Natural Sciences CLEP
Free Study Guide

Chemistry CLEP Study Guide

Name of Exam: Natural Sciences CLEP

Number of Questions: 120

Time Limit: 90 Minutes

ACE Recommended Passing Score: 50

Practice Test Available?: Yes - Click here

Cost: $80 + Sitting Fee (Usually no more than $20) at your testing site. Military can take CLEPs for free with Tuition Assistance. Check with your Educational Officer!

Difficulty 1-5 : 3 If you've taken the Biology CLEP (4 if not)
(One being the easiest, and five being the hardest)

Exam Description:

The Natural Sciences CLEP covers the material you would normally see in introductory courses in Biology and Physical Sciences. There will be questions over a wide range of subjects in both of these topics, as well as questions on issues such as environmental pollution, scientific methods, depletion of energy, and the philosophy and history of science.

Personal Thoughts:

Yikes, another six credit CLEP exam with all the joy that it brings! Like the other six credit CLEP exams, the Natural Sciences CLEP tests the knowledge you'd normally receive over two semesters. That means the test is extremely broad, but doesn't go very deep.

This free CLEP study guide isn't going to be able to cover every possible question you may get hit with, simply because it would be entirely too long. If you thought the Biology CLEP Study Guide was tough to get through, imagine combining it with the Chemistry CLEP Study Guide. Are your eyes bleeding yet?

Instead, I'll pull from both of those, along with some other resources to hopefully target just what's on the Natural Sciences CLEP without going too deeply. Keep in mind there are 120 questions for this CLEP exam, and multiple versions. Just like I do for all six credit test preparation I highly, highly suggest you use InstantCert for the Natural Sciences CLEP. Knowing exactly what others have been tested on helps to target what you need to study for in turn.

I also always recommend people take the Biology CLEP before the Natural Sciences CLEP exam. The Biology CLEP is a pain to study for, but the same material makes up half of this exam. The extra studying you'll do for the Biology CLEP will only help you pass this one.

Exam breakdown:

According to the College Board website, the Natural Sciences CLEP is broken down as follows:

50% - Biological Science

20% Structure, function, and development in organisms and patterns of heredity
10%Concepts of population biology with an emphasis on ecology
10% Origin & Evolution of life and the classification of organisms
10%Cell organization, chemical nature of the gene, biosythesis, bioenergetics, and cell division.

50% - Physical Science

12% Thermodynamics, Heat, and states of matter. Classical Mechanics, Relativity
10%Chemical elements, molecular structure and bonding, compounds and reactions
10% Earth - Atmosphere, structure, surface features, history, geological processes, hydrosphere, properties
07% The Universe - The Solar System, Stars, and Galaxies.
07% Nuclear and Atomic properties and structure. Elementary particles and nuclear reactions
04% Waves, sound and light. Electricity and magnetism.

Areas of Study

I'm going to break down the percentages above with the topics that fall under each category. This should allow you to decide what you need help with, and only study those areas in which you feel a little weak. Less wading through masses of resources, and more targeted studying.

Biological Science
(50% of the Natural Sciences CLEP)

  • Plant Biology Part 1 and Part 2 - You'll need to know the different parts of a plant, as well as what each part's function is. You'll also need to be able to identify the parts in a picture. The first site has a good overview of the different parts of the plant, click on each get a brief description. It also has a quiz. The second site is more of a read but goes into more detail.
  • How Roots Work - A very simple explanation of how the roots of a plant draw the water and nutrients from the surrounding soil.
  • Overview of Photosynthesis - Understand the process as well as the chemical equation. Don't get upset that this is a site for kids. It has a lot of good information in it. You wouldn't believe how hard it is to find a decent illustration of the process of photosynthesis. The best one I've found can be seen here.
  • Alternation of Generations - The most basic explanation I've found. A more in-depth explanation can be found on the Wikipedia entry for this topic.
  • Plant Reproduction - Know Meiosis, Diploid, Haploid, Gametes, Mitosis, and pretty much every other underlined word on these pages, just follow the links. May be overkill for the Natural Sciences CLEP, but better safe than sorry, eh?
  • Plant structure and growth - Builds off the before mentioned material, but is in a quiz format. You probably won't know this at first, so answer what you do know and study the rest. Has the best diagrams for this that I've seen.


  • Cell Organelles - Subunit of cells with specialized purpose. Atoms are organized into molecules. Molecules are organized into organelles. Organelles are organized into cells......
  • Cell Membranes - Know the purpose as well as the makeup.
  • Prokaryotic Cells - Organisms whose cells do not contain a Nucleus.
  • Eukaryotic Cells - Organisms whose cells contain a Nucleus. Most living organisms fall under this category (including humans).


