Biology Chapter 3: Chemical Building Blocks of Life

Compared to an unsaturated fat, a saturated fat with the same number of carbon atoms will have which of the following?

- A higher melting point - More hydrogen atoms

Which nitrogenous bases are present in RNA?

- Adenine - Cytosine - Uracil - Guanine

Which of the following are the three elements generally found in a simple, unmodified carbohydrate, such as glucose?

- C (Carbon) - H (Hydrogen) - O (Oxygen)

What are the two major functional groups found in an amino acid, which allow it to form a peptide bond with another amino acid?

- Carboxyl group - Amino group

What are the three major structural components of an amino acid?

- Carboxyl group - Amino group - Side chain (R)

From the list below, select all that are polysaccharides.

- Cellulose - Starch - Chitin - Glycogen

Alpha helices create regions of the protein that are ____, while beta sheets create regions that are ____.

- Cylindrical (Tubular) - Planar (Flat)

The two classes of nucleic acids are ____ and ____ .

- DNA - RNA

Match each interaction that can potentially contribute to a protein's shape with the phrase that best describes it. - Disulfide bridge - Ionic bond - Hydrophobic exclusion

- Disulfide bridge a. Formation of a covalent bond between 2 cysteine side chains - Ionic bond a. Formation of a bond between groups with opposite charge - Hydrophobic exclusion a. Hydrophobic portions of the protein gather in the interior of the protein

Which of the following are lipids?

- Fats - Steroids

Which of the following interactions help determine a protein's tertiary structure?

- Ionic bonds - Hydrophobic exclusion - Disulfide bridges - Hydrogen bonds

Protein denaturation may be caused by an increase in which of the following?

- Ionic concentration - Temperature - pH

Which of the following statements about carbon are true? - The molecules it is found in are always straight chains. - It forms the framework of biological molecules. - A single carbon atom always bonds with four other atoms. - It can form covalent bonds.

- It forms the framework of biological molecules. - It can form covalent bonds.

Select amino acids that are most likely to be found in the interior of a protein.

- Leucine - Valine - Phenylalanine

The 4 main groups of biological macromolecules are nucleic acids, ____, ____, ____.

- Lipids - Carbohydrates - Proteins

Select the 4 main groups of biological macromolecules.

- Lipids - Carbohydrates - Proteins - Nucleic acids

Match the following special amino acid to their unique functions in proteins. - Methionine - Proline - Cysteine

- Methionine a. Often the first amino acid - Proline a. Causes kinks in the chain - Cysteine a. Links two chains together

Choose all of the following that accurately describe oils, such as olive oil?

- Oils have low melting points and are liquid at room temperature. - Oils are fats that are high in unsaturated fatty acids.

Which of the following subunits are found in all phospholipids?

- Phosphate group - Fatty acids - Glycerol

What are the three basic components of a nucleotide?

- Phosphate group - Pentose sugar - Nitrogenous base

Match the level of protein organization with the proper description. - Primary - Secondary - Tertiary - Quaternary

- Primary a. The linear sequence of amino acids - Secondary a. Repetitive folding patterns such as alpha helix and beta pleated sheet - Tertiary a. The overall 3-D shape of each polypeptide - Quaternary a. How two or more polypeptides interact to form a protein

Match the type of fatty acid with the correct description. - Saturated fatty acids - Polyunsaturated fatty acids - Monounsaturated fatty acids

- Saturated fatty acids a. No double bonds between carbon atoms - Polyunsaturated fatty acids a. Two or more double bonds between carbon atoms - Monounsaturated fatty acids a. One double bond between carbon atoms

Match the two polysaccharides to their characteristics. - Starch - Cellulose

- Starch a. Choice Contains glucose connected by α linkages b. (Choice Functions as a storage molecule) - Cellulose a. Choice Contains glucose connected by β linkages b. Functions as a structural molecule

From the following list, choose all lipids.

- Terpenes - Oils - Fats

Which of the following statements about the relationship between enzymes and environmental conditions are true?

- The optimum conditions for enzyme activity are usually similar to the conditions where the enzyme normally functions. - Changing environmental conditions may alter the activity of enzymes. - Changing environmental conditions may alter the structure of enzymes.

Which of the following is important for the function of chaperonins as they refold misfolded proteins?

- They can hydrolyze ATP to power the changes in protein structure. - They have a very flexible structure.

Of the following list, choose the functions of proteins in living cells.

