Cells and Life Lesson 1

Cells and Life Lesson 1

By Deena Baber

How did scientists' understanding of cells develop?

What basic substances make up a cell?​

​Key Concepts

cell theory

macromolecule

nucleic acid

protein

lipid

carbohydrate​

Vocab

Key Concepts and Vocab

Understanding Cells

400 or so years ago, Robert Hooke was using an early version of the microscope. He was studying pieces of cork and noticed what looked like the openings of a honey comb. He named these small spaces cells.

​The Cell Theory

​At this time, many other scientists started researching, with new tech and ideas. The cell theory states that all living things are made of one or more cells, the cell is the smallest unit of life, and all new cells come from preexisting cells.

Basic Cell Substances

Similar to how train cars are linked together, cell substances are made of smaller parts that are joined together. These substances, called macromolecules, form by joining many small molecules together. Macromolecules cannot function without one major substance-water.​

Open Ended

Why is water such an important part of life?

The Main Ingredient

The main substance in any cell is water. It makes up more than 70% of a cell's volume and is essential for life. Water also surrounds cells which helps to maintain homeostasis. The structure of a water molecule makes it great for dissolving substances. Substances must be in a liquid to move in and out of cells. ​Water molecules have two parts:

​

A part that is more negatively charged, called the negative end. This can attract a positive part of another substance.​

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A part that is more positively charged, called the positive end. This can attract a negative part of another substance.​

​

Macromolecules

​Remember that macromolecules are large molecules that form when small molecules join together. There are four types of macromolecules in cells:

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Subject | Subject

Some text here about the topic of discussion

• nucleic acids

• proteins

• lipids

• carbohydrates

Open Ended

What are the four types of macromolecule?

Nucleic Acids

The two types of nucleic acids are deoxyribonucleic acid and ribonucleic acid, otherwise known as DNA and RNA. Nucleic acids are macromolecules that form when long chains of molecules called nucleotides join together. The order of these nucleotides matter because this is the genetic information of a cell. Changing that order changes the cell.

The genetic information in nucleic acids are important because they can be passed on to offspring. The DNA includes instructions for basic functions and are used to make other substances in cells. DNA is used to make RNA which is used to make proteins. ​

Proteins

The macromolecules necessary for nearly everything cells do are proteins. Proteins are long chains of amino acid molecules. You just learned that RNA is used to make proteins. RNA holds instructions for how to join amino acids together.

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Cells contain hundreds of proteins, each with its own purpose. For example, one protein called amylase, which is in saliva, breaks down nutrients in food. Another example, a protein called keratin, is found in hair, horns, and feathers, and provides structural support.​

​Lipids

A lipid is a large macromolecule that does not dissolve in water. Because lipids do not mix with water, they play an important role as protective barriers in cells. They are also the major part of cell membranes. Lipids help with energy storage and cell communication. Some examples are cholesterol, phospholipids, and vitamin A​

​Carbohydrates

One sugar molecule, two sugar molecules, or a long chain of sugar molecules make up carbohydrates. Carbs store energy, provide structural support and are used in cell communication.

Sugars and starches are carbs that store energy. Fruits contain sugars. Breads and pastas are mostly starch. The energy in sugars and starches can be released quickly through chemical reactions in cells.

Cellulose is a carb in the cell walls of plants that provides structural support. ​

Multiple Choice

What macromolecule is made from amino acids?

• carbs

• lipids

• proteins

• nucleic acid

Draw

Draw what a water molecule looks like with its charges.

Multiple Choice

What macromolecule contains genetic information?

• lipids

• proteins

• nucleic acids

• carbs