  • Enzyme-substrate complex - Because I like pictures with my explanations.
  • Coenzymes - A cofactor that is loosely bound to a protein
  • ATP - It's not formally part of this section, but it's going to be hard to understand the below topics if you don't understand ATP.
  • Glycolysis - Understand what goes in and what comes out
  • Aerobic Respiration
  • Anaerobic Pathways
  • Photosynthesis - We covered it earlier, but here's another look.
  • Chromosome Structure - Interesting in its own right, but make sure you know the basic structure along with the different stages below.
  • Meiosis and Mitosis - Best explanation I've seen for this.
  • Cytokinesis - Know what it is, and know what the exception is.
  • Watson-Crick Model - A good overview. Try this link for the background story. It's a fascinating one to read.
  • DNA Replication - A good overview of the process as well.
  • Mutation - Know the different types of mutations. To be safe I would check out the previous page as well on Chromosome mutations. A bit of extra knowledge won't hurt. Check out this resource as well for some more depth and causes of mutation. No need to go too deep on that one.
  • Control of Protein Synthesis - A great overview that touches on the below topics as well.
    • Transcription - A good explanation of the process.
    • Translation - If you kept reading on the above link, you've likely already seen this. If not, then read it here and know it well!
    • Posttranscriptional Processing - This was probably the easiest portion of this entire section for me to grasp.
  • Structural and Regulatory Genes - I wish I could find something for you a bit more detailed on Regulator Genes, though it's pretty straightforward concept. Just know what both of these are and what they do.
  • Transformations
  • Viruses - Spend some time on this one. Understand what they are, how they spread and how they are treated. Understand what vaccines are as well (Dead or weakened forms of the virus). Another great source with pics!

Principles of Ecology

  • Energy Flow and productivity in ecosystems - I usually try not to dip too deeply into Wikipedia sources, but they really nail Ecology so expect to see more of it.
  • Population Growth Rate - It's a good idea to remember this one. I think it shows up on the Biology CLEP, World Population Excelsior exam and the Sociology CLEP as well. I'm not so sure for the Natural Sciences CLEP, but you may as well learn it now. Besides, it may win you some money on Jeopardy one day. ;)
  • Community structure, growth, and regulation - Everything you'll need to know about ecological communities.
  • Kin Selection

Principles of Evolution

Principles of Behavior

  • Human Population Growth - Remember this page? I knew I remembered that formula from the Biology CLEP! Read the whole page this time, not just the formula.
  • Human intervention in the natural world - The gist of this section is - "Humans are wrecking the planet!" Using up resources, destroying the natural order of things, etc. You may get one or two questions asking about humanity's impact on the natural order, which is almost always a bad thing.

Physical Science
(50% of the Natural Sciences CLEP)

*Pant.. pant.. halfway done!*

Binding forces


Relationships in the periodic table (Know how to read it and what each number stands for):

First law of Thermodynamics:

Second Law:


Light and Sound


Earth Sciences - There's a lot of them, but a simple grasp will suffice for the Natural Sciences CLEP. This is a great site and basically a Natural Sciences tutorial. Check out the Physics portion as well.

Recommended bargain-priced study resources

Always check your library first! You may be able to find some of these for free. You don't have to buy the officially recommended resources all the time. If you're the type of person that prefers to study from a textbook source however, then please see below.

CLEP Natural Sciences with CD-ROM (REA) - Published a month ago at the time of this writing, so I haven't been able to get a copy to review. Placed here on the strength of REA's other offerings, and the fact that there's not much out there for the Natural Sciences CLEP in terms of dedicated material to study. As with all of these, I recommend you use them in conjunction with InstantCert.

Cracking the CLEP, 5th Edition (College Test Preparation) - Hopefully you took my advice on one of the other CLEP's this covers and you still have the book. This covers English Composition, College Mathematics, Humanities, Social Sciences, and the Natural Sciences CLEP. Quite the bang for the buck. I wouldn't use it as a stand-alone source, but with IC it should give you enough to smoke this exam. Save it for the rest of the CLEPs if you plan on taking them.

Review For the CLEP Natural Science Examination - This wouldn't be here if there wasn't a lack of study material for this exam. I've never been a fan on the "Official" study guides, mainly because the value usually just isn't there. I would definitely not use this as your primary source of study, but it's a good secondary (or tertiary) study resource. Included here just to give you some options. Most libraries do carry these, so check there before you shell out any money.

InstantCert Academy - Natural Sciences Exam Feedback - Three pages of great notes, after action reports, and study material for the Natural Sciences CLEP.

If you don't know what InstantCert is, then click here for the scoop as well as a discount code: **InstantCert Academy**

You'll find an InstantCert link for every exam here if that gives you an idea of the amount of information they have available. It's an outstanding resource.

Closing Thoughts

If you've already taken and passed the Biology CLEP, then you're over halfway there to successfully passing the Natural Sciences CLEP as well. If you haven't take the Biology CLEP yet, then I'd seriously suggest you at least consider it. It's worth six credits, fulfills most of the same requirements as the Natural Sciences CLEP, and the extra study will only do you good.

Whether or not you take my advice, make sure you have the Biology portion down cold for this one, and then work on the Chemistry, Physics, Geology, and Astronomy in that order. Use the Chemistry CLEP Study Guide to brush up on the sections you're weak on (especially isotopes, catalysts, etc). It does go deep, but you need to know what they all are and what they do. Terminology is the name of the game for this CLEP, so know your terms well.

This is for another six credits, so go get 'em!

Best of luck!

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