Biological Molecules and Polymers

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Questions and Answers

Which of the following biological molecules is NOT a polymer formed from repeating monomer subunits?

Nucleic acids
Proteins
Carbohydrates
Lipids (correct)

Condensation reactions, specifically dehydration reactions, involve the consumption of a water molecule to link monomers together to form polymers.

False (B)

What type of bond links amino acids together to form proteins?

Peptide bond

__________ are built from nucleotide monomers and serve as the units of information storage.

Nucleic acids Signup and view all the answers

Match the following biological molecules with their primary functions:

Carbohydrates = Energy storage and structural support Lipids = Energy storage and membrane formation Proteins = Catalyzing reactions and performing cellular functions Nucleic acids = Information storage Signup and view all the answers

Why can humans digest starch but not cellulose?

Humans lack the enzymes to digest the β linkages in cellulose. (A) Signup and view all the answers

Triglycerides are characterized by polar COOH at both of their hydrocarbon chain ends, making them highly hydrophilic.

False (B) Signup and view all the answers

__________ are lipids similar to phospholipids, but their polar head group is replaced by a carbohydrate involved in cell-cell communication.

Gangliosides Signup and view all the answers

Match the following components with their characteristics:

Amino Acids = Building blocks of proteins with variable R groups Triglycerides = Energy storage molecules with hydrocarbon chains and a polar COOH group at one end GM2 Ganglioside = Lipid involved in cell-cell communication and neuronal plasticity β-hexosaminidase A = Enzyme that metabolizes GM2 ganglioside Signup and view all the answers

According to the diagram, what designation is given to a hydroxyl group positioned above the plane of the sugar ring?

Beta (β) (B) Signup and view all the answers

A glycosidic linkage is formed through a hydrolysis reaction.

False (B) Signup and view all the answers

In the context of describing sugar linkages, if Sugar A has a β1 hydroxyl group and Sugar B has an α4 hydroxyl group participating in a condensation reaction, how would this glycosidic linkage be described?

β 1->4 Signup and view all the answers

The vast array of branched polysaccharide structures is possible because sugar molecules have multiple ______ groups at various positions.

OH Signup and view all the answers

Why can humans digest starch but not cellulose, even though both are polymers of glucose?

Humans lack the enzyme needed to break down the beta linkages in cellulose. (B) Signup and view all the answers

Match the descriptions to the correct terms:

Above the plane of the ring = β Below the plane of the ring = α Reaction forming glycosidic bonds = Condensation Polymer of glucose indigestible by humans = Cellulose Signup and view all the answers

What type of reaction links two monosaccharides together to form a disaccharide?

Condensation (A) Signup and view all the answers

The position of OH groups attached to each carbon in a sugar ring is not important for determining the sugar's properties.

False (B) Signup and view all the answers

Which of the following statements best describes the role of energy input in maintaining order within a cell?

Energy input is used to generate order within the cell, with some energy being converted into heat, increasing overall entropy. (D) Signup and view all the answers

Cells can create order (reduce entropy) without expending energy.

False (B) Signup and view all the answers

What type of molecule primarily performs most of the cell's functions?

Proteins Signup and view all the answers

__________ are composed of fatty acids, usually linked to glycerol, and serve as energy storage while assembling into membranes.

Lipids Signup and view all the answers

Match the following macromolecules with their primary functions:

Carbohydrates = Energy storage and structural support Lipids = Energy storage and membrane formation Proteins = Performing cellular functions Nucleic Acids = Information and short-term energy storage Signup and view all the answers

According to the first law of thermodynamics, what happens to the total amount of energy in a closed system?

It remains constant. (A) Signup and view all the answers

Energy conversions within a cell are 100% efficient, meaning no energy is lost during the process.

False (B) Signup and view all the answers

The second law of thermodynamics suggests that all processes in the universe are driven towards:

Decreasing useable energy. (C) Signup and view all the answers

A reaction that decreases the amount of useable energy is considered energetically ______ and will occur spontaneously.

favorable Signup and view all the answers

In the context of chemical reactions, what defines a 'spontaneous' reaction?

A reaction that occurs without a net addition of energy. (A) Signup and view all the answers

Which of the following is a characteristic of living organisms that distinguishes them from non-living matter?

The capacity to create and maintain order within a disorderly universe. (C) Signup and view all the answers

Since cells increase biological order, they violate the second law of thermodynamics.

