Hydrogen Bonds, Water Properties, and pH in Biology

What types of bonds can hydrogen form?

Hydrogen can form both ionic and covalent bonds.

What happens when hydrogen loses its electron?

It becomes an ion, which can bond with elements like chlorine to form HCl.

Can carbon, nitrogen, and oxygen form ionic bonds with hydrogen?

No, they form covalent bonds with hydrogen.

What are hydrogen bonds?

Weak interactions that occur between adjacent molecules with polar covalent bonds.

What is the significance of hydrogen bonds in biological systems?

They govern how molecules interact within cells and are crucial for the structure of DNA.

What are the properties of water affected by hydrogen bonding?

Cohesion, temperature moderation, and its ability to act as a solvent.

What is cohesion in water?

The tendency of water molecules to stick to each other due to hydrogen bonds.

How does water's high specific heat benefit life on Earth?

It minimizes temperature fluctuations, preserving liquid water and affecting climate.

Why does ice float on water?

Ice is less dense than liquid water due to the arrangement of hydrogen bonds.

What is the role of water in biochemical reactions?

Water is the solvent for all essential biochemical reactions in living organisms.

What is the difference between hydrophilic and hydrophobic molecules?

Hydrophilic molecules interact well with water, while hydrophobic molecules do not.

What types of molecules can dissolve in water?

Molecules with polar covalent bonds and ionic bonds can dissolve in water.

What is the effect of increased acidity in rainwater?

It can have negative effects on ecosystems and human health.

What is the pH scale?

A measure of acidity or alkalinity of a solution, affecting how acids and bases behave in water.

What is a common example of a hydrophobic molecule?

Oils are classic examples of hydrophobic molecules.

How do phospholipids behave in water?

They organize themselves with hydrophilic heads in water and hydrophobic tails away from it.

What is the importance of water's ability to moderate temperature?

It helps maintain stable environmental conditions that are conducive to life.

How does sweating cool the human body?

Sweat absorbs heat from the body before it evaporates, cooling the skin.

What happens to water's temperature when it absorbs heat?

It changes temperature less due to the energy required to break hydrogen bonds.

What is the most dense state of water?

Water is most dense at 4°C.

What is the significance of water's hydrogen bonds in temperature changes?

Hydrogen bonds must be broken or formed to change water's temperature or phase.

What is the role of water in the human body?

The human body is about 60% water, essential for various physiological processes.

What is the relationship between water and life on Earth?

All forms of life require water, which is crucial for biochemical reactions.

What is the effect of hydrogen bonds on water's surface tension?

Hydrogen bonds result in high surface tension, allowing water to form droplets.

What is the role of acids in biological systems?

Acids can donate H+ ions, increasing the H+ concentration in a solution.

What is the role of bases in biological systems?

Bases can accept H+ ions, reducing the H+ concentration in a solution.

What is the dissociation of water?

Water can dissociate into H+ and OH- ions: H2O ⇌ H+ + OH-.

What defines a neutral solution in terms of H+ and OH- concentrations?

In a neutral solution, [H+] = [OH-].

What happens to the pH when an acid is added to water?

The pH decreases, indicating an increase in H+ concentration (pH < 7).

What happens to the pH when a base is added to water?

The pH increases, indicating a decrease in H+ concentration (pH > 7).

What is denaturation in the context of proteins?

Denaturation is the process where the three-dimensional structure of a protein is disrupted, often due to heat or changes in pH.

How do acids affect protein structure?

Acids can disrupt ionic and hydrogen bonds that maintain a protein's three-dimensional shape, affecting its function.

What is the function of HCl in the stomach?

HCl aids in digestion by breaking down food and creating an acidic environment for enzymes.

How do stomach cells protect themselves from acid?

Stomach cells produce mucus to coat the epithelium and bicarbonate ions to neutralize excess acid.

What is a buffer?

A buffer stabilizes pH by either donating or accepting H+ ions, maintaining a relatively constant pH in solutions.

What is the impact of acid rain on freshwater ecosystems?

Acid rain can lower the pH of freshwater, harming aquatic life, especially eggs and adults of freshwater species.

Why is it important to maintain neutral pH in drinking water?

Acidic drinking water can dissolve lead from pipes, posing health risks, particularly to vulnerable populations.

What happened during the Flint water crisis?

Flint's water supply switch led to lead contamination, affecting residents' health and raising awareness about water quality issues.

What is the significance of Dr. Mona Hanna-Attisha during the Flint water crisis?

Dr. Hanna-Attisha raised awareness about elevated lead exposure in Flint children and advocated for community action.

What are the consequences of lead exposure from drinking water?

Lead exposure can disrupt brain development, particularly in pregnant women and children.

How does the pH scale relate to H+ concentration?

The pH scale is logarithmic; each unit change in pH represents a tenfold change in H+ concentration.

What is the role of bicarbonate ions in the stomach?

Bicarbonate ions act as buffers to neutralize excess stomach acid, protecting the stomach lining.

What does it mean when a solution is acidic?

An acidic solution has a higher concentration of H+ ions compared to OH- ions (H+ > OH-).

What does it mean when a solution is basic?

A basic solution has a higher concentration of OH- ions compared to H+ ions (H+ < OH-).

What is the importance of water's unique properties in biological systems?

