell movement in the a
surface).
Microfilaments are visualized under fluorescence microscopy with the aid of antiactin antibodies (obtained from
actin opponents in animals) or with the fluorescent analogue falotoxin (derived from the fungus Amanita
phalloides ), which typically binds to the actin molecule (or actin-like).
Microfilaments are cell organelles made up of actin and myosin proteins. Microfilaments are
almost similar to microtubules, but have differences in texture and size. Microfilaments have a
softer texture with a smaller diameter. Its function is as cell movement, exotic, and
endocytosis.
6. Lysosomes
Lysosomes are membrane bound sacs containing hydrolytic enzymes. Lysosomes are located in
eukaryotic cells, this section is useful for controlling intracellular digestion under any conditions.
Lysosomes function to control intracellular digestion, digest material using phagocytosis, destroy
damaged cell organelles, and enter macromolecules from the outside into the cell through the mechanism of
endocytosis.
7. Peroxisomes
Peroxisomes, also known as micro bodies, are small sac organelles that contain the catalase enzyme.
Its function is to decompose peroxide (H2O2) or metabolism which is toxic and converts fat into
carbohydrates. Peroxisome organelles can be found in the liver and kidney cells.
8. Ribosomes
Ribosomes are cell organelles that have a dense texture with a small size, which is about 20 nm in
diameter. This organelle consists of 65% ribosomal RNA and 35% ribosomal protein or
ribonucleoprotein. Ribosomes in animal cells translate RNA to form polypeptide chains or
proteins using amino acids during the translation process. Ribosomes are attached to the rough
endoplasmic reticulum or the cell nucleus membrane which serves as the site for the process of protein
synthesis.
9. Centrioles
Centrioles are tube-shaped organelle structures in eukaryotic cells. These organelles play an
important role in the process of cell division by forming spindle threads and forming cilia and flagella.
Not only that, a pair of centrioles can also form a combined structure called a centrosome.
10. Microtubules
The next cell organelle is the microtubule which is located in the cytoplasm. Microtubules can
also be found in eukaryotic cells which are long hollow cylinders. This organelle has a
diameter of about 12 nm and an outer diameter of about 25 nm.
Microtubules are made up of several spherical globular protein molecules called tubulin. In an
unconscious position, these organelles are able to combine to form hollow cylinders under certain
conditions. Not only that, microtubules are also rigid which cannot be changed in shape.
Based on this definition, microtubules function to protect cells, give cells shape, and form cilia, flagella, and
centrioles.
11. Golgi apparatus
The Golgi apparatus, also known as the Golgi apparatus, is an organelle related to the excretory function
of animal cells. Its position is right on eukaryotic cells that play a role in the excretion
process, such as the kidneys. It looks like a flat bag of varying sizes and is bound by a
membrane. Each animal cell has around 10-20 golgi bodies.
The structure of the Golgi apparatus consists of bundles of disc-shaped sacs which branch into a series of
very small vessels at the ends. Because of its close relationship with the cell’s excretory
function, vessels collect and package carbohydrates and other substances for transport to the cell
surface.
The vessels also contribute materials for the formation of the cell wall. The Golgi body is
built by a membrane which is shaped like tubules and also vesicles. From the tubules are
released small sacs that contain the necessary materials such as enzymes that form the cell wall.
12. Nucleus
The nucleus is the smallest organelle that regulates and controls the activities of animal cells.
This process starts from metabolism to cell division. The nucleus contains genetic
material in the form of long linear DNA forming chromosomes. This organelle can be found in
eukaryotic cells which consists of several parts, such as the nuclear membrane, nucleoplasm, chromosomes,
and nucleus.
13. Nucleolus
The nucleolus (plural nucleoli , Latin: nucleolus , also known as the daughter cell
nucleus) is a non-membrane bound structure consisting of proteins and nucleic acids in the cell nucleus
(nucleus). Ribosomal RNA (rRNA) is transcribed and assembled in the nucleolus.
The ultrastructure of the nucleolus can be visualized via electron microscopy, while the
organization and dynamics can be studied through tagging of fluorescent proteins and fluorescent
recovery after photobleaching (FRAP).
The nucleolus is an organelle present in the cell nucleus or nucleus. Its function is to form
proteins using RNA or ribonucleic acid. Nucleolar damage can be the cause for several human
diseases. Required up to about 25% of nuclear volume.
14. Nucleoplasm
Nucleoplasm has a dense texture inside the cell nucleus or nucleus. It contains dense
chromatin fibers and forms chromosomes. Moreover, the nucleoplasm is responsible for carrying
the genetic information.
15. Nuclear Membrane
The nuclear membrane is the main structural element of the nucleus that encloses all the organelles of the
animal cell. In addition, this organelle acts as a separator between the cytoplasm and the
nuclear region. The nuclear membrane is non-permeable or cannot be passed by all substances,
whether solid or liquid, so that most of the molecules that make up the nucleus require the presence of a
core pore.
Well, that’s a brief explanation of the meaning, parts, functions, and structure of animal cells.
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about the most dangerous animals in the world so they can fully understand them. Happy
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