False (B) Signup and view all the answers

Explain how cells are able to increase biological order without violating the second law of thermodynamics.

Cells exchange energy with their environment. Signup and view all the answers

ATP is primarily utilized for long-term energy storage within a cell.

False (B) Signup and view all the answers

What chemical feature is common among nucleotides?

uniform chemical structure Signup and view all the answers

Match the following terms with their definitions:

Thermodynamics = The study of energy and its transformations. Entropy = A measure of disorder or randomness in a system. Spontaneous Reaction = A reaction that occurs without a net addition of energy. Energy Conversion = The process of changing energy from one form to another. Signup and view all the answers

The pH at which half of all molecules of an ionizable substance are charged is known as the ____.

pK Signup and view all the answers

Which of the following amino acids is classified as acidic at neutral pH?

Aspartic acid (B) Signup and view all the answers

Which of the following amino acids is a basic amino acid?

Arginine (B) Signup and view all the answers

Match the following molecules with their primary function in the cell:

ATP = Short-term energy carrier Nucleotides = Building blocks of nucleic acids Amino Acids = Building blocks of proteins Signup and view all the answers

Which of the following statements best describes the role of ATP in cellular processes?

It acts as the primary short-term energy currency for the cell. (C) Signup and view all the answers

Explain why humans can digest starch but not cellulose, despite both being composed of glucose monomers.

Humans have enzymes that can break down the alpha linkages in starch but lack enzymes to break down the beta linkages in cellulose. Signup and view all the answers

Describe the key chemical feature that defines lipids and explain how this feature contributes to their function as membrane barriers.

Lipids are primarily defined by their hydrophobic hydrocarbon chains. These hydrophobic chains allow them to form barriers in water. Signup and view all the answers

How does the structure of a phospholipid, with its amphipathic nature, contribute to its function in forming biological membranes?

The amphipathic nature (possessing both a polar and nonpolar region) allows phospholipids to form bilayers in aqueous settings due to hydrophobic and hydrophilic interactions. Signup and view all the answers

Describe the general chemical structure of an amino acid, highlighting the features that are constant across all amino acids and the feature that varies.

Amino acids have a uniform structure with an amino terminus, a carboxyl terminus, and a side (R) group attached to a central carbon. Only the 'R' group varies. Signup and view all the answers

In the context of cellular biology, discuss the relationship between energy input, order, and entropy. Use the example of chemical fusion in the sun to illustrate your point.

Cells use energy to create order, reducing their entropy. This energy originates from external sources like the sun, where chemical fusion increases entropy. Part of the energy used by cells is converted to heat, further increasing entropy in the cell’s environment. Signup and view all the answers

Describe the role of carbohydrates in cells, differentiating between their functions in energy storage and structural support. Provide an example of each.

Carbohydrates function as energy storage (e.g., glycogen in animals, starch in plants) and provide structural support (e.g., cellulose in plant cell walls). Signup and view all the answers

Compare and contrast the roles of lipids and nucleic acids in a cell, focusing on their monomeric components and primary functions.

Lipids, composed of fatty acids and glycerol, primarily store energy and form membranes. Nucleic acids, composed of nucleotide monomers, store information and provide short-term energy. Signup and view all the answers

Explain how cells adhere to the second law of thermodynamics while simultaneously creating order within their structures.

Cells reduce entropy internally by using energy. However, in doing so, they release heat to their surroundings, increasing entropy outside the cell, thus adhering to the second law of thermodynamics. Signup and view all the answers

Relate the concept of monomers and polymers to two different classes of macromolecules found in cells, and briefly describe how this structural organization contributes to their respective functions.

Proteins consist of amino acid monomers and carry out most cellular functions. Nucleic acids consist of nucleotide monomers, storing information and providing short-term energy. The specific sequence of monomers determines the macromolecule’s unique properties and function. Signup and view all the answers

Explain how a condensation reaction, specifically a dehydration reaction, leads to the formation of a glycosidic bond between two monosaccharides.

In a dehydration reaction, a water molecule is removed. Specifically, an -OH group is removed from one monosaccharide and a hydrogen atom (H) from the other. The remaining oxygen atom then forms a bridge, creating a glycosidic bond between the two monosaccharides. Signup and view all the answers

A scientist analyzes a biological sample and finds it contains a high proportion of nonpolar molecules. Which class of biological molecules is most likely to be abundant in this sample, and what is its primary function?

