GED Life Science Practice

Life science is the largest single slice of the GED Science test at roughly 40 percent. These questions cover the specific subtopics the exam returns to again and again.

Question 1 of 10

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Which cell structure releases most of the energy a cell uses?

Cells and energy

Know what each major organelle does in one sentence: mitochondria release energy, ribosomes build proteins, the nucleus stores DNA, chloroplasts capture light. Then know the two energy processes as a pair. Photosynthesis takes in carbon dioxide and water and produces glucose and oxygen; cellular respiration does the reverse. Questions often set them side by side and ask what happens if one is disrupted.

Mitosis produces two identical cells for growth and repair. Meiosis produces sex cells with half the chromosome number. The GED rarely asks for the phases by name, but it does ask which process fits a described situation.

Genetics and heredity

Punnett squares appear consistently. A cross of Tt with Tt gives one TT, two Tt, and one tt — so 75 percent show the dominant trait and 25 percent show the recessive one. Practice until you can draw and read the square in under thirty seconds.

Also expect questions about the difference between an inherited trait and an acquired one, and about how mutations introduce variation that natural selection can then act on.

Ecosystems and evolution

Food chain questions ask about energy flow: producers capture energy, consumers pass it along, decomposers return nutrients to the soil. Energy decreases at each level, which is why a pyramid diagram narrows toward the top.

Natural selection questions are usually written as short scenarios. The correct answer will describe a heritable trait improving survival and reproduction in a specific environment — not an organism choosing to change, and not the environment creating a new gene.

Frequently asked questions

What percentage of GED Science is life science?
About 40 percent of the Science test covers life science content.
Do I need to know the phases of mitosis by name?
Rarely. The test is more likely to ask what mitosis accomplishes and how it differs from meiosis.