These worksheets will help you learn more about all the organelles found within cells. We start by exploring the main structures that function to keep the basic units of life thriving. We investigate how they interact and the movement of substances within the plasma membrane. We identify features that are distinct to both plant and animal forms of these structures. We also look at the history behind how we learned all of this. These worksheets breakdown each organelle in great detail. They are super helpful to understand the functions and processes of these individual cell parts.
Organelles are tiny structures inside the cells of organisms. In the same way that each organ in the body does a specific job, each organelle has its own distinct way of contributing to the overall health of the unit.
The cells of plants and animals also have organelles that are specific to them, because each for needs to perform some very different kinds of functions. When you make your own food, you need some more ingredients for your recipe.
A nucleus functions like a "brain," directing the actions of all the other organelles. Most cells only have one nucleus.
The endoplasmic reticulum is a core organelle that plays a role in producing, processing, and transporting proteins and lipids.
Chloroplasts contain a green pigment called chlorophyll. In the first step of photosynthesis, the chloroplasts capture sunlight when molecules of chlorophyll absorb energy.
Storage granules are another kind of specialized organelle in cells that produce a lot of material that needs to be released from the cell.
The most important function that the nucleus performs is to store deoxyribonucleic acid, more commonly known as DNA.
The number of mitochondria in a cell vary, depending on what kind of cell it is. Simple bodies require less energy and contain only one or two mitochondria.
The structure of mitochondria is as follows. The organelle is protected by a smooth outer membrane. The shape of this membrane varies.
The ribosome is made up of two main parts (subunits) that join together in order for the ribosome to make a new protein.
Messages containing these specific instructions are transmitted to the cell by messenger RNA.
The ER is a continuous membrane system, and the space within the ER is called the lumen. The ER extends from the cell membrane through the cytoplasm and is continually connected to the nuclear envelope.
The smooth endoplasmic reticulum is a transitional area for transport vesicles and plays a role in the creation of carbohydrates and lipids.
While chloroplasts are generally oval-shaped, their shape can vary. They vary in size as well, sometimes taking up most of the space inside of a cell.
But it wasn't until the invention of the transmission electron microscope in 1933 that scientists were able to observe and study cells more closely.
Vacuoles are fluid-filled sacs separated from the cytoplasm by a single membrane called the tonoplast.
Vacuoles are also used by the cell for storage. They keep important minerals, water, nutrients, ions, waste products, smaller molecules, enzymes, and plant pigments separate from the cytoplasm.
What Are Cell Organelles?
All living things are made up of a bunch of cells. What is pretty each, when it comes to humans, is that there are more bacterial cells in or on you than there you have actual human forms. Each of these units of life are made up of much smaller units that each perform a different job. These smaller parts are called organelles. Organelles can be thought of as organs of the cells they are in. Each organelle is vital to complete all the tasks for the body itself. Each of these units is surrounded by a protective shield that is made from protein and lipids (fats) called the plasma membrane. This membrane decides what can go into and come out of the unit itself. There is a control center of the cell called a nucleus that has all the instructions for carrying out every activity within the entire unit. This is a small compact organelle called the mitochondria that helps it make usable energy from food. Everything in the cell is covered in a jelly-like substance called cytoplasm this helps things move around and be used by other parts. The body of the cell is held up by an organelle called endoplasmic reticulum and it allows things to be transported to neighboring cells.
A cell is the basic functional unit of life. It is a self-contained system consisting of tiny powerhouses, storehouses, control centers, and transport channels. It can sustain itself, thanks to the presence of cell organelles.
Cell organelles are structures found within the cytoplasm of a cell. They are considered to be either non-membrane or membrane-bound. Each organelle varies in shape and function but coordinates with each other for the proper functioning of the cell.
In this article, you'll briefly learn about the various cell organelles, as well as their structures and functions. But first, I'll highlight their categories.
Organelles Can Be Membranous or Non-Membranous
Membranous organelles are those that are surrounded by a membrane of their own. Some are bound by a single membrane, while others have a double membrane. These organelles are exclusively found in eukaryotic cells.
Non-membranous organelles, on the other hand, do not possess bounding membranes. These organelles can be found in both eukaryotic and prokaryotic cells.
Let's now look at the organelles in each category in detail.
These membranous organelles play important roles in eukaryotic cells:
- Plasma membrane
- Endoplasmic Reticulum
- Golgi apparatus
The plasma membrane is the outer covering of the cell that separates the intracellular environment from the extracellular. It's composed of phospholipids and proteins. It is also semi-permeable, allowing only certain materials to enter or exit it.
The nucleus is the largest organelle and the "command center.” It is dark and round. It monitors all cellular activities using the genetic information (DNA) it stores. Inside the nucleus is the nucleolus, a structure that synthesizes and stores RNA.
The endoplasmic reticulum (ER) is a network of fluid-filled tubules that connects to other cell organelles. It is the cell's transport system.
The rough endoplasmic reticulum (rER) is studded with ribosomes and is involved in the synthesis and transportation of proteins. The smooth endoplasmic reticulum (sER), on the other hand, synthesizes and transports lipids.
The mitochondria are sausage-shaped organelles. They are sites for energy production (respiration), known by many as the powerhouse. They are abundant in cells that require high amounts of energy to function, such as the muscle and sperm cells.
Chloroplasts are found in plant cells and that of certain algae. They are sites for photosynthesis. They contain chlorophyll, a pigment that absorbs sunlight and is used in food production. Chlorophyll is also responsible for the green color in plants.
Also called the Golgi complex, the Golgi apparatus is a series of cisternae that serves as a “factory” or “warehouse” within the cell. It receives proteins from the rER, which it further processes (if required), packages, and transports to other areas.
Lysosomes are tiny sacs containing digestive enzymes. In unicellular organisms, they digest food products and remove waste materials. In multicellular organisms, lysosomes digest and recycle worn-out organelles. They are essential to the removal of waste from within the cell.
Vacuoles are fluid-filled storage sacs containing nutrients and other essential materials the cell needs for survival, mainly in unicellular organisms. They also store and excrete waste materials. In plants, vacuoles help maintain the turgidity of cells through turgor pressure.
Non-membranous organelles include the following:
- Cell wall
Cell walls are absent in animal cells but present in most plants, fungi, algae, and bacteria. In plant cells, they're mainly made of cellulose, providing mechanical support and protection from external damage. They also serve as storehouses for carbohydrates used for growth in seeds.
Ribosomes serve as micro-machines for protein synthesis. They can be found free-floating in the cytoplasm or bound on the surface of the rER. The structure of a ribosome is composed of ribonucleic acid (RNA) and proteins.
Centrioles are cylindrical-shaped organelles found near the nucleus. They are present in animal cells only. They play a significant role in cell division and in the formation of cilia and flagella - locomotive structures in most unicellular organisms.
The cytoskeleton is a complex system of fibers that run throughout the cell cytoplasm forming its "infrastructure." It fulfills the following functions:
- Maintaining the shape
- Holding organelles in position
- Facilitating cell migration
- Forming vacuoles
In a Nutshell
Cell organelles are fascinating entities. They execute varied functions, including protein synthesis, respiration, transportation, movement, support, and more. Hence, they can be viewed as the infrastructure that makes the cell an autonomous city.