- They play a key role in moving materials within cells. - They catalyze chemical reactions. - They help the body recognize and destroy foreign microbes and cancer cells. - They transport oxygen in the blood of vertebrates.

Which of the following are functions of proteins?

- They provide structural support for many animal tissues. - They transport ions and molecules across cell membranes. - They catalyze chemical reactions. - They play a key role in the contraction of muscles.

Match amino acids to the group they belong to (based on their R group). - Threonine - Leucine - Glutamic acid - Phenylalanine

- Threonine a. Polar uncharged - Leucine a. Nonpolar - Glutamic acid a. Charged - Phenylalanine a. Aromatic

Identify functions of ATP.

- To power transport across cell membranes - To power the movement of cells - To drive energetically unfavorable reactions

How many polypeptides are present in a protein whose highest level of structure is tertiary structure?

1 polypeptide only

The two major functional groups found in all amino acids are the basic ____ group and the acidic ____ group.

1. Amino 2. Carboxyl

When two amino acids are linked together, a peptide bond is formed between the ____ group of one and the ____.

1. Amino 2. Carboxyl

During protein synthesis in living organisms, information stored in molecules of ____ is transcribed to form complementary molecules of ____, which are responsible for actually assembling the protein.

1. DNA 2. RNA

Both DNA and RNA's nucleotides contain a pentose. The nucleotides of DNA molecules contain the sugar ____, while the nucleotides in RNA contain the sugar ____.

1. Deoxyribose 2. Ribose

The structure of DNA consists of two strands coiled around each other to form a ____ ____.

1. Double 2. Helix

A(n) ____ ____ consists of a long-chain hydrocarbon with a carboxyl group attached at one end.

1. Fatty 2. Acids

Many lipids are composed of two main kinds of molecules, ____ acids and 3-carbon polyalcohol ____.

1. Fatty 2. Glycerol

A nucleotide is made of three components: a 5-carbon sugar, a phosphate, and a(n) _____ _____.

1. Nitrogenous 2. Base

When looking at the structure of a protein, it is convenient to consider four hierarchical levels known as the protein's ____, ____, ____, and ____.

1. Primary 2. Secondary 3. Tertiary 4. Quaternary

Regarding polypeptides, the two basic types of ____ structure are alpha ____ and beta-pleated sheet.

1. Secondary 2. Helix

Hydrogen bonds between the amino and carboxyl groups of the polypeptide backbone help determine protein ____ structure while hydrogen bonds between the amino acid side chains help determine protein ____ structure.

1. Secondary 2. Tertiary

Three main environmental factors that cause protein denaturation are the solution's ____, its temperature, and its ____ strength.

1. pH 2. Ionic

All carbohydrates contain the elements carbon, hydrogen, and oxygen in the approximate molar ratio of which of the following?

1:2:1

Proteins are polymers made up of how many different amino acids?

20

The structure of proteins is usually discussed in terms of a hierarchy of how many levels?

4

Which of the following accurately describes the chemical structure of a typical amino acid found in a protein?

A central carbon atom is bound to an amino group, carboxyl group, a side chain, and a hydrogen atom.

When a carbohydrate is formed by linking two monosaccharides by a condensation reaction, we get water plus which of the following?

A disaccharide

Select the disease type that could result from a deficiency in chaperone proteins.

A disease caused by improper folding of proteins.

____ is often referred to as the "energy currency of the cell."

ATP (adenosine triphosphate)

What are the building blocks of proteins?

Amino acids

Where are the peptide bonds located in a polypeptide?

Between the amino group of one amino acid and the carboxyl group of another

A helix-turn-helix motif, which consists of two α helices connected by a bend, is often found in proteins that ____.

Bind to the DNA double helix

Which of the following bonds is essentially nonpolar?

C--H

Diseases caused by the improper folding of proteins may be due to deficiencies in ____ proteins.

Chaperone

Identify the two major classes of nucleic acids.

DNA and RNA

During protein synthesis, amino acids are linked together using a ____ reaction. As a result, a covalent bond is formed.

Dehydration

What type of reaction is responsible for linking amino acids together to form polypeptides?

Dehydration synthesis

Changes in a protein's environment can cause the protein to unfold and lose its shape in a process called which of the following?

Denaturation

Which sugar is found in the backbone of DNA molecules?

