Cells! Just how important are they? Okay, let us put it in the simplest possible fashion. No cells, no life. Does that answer your question about how important cells are?
Now that you have a fair idea about what cells mean to every living organism on this planet Earth, we can move ahead and pen down some really interesting cell facts that you should be aware of.
Be it a quiz competition or your school project, you will definitely find these facts handy. So, instead of wasting time any further, let us get started…
Interesting Cell Facts: 1-5
1. Everything that has life – from humans to plants to animals to birds to microorganisms – everything is made of cells. Some living organisms can be single-celled while some are multicellular. For example, bacteria are single-celled organisms while trees, birds, animals, humans – they are all multicellular organisms.
2. Now, we know from our scientists worldwide that live just evolved on Earth somewhere in the distant past. For life to evolve, cells were required. So, somewhere in the distant past, the first cell originated on this planet. Just how back in past we are look into? According to speculations of scientists, the first cell originated on Earth some 3.8 billion years ago.
3. Here is something interesting – there are some nonliving objects on earth that are also made of cells but they (those cells) were once living. For instance wood (dead cells of plants), dust in our house (a portion of that contains dead cells), wool, hair, leather (they were also living cells at one point). Things like steel, iron, ceramics, aluminum etc. are not made of cells.
4. There are two primary types of cells – the Eukaryotic cells and the Prokaryotic cells. Difference between the two? Well, here is the difference: Eukaryotic cells have a membrane enclosing a true nucleus. Prokaryotic cells on the other hand do not have a definite nucleus.
5. The first ever cell that originated on Earth was a Prokaryotic cell. Eukaryotic cells later evolved from the Prokaryotic cells.
Interesting Cell Facts: 6-10
6. Cells are really tiny. So tiny that we cannot see them using our naked eyes. We usually need microscope to see those cells. However, exceptions are always there. Nerve cells or neurons that can stretch right up to our toes starting from our hips.
7. Here is something really interesting that you should know. The size of a cell is usually determined by its diameter and not by the length. The usual size of a typical cell in human body can range anywhere between 10 µm and 100 µm (µm stands for micron, which is 1 millionth of a meter or 1 thousandth of a millimeter).
8. The largest cell in human body is approximately 120 µm. It is the female mature egg and the smallest cell in human body is the spermatozoon’s head with the size of 5 µm.
9. Though humans are made of Eukaryotic cells, there are are 200 different types of cells in human body. Yes, Eukaryotic cells have variants.
10. Wondering what are the different types of cells that are present in our body? We can come up with a few names like the nerve cells, bone cells, skin cells, egg cells, etc. Come on, we cannot list all 200 here.
Interesting Cell Facts: 11-15
11. Bacteria are basically cells. But did you know that we carry around 3 to 5 pounds of bacteria on our body. That much bacteria means, the number of bacteria we carry on our body actually vastly outnumber the number of cells we have in our body. Still, these bacteria only make up 3% of our entire body mass. That’s because, bacteria are way smaller than our cells.
12. Talking about the bacteria outnumbering the number of cells in our body, the question is, ‘how many cells do we have in our body? Don’t be surprised! It is 37.2 trillion!
13. Cells are the smallest life units on this planet. They are self-sustaining and they are very much capable of replicating on their own through a process known as cell division.
14. Do you have any idea of how much time human (and animals in general) cells take to complete a cycle of birth and then division to form new cells? 24 hours to be exact. Yes, a cell will take 24 hours to form and then divide to form new cells.
15. The red blood cells present in human body can live up to 120 days approximately. But different types of cells in human body have different lifespan. For example, neurons have the same lifespan as that of the individuals while skin cells for instance can live only for a few weeks.
Interesting Cell Facts: 16-20
16. Approximately 50 billion to 70 billion cells in human body die every single day. Don’t worry! Remember cell division? You are smart! The commonest cells that die on such large scale are blood cells, skin cells a few other types of cells which line up glands and organs.
17. Heard the word ’tissue’? Well, tissues are formed by a number of cells. Again, a number of tissues form an organ. A number of organs actually form a system.
18. We humans, when we take birth, we actually start off as a single cell. Later, when we are born and when we grow up, we have 37.2 trillion cells. Now that’s incredible! Guess what? That number doesn’t include the bacteria and microbes that reside inside our body.
