In each of the following groups, one of the items does not belong in the group. Identify the odd item in the group and explain why it is different. Explain how the other items are related. a. glycogen, starch, fructose, and cellulose b. amino acids, dipeptides, polypeptides, and proteins c. fats, oils, and fatty acids d. cytosine, adenine, and uracil

Polysaccharides are large, complex carbohydrates composed of long chains of monosaccharide units. These monosaccharides are simple sugars, and when linked together, they form a variety of essential polysaccharides. Glycogen, starch, and cellulose are examples.

Glycogen serves as a form of energy storage in animals. Starch performs a similar role in plants. Cellulose, in contrast, is a structural component in the cell walls of plants and provides rigidity.

Unlike monosaccharides, polysaccharides have more complex structures and properties. They play critical roles in both energy storage and structural integrity within various organisms. Understanding their function can illuminate much about cellular processes and nutrition.

When comparing glycogen, starch, and cellulose to fructose, fructose is a monosaccharide and significantly different. It does not form long chains and serves different purposes within the body, such as being a readily available energy source.

Amino acids are the building blocks of proteins. They are small molecules that link together to form chains called polypeptides. When these chains fold into specific three-dimensional shapes, they become functional proteins.

Proteins perform countless vital roles in the body, including catalyzing biochemical reactions (enzymes), providing structural support, and regulating processes (hormones).

There are 20 standard amino acids, and each has a unique side chain that affects its chemical properties and role in protein structure. Amino acids can form dipeptides (two linked amino acids) and polypeptides (many linked amino acids). Ultimately, these polypeptides fold and bond into complex proteins.

When analyzing the group amino acids, dipeptides, polypeptides, and proteins, the amino acids are the simplest form. They constitute the building blocks from which the other components are constructed.

Triglycerides are a type of fat found in your blood. These molecules comprise one glycerol molecule bound to three fatty acids. They are a significant source of energy and serve as the primary storage form of fat in the body.

Dietary fats and oils are mostly triglycerides. They can be either saturated or unsaturated, depending on the nature of the fatty acids they contain. Saturated fats are typically solid at room temperature, while unsaturated fats (oils) are liquid.

Fatty acids themselves are long chains of carbon and hydrogen atoms. They are components of triglycerides but are not triglycerides themselves. This distinction is crucial for understanding dietary fats and metabolism.

In the comparison between fats, oils, and fatty acids, the fatty acids are the less complex components that make up the more complex triglycerides.

Nitrogenous bases are the parts of nucleotides that make up the building blocks of DNA and RNA. There are five primary nitrogenous bases: adenine, guanine, cytosine, thymine, and uracil.

These bases form complementary pairs, enabling the double-helix structure of DNA. Adenine pairs with thymine, and cytosine pairs with guanine in DNA. In RNA, uracil replaces thymine and pairs with adenine.

Cytosine and adenine are found in both DNA and RNA, whereas uracil is unique to RNA. This difference highlights the structural diversity between these nucleic acids and their respective roles in genetics and protein synthesis.

By examining the examples cytosine, adenine, and uracil, we see uracil as the outlier since it is not found in DNA but only in RNA.