Deoxyribose

____ is the general term for carbohydrates composed of two monosaccharides.

Disaccharides

Which type of interaction involves the formation of a covalent bond between two different amino acid side chains?

Disulfide bridge

The presence of ____ bonds between some of the carbon atoms in the hydrocarbon chains of a fat influences whether it is a solid or liquid at room temperature.

Double

Which of the following best describes the relationship between temperature and enzyme activity?

Each enzyme has an optimum temperature where it functions best.

Triglycerides or triacylglycerols are also known as ____.

Fats

Which group of biomolecules is the most efficient for storing energy?

Fats and oils

A phospholipid is structurally similar to a triglyceride except that in a phospholipid, a charged phosphate group replaces one of the ____.

Fatty acids

The structure of a phospholipid can best be described as which of the following?

Glycerol joined to 2 fatty acids and a phosphate group

The peptide bond ____.

Has a partial double-bond character that prohibits rotation

A liquid oil can be converted into a solid fat by chemically adding ____.

Hydrogen

Two strands of DNA are bound together by ____ bonds and then wrapped around a common axis to form a double helix.

Hydrogen

Which type of interaction plays a key role in determining both the secondary and tertiary structure of a protein?

Hydrogen bonds

A liquid oil may be converted into a solid fat by which of the following processes?

Hydrogenation

The amino acid sequence of its polypeptides is called the ____ structure of a protein.

Primary

A protein's final structure can include which of the following?

Regions shaped like an α-helix and regions shaped like a β-pleated sheet.

Why do fats with a greater number of saturated fatty acids have higher melting points than those with fewer saturated fatty acids?

Saturated fatty acids can align together very tightly, making them solid at room temperature and more difficult to melt.

Which characteristic of a protein determines its function?

Shape

How are starch and cellulose different in their composition?

Starch is composed of α-glucose subunits and cellulose is composed of β-glucose subunits.

Glucose and galactose are ____.

Stereoisomers

Glucose and fructose can be described as which of the following?

Structural isomers

The tertiary structure of a protein is determined primarily by interactions involving which of the following?

The R groups of the amino acids

What is the primary structure of a polypeptide?

The amino acid sequence of the polypeptide.

Chaperonins may require an input of energy to refold a misfolded protein. This energy come from ____.

The hydrolysis of ATP

Where are the sugar-phosphate backbones and the nitrogenous bases located in the DNA double helix?

The sugar-phosphate backbones run along the outside of the double helix while the nitrogenous bases pair in the middle.

The 20 common amino acid are classified into five chemical classes based on which of the following?

Their R groups

Which of the following is a characteristic that all lipids share?

They are largely insoluble in water.

Why are fats and oils more efficient in storing energy than carbohydrates or proteins?

They have a higher ratio of energy storing C--H bonds.

A fatty acid that has double bonds between one or more pairs of successive carbon atoms is said to be ____.

Unsaturated

How do saturated and unsaturated fats differ in their ability to pack together?

Unsaturated fats cannot pack as tightly as saturated fats because of the presence of double bonds between the carbon atoms.

What are the two basic types of secondary structure in proteins?

α- helix and β-pleated sheet

The main chemical characteristic that lipids share is that they are ____ in water.

Insoluble

A general (all-inclusive) term for organic molecules that have the same molecular formula, but that differ in their structure or in the spatial arrangement of their atoms, is

Isomers

Organic molecules with the same molecular formula may exist in different forms called which of the following?

Isomers

If the interactions that maintain the 3-dimensional shape of a protein are disrupted so that the polypeptide chains completely unfold, how is this protein described?

It is denatured.

Which of the following determines the function of a protein molecule?

Its shape.

Fats containing polyunsaturated fatty acids have ____ melting points.

Lower

You are studying a protein and notice that it contains two regions made of beta-sheets connected by an alpha-helix. This type of recurring structure that can be found in proteins with very different functions is called a ____.

Motif

In general, where are nonpolar and polar amino acids found in a folded protein?

Non-polar - interior; polar - exterior

C--C and C--H bonds are best described as which of the following?

Nonpolar

The building blocks of nucleic acids are monomers called ____.

Nucleotides

What are the monomers of nucleic acids?

Nucleotides

Which of the following is an accurate description of a triglyceride?

One glycerol molecule joined to three fatty acids

Which group of molecules forms the core of all biological membranes?

Phospholipids

Long polymers made of monosaccharides that have been linked through dehydration reactions are called

Polysaccharides