19. There are 23 pairs of chromosomes inside a single cell. That means, there are 46 chromosomes inside a single cell in human body! Imagine how tiny these chromosomes need to be! These chromosomes are actually inside the nucleus of the cell.
20. Apart from chromosomes, a single human cell actually contains a lot more things than we think. There’s Endoplasmic Reticulum, Golgi Apparatus, Mitochondria, Lysosomes, Microtubules, Microfilaments and Peroxisomes. That’s quite a lot for a tiny cell!
Interesting Cell Facts: 21-25
21. Earlier (#4) we talked about Prokaryotes and Eukaryotes. We also said that Prokaryotes do not have true nucleus while Eukaryotes have true nucleus. However, that’s not the only different. Prokaryotes do not have organelles while Eukaryotes have organelles.
22. Wondering what organelles are? Well, just like our body has organs such as heart, lungs, kidneys, liver etc. that perform some special functions, the cells also have some organs (at cellular level of course). These cellular organs are also designed to perform specific functions. These cellular organs are called organelles.
23. The most important feature of organelles is that they are bound by membranes . If something is inside the cell and is not bound by membranes, it cannot be classified as organelle.
24. Talking of Cell Membrane, both Prokaryotic and Eukaryotic cells have Cell Membrane or Plasma Membrane. In fact, they are same in both types of cells with a few exceptions of course.
25. The job of the Plasma Membrane is to ensure that the cell components (that is, the things that are present inside the cell) are held together. Also, the Plasma Membrane or the Cell Membrane is responsible for substance passage in and out of the cell.
Interesting Cell Facts: 26-30
26. Inside the Cell Membrane or the Plasma Membrane, you can find what is known as Cytoplasm. This Cytoplasm is present in both Eukaryotes and Prokaryotes.
27. The organelles that are present in Eukaryotes are embedded in the Cytoplasm. Since Prokaryotes don’t have any organelles, you won’t find any organelle embedded in the Cytoplasm of the Prokaryotes.
28. Inside both Eukaryotes and Prokaryotes, you will find something called Ribosomes. These Ribosomes are not organelles because they do not satisfy the necessary condition – that is, they are not bound by membranes.
29. These Ribosomes are actually sites of protein production inside the cells. Proteins are actually extremely important because they are needed not only for the functioning of the cells but also for the structure of the cells.
30. When you put a cell under a microscope, you will see various things. In case you put a plant cell under a microscope, you will see what is known as Cell Wall. This Cell Wall is absent in case of animals (including humans).
Interesting Cell Facts: 31-35
31. Exact location of the Cell Wall? It is an extra layer right over the Cell Membrane or the Plasma Membrane. It is tougher than the Cell Membrane. This Cell Wall can also be found in bacteria, which are basically Prokaryotic cells.
32. Again, under the microscope, you may notice that some cells have small projections over the surface of the cells. These projections are on the outside and not inside. The purpose of these small projections is to allow movement. These small projections are referred to as Cilia.
33. Inside the cells, as we said before, is the Cytoplasm. This Cytoplasm is semifluid substance and always invariably remains closed by the Cell Membrane or the Plasma Membrane.
34. Then there is something interesting inside the cells. There is a network of tiny filaments. The purpose of these filaments is to ensure that the cell maintains its shape and they (filaments) also ensure that the organization of components inside the cells are maintained. These filaments also help cells with movement and even cell division. These tiny filaments’ structure is known as the Cytoskeleton.
35. And then there is Endoplasmic Reticulum, which too is an organelle. It is present in most of the Eukaryotic cells and it is the largest organelle inside a cell. It extends all the way from the Plasma Membrane or the Cell Membrane all the way up to the Nuclear Envelope. It is embedded in the Cytoplasm.
Interesting Cell Facts: 36-40
36. The Endoplasmic Reticulum (usually referred to as ER) is not present in Prokaryotic cells because as we mentioned earlier, organelles are absent in Prokaryotic cells.
37. The Endoplasmic Reticulum is a continuous network of flattened sacs and tubules, which are enclosed in membranes. The ER has a number of functions and it actually makes up more than 50% of membranous substances that are found inside a cell.