Lipids are most likely abundant in the sample because they are primarily nonpolar. Lipids serve as energy storage and can assemble into membranes. Signup and view all the answers

Compare and contrast the roles of carbohydrates and lipids in providing energy for cells. What are the key differences in their structures or function?

Both carbohydrates and lipids serve as energy sources, but lipids store more energy per gram than do carbohydrates. Carbohydrates are readily accessible for quick energy. Lipids are better for long-term storage. Carbohydrates are polar molecules, while lipids are nonpolar. Signup and view all the answers

If a newly discovered organism's cells are found to be unable to form peptide bonds, what level of protein structure would be directly affected, and how would this impact the protein's function?

The primary structure of proteins would be directly affected. Because peptide bonds link amino acids, without them, the protein could not form a chain of amino acids. Without a primary structure, the protein cannot fold properly and therefore cannot properly function. Signup and view all the answers

How does the arrangement of carbon atoms in a sugar ring lead to the diversity of carbohydrate structures, and how does this diversity contribute to these molecules' various functions?

The carbons in the ring are numbered, allowing for different glycosidic linkages (alpha 1-4, beta 1-4, etc.). This creates different structures with different properties. Carbohydrates can be used for energy storage, structural support, and cell-to-cell recognition. Signup and view all the answers

Based on the provided text, describe the difference between alpha ($\alpha$) and beta ($\beta$) configurations of hydroxyl (OH) groups attached to a sugar ring.

Alpha ($\alpha$) indicates the OH group is below the plane of the ring, while beta ($\beta$) indicates it is above the plane. Signup and view all the answers

Explain what a glycosidic linkage is and how it is formed between two sugar molecules, according to the text.

A glycosidic linkage is a bond formed by a condensation reaction between the hydroxyl groups of two sugar molecules, as shown in the diagram. Water is released as a byproduct. Signup and view all the answers

Explain how the first law of thermodynamics applies to cells, and provide a specific example related to cellular energy transformations.

The first law states energy cannot be created or destroyed, only converted. In cells, chemical energy from food is converted to kinetic energy for movement, with some lost as heat. Signup and view all the answers

What does '$\beta$ 1$\rightarrow$4 linkage' mean in the context of polysaccharide structure?

It refers to a glycosidic bond where the carbon 1 (C1) of the first sugar (in the beta configuration) is linked to the carbon 4 (C4) of the second sugar. Signup and view all the answers

Describe the relationship between the second law of thermodynamics and entropy. How does this relate to the directionality of reactions within cells?

The second law states that all processes increase disorder (entropy). Reactions that increase entropy are energetically favorable and spontaneous. Signup and view all the answers

According to the information provided in the text, why is it possible to form a wide variety of branched polysaccharide structures?

Because sugar molecules have multiple OH groups at various positions, which allows them to link to other sugars in many different ways. Signup and view all the answers

How many different ways can D-glucose disaccharides be formed?

There are 11 different ways to form D-glucose disaccharides. Signup and view all the answers

Explain in your own words what is meant by a spontaneous reaction in the context of cellular thermodynamics. Provide an example.

A spontaneous reaction occurs without a net input of energy. An example is the breakdown of glucose to release energy. Signup and view all the answers

Based on the text, what reaction occurs to link two sugars together?

A condensation reaction. Signup and view all the answers

Cells maintain a high level of biological order. How is this possible given the second law of thermodynamics, which dictates an increase in entropy?

Cells are not isolated systems and exchange energy with their environment. They use energy to create order, increasing entropy outside the cell. Signup and view all the answers

Consider a cell performing work, such as synthesizing a protein. Describe how this process relates to both the first and second laws of thermodynamics.

By the First Law, the total energy in the system (cell + surroundings) remains constant. By the Second Law, the protein synthesis increases order (decreases entropy) within the cell, but this requires energy that is ultimately dissipated as heat, increasing entropy in the surroundings. Signup and view all the answers

Starch and cellulose are both polymers of glucose. According to the text, provide a possible reason why humans can digest starch, but not cellulose.

Because starch is an energy storage molecule, but cellulose is a structural molecule . Signup and view all the answers

Based on the text, would a glycosidic linkage between a $\beta$1 OH on sugar A and a $\beta$4 OH on sugar B be possible? Briefly explain your reasoning.

