Untitled Quiz

Questions and Answers

What are carbohydrates?

Carbohydrates

Which of the following is not a polymer?

Cellulose

Glucose (correct)

Starch

Chitin

DNA

What is the chemical reaction mechanism by which cells make polymers from monomers?

Ionic bonding of monomers

The formation of disulfide bridges between monomers

Hydrolysis

Dehydration reactions (correct)

Phosphodiester linkages

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?

10 Signup and view all the answers

Which of the following is an exception to the statement that large organic molecules are usually assembled by polymerization of a few kinds of simple subunits?

A steroid Signup and view all the answers

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. Signup and view all the answers

Polysaccharides, triacylglycerides, and proteins are similar in that they:

Are synthesized from subunits by dehydration reactions. Signup and view all the answers

Dehydration reactions are used in forming which of the following compounds?

Triacylglycerides, polysaccharides, and proteins Signup and view all the answers

DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase?

The phosphodiester bonds between deoxyribose sugars would be broken. Signup and view all the answers

Which of the following polymers contain nitrogen?

Chitin Signup and view all the answers

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

C18H32O16 Signup and view all the answers

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down?

Starch Signup and view all the answers

On food packages, to what does the term insoluble fiber refer?

Cellulose Signup and view all the answers

A molecule with the chemical formula is probably a:

Carbohydrate and monosaccharide only Signup and view all the answers

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

As a disaccharide Signup and view all the answers

All of the following are polysaccharides except:

Lactose Signup and view all the answers

Which of the following is true of both starch and cellulose?

They are both polymers of glucose. Signup and view all the answers

Which of the following is true of cellulose?

It is a major structural component of plant cell walls. Signup and view all the answers

Humans can digest starch but not cellulose because:

Humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. Signup and view all the answers

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA:

Contains one less oxygen atom. Signup and view all the answers

If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled?

Both phospholipids and nucleic acids Signup and view all the answers

How will brief heating (to 95°C) affect macromolecular structures in aqueous solution?

DNA duplexes will unwind and separate, and proteins will unfold (denature). Signup and view all the answers

If cells are grown in a medium containing radioactive 15N, which of these molecules will be labeled?

Both proteins and nucleic acids Signup and view all the answers

Which of the following is not a monomer/polymer pairing?

Triglyceride/Phospholipid bilayer Signup and view all the answers

Among biological polymers, which has the least structural variety?

DNA Signup and view all the answers

Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. Which class of biological polymer has the greatest functional variety?

Proteins Signup and view all the answers

Which class of biological polymer has the greatest information-coding capacity?

DNA Signup and view all the answers

Which of the following statements concerning saturated fats is not true?

They have multiple double bonds in the carbon chains of their fatty acids. Signup and view all the answers

A molecule with the formula C18H36O2 is probably a:

Fatty acid Signup and view all the answers

Which of the following statements is true for the class of biological molecules known as lipids?

They are insoluble in water. Signup and view all the answers

The label on a container of margarine lists 'hydrogenated vegetable oil' as the major ingredient. What is the result of adding hydrogens to vegetable oil?

The hydrogenated vegetable oil stays solid at room temperature. Signup and view all the answers

Which of the following is true regarding saturated fatty acids?

They are the principal molecules in lard and butter. Signup and view all the answers

Why are human sex hormones considered to be lipids?

They are not soluble in water. Signup and view all the answers

All of the following contain amino acids except:

Cholesterol Signup and view all the answers

The bonding of two amino acid molecules to form a larger molecule requires:

The release of a water molecule. Signup and view all the answers

There are 20 different amino acids. What makes one amino acid different from another?

Different side chains (R groups) attached to an α carbon Signup and view all the answers

Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein?

99 Signup and view all the answers

How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids?

20^12 Signup and view all the answers

Which bonds are created during the formation of the primary structure of a protein?

Peptide bonds Signup and view all the answers

What maintains the secondary structure of a protein?

Hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond Signup and view all the answers

Which level of protein structure do the α helix and the β pleated sheet represent?