38. The ER has two distinct parts – the Smooth Endoplasmic Reticulum and the Rough Endoplasmic Reticulum. The tubules network form the Smooth ER part while the flattened sacs form the Rough ER part.
39. Why smooth and rough? The Rough part is basically where Ribosomes are attached on the membrane of ER on the side facing the Cytoplasm. These attached Ribosomes give it a rough appearance. The Smooth part is basically where no Ribosomes are attached and hence, doesn’t have a rough appearance.
40. The space inside the Endoplasmic Reticulum is known as the Lumen. Now, ER is connected to the Nuclear Envelope and hence, there has to be space inside the Nuclear Envelope. This space inside the Nuclear Envelope and the Lumen together form the part of the same compartment.
Interesting Cell Facts: 41-45
41. Both plant cells and animal cells have something known as Golgi Body or Golgi Apparatus. This too is an organelle.
42. The Golgi Apparatus works similar to that of a company’s receiving and shipping department. The job of the Golgi Body is to first sort and then modify and finally package all the large molecules that either the cell secrets or uses internally for a wide range of functions.
43. Golgi Apparatus is not present in Prokaryotic cells because it is an organelle (membrane-bound structure).
44. Ever seen pancakes? Stack them up and what you see is the shape of the Golgi Apparatus. Basically, the Golgi Body is nothing but piled up flattened sacs, each of which are bounded by membrane.
45. Along with that unusual looking flattened sac pile that is known as the Golgi Body, what you will also notice is a bunch of small particle-like structures surrounding the apparatus. These are called Vesicles, which are also membrane-bound.
Interesting Cell Facts: 46-50
46. What do Vesicles do? They basically contain molecules (various types of molecules). These Vesicles are spherical in shape. They have various functions but one of the commonest function you will find is that they transport molecules either from Endoplasmic Reticulum to Golgi Body or from Golgi Body to other destinations.
47. The cells (of course the Eukaryotic ones) contain what is called Mitochondria. Resembling a sausage in terms of shape, the Mitochondria is known as the powerhouse of the cell. Though Mitochondria is actually present in every type of Eukaryotic cell, there are some exceptions. For instance, mature red blood cells of mammalians do not have Mitochondria.
48. Wondering why Mitochondria is called the powerhouse of the cells? That’s because they perform cellular respiration, that is, they are responsible for producing energy from food particles.
49. Cells have something called Nucleus. Only Eukaryotic cells have Nucleus. It is actually a cell’s command center. Put a cell under a microscope and you will find a dark region. That is the Nucleus.
50. If you see properly through a microscope, you will notice a darker spot on the already dark nucleus. That darker spot is the Nucleolus. It is this Nucleolus which is responsible for manufacturing the Ribosomes.
Interesting Cell Facts: 51-55
51. This Nucleus is surrounded by something called the Nuclear Envelope. This envelope is a double membrane structure with space inside the membranes. This space is what connects with the Lumen in Endoplasmic Reticulum (read our previous article).
52. There are tiny openings on the Nuclear Envelope. Those openings are know as the Nuclear Pores. These pores are responsible for regulation of molecule transportation between the Nucleus and the Cytoplasm.
53. The Nucleus plays a very important role in directing every cellular activity by directly controlling protein synthesis. In case you are wondering what proteins do, here is what you need to know for the time being. Everything that a cell does is controlled by proteins, which are basically chemical compounds. They are extremely critical because cells and each and every part of the cells are made out of proteins.
54. Inside the Nucleus is a special type of molecule called the DNA. It has a double helix structure and stores the information required for protein making. DNA stands for Deoxyribonucleic Acid.
55. This DNA has something called nitrogen bases. These bases have special arrangement and each arrangement a specific instruction.
Interesting Cell Facts: 56-60
56. Plant cells and animal cells share a lot in common. However, there are major differences as well. For instance, a plant cell will have Plastids – which are basically organelles. These Plastids are not found in animal cells. There are different types of Plastids. For instance, Chloroplasts, Chromoplasts, Amyloplasts etc.
57. Chloroplasts for instance are designed for converting carbon dioxide and water in sugar using a process known as Photosynthesis.
58. Chromoplasts on the other hand are known for storing pigment molecules. Have you ever noticed that some plants have bright yellow and orange colors? Well, that’s because of the Chromoplasts.