Yes, it is possible. The text describes a glycosidic linkage between a $\beta$1 OH and an $\alpha$4 OH, but the linkage could also involve two beta configurations depending on the specific enzyme catalyzing the reaction. Signup and view all the answers

Explain why energy is only useable if it is 'confinable' or 'stored'. Give an example of confinable energy that cells utilize.

Confinable energy can be harnessed to perform work. An example is chemical energy stored in the bonds of ATP. Signup and view all the answers

Many cellular processes involve energy conversions. Describe one such conversion, and explain why these conversions are never 100% efficient.

Conversion of glucose chemical energy into ATP mechanical energy. Not 100% efficient, because some energy is always lost as heat. Signup and view all the answers

How do unfavorable reactions occur in cells, considering they are not spontaneous and increase the availability of useable energy?

Unfavorable reactions are coupled with favorable reactions that release energy. The net change in free energy for the combined reactions must be negative for the process to occur. Signup and view all the answers

How do the chemical properties of amino acid side chains contribute to the overall structure and function of a protein?

The diverse chemical properties of amino acid side chains (e.g., hydrophobicity, charge, size) dictate how a protein folds and interacts with other molecules, influencing its overall structure and function. Signup and view all the answers

Explain the significance of the pK value of an ionizable amino acid side chain in a biological system.

The pK value determines the protonation state (charged or uncharged) of the amino acid side chain at a given pH, influencing its ability to participate in electrostatic interactions and hydrogen bonding, which is crucial for protein structure and function. Signup and view all the answers

Describe the role of ATP (adenosine triphosphate) as a short-term energy carrier in the cell and relate its function to the cell's ability to maintain order.

ATP stores energy in its phosphate bonds, which can be released to drive cellular processes. ATP enables the cell to perform work, counteract entropy, and maintain a highly organized state. Signup and view all the answers

Explain how the polar, charged nature of nucleotides contributes to their function within the cell.

The polar, charged nature of nucleotides allows them to be soluble in the aqueous cellular environment and facilitates their role in carrying charged phosphate groups (like in ATP) or forming stable, hydrogen-bonded structures in nucleic acids (DNA, RNA). Signup and view all the answers

How do acidic and basic amino acids contribute to a protein’s ability to interact with other molecules in a cell?

Acidic amino acids (Aspartate, Glutamate) can form ionic bonds or salt bridges with positively charged molecules, while basic amino acids (Histidine, Lysine, Arginine) can interact with negatively charged molecules. These interactions contribute to protein folding, stability, and binding specificity. Signup and view all the answers

Consider a scenario where a protein's function is highly dependent on a specific Histidine residue being protonated. How would a change in cellular pH affect the protein's activity, and why?

Since Histidine’s pK is close to neutral pH, a small change in pH can significantly alter the protonation state of Histidine. If the protein's function relies on protonation, an increase in pH (more basic) might deprotonate the Histidine, disrupting the protein's activity. A decrease in pH may cause a different conformation, also disrupting activity. Signup and view all the answers

Relate the concept of maintaining order in living systems to the role of ATP in driving specific cellular processes. Provide an example.

Living systems combat entropy by using ATP to drive energetically unfavorable reactions. For example, muscle contraction requires ATP hydrolysis to move myosin along actin filaments, maintaining the organized arrangement of muscle fibers and enabling movement rather than disorder. Signup and view all the answers

If a drug were designed to inhibit ATP production in a cell, what overall effects would you expect to observe regarding the cell's ability to maintain its internal organization and carry out essential functions?

Inhibiting ATP production would reduce the cell's ability to perform energy-requiring processes like protein synthesis, active transport, and maintaining membrane potentials. This would lead to a loss of internal organization, disruption of homeostasis, and ultimately, cell death if ATP depletion is severe. Signup and view all the answers

Flashcards

Monomers

Small, carbon-based molecules that form the building blocks of cells. They are consistent across all living species.

Carbohydrates

Polymers of sugar monomers providing energy storage and structural support. They are highly polar molecules made of a linear chain ring with several OH groups.

Nucleic Acids

Units of information storage and also serve as sources of short-term energy.

Dehydration Reaction

A reaction where monomers are linked together to form polymers, with the release of a water molecule.