Secondary Signup and view all the answers

Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?

Hydrogen bonds Signup and view all the answers

The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary structure is stabilized by:

Hydrogen bonds Signup and view all the answers

The tertiary structure of a protein is the:

Unique three-dimensional shape of the fully folded polypeptide. Signup and view all the answers

What type of covalent bond between amino acid side chains (R groups) functions in maintaining a polypeptide's specific three-dimensional shape?

Disulfide bond Signup and view all the answers

At which level of protein structure are interactions between the side chains (R groups) most important?

Tertiary Signup and view all the answers

The R group or side chain of the amino acid serine is -CH2-OH. The R group or side chain of the amino acid leucine is -CH2-CH(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution?

Leucine would be in the interior, and serine would be on the exterior of the globular protein. Signup and view all the answers

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?

Alzheimer's and Parkinson's only Signup and view all the answers

Changing a single amino acid in a protein consisting of 325 amino acids would:

Always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity. Signup and view all the answers

Humans and mice differ because:

Their cells have some differences in the sequence of nucleotides in their nucleic acids. Signup and view all the answers

Molecules with which functional groups may form polymers via dehydration reactions?

Either hydroxyl or carboxyl groups Signup and view all the answers

Which of these molecules is not formed by dehydration reactions?

Fatty acids Signup and view all the answers

Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?

Carbohydrates Signup and view all the answers

Which of the following is not a polymer?

Glucose Signup and view all the answers

What is the chemical reaction mechanism by which cells make polymers from monomers?

Dehydration reactions Signup and view all the answers

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. Signup and view all the answers

Which of the following polymers contain nitrogen?

Chitin Signup and view all the answers

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

C18H32O16 Signup and view all the answers

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the 'a' form. Which of the following could amylase break down?

Glycogen Signup and view all the answers

On food packages, to what does the term insoluble fiber refer?

Cellulose Signup and view all the answers

A molecule with the chemical formula C6H12O6 is probably a?

Carbohydrate and monosaccharide only Signup and view all the answers

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

As a disaccharide Signup and view all the answers

All of the following are polysaccharides except:

Lactose Signup and view all the answers

Which of the following is true of both starch and cellulose?

They are both polymers of glucose. Signup and view all the answers

Which of the following is true of cellulose?

It is a major structural component of plant cell walls. Signup and view all the answers

Humans can digest starch but not cellulose because:

Humans have enzymes that can hydrolyze the a glycosidic linkages of starch but not the glycosidic linkages of cellulose. Signup and view all the answers

Which of the following statements concerning saturated fats is not true?

They have multiple double bonds in the carbon chains of their fatty acids. Signup and view all the answers

A molecule with the formula C18H36O2 is probably a:

Fatty acid Signup and view all the answers

Which of the following statements is true for the class of biological molecules known as lipids?

They are insoluble in water. Signup and view all the answers

The label on a container of margarine lists 'hydrogenated vegetable oil' as the major ingredient. What is the result of adding hydrogens to vegetable oil?

The hydrogenated vegetable oil stays solid at room temperature. Signup and view all the answers

Which of the following is true regarding saturated fatty acids?

They are the principal molecules in lard and butter. Signup and view all the answers

Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement?

A steroid Signup and view all the answers

Which modifications of fatty acids will best keep triglycerides solid at warmer temperatures?

Adding hydrogens and trans double bonds to the fatty acids Signup and view all the answers

Why are human sex hormones considered to be lipids?

They are not soluble in water. Signup and view all the answers

All of the following contain amino acids except:

Cholesterol Signup and view all the answers

The bonding of two amino acid molecules to form a larger molecule requires:

The release of a water molecule. Signup and view all the answers

There are 20 different amino acids. What makes one amino acid different from another?

Different side chains (R groups) attached to an α carbon Signup and view all the answers

The bonding of two amino acid molecules to form a larger molecule requires which of the following?

Removal of a water molecule Signup and view all the answers

Polysaccharides, triacylglycerides, and proteins are similar in that they:

Are synthesized from subunits by dehydration reactions. Signup and view all the answers

Dehydration reactions are used in forming which of the following compounds?

