chemistry part 2 lipids and stuff Flashcards
(10 cards)
functional groups in molecules
Most organic compounds are very large molecules, but their interactions with other molecules typically involve only small, reactive parts of their structure called functional groups (acid groups, amines, and others).
what are polymers and why are they made
Polymers are large molecules made by linking smaller, similar molecules called monomers. Think of a polymer like a beaded necklace, where each bead is a monomer and the whole chain is the polymer.
Now, how do they join together? This is where dehydration synthesis comes in. Here’s what happens step by step:
Dehydration (removal of water): When two monomers come together, a hydrogen atom (H) is removed from one monomer and a hydroxyl group (OH) is taken away from the other. This removes a molecule of water (H₂O).
Synthesis (bond formation): A covalent bond then forms between the two monomers, linking them together. Each time this happens, more monomers are added to the chain, and a water molecule is released with every addition.
This process is how polymers like carbohydrates (such as starch or cellulose) and proteins (which are made of amino acids) are built.
Example:
Carbohydrates: A simple sugar molecule (like glucose) links to form longer chains called polysaccharides (like starch).
Proteins: Amino acids link together to form polypeptides (which fold into functional proteins).
A polymer is just a term for a large molecule that’s built by linking together smaller monomers in a specific sequence. Think of it like a chain made up of many links, where each link represents a monomer.
how polymers are broken down
When polymers must be broken down or digested to their monomers, the reverse process, called hydrolysis, occurs (Figure 2.13b). As a water molecule is added to each bond, the bond is broken, releasing the monomers. All organic molecules covered in this chapter—carbohydrates, lipids, proteins, and nucleic acids—are formed by dehydration synthesis and broken down by hydrolysis.
carbohydrates
Carbohydrates are a type of molecule that includes sugars and starches. They are made up of carbon (C), hydrogen (H), and oxygen (O) atoms.
In most carbohydrates, hydrogen and oxygen appear in a 2:1 ratio, which is the same ratio found in water (H₂O). That’s why they’re called carbohydrates — it means “hydrated carbon” (carbon with water).
For example:
Glucose, a simple sugar, has the chemical formula C₆H₁₂O₆. That’s 12 hydrogen and 6 oxygen atoms — a 2:1 ratio.
Ribose, another sugar found in RNA, has the formula C₅H₁₀O₅ — again, 10 hydrogen and 5 oxygen atoms (2:1). so bassically showing us how carbohydrates are like water.
monosacharides,polysachrides and diasacharides
Carbohydrates are classified according to size and solubility in water as monosaccharides, disaccharides, or polysaccharides. Because monosaccharides are joined to form the molecules of the other two groups, they are the structural units, or building blocks, of carbohydrates.
You can think of monosaccharides as the individual beads in a bracelet, and polysaccharides or disaccharides as the bracelet or necklace formed by linking the beads (monosaccharides) together.
Monosaccharides = beads (individual sugar units).
Polysaccharides and disaccharides = bracelet/necklace (a chain of linked sugar units).
Dehydration synthesis = stringing the beads together by removing a water molecule each time you add a bead to the string (forming a bond between the beads).
Hydrolysis = breaking the bracelet/necklace apart by adding water to break the bonds between the beads, releasing them as individual beads again.
Polysaccharides are chains of monosaccharides. So, a polysaccharide does not already exist; it’s created by linking monosaccharides together through dehydration synthesis.
Monosaccharides
are the simplest form of carbohydrates
They are simple sugars (like glucose, fructose, and galactose)
They are the building blocks of more complex carbohydrates (like disaccharides and polysaccharides)-meaning they get togheter to make disaccharides and polysaccharides.
The most important monosaccharides in the body are glucose, fructose, galactose, ribose, and deoxyribose.
Glucose: The main sugar in your blood and the primary energy source for cells
Fructose & Galactose: Found in fruits and dairy; your body converts them into glucose for use by body cells.
Ribose: Sugar used in RNA
Deoxyribose: Sugar used in DNA
Ribose and deoxyribose form part of the structure of nucleic acids, another group of organic molecules responsible for genetic information.
Disaccharides
Disaccharides, or double sugars (Figure 2.14b), are formed when two simple sugars are joined by dehydration synthesis. In this reaction, as noted earlier, a water molecule is lost as the bond forms (Figure 2.14c).
Some of the important disaccharides in the diet are sucrose (glucose-fructose), which is cane sugar; lactose (glucose-galactose), found in milk; and maltose (glucose-glucose), or malt sugar. Because the double sugars are too large to pass through cell membranes, they must be broken down (digested) to their monosaccharide units to be absorbed from the digestive tract into the blood; this is accomplished by hydrolysis (see Figures 2.14b and 2.13b).
Polysaccharides
Long, branching chains of linked simple sugars are called polysaccharides (literally, “many sugars”) (Figure 2.14d). Because they are large, insoluble molecules, they are ideal storage products. Another consequence of their large size is that they lack the sweetness of simple and double sugars.
Only two polysaccharides, starch and glycogen, are of major importance to the body. Starch is the storage polysaccharide formed by plants. We ingest it in the form of “starchy” foods, such as grain products (corn, rice) and root vegetables (potatoes and carrots, for example). Glycogen is a slightly smaller, but similar, polysaccharide found in animal tissues (largely in the muscles and the liver). Like starch, it is a polymer of linked glucose units.
the main scource of energy
Carbohydrates are the body’s main source of energy. Glucose, a simple sugar, is especially important because cells use it first for fuel. When the body breaks down glucose using oxygen, it produces carbon dioxide, water, and energy. This energy is stored in ATP, which powers all cell activities. If the body doesn’t need the glucose right away, it stores it as glycogen (in the liver and muscles) or turns it into fat. A small amount of carbohydrates is also used to build parts of cells or helps with cell communication.
