Chemistry of Life: Ingredients for Life

You have two solutions. One of them has a pH of 5. The other has a pH of 2. What is the magnitude change of H+ ion concentration in the second solution compared to the first?

1000

Opioid receptors in the brain are proteins. This function is just one of the many carried out by these very versatile biomolecules. The diverse structure and function of proteins are in part due to the variety of possible combinations of how many amino acids?

20

One reason carbon is an excellent element to form the basis of life on Earth is that each carbon can bond with what number of other atoms?

4

What is a neutral pH?

7

Match the type of bond to its description.

A partially positively charged hydrogen atom bound to a partially negatively charged atom. - Hydrogen Attraction of a negatively charged atom or molecule with a positively charged one. - Ionic Atoms that share electrons. - Covalent

Shown here are the chemical formulas for three monomers used to make major biomolecules. Match the name of the monomer to the chemical formula.

Amino acid - NH2CH2COOH Simple Sugar -C6H12O6 Nucleotide - C5H5N5O

Classify each molecule according to its organic molecule type.

Carbohydrate: Starch Cellulose Lipid: Phospholipid Cholesterol Triglyceride

All biomolecules contain the element X and are known as X. The value of this versatile element to forming molecules is due to the availability of X that allow it to bond with up to X other atoms, forming strong X bonds.

Carbon Organic Valence electrons Four Covalent

Watch the animation on protein structure, and then answer the question. Order the levels of protein structure from simplest to most complex

Chain of amino acids Chain folded into coils and sheets Chain folded into 3D shape Two or more proteins joined together

Carbon-based molecules form the basis of life as we know it. The reasons for this include which of the following?

Correct: Carbon molecules can from a diversity of long chains, branches and ringed molecules It can from both polar and nonpolar molecules Incorrect: It always forms hydrophilic molecules that can dissolve in water It always forms neutral molecules and thus does not form harmful acids or bases

Based on what you've learned about what happens when water freezes, which of the following helps explain why road salt is added in the winter to help prevent ice from forming on roadways and sidewalks?

Correct: Since salt is polar, it dissolves in water and disrupts hydrogen bonding Salt disrupts the crystal lattice by getting between the water molecules Incorrect: Salt generates covalent bonds with water and prevents freezing Salt causes the water molecules to vibrate and heat up

When you add a base to an acidic solution, what happens to the solution?

Correct: The pH increases The solution becomes less acidic Incorrect: The pH decreases The solution becomes more acidic

What type of bonds are the bonds between simple sugar molecules in a carbohydrate?

Covalent

Order the following types of bonds from strongest to weakest

Covalent Ionic Hydrogen

Computers and books are excellent ways to store information in the modern age. However, without electricity, computers are useless and books are prone to decomposition over time. Certain biomolecules are extremely stable on a geologic time scale and have been preserved for millennia. Thus, some scientists are preparing to encode and store modern information in which of the following biomolecules?

DNA

Match the monomer to the polymeric macromolecule that it can form.

DNA and RNA - Nucleotide Proteins - Amino Acid Carbohydrate - Monosaccharide

Pure water has a neutral pH of 7 and no free H+ ions.

False

Carbohydrates fulfill a variety of functions. The variation in function in carbohydrates is related to the number of monomers making up each carbohydrate molecule. Order the kinds of carbohydrates from shortest to longest (glucose, sucrose starch, cellulose).

Glucose Sucrose Starch Cellulose

There is an enormous diversity of biomolecules used in cellular life. Each of the molecules requires one or more proteins to be synthesized, folded, and/or regulated. Scientists are interested in understanding the minimum number of proteins, coded for by genes, required for life. Most free-living bacteria carry between 1,000 to 2,000 genes. However, parasitic bacteria such as Mycoplasma spp. carry as few as 500 genes. Based on this knowledge, what do you think might be the minimum number of genes required for life?

Hundreds

While carbon is an essential element to organic molecules, other atoms are also important to different kinds of biomolecules. Which element would you also expect to find, along with carbon, in all organic molecules?

Hydrogen

Organic biomolecules are all comprised of subunits that include carbon and X. Carbohydrates are made up of simple X that also contain X. These three molecules are also found in proteins and are made up of 20 different X, all of which also contain the element X. Nucleic acids have X, which always include the addition of the element X.

Hydrogen Sugars Oxygen Amino Acids Nitrogen Nucleotides Phosphorus

Which of the following are hydrophilic?

Hydrophilic: Polar molecules Ions NaCl Not hydrophilic: nonpolar molecules

NASA has been scanning neighboring planets for signs of life, but there is always the possibility that life on other planets could be based on an element other than carbon. Based on your understanding of carbon's properties, what qualities should NASA be looking for in other elements that might replace carbon on an alien planet?

Possible Carbon Replacement: Prefers to form covalent bonds Can form long chains or rings with other atoms Capable of forming a large number of bonds Not a Likely Carbon Replacement: Is extremely stable and nonreactive to other molecules prefers to form ionic bonds Capable of forming a few strong bonds at a time Forms rigid chains when bound to other elements

The biomolecules known as X are the most numerous and versatile category of biomolecules. These complex X are constructed of different combinations of 20 X that allow them to vary in size and shape. These combinations are the foundation of the X structural levels of these molecules.

Proteins Polymers Amino Acids Four

Astrobiologists (scientists who study the possibility of life in the universe beyond Earth) have speculated that there could be life-forms that do not rely on carbon as a central organizing element in their biomolecules. Which of the elements below might be a possible substitution for carbon?

Silicon,Si,atomic number 14 with four valence electron

In addition to opioids like morphine, organic molecules also include the biomolecules that make up the basic building blocks of life. Match each biomolecule below with the subunit it contains (if any).

Simple Sugars - Complex Carbohydrates Amino Acids - Protein Nucleotides - Nucleic Acids

Lipids are not true polymers because they are not constructed of repeating chains of monomers.

True

One reason carbon is an excellent element to form the basis of life is the fact that it can form extremely long chains.

True

Egg whites solidify in the presence of acids. Would lemon juice (pH 2.3) or orange juice (pH 3.5) be better for solidifying egg whites? Why

Lemon juice, because it donates more H+ ions than orange juice

A structurally diverse group of biomolecules, X are not made of chains of X. These molecules are mainly composed of X, which can be formed into steroid rings or made up of X attached to glycerol.

Lipids Monomers Hydrocarbons Fatty Acids

Milk is relatively neutral with a pH of 6.5, just under 7. For each of the noted items on the pH scale, match the label that indicates (roughly) how many times more acidic they are compared to water.

Natural rainwater - 10 Tomatoes - 100 Oranges - 1,000 Lemons - 10,000

One of the most essential biomolecules in cells is adenosine triphosphate (ATP). This "cellular energy currency" is used by cells to transfer energy and power reactions. An ATP molecule is made up of a five-carbon sugar, a nitrogenous base, and phosphate groups. Based on this information, what type of biomolecule is ATP

Nucleic acid

Which of the following compounds are organic?

Organic: Proteins Carbohydrates Inorganic: Water Nitrogen Gas