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Preparing to study biology

Biology is build on top of physics, chemistry, math, and statistics.

What should I know before starting biology?

If you are curious about biology or plan to study it in the future, you may be wondering what "prerequisites" it has – that is, what other knowledge will give you a solid foundation to learn biology. If so, big kudos for thinking ahead!
In my opinion, the only strict prereqs for biology are curiosity, an open mind, and a willingness to think critically about the natural world. If you have those, you can start learning biology without other background, as long as you're willing to pick up bits of chemistry, physics, statistics, and math along the way.
That said, you may find your journey through biology smoother and more satisfying if you already have some familiarity with topics in other areas, particularly chemistry. Below are some foundational topics that will help you get the most out of Khan Academy's biology materials (or any biology class).

General science skills

  • The scientific method. Are you rusty on what a hypothesis is or how it gets tested? How about experiments? These basic concepts will help you not only in biology, but also in any other area of science.


  • Introduction to chemistry. A big picture view of chemistry and why it is important to math and other sciences, like biology.
  • General chemistry. Get a feel for atoms, molecules, and how they interact with each other. After all, that's what you (and all life) are made up of.
  • Acid-base chemistry. A lot of the chemistry in your body is acid-base chemistry that takes place in watery solutions. Knowing what acids and bases are will get you a long way with biochemistry.


  • Laws of thermodynamics. Get a feeling for what energy is and what rules govern its transfer. Energy is constantly flowing through ecosystems, organisms, and cells, and is essential to keep these systems running.


  • Basics of probability. Probability is a key concept in biology. You don't need to know tons of details or formulas, but if you understand the basic concepts, that will help you a lot with genetics and population genetics.
  • Statistics. Remind yourself about the basic ways we can describe sets of data, such as mean, median, and mode. If you go even deeper and learn about hypothesis testing, you'll definitely be ahead of the curve!


  • Basic algebra and graphing. Most intro bio classes are not that math-intensive, but having an understanding of basic algebra and graphs (e.g., the meaning of slope) will help you understand figures and data in biology.

Do I have to know all these before starting?

Not necessarily. As I mentioned, you can also learn as you go. You just need to be willing to work on these topics in parallel with your learning of biology. So, don't be deterred from biology if you haven't yet mastered all of these topics.

What if I don't like [chem/physics/stats/math]?

Don't be deterred from biology if some of these topics are not your favorites (yet!). Biology is a huge, diverse field. All biologists need to have some basic, foundational understanding of chemistry, physics, math, and statistics. But they don't have to become specialists in all these topics.
Also, if you had a bad experience with one of these topics in the past, why not give it a shot on Khan Academy? You may find it's more fun than you expect!

Want to join the conversation?

  • blobby green style avatar for user adelynnbettenbrock
    is it weird if a 9th grader takes this class in the middle of the summer for fun or is my life just sad
    (67 votes)
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  • blobby green style avatar for user toyia.barnes
    do we have the same genes as our ancestors
    (13 votes)
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    • duskpin ultimate style avatar for user Liam
      mostly. You see all humans on earth have a 99.9% identical genitic makeup.The remaning .1% sperates you from the world. Usually your genetics are similar to your ancestors but not fully. Over time genes change and can mutate. If you can find some photos of your recent ancestors look at their face shape jawline bodybuild. Most likely it is similar to yours. In the end yes you do have the same genes as your ancestors, but only to an extent.
      (48 votes)
  • blobby green style avatar for user Jas Sal
    Why do we cry? I know how but why
    (0 votes)
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    • male robot donald style avatar for user Tybalt
      There are actually three types of tears. Each type is produced for different reasons, meaning that not all cries are alike.

      1. Emotions. The most known reason as to why we cry. Some scientists propose that this is to relieve the body of chemicals that cause stress, as it has been noted that stress hormones are more present in emotional tears.

      2. A reflex. If something gets into your eye, your body wants it out as soon as possible to prevent infection or damage. You thus cry what are known as reflex tears. Have you ever got a dust particle or bug in your eye, or chopped an onion (releasing irritating fumes)? Your eyes watered, and you started to cry. You likely did not feel sad or happy, but you still cried. These tears have more water in them in order to flush the object out.

      3. Moisturizing your eyes. Yes, your eyes are constantly producing tears, so you are technically crying all the time! However, these tears are there just to lubricate the eye and nourish the cornea. If you had dry eyes, your eyes would get irritated and your ability to see would be reduced.

      Let me know if you need more help.
      (44 votes)
  • blobby green style avatar for user M.E888
    bruhhhh science is sooo hard
    (11 votes)
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  • male robot donald style avatar for user jbarker.rise
    Why is the coronavirus going on in this world is it going to stop or keep on evolving than the first wave of this virus going on?
    (7 votes)
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    • female robot amelia style avatar for user Johanna
      The only virus humans have ever eradicated is smallpox (though two laboratories do still hold some). Given our track record, then, it doesn't seem terribly likely that covid will ever go away completely. Of course it's not completely impossible, so we'll see what happens.

      Covid, like all viruses and living things, is always evolving. We tend to notice this when new variants like those from the UK, South Africa, and Brazil come into the spotlight largely because they likely affect the virus's behavior.

      Did this help?
      (13 votes)
  • duskpin ultimate style avatar for user Annalisia Wilson
    I'm planing on becoming a chemical engineer when I'm older, what course do i take to get more information on chemical engineering?
    (6 votes)
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  • blobby green style avatar for user Kaveesh Balaji
    I have 2 questions.
    1) Do I need a basic understanding of biology to become a dentist?
    2)If not, then what do I need to do to become a dentist?
    (7 votes)
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    • piceratops ultimate style avatar for user Ali Malek
      Pretty late answer, but yes you do need to learn biology to become a dentist. A dentist specializes in teeth which is part of the body. Learning how the body works is essential. In fact, teeth are the last thing dentists learn about in dentistry school. They have to learn about the entire body before learning about the teeth. Hope that helps, and sorry for the late answer. :)
      (0 votes)
  • blobby green style avatar for user Haley.Askin60
    how many genes do we have
    (3 votes)
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    • aqualine ultimate style avatar for user Yaelle
      Humans have around 25 000 genes. It is not much at all compared to the size of our chromosomes, actually it means that less than 10% of the length of our DNA gets translated into proteins ! This shows how eucaryote DNA contains not only genes and genetical information, but also a huuuge part of non-coding or "junk" DNA. Studies have shown that part of this DNA has regulatory functions.
      (6 votes)
  • blobby green style avatar for user umaraminat5
    Can one study biology without these subjects/topics?
    (5 votes)
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  • purple pi pink style avatar for user Cael
    The Orange Juice Squid has arrived.
    (5 votes)
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