The Chemistry of Life--Lab exam

Nucleic Acids

All genetic material is composed of nucleic acids. Two essential types of nucleic acids in living organisms are deoxyribonucleic acid and ribonucleic acid. Nucleic acids are composed of subunits called nucleotides.

Which of the following is not an organic molecule: methane (CH4), fructose (C6H12O6),rosane (C20H36), or ammonia (NH3)? How do you know?

Ammonia should be inorganic since it lacks carbon.

Which of the following describes hydrogen bonding

Interactions between positive and negative regions of polar molecules

Disaccharide

When two monosaccharides link together. Examples include sucrose (table sugar) lactose, and maltose.

DNA

A double stranded macromolecules composed of four different nucleotides. Adenine, Thymine, Cytosine, and Guanine. The two strands of DNA form a double helix that is held together by hydrogen bonds between the complementary nucleotides of each strand. AT GC

Lipids

Aka fats are composed of long hydrocarbon chains. Typically non polar. Essential for cell structure, form cellular membranes that encapsulate organelles in eukaryotic cells. Stored in living organisms to provide energy. Two groups based on type of carbon-carbon bonds present. Saturated fat single bonds. Unsaturated fat one or more double bonds.

Carbohydrates

Aka sugars, are generally composed of carbon, hydrogen, and oxygen. They are one of the primary sources of energy for all living organisms. Carbohydrates can be classified into several different groups. Mono, Di, olgio, poly.

Inorganic molecules

Generally do not contain a carbon backbone or carbon-hydrogen bonds. These molecules include sodium chloride (NaCl) and water (H20). Some inorganic molecules contain carbon, like carbon dioxide.

What color does biruet solution turn when there is protein?

Biuret solution contains copper ions. In the absence of proteins, it is blue in color. However, when proteins are present, the chemical state of the copper ion causes them to form a chemical complex with the pep tide bonds between amino acids, changing the color of the solution. In the presence of short peptides, the solution will turn pink, and in the presence of long polypeptides, the solution will turn violet.

Polysaccharides

Composed of more than ten monosaccharides. Starch, glycogen cellulose.

Ogliosacchardies

Composed of three to ten monosaccharides.

Iodine-Potassium Iodide (IKI)

Contains tri-iodine ions that interact with the coiled structure of a starch polymer. Prior to a reaction IKI is yellow-brown, in the presence of starch, it turns black or dark purple.

Benedict's reagent

Copper ions react with the free end of any reducing sugars, such as glucose, when heated-- originally blue, orange red in the presence of sugar.

R group

Each of the 20 amino acids has a specific side chain, known as an R group, that is also attached to the α carbon. The R groups have a variety of shapes, sizes, charges, and reactivities. This allows amino acids to be grouped according to the chemical properties of their side chains.

Which of the following are organic molecules? Methane, Glucose, Carbon Dioxide, Water, ATP

Methane, Glucose, ATP (not water or Carbon dioxide)

Organic molecules

Molecules that contain a carbon backbone and are typically identified by the presence of carbon-hydrogen bonds. Examples are proteins, carbohydrates, and lipids.

Elements

Pure substances composed of only one type of atom. There are more than 100 known elements in the periodic table. Living organisms generally require only 20.

Proteins

Most abundant macromolecules in living systems. They perform a variety of functions. Proteins are the major component of tendons, ligaments, and muscles in the body. At the cellular level, they also function as enzymes, hormones, transport molecules, and signaling molecules--regulating processes necessary for life.

Macromolecules

Most important organic compounds. Macro means large, thus macromolecules are large molecules. They are typically formed through covalent bonds, as a result, they can be polar or non polar. They can also contain polar or non polar regions. They participate in hydrogen bonding. The four types of macromolecules present in all living organisms are: carbohydrates, proteins, nucleic acids, and lipids.

Nitrogen fixation is a natural process by which inert or unreactive forms of nitrogen are transformed into usable nitrogen. Why is this process important to life?

Nitrogen is a necessary element for living organisms—it is one of the four elements which make up more than 90% of all matter. All four types of biologically important macromolecules contain nitrogen.

Nucleotides

Nucleic acids are composed of nucelotides. Made of sugar, a phosphate group, and a nucleic base.

Unsaturated fats

One or more double bonds between carbons

Saturated fat

Only single bonds between carbon atoms.

More than 90% of all matter is composed of..

Oxygen Carbon Hydrogen Nitrogen

Water as a polar molecule

Oxygen has a slight negative charge. Hydrogen has a slight positive charge.

Hydrogen bonding

Result from the interaction of the positive region of one polar molecule and the negative region of another polar molecule. Relatively weak but these bonds are extremely important for the maintenance of chemical structures. The DNA double helix and water molecules are held together by hydrogen bonds.

Monosaccharides

Simple sugars--most basic carbs and include glucose, fructose, and galactose. Building blocks for larger categories of carbohydrates. When two monosaccharides link together, a disaccharide forms.

Given what you have learned about the hydrogen bonding shared between nucleic acids in DNA, which pair is more stable under increasing heat: adenine and thymine, or cytosine and guanine? Explain why

Since adenine and thymine are paired with two hydrogen bonds, and cytosine and guanine are paired with three hydrogen bonds, it would stand to reason that cytosine and guanine would be more stable under increasing heat

RNA

Single stranded macromolecule. Several types, ribosomal RNA (rRNA), Transfer RNA (tRNA), and messenger RNA (mRNA), each of which have a unique role. Composed of nucleotides adenine, cytosine, guanine, uracil.

Amino Acids

The building blocks of proteins. There are twenty amino acids that are incorporated into proteins in different combinations. These amino acids can be polar or non polar. Both the number of amino acids and the polarity of these amino acids dictate the structure and function of the protein, allowing different proteins to regulate different tasks in organisms.

Tertiary Structure

The secondary structures interacting even further into three dimensions.

Molecule

Two or more atoms bonded together.

Which nucleotide is not found in DNA? Uracil, thymine, guanine, or adenine?

Uracil

Omega-3 fatty acid is classified as

a lipid

What type of macromolecule is often referred to as sugar?

carbohydrates

Which type of macromolecule is composed of amino acids?

proteins

Primary protein structure

sequence of amino acids.

secondary structure

two dimensional folds/helices that result from the polar and non polar interactions of amino acid R groups