Triacylglycerides, polysaccharides, and proteins Signup and view all the answers

What aspects of protein structure are stabilized or assisted by hydrogen bonds?

Secondary, tertiary, and quaternary structures, but not primary structure Signup and view all the answers

Which bonds are created during the formation of the primary structure of a protein?

Peptide bonds Signup and view all the answers

What maintains the secondary structure of a protein?

Hydrogen bonds between the amino group of one peptide bond and the carboxyl group of another peptide bond Signup and view all the answers

Which type of interaction stabilizes the α helix and the β pleated sheet structures of proteins?

Hydrogen bonds Signup and view all the answers

Which level of protein structure do the α helix and the β pleated sheet represent?

Secondary Signup and view all the answers

The amino acids of the protein keratin are arranged predominantly in an α helix. This secondary structure is stabilized by:

Hydrogen bonds Signup and view all the answers

The tertiary structure of a protein is the:

Unique three-dimensional shape of the fully folded polypeptide Signup and view all the answers

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?

Alzheimer's and Parkinson's only Signup and view all the answers

What methods may be used to elucidate the structures of purified proteins?

Both X-ray crystallography and NMR spectroscopy Signup and view all the answers

In a normal cellular protein, where would you expect to find a hydrophobic amino acid like valine?

In the interior of the folded protein, away from water, or in a transmembrane portion interacting with lipid fatty acid chains Signup and view all the answers

Which of the following techniques uses the amino acid sequences of polypeptides to predict a protein's three-dimensional structure?

Bioinformatics Signup and view all the answers

One of the primary functions of RNA molecules is to:

Function in the synthesis of proteins Signup and view all the answers

Which of the following descriptions best fits the class of molecules known as nucleotides?

A nitrogenous base, a phosphate group, and a pentose sugar Signup and view all the answers

Which of the following are nitrogenous bases of the pyrimidine type?

Cytosine and uracil Signup and view all the answers

Which of the following are nitrogenous bases of the purine type?

Guanine and adenine Signup and view all the answers

Which of the following is an example of hydrolysis?

The reaction of a fat, forming glycerol and fatty acids with the consumption of water Signup and view all the answers

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?

5'-ATGC-3' with 5'-GCAT-3' Signup and view all the answers

Molecules with which functional groups may form polymers via dehydration reactions?

Either hydroxyl or carboxyl groups Signup and view all the answers

Which of these molecules is not formed by dehydration reactions?

Fatty acids Signup and view all the answers

Study Notes

Biological Molecules and Reactions

Humans and mice differ in nucleotide sequences of nucleic acids.
Polymers can be formed via dehydration reactions involving hydroxyl or carboxyl groups.
Fatty acids are not formed through dehydration reactions—this applies to DNA, proteins, and disaccharides.

Bio-macromolecule Classes

Carbohydrates consist of small molecules and macromolecular polymers, unlike lipids, proteins, and nucleic acids which consist only of macromolecular polymers.
Glucose is not a polymer, whereas starch, chitin, cellulose, and DNA are.
Dehydration reactions are responsible for forming polymers from monomers.

Enzymatic and Digestive Processes

Amylase specifically breaks down glycogen due to its ability to hydrolyze "a" glycosidic linkages, unlike cellulose which contains "b" linkages.
Insoluble fiber on food packages refers to cellulose.
Humans digest starch but not cellulose because they lack enzymes to hydrolyze the "b" linkages of cellulose.

Fatty Acids and Lipids

Saturated fats contain no double bonds between carbon atoms and are more common in animal products.
Hydrogenated vegetable oils result in products that stay solid at room temperature.
Fatty acids characterized by the formula C18H36O2 are classified as fats.

Protein Structure

Proteins are formed by the bonding of amino acids through peptide bonds. This process requires the release of a water molecule.
Hydrogen bonds stabilize the secondary, tertiary, and quaternary structures of proteins.
The secondary structure includes "a" helices and "b" pleated sheets, maintained by hydrogen bonds.

