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Parts of the Cell — Reading Comprehension

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MS-LS1-1
MS-LS1-2

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This informational science passage, aligned with NGSS standard MS-LS1-1, introduces students to the parts of the cell and their functions. Students will learn how organelles like the nucleus, mitochondria, ribosomes, and chloroplasts each have a specific role to keep the cell alive and functioning. Written at a middle school reading level, this passage supports reading comprehension in science and uses age-appropriate explanations and real-life connections to help students understand how cells work like tiny factories. This passage is ideal for teaching about life science, structure and function, and the NGSS Disciplinary Core Idea LS1.A: Structure and Function.

CONTENT PREVIEW

All living things are made of cells, which are the basic units of life. Cells carry out all the processes that keep an organism alive, such as using energy, growing, and reproducing. Inside a cell, there are many specialized structures, each with a specific job. These structures are called organelles, and they work together like parts of a machine to keep the cell functioning properly.

One important organelle is the nucleus, which acts like the control center of the cell. It contains the cell’s DNA, which holds the instructions for how the cell works and when it should divide. Another key structure is the cell membrane, which surrounds the cell and controls what enters and leaves. This helps maintain balance inside the cell.

Cells also contain mitochondria, often called the "powerhouses" of the cell. They break down food and release energy the cell can use. Ribosomes are another important part; they help make proteins, which are needed for building cell parts and carrying out many of the cell’s functions. Proteins are assembled in the ribosomes and then processed and transported by the endoplasmic reticulum and the Golgi apparatus.

In plant cells, you will also find chloroplasts, which use sunlight to make food through photosynthesis. Plant cells also have a cell wall that gives them extra support and shape. Another shared feature in many cells is the cytoplasm—a jelly-like substance where the organelles are suspended and where many chemical reactions occur.

Cells are like tiny factories, with each part working to keep the whole system running. Understanding the parts of the cell helps scientists learn how living things grow, respond to their environment, and stay healthy.

Fun Fact: Your body has over 30 trillion cells, and each one contains many of the same organelles working together to keep you alive!

What is the basic unit of life in all living things?

OrganCellTissueAtom

Which part of the cell acts like the control center?

RibosomeCytoplasmNucleusMitochondria

What is the main function of mitochondria?

Store waterMake sunlightControl cell divisionProduce energy

What structure controls what enters and leaves the cell?

NucleusCell membraneCytoplasmGolgi apparatus

Which organelles are involved in protein production and transport?

Ribosomes, endoplasmic reticulum, Golgi apparatusChloroplasts, mitochondria, cytoplasmNucleus, vacuole, cell wallRibosomes, chloroplasts, cell membrane

Why is cytoplasm important in a cell?

It holds DNAIt controls the cellIt produces energyIt supports organelles and reactions

What is the main idea of the passage?

Cells are only found in animalsCells are tiny machines with special partsCells are made of only one partOnly plant cells have organelles

How would a cell be affected if the cell membrane didn’t work?

Proteins would be made too fastDNA would stop workingHarmful substances could enter the cellThe cell would produce more energy