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Clep natural sciences (rea) (clep test preparation)

Description: Clep natural sciences (rea) (clep test preparation)
File name: Clep natural sciences (rea) (clep test preparation)
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: + Sitting Fee (Usually no more than ) 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% 10% 10% 10%
Structure, function, and development in organisms and patterns of heredity
Concepts of population biology with an emphasis on ecology
Origin & Evolution of life and the classification of organisms
Cell organization, chemical nature of the gene, biosythesis, bioenergetics, and cell division.

50% - Physical Science

12% 10% 10% 07% 07% 04%
Thermodynamics, Heat, and states of matter. Classical Mechanics, Relativity
Chemical elements, molecular structure and bonding, compounds and reactions
Earth - Atmosphere, structure, surface features, history, geological processes, hydrosphere, properties
The Universe - The Solar System, Stars, and Galaxies.
Nuclear and Atomic properties and structure. Elementary particles and nuclear reactions
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. See this diagram for an example of parts you'll likely be asked to identify.
  • Overview of Photosynthesis - Understand the process as well as the chemical equation. 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 Part 1 and Part 2 - Know Meiosis, Diploid, Haploid, Gametes, Mitosis, and pretty much every other underlined word on these two pages. 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.
  • Major body systems - Skim these. You don't have to memorize everything like you would for the Biology CLEP.
    • Muscular/Skeletal Systems
    • Circulatory System
    • Digestive System
    • Nervous System
    • Respiratory System
    • Reproductive System
    • Excretory System
    • Endocrine System
    • Lymphatic/Immune Systems
    • Integumentary System
  • Homeostasis - Know what it is along with how the major systems contribute
  • Gamete Formation and Fertilization - High school biology review for the most part, but make sure you understand this.
  • Cleavage and Gastrulation - Covers both topics well.
  • Differentiation and Germ Layer - Once again, know both of these terms and how they apply to an organism's development.
  • Embryonic Circulation - Know the role the placenta plays in blood/waste transport, as well as the early circulatory system in the embryo.
  • Mendelian Inheritance - This can get complicated very quickly, so just understand who came up with it, and what the general idea is behind it. Once you've covered some of the future topics, you can come back to this one and hopefully find it a bit easier.
  • Mendellian Inheritance Tutorial - A quasi-game that helps explain Mendelian Inheritance. May help those who are having trouble understanding the first link. Don't go too deeply in this for the Natural Sciences CLEP.
  • Polygenic Inheritance - Simple definition of Polygenic Inheritance
  • Polygenic Inheritance (Detailed) - Actually gives the breakdown of how it works.
  • Multiple Alleles - One of the most down-to-earth explanations I've seen for this topic. Cookies for everyone! (But you only get two)
  • Chemical Bonds and Reactions - Obviously understand what each is, but also understand the sub groups (Ionic Bonds and Covalent Bonds)
  • Water and its properties - Just start at the top and work your way down.
  • Biomolecules - Know what each of the below are, and how organisms use them. Don't get too hung up on these for the Natural Sciences CLEP, but you'll need to have them cold for the Biology CLEP.
    • Carbohydrates -
    • Lipids
    • Proteins
    • Nucleic Acids
  • Origin of Life - Philosophical debates aside, know the Big Bang Theory as well as the different accepted periods of life on earth. Also of note is the bottom portion talking about Microscopes.


  • 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.
  • Dark Reactions in Photosynthesis - You'll probably get asked about this one on the Natural Sciences CLEP.
  • 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.
  • DNA and RNA - Know what both of these are, characteristics, and what they each do.
  • Watson-Crick Model - A good overview. Try this link for the background story. It's a fascinating one to read.
  • DNA Replication - You can find another resource here.
  • 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 causes of mutation and a quiz at the bottom.
  • Control of Protein Synthesis - A great overview that touches on the below topics as well.
    • Transcription - Check this one out too. I can't decide which one explains it better.
    • Translation - Make sure you expand the menu on the left. They're missing a continue button between the subtopics.
    • 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

  • Modern Concepts of Natural Selection - Know the background (remember Mendel from earlier?), and then see this continuation.
  • Classification of living organisms - I'm going to put it in caps for you in case you're scanning the page. KNOW THIS!! Just remember the phrase "King Phillip Came Over For Good Soup". I can 99% guarantee you will be asked about this on at least three tests out there including the Natural Sciences CLEP.
  • Evolutionary history of humans - Don't get lost in the details. The CLEP will only ask you for the basics.

Principles of Behavior

  • Learned Behavior
  • Societies - Know the different types besides human, such as the Insect Society
  • 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!

  • Atomic theory and atomic structure
  • Atomic weight
  • Atomic masses
  • Atomic number
  • Mass Number
  • Isotopes
  • More Isotopes
  • li>Periodic Relationships
  • Atomic Radii
  • Ionization Energies

Binding forces


  • Covalent
  • Ionic
  • Metallic
  • Macromolecular (or network)
  • Dispersion - Know the three different types. Follow the links on the main page.
  • Hydrogen bonding
  • Nuclear Equations
  • Half Lives
  • Radioactivity
  • Liquids and solids
  • Liquids and solids from the kinetic-molecular viewpoint - Tons of great information in this book. I've linked directly to the liquids section but the solids are just below it. Check out the rest of this online book for any other subjects that are giving you a hard time.
  • Solutions
  • More on Solutions and Solubility

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

  • Horizontal
  • Vertical
  • Covalent bonds
  • Formation
  • Cleavage
  • Balancing of equations, including those for redox reactions
  • pK
  • pH

First law of Thermodynamics:

  • Heat of formation
  • Heat of reaction
  • Change in enthalpy
  • Hess's law
  • Heat capacity
  • Heats of vaporization
  • Heat capacity
  • Fusion

Second Law:

  • Free energy of formation
  • Free energy of reaction


  • Planets
  • Types of stars
  • Types of Galaxies
  • Moon Phases
  • The Moon's influence on Earth's tides
  • Solar Eclipse
  • Equinox and Solstice
  • Comets

Light and Sound


  • AC and DC Current
  • Electromagnetism

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.

  • Minerals
  • Different types of rocks
  • Plate Tectonics
  • Climate Change Past and Present
  • Magnetosphere
  • Different layers of the atmosphere
  • Ozone Layer
  • Earth's Interior

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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