Structure and Function: Carbs, lipids, proteins, nucleic acids

Life on Earth comes in many forms, from microscopic bacteria to giant redwood trees. Despite their differences, all living things are made up of the same types of molecules. Many of these molecules contain carbon and are called organic compounds. There are four main groups of organic compounds found in cells. One of these groups is carbohydrates.

Which of the following are the primary functions of carbohydrates?

Select the two best choices.

• to store information needed for an organism's growth and development

• to supply energy for a cell's immediate use

• to control chemical reactions

• to form the rigid cell wall in a plant cell

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NGSS.MS-LS1-7

Carbohydrates come in different sizes. Complex carbohydrates are large compounds made up of many small carbohydrate molecules. These small molecules are sometimes called building blocks.

Which of the following are the building blocks of complex carbohydrates?

• amino acids

• nucleotides

• fatty acids

• simple sugars

• starches

Starch and glucose are carbohydrates that can serve as energy sources for cells. To use starch for energy, plants and animals must first break down the starch into glucose molecules.

Complete the sentence.

Starch is a ​ (a)   , and glucose is a ​ (b)   .

• complex carbohydrate
• simple sugar
• protein
• amino acid

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NGSS.MS-LS1-7

Complete the text.

There is one complex carbohydrate that has a unique role in plant cells. This complex carbohydrate, called ​ (a)   , does not provide plant cells with energy. Instead, it gives strength and structure to plants. It is the main component of the cell wall.

• cellulose
• glucose
• starch
• fructose

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NGSS.MS-LS1-2

The model below represents the chemical structure of cellulose, a complex carbohydrate. This model shows that cellulose is made up of many simple sugars linked together in a chain. Cellulose can be made up of thousands of sugars. Only a section of a cellulose molecule is shown in the model.

Which of the following models represents the simple sugar that is the building block of cellulose?

• 
• 
• 
• 

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NGSS.HS-LS1-6

Like carbohydrates, lipids are one of the main groups of organic compounds found in cells.

Which of the following are the primary functions of lipids?

Select the two best choices.

• to control cell processes, such as growth and repair

• to supply energy for a cell's immediate use

• to be stored for later use as an energy source

• to form cell membranes that separate the contents of cells from the environment

Match each type of lipid to its main function in cells.

• steroids

• chemical substance produced by the cells for control contains for carbon rings.

• fats

• form cell membranes that separate the contents of cells from the environment

• phospholipids

• be stored for later use as an energy source

The lipids in cells are made up of building blocks. ​ (a)   are building blocks that can be linked together with other small molecules to make larger, more complex compounds, including fats and phospholipids.

• Fatty acids
• nucleotides
• simple sugars
• amino acids

Different types of lipids have different chemical structures, but there are three chemical elements that all lipids contain. Which of the following elements are found in all lipids?

• nitrogen

• carbon

• hydrogen

• oxygen

• phosphorus

The two models below show the chemical structures of a fatty acid and a phospholipid.

Fatty acids are made up of carbon, hydrogen, and oxygen. A phospholipid is made up of two fatty acids, called the tails, and one other section, called the head. This structure helps phospholipids form cell membranes. All phospholipids are made up of at least four chemical elements. Many phospholipids, like the one below, are made up of five elements.

According to the models, which elements are found in this phospholipid but not in all lipids?

• hydrogen

• carbon

• nitrogen

• oxygen

• phosphorus

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NGSS.HS-LS1-6