Protein Function and Interactions

Misfolded polypeptides can lead to diseases such as Alzheimer's and Parkinson's.
The tertiary structure of proteins is the unique three-dimensional shape achieved by the folding of the polypeptide chain.
Hydrophobic amino acids typically reside in the interior of proteins, away from water, or can be found in transmembrane regions.

Nucleotides and Nucleic Acids

Nucleotides consist of a nitrogenous base, a phosphate group, and a pentose sugar.
Pyrimidine nitrogenous bases include cytosine and uracil, while purine bases are adenine and guanine.
RNA molecules function in protein synthesis and are vital for cellular activities.

Hydrolysis and Dehydration Reactions

Hydrolysis involves the addition of water to break down macromolecules, contrasting with dehydration reactions that build polymers.
To completely hydrolyze a polymer with 11 monomers, 10 molecules of water are required.

Techniques for Structural Elucidation

X-ray crystallography and NMR spectroscopy (nuclear magnetic resonance) are techniques used to determine the three-dimensional structures of proteins.
Bioinformatics can predict protein structures based on amino acid sequences.

General Characteristics and Functions

Large organic molecules like polysaccharides, triacylglycerides, and proteins are typically synthesized from subunits through dehydration reactions.
Enzymes are crucial for catalyzing reactions involving the formation or breakdown of macromolecules.### Biological Molecules and Reactions
Macromolecules like proteins, polysaccharides, and triacylglycerides are synthesized from subunits through dehydration reactions.
Peptide bonds form between monomers, making proteins unique and essential.
Polymers such as starch and cellulose consist of glucose, while chitin contains nitrogen in its structure.

Enzymatic Reactions

DNAase hydrolyzes phosphodiester bonds in DNA, initially breaking connections between deoxyribose sugars.
Amylase specifically breaks down starch, which contains α glycosidic linkages, whereas it cannot digest cellulose, which has β linkages.

Carbohydrates and Polysaccharides

Lactose is classified as a disaccharide consisting of glucose and galactose.
Lactose is distinct from polysaccharides like chitin, glycogen, and amylopectin; only chitin contains nitrogen.
The molecular formula for a polymer formed from three glucose molecules linked by dehydration reactions is C18H32O16.

Protein Structure and Bonds

Proteins consist of 20 different amino acids, and their primary structure is linked by peptide bonds.
Secondary structure includes α helix and β pleated sheets stabilized by hydrogen bonds.
Tertiary structure represents the overall 3D shape of a protein, influenced by various interactions among R groups.

Lipids and Saturated Fats

Lipids are hydrophobic and insoluble in water, contributing to cell membrane structures.
Saturated fats are more common in animal products and solid at room temperature, containing no double bonds in their fatty acid chains.

Genetic Material and Nucleic Acids

DNA and RNA consist of four nucleotides and serve distinct functions in genetic coding and expression.
Cells incorporate radioactive labels into nucleic acids and proteins when grown in specific media, indicating the synthesis of these macromolecules.

Misfolding and Disease

Misfolded polypeptides lead to diseases such as Alzheimer's and Parkinson's, underlining the importance of proper protein folding.
A single amino acid change can significantly impact a protein's primary structure and potentially alter its biological function.

Interaction of Amino Acids

The side chain of amino acids determines their position in a globular protein; hydrophilic amino acids tend to be on the exterior while hydrophobic ones are internal.
Disulfide bonds play a crucial role in stabilizing the specific 3D shapes of folded polypeptides.

Summary of Structure Types

Primary: Sequence of amino acids in a polypeptide.
Secondary: α helices and β sheets formed by hydrogen bonding.
Tertiary: Overall 3D structure influenced by interactions among R groups.
Quaternary: Structure formed by multiple polypeptide subunits associating together.

Key Takeaways

Enzymatic and chemical reactions are vital in macromolecule synthesis and metabolism.
Understanding the structure and properties of biological macromolecules is essential for comprehending their functions in living organisms.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.