59. Vacuoles are another thing that you can find in plant cells. These Vacuoles are basically large vesicles. There are some plants in which 90% of all the space found in their cells are covered by these Vacuoles. Vacuoles have a wide array of functions and one of those functions is the storage. They store a lot of things including waste products, poisonous compounds, pigments and organic compounds.
60. In our previous article we talked about Cell Wall, which is present in plant cells and bacteria. In case of plants, the Cell Wall is made of basically a very tough carbohydrate. This tough carbohydrate is known as cellulose. The cellulose in turn lays in a network or medium of other carbohydrates.
Interesting Cell Facts: 61-65
61. Cells in animals do not follow any specific shape. They have various shapes and each shape is defined by the function of cells. Some cells even change shape as and when required. For example, Lymphocytes, which are immune cells, can change shape.
62. Plant cells on the other hand have a fixed shape – more or less square or rectangular. That’s because such shape allows dramatic reduction in interstitial shape and even helps in building Cell Wall.
63. All Eukaryotic cells – whether plant cells or animal cells have something known as Peroxisomes. They are also known as microbodies.
64. Peroxisomes are organelles because they are bound by a membrane. There are various jobs assigned to the Peroxisomes. The most vital of these jobs is to oxidize and decompose the organic molecules.
65. There are enzymes present in the Peroxisomes that are responsible for decomposing organic molecules. However, such decomposition actually leads to production of hydrogen peroxide.
Interesting Cell Facts: 66-70
66. The problem with hydrogen peroxide is that it is actually toxic or poisonous for the cells. So, this toxin has to be neutralized right? How does that? Any guess? It is the same organelle that produces the toxin in the first place. Yes, Peroxisomes have another enzyme that takes on hydrogen peroxide and converts it into water.
67. We didn’t speak of Lysosomes, did we? Lysosomes are basically spherical sacs covered with membrane. These sacs store enzymes. Lysosomes are present in most of the animal cells and plant cells.
68. The enzymes that are present inside the Lysosomes are acidic hydrolase enzymes. These enzymes are responsible for digesting the macromolecules. However, there is a problem. It’s acid! Cells cannot really take acid. Solution?
69. The membrane of the Lysosome comes to rescue. It is responsible for keeping the interior of the Lysosome acidic while ensuring that the rest of the cell has no contact with the digestive enzyme.
70. While Lysosomes are often called as digesters of the cells, they are also known as the garbage disposers. They are responsible for recycling organic material in the cells. Lysosomes are often found involved in what is known as “programmed cell death” in various organisms.
Interesting Cell Facts: 71-75
71. Centrioles is yet another fascinating thing found in cells. They are responsible for organizing microtubules assembly during the cell division. Centrioles play a very important role in ensuring that daughter cells get the adequate number of chromosomes.
72. Heard of the term Apoptosis? It is a process of programmed cell death. It is highly regulated and this regulation has to be there because once the process of Apoptosis starts, it cannot stop.
73. There are two ways in which Apoptosis can occur. First is called intrinsic pathway in which the cell actually senses stress and kills itself.
74. The next way that Apoptosis can occur is called extrinsic pathways in which other cells start sending signal to a cell to kill itself and the cell kills itself.
75. Let’s get back to Ribosomes. Remember we said in an earlier article that Ribosomes are attached on Endoplasmic Reticulum? Well, that’s not the only place where Ribosomes are found. They can be found floating freely throughout the entire cell.
Interesting Cell Facts: 16-20
76. Did you know that bacteria are way smaller than animal cells? Well, because they are smaller, they can actually enter inside the cells and wreak havoc. This is where Lysosomes come in and they destroy the bacteria.
77. Ever wondered what’s inside the Cell Nucleus? Well, what you get inside the Cell Nucleus is known as Chromatin, which is basically a combination of histones (a type of protein), ribonucleic acids and DNA.
78. In human body, the only cells that do not have Mitochondria and Nucleus are the Red Blood Cells.
79. Blood cells in human body are known for existing individually but most of the cells in our body are actually connected to each other through a process known as Cell Adhesion. There are special types of proteins that help to fasten the adjoining cells together.
80. Here is something really interesting. The nerve cells in human body are known for sending and receiving message. But how? These neurons make use of electricity!