Water's properties, such as its ability to dissolve substances and participate in chemical reactions, are crucial for life.

What are the potential health effects of drinking acidic water?

Drinking acidic water can lead to lead leaching from pipes, posing serious health risks.

What is the relationship between pH and protein function?

The pH can affect the charge and structure of proteins, influencing their function and stability.

What is the significance of the WHO's statistic on water access?

According to the WHO, 1 in 3 people lack access to clean drinking water, highlighting a global health crisis.

What is the role of Dr. Márcia Barbosa in water purification?

Dr. Barbosa is developing novel water purification technologies using the unique chemistry of water.

What is the atomic number of carbon?

6

How many protons does carbon have?

6

How many electrons does carbon have in total?

6

How many electrons does carbon have in its valence shell?

4

What is the bonding capacity of carbon?

Carbon can form 4 bonds.

What types of bonds is carbon likely to form?

Covalent bonds.

What are hydrocarbons?

Compounds consisting only of hydrogen and carbon atoms.

What is the significance of hydrocarbons in organic molecules?

They are major components of many organic molecules and contain a lot of potential energy.

What are isomers?

Compounds with the same molecular formula but different structures and properties.

What are structural isomers?

Isomers that have different covalent arrangements of their atoms.

What are cis-trans isomers?

Isomers that have the same covalent bonds but differ in their spatial arrangements.

What are enantiomers?

Isomers that are mirror images of each other.

Why are enantiomers important in the pharmaceutical industry?

Different enantiomers may have different biological effects.

What are functional groups?

Components of organic molecules that are commonly involved in chemical reactions.

List the seven functional groups important in the chemistry of life.

Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl.

What are the four major types of organic molecules found in living organisms?

Carbohydrates, proteins, nucleic acids, lipids.

What are polymers?

Large molecules made of multiple, repeated smaller building blocks called monomers.

What monomers make up carbohydrates?

Monosaccharides (simple sugars).

What monomers make up proteins?

Amino acids.

What monomers make up nucleic acids?

Nucleotides.

Are lipids considered polymers?

No, lipids are organic molecules but not polymers.

What is a dehydration reaction?

A chemical reaction that links monomers together to form polymers, requiring energy input.

What is a hydrolysis reaction?

A reaction that breaks down polymers into monomers, releasing energy.

Where does the carbon in our bodies ultimately come from?

From the air, as plants convert carbon dioxide into organic molecules via photosynthesis.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary structure.

What is the primary structure of a protein?

The sequence of amino acids in a polypeptide chain.

What types of interactions can amino acid side chains participate in?

Hydrogen bonds, ionic bonds, di-sulfide bonds, hydrophobic interactions, and van der Waals interactions.

What is the secondary structure of a protein?

The three-dimensional shapes formed by interactions between amino acid R groups, commonly alpha helices and beta sheets.

What determines a protein's tertiary structure?

The many internal interactions among a protein's amino acids that generate a unique three-dimensional shape.

What is quaternary structure in proteins?

The functional structure formed when multiple polypeptide chains aggregate.

What role does collagen play in the body?

Collagen provides structural support for bones, cartilage, and other tissues, making up 30% of the dry weight of the body.

What are some functions of proteins in the body?

Energy sources, cell signaling, internal transport, contraction, and enzymes for chemical reactions.

How do amino acid R groups affect protein structure?

R groups determine how amino acids interact with water, each other, and other molecules, affecting protein structure and properties.

What is the basic structure of nucleic acids?

Nucleic acids are made up of nucleotide monomers, which consist of a sugar, a phosphate group, and a nitrogenous base.

How does RNA differ from DNA?

RNA is typically single-stranded and contains ribose sugar, while DNA is double-stranded and contains deoxyribose sugar.

What are the rules of base-pairing in DNA?

Adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G).

What is the significance of the sequence of nucleotides in DNA and RNA?

The sequence determines the genetic information and the function of the nucleic acids.

What is the role of enzymes in cellular functions?

Enzymes catalyze nearly all chemical reactions in the cell.

What is the N-terminus and C-terminus of a protein?

The N-terminus is the start of the amino acid chain, while the C-terminus is the end of the chain.

What are neutralizing antibodies?

Antibodies that prevent pathogens from entering or infecting host cells.

What are non-neutralizing antibodies?

Antibodies that cannot block pathogen entry but can help the immune system fight off the pathogen.

What is the significance of protein folding?

Proper folding is critical for the formation of active sites and overall protein function.

How can mutations affect protein function?

Mutations can alter amino acids in active sites, disrupting binding to substrates and enzyme function.

What are the common three-dimensional shapes of secondary structures?

Alpha helices and beta sheets.

What types of groups can R groups contain?

Functional groups such as methyl, hydroxyl, carbonyl, carboxyl, and amino groups.

What is the role of hydrogen bonds in protein structure?

Hydrogen bonds help stabilize the secondary structure of proteins.

What is the relationship between protein structure and function?

The specific structure of a protein is directly related to its function.

What is the significance of the amino acid sequence?

The sequence determines the protein's primary structure and influences its overall shape and function.

What is the role of the cytoskeleton proteins?

Cytoskeleton proteins, like actin and tubulin, provide structural support and shape to cells.

What are the two types of nucleic acids critical to cell function?

DNA and RNA

What is the primary function of DNA?

To store genetic instructions within the cell