AP Bio Chapter 5

What is a glycosidic linkage?

A glycoside linkage is a covalent bond formed between two monosaccharides by a dehydration reaction.

What is a polymer? What is a monomer?

A polymer is a long chain-like molecule, consisting of many similar or identical building blocks linked by covalent bonds. A monomer is a smaller molecule that serves as the building blocks of polymers.

polypeptide:

A polymer of many amino acids linked by a peptide bond.

dipeptide:

A polymer of two amino acids linked by a peptide bond.

What is a trans fat? Why should you limit them in your diet?

A trans fat is an unsaturated fat with a trans double bond; the result of the process of hydrogenating vegetable oils to prevent lipids from separating out in liquid (oil) form. Trans fats should be limited in your diet because they have been found to contribute to atherosclerosis, a cardiovascular disease caused by plaque buildup within the walls of blood vessels.

Notice that there are five nitrogen bases. Which four are found in DNA?

Adenine, guanine, cytosine, thymine

Which four are found in RNA?

Adenine, guanine, cytosine, uracil

Lipids include fats, waxes, oils, phospholipids, and steroids. What characteristic do all lipids share?

All lipids mix poorly, if at all, with water.

Most monosaccharides are some multiple of (CH2O). For example, ribose is a 5-carbon sugar with the formula C5H10O5. It is a pentose sugar. (From the root penta-, meaning five.) What is the formula of a hexose sugar?

C6H12O6

The large molecules of all living things fall into just four main classes. Name them.

Carbohydrates, Lipids, Proteins, Nucleic Acids

Circle the three classes that are called macromolecules. Define macromolecule.

Carbohydrates, Proteins, Nucleic Acids Macromolecules are extremely large on the molecular scale, sometimes consisting of thousands of atoms.

Secondary α helix β pleated sheet

Coils and folds resulting from the hydrogen bonds between the repeating constituents of the polypeptide backbone Alpha helix: Delicate coil held together by hydrogen bonding between every fourth amino acid Beta pleated sheet: Two or more strands of the polypeptide chain lying side by side, connected by hydrogen bonds between parts of the two parallel polypoptide backbone Protein of hair Protein of spider web

Polymers are assembled and broken down in two types of reactions: dehydration synthesis and hydrolysis. Which kind of reaction is this?

Dehydration synthesis

Besides mutation, which changes the primary structure of a protein, protein structure can be changed by denaturation. Define denaturation, and give at least three ways a protein may become denatured.

Denaturation is the changing of a protein during which the protein unravels and loses its native shape because the weak chemical bonds and interactions within a protein have been destroyed. Possible examples of ways a protein may become denatured include alteration of pH, salt concentration, temperature, transfer from aqueous environment to nonpolar solvent, chemicals, and excessive heat.

How do ribose and deoxyribose sugars differ?

Deoxyribose sugar lacks an oxygen atom on the second carbon in the ring.

List four important functions of fats.

Energy storage, long-term food reserve in mammals, adipose tissue cushions vital organs, body insulation.

Why can you not digest cellulose? What organisms can?

Humans cannot digest cellulose because they lack the enzyme that can hydrolyze its beta linkages. Humans do posses enzymes that digest starch by hydrolyzing its alpha linkages; however, these enzymes cannot hydrolyze the beta linkages of cellulose because of the distinctly different shapes of these two molecules.

Level of Protein Structure: Primary

Linked series of amino acids with a unique sequence Transthyretin

Is C6H12O6 (glucose) a monomer, or a polymer?

Monomer

Monomers are connected in what type of reaction? What occurs in this reaction?

Monomers are connected in a dehydration reaction. During a dehydration reaction, two monomer molecules are covalently bonded to each other, with the loss of a water molecule. In this reaction, each monomer contributes part of the water molecule that is released during the reaction. This reaction is repeated as monomers are added to the chain one by one, making a polymer.

Let's look at carbohydrates, which include sugars and starches. First, what are the monomers of all carbohydrates?

Monosaccharides, or simple sugars

Quaternary

Overall protein structure that results from the aggregation of these polypeptide subunits Globular transthyretin protein, collagen, hemoglobin

Tertiary

Overall shape of the polypeptide resulting from interactions between the side chains (R groups) of the various amino acids Transthyretin polypeptide

To summarize, what are the three components of a nucleotide?

Phosphate group, sugar, nucleoside

Large molecules (polymers) are converted to monomers in what type of reaction?

Polymers are disassembled to monomers by hydrolysis, a process that is essentially the reverse of the dehydration reaction.

Name two saturated fats.

Possible examples include lard, butter, or most animal fats.

Name two unsaturated fats.

Possible examples include olive oil, cod liver oil or most plant or fish fats.

What is represented by R? How many are there?

R refers to the side chains of amino acids. There are 20.

What two molecules make up the "uprights"?

Sugar and phosphate

Why are the "tails" hydrophobic?

The "tails" are hydrophic (avoid water) because they are hydrcarbon. As previously discussed in chapter 4, hydrocarbons are hydrophobic compounds because the great majority of their bonds are relatively non polar carbon-hydrogen

What are the building blocks of fats? Label them on this figure.

The building blocks of fats are glycerol and fatty acids. In the figure below, the glycerol molecule is in gray, and the three fatty acids are in yellow.

Why are many unsaturated fats liquid at room temperature?

The kinks where the cis bonds are located prevent the molecules from packing together closely enough to solidify at room temperature.

The flow of genetic information is from DNA RNA protein. Use this figure to explain the process. Label the nucleus, DNA, mRNA, ribosome, and amino acids.

The mRNA molecule interacts with the cell's protein-synthesizing machinery to direct production of a polypeptide, which folds into all or part of a protein. The sites of protein synthesis are tiny structures called ribosomes. In a eukaryotic cell, ribosomes are in the cytoplasm, but DNA resides in the nucleus. Messenger RNA conveys genetic instructions for building proteins from nucleus to the cytoplasm

Why are the strands said to be antiparallel?

The strands are said to be antiparallel because they run in opposite 5' 3' directions from each other.

type of protein: enzymes

accelerates chemical reactions Examples: Maltase, pepsin, sucrase

Structural polysaccharide that comprises plant cell walls

cellulose

Structural polysaccharide that gives cockroaches their crunch

chitin

two examples of steroids

cholesterol, sex hormones

Glucose+ __________ form sucrose

fructose

Monosaccharide commonly called "fruit sugar"

fructose

Two monomers of this form maltose

glucose

Is a storage polysaccharide produced by vertebrates; stored in your liver

glycogen

The root words of hydrolysis will be used many times to form other words you will learn this year. What does each root word mean?

hydro- water lysis break

"Milk sugar"

lactose

Malt sugar; used to brew beer

maltose

Type of protein: Motor and contractile protiens

movements actin and myosin are responsible for the contraction of the muscles

Has 1-4 B glucose linkages

starch

type of protein: storage

storage of amino acids Examples: Casein, which is the major source of amino acids for baby mammals; ovalbumin, the protein of egg white

Have you noticed that all the sugars end in -ose? This root word means

sugar

Type of protein: structural

support Keratin is the protein of hair, horns, feathers, and other skin appendages. Insect use skin fivers to make cocoons and webs

Type of protein: transport

transport of substances Proteins embedded in the plasma membranes; aquaporins; hemoglobin

To summarize, when two monomers are joined, a molecule of ________ is always removed

water

peptide bond:

A covalent bond in which two amino acids are joined by a dehydration reaction.