Biochemistry and Properties of Water Practice Flashcards

Flashcards generated from the biochemistry lecture sources covering properties of water, chemical bonds, essential elements, functional groups, organic compounds, and metabolic reactions.

What is cohesion in water, and what is a specific biological example of its effect?

Cohesion is the attraction of water molecules to one another by forming hydrogen bonds. An example is a water strider walking on the surface of a pond due to high surface tension.

What is adhesion, and what physical phenomenon does it cause in narrow tubes?

Adhesion is the attraction of water molecules to other polar or dissimilar molecules. It causes capillary action, making water creep up narrow glass tubes, paper, or plant stems.

How does water's high specific heat capacity benefit living organisms?

Hydrogen bonding causes water to absorb a large amount of heat before its temperature increases and lose a large amount of heat before its temperature drops, helping organisms maintain a constant body temperature.

What process allows animals to dissipate heat using water's high specific heat of vaporization?

Evaporative cooling, which occurs when liquid water absorbs a large amount of heat to become a gas as animals sweat or pant.

At what temperature does water reach its highest density, and why is solid water less dense?

Water reaches its highest density at $4^\text{C}$. As it cools below $0^\text{C}$, it forms a crystal structure that is less dense than liquid water, allowing ice to float so aquatic organisms can survive in winter.

Why is water considered a universal solvent?

More substances dissolve in water than anything else because of its polar nature, allowing things like salt and sugar to dissolve and enabling blood to efficiently carry nutrients throughout the body.

According to the notes by Chemist Joey Aziz, what is a hydrogen bond and which elements facilitate it?

A hydrogen bond is the electrostatic attraction between two polar groups. It occurs when a hydrogen (H) atom is covalently bound to a highly electronegative atom such as nitrogen (N), fluorine (F), or oxygen (O).

What is the difference between intramolecular bonds and intermolecular bonds?

Intramolecular bonds are forces that hold atoms together within a single molecule (e.g., covalent or ionic bonds). Intermolecular bonds are interactions that exist between molecules (e.g., hydrogen bonding and hydrophobic/hydrophilic interactions).

What are the definitions and properties of hydrophilic and hydrophobic substances?

Hydrophilic substances are polar, 'like water,' and can be dissolved in water. Hydrophobic substances are non-polar, 'don't like water,' and cannot be dissolved in water.

How is electronegativity defined in biochemistry?

Electronegativity is the ability of an atom in a particular molecule to attract electrons to itself, which is used to determine whether a given bond will be nonpolar covalent, polar covalent, or ionic.

According to the transcript, what energy changes occur when covalent bonds are formed and broken?

Forming a covalent bond requires adding energy, while breaking a covalent bond releases energy.

How is a polar covalent bond characterized in terms of electron sharing and charges?

A polar covalent bond occurs when a pair of valence electrons is unequally shared between non-metal atoms. The atom with the larger nucleus attracts electrons more and has a slightly negative charge ($\delta^-$), while the other atom is slightly positive ($\delta^+$).

What six elements make up $98\%$ of living things, and how many bonds does each typically form?

Carbon (C, 4 bonds), Oxygen (O, 2 bonds), Nitrogen (N, 3 bonds), Hydrogen (H, 1 bond), Phosphorus (P, 5 bonds), and Sulphur (S, 2 bonds).

Out of the 92 natural elements, how many are essential for life and how many are classified as trace elements?

25 elements are essential for life. 6 are the main structural building blocks ($98\%$ of living matter), and the remaining 19 are trace elements required in very small quantities.

What is the definition of biochemistry?

Biochemistry is the study of the activity and properties of biologically important molecules.

What defines an organic compound, and why are oxygen ($\text{O}_2$), water ($\text{H}_2\text{O}$), and carbon dioxide ($\text{CO}_2$) classified as inorganic?

Organic compounds are molecules that contain both carbon and hydrogen. Oxygen, water, and carbon dioxide are inorganic because they do not contain both carbon and hydrogen.

What unique structural properties of carbon make it the basis of organic molecules?

Carbon is a small, relatively light element with 4 single valence electrons oriented toward the vertices of a regular tetrahedron. It can form up to 4 stable single, double, or triple bonds in straight chains, branched chains, and ring structures.

What are hydrocarbons and why are they non-polar?

Hydrocarbons are organic molecules that contain only carbon and hydrogen. They are non-polar because of the symmetrical arrangement of their bonds.

What are the structural properties and functional location of the amino group?

The amino group has the formula $-\text{NH}_2$, is polar, accepts a proton, and is found in proteins and nucleic acids.

What are the characteristics and biological location of the sulfhydryl functional group?

The sulfhydryl group has the formula $-\text{SH}$, is slightly polar/polar, and is found in proteins.

What are the definitions of dehydration synthesis and hydrolysis, and what reaction types are they?

Dehydration synthesis is an anabolic reaction that combines molecules through the removal of a water molecule. Hydrolysis is a catabolic reaction that separates molecules by adding a water molecule.

What disaccharide compounds result from dehydration synthesis reactions involving glucose?

Glucose + Glucose forms Maltose; Glucose + Galactose forms Lactose; Glucose + Fructose forms Sucrose (joined by a glycosidic linkage/bond).

What lipid molecules are produced by dehydration synthesis of glycerol with fatty acids?

Glycerol + 3 Fatty Acids produces a Triglyceride; Glycerol + Phosphate + 2 Fatty Acids produces a Phospholipid.

What nucleic acid polymers are produced by dehydration synthesis of ribonucleotides and deoxyribonucleotides?

Many ribonucleotides combine to form RNA, and many deoxyribonucleotides combine to form DNA.