Unit 1 - Module 3: Carbohydrates and Lipids

Flashcards covering the fundamental concepts of carbohydrates and lipids from Unit 1 Module 3.

Which four elements account for approximately $90\%$ of the total dry mass of human cells?

$C$, $H$, $O$, and $N$ ($CHON$)

How many covalent bonds is a carbon atom able to form based on its electron configuration?

Four covalent bonds

What are the chemical compositions (elements) for the four macromolecules: lipids, carbohydrates, proteins, and nucleic acids?

Lipids: $CHO$; Carbohydrates: $CH_{2}O$; Proteins: $CHONS$; Nucleic Acids: $CHONP$

What are the basic units of carbohydrates that serve as sources of energy and components of plant and fungi cell walls?

Monosaccharides

Monosaccharides are composed of $C$, $H$, and $O$ atoms, usually in what specific ratio?

$$1:2:1$$

Which five-carbon sugars are components of $RNA$ and $DNA$?

Ribose ($RNA$) and deoxyribose ($DNA$)

What specific type of bond joins monosaccharides to create complex carbohydrates?

Glycosidic bonds

Through what type of reaction are glycosidic bonds formed, and what is lost during the process?

Dehydration synthesis reactions, which result in the loss of a water molecule

What are three examples of complex carbohydrates mentioned as polysaccharides?

Glycogen, starch, and cellulose

What physical property defines lipids and distinguishes them from carbohydrates, proteins, and nucleic acids?

Lipids are hydrophobic and they are not polymers

What is the structural difference between saturated and unsaturated fatty acids?

Saturated fatty acids have no carbon–carbon double bonds and are solids, while unsaturated fatty acids have one or more carbon–carbon double bonds and are oils

What type of weak, noncovalent interaction is responsible for the tight packing of fatty acids in lipids?

van der Waals forces

Why are steroid hormones able to pass directly through cell membranes?

They are nonpolar lipid hormones