Biochemistry Class Quiz

Chemical Level of Organization, Part 1

• Water's properties in aqueous solutions are described.
• Concepts of concentration and osmolarity are detailed.
• Enzymes and activation energy are reviewed.
• Differences between inorganic and organic compounds are identified.
• pH and its physiological importance are explained.
• Macromolecules' structures and functions are described, along with their classification.
• Cellular respiration's steps are outlined.

Four Most Common Elements in the Body

• Oxygen accounts for 65% of the body's elements.
• Carbon makes up 18.6%.
• Hydrogen comprises 9.7%.
• Nitrogen constitutes 3.2%.
• These four elements total 96.5% of the body's elements.

What Is an Atom?

• Atoms are the smallest unit of matter.
• Atoms are composed of subatomic particles, including protons, neutrons, and electrons.
• Atoms combine to form molecules.

Chemical Bonding

• Atoms join to form chemicals with distinct characteristics through bonds.
• Four types of bonds are discussed: polar covalent, pure (non-polar) covalent, ionic, and hydrogen bonds.

Pure (Non-Polar) Covalent Bond

• Electrons are equally shared by atoms of the same element.
• Atoms' charges are equal.
• Diatomic molecules can bond with themselves.

Polar Covalent Bond

• Electrons are unequally shared.
• One atom has a stronger electron pull.
• Electrons spend more time with one atom, making one side negatively charged and the other positively charged.

Ionic Bond

• Electrons are unequally shared; one atom takes an electron from the other.
• A positively charged ion (cation) is formed when an atom loses an electron.
• A negatively charged ion (anion) is formed when an atom gains an electron.

Covalent Bond: Water

• Covalent bonds occur between one oxygen and two hydrogen atoms.
• This bond is polar covalent, due to unequal electron sharing.
• Oxygen holds onto electrons more tightly than hydrogen. This makes oxygen negatively charged and hydrogen positively charged.

Hydrogen Bonds

• Hydrogen bonds form between water molecules.
• These bonds contribute to water's surface tension.

Hydrogen Is Special

• Hydrogen has one proton, no neutrons, and one electron.
• It is depicted diagrammatically with a central proton and surrounding electrons.

Surface Tension & The Lungs

• High surface tension in the lungs can cause them to collapse.
• Surfactant's role is to lower surface tension.
• Surfactant disrupts hydrogen bonds between water molecules.
• Premature infants often lack surfactant, making breathing difficult.

H₂O Surface Tension & The Lungs

• High surface tension in the lungs might cause collapse, especially for premature infants.
• Premature infants often lack surfactant, which is needed in lungs to support respiratory function.

Water

• An average adult male can survive for 30-40 days without food.
• An average adult's survival time without water is estimated to be 8-14 days.
• Water is vital for many bodily functions.

Four Properties of Water

• Solubility: Water's ability to dissolve solutes.
• Reactivity: Most body chemistry uses water.
• High Heat Capacity: Water's ability to absorb and retain heat, aiding homeostasis.
• Lubrication: Water moistens and reduces friction.

Molecules and Water

• Hydrophilic molecules react with water.
• Hydrophobic molecules do not react with water.

Electrolytes

• Electrolytes are substances that dissolve in water and dissociate into ions.
• Imbalances of electrolytes can disrupt body functions. Sodium and potassium are important electrolytes.

Importance of Electrolytes

• Electrolyte imbalance can result in issues like muscle cramps and irregular heartbeats.
• Maintaining homeostasis, the balance of ions, is crucial.
• Kidneys are involved in excreting or retaining electrolytes.

What is pH and Why Do We Need Buffers?

• pH is the measure of hydrogen ions and hydroxide ions in solution.
• A critical issue is managing pH in living organisms and environments.

Acids and Bases

• Acids release hydrogen ions, while bases release ions that combine with hydrogen ions.

pH (the Power of Hydrogen)

• pH describes the relative concentrations of hydrogen and hydroxide ions in a solution.
• Neutral pH is 7.0, indicating equal concentrations.
• Lower pH (acidic) has more hydrogen ions, and higher pH (basic) more hydroxide ions. The pH scale runs from 0 (most acidic) to 14 (most basic) with a neutral value of approximately 7.

Which Side is Acidic and Basic?

• The side with a higher concentration of hydrogen ions is acidic, and the side with a higher concentration of hydroxide ions is basic.

pH Scale

• pH has an inverse relationship with hydrogen ion concentration.
• Higher concentrations of hydroxide ions mean a higher pH, whereas lower concentrations mean a lower pH.

Acids & Bases in the Body

• Blood pH is usually between 7.35-7.45.
• An excess of hydrogen ions can damage cells and tissues.
• An excess of hydroxide ions can cause uncontrolled, sustained muscle contractions.

Acid and Alkaline

• Acidosis is caused by excess hydrogen ions in the body fluids (lower pH).
• Alkalosis results from excess hydroxide ions (higher pH).

pH Homeostasis

• Buffers resist changes in pH.
• Weak acid/salt compounds are examples of buffers, acting to neutralize strong acids or bases, maintaining homeostasis.

Organic and Inorganic Molecules

• Organic: contain carbon bonded to hydrogen (often hydrocarbon chains)
• Inorganic: typically do not contain carbon and hydrogen atoms as primary structure components. Examples include water, oxygen, carbon dioxide, acids, bases, and salts.

Label These Molecules Organic or Inorganic

• Molecules are identified as either organic or inorganic.

Functional Groups

• Groups of atoms in molecules that can affect interactions and reactions are identified. Examples include carboxyl, amino, hydroxyl, and phosphate groups.

Macromolecules

• Important biological macromolecules are identified as carbohydrates, proteins, fats (lipids), and nucleic acids.

Biomolecule Building Blocks

• Building blocks for carbohydrates, proteins, lipids, and nucleic acids are listed in a table format (this section does not seem to provide specific blocks, so a table cannot be generated)

Carbohydrates: Starches & Sugars

• Hydrophilic organic molecules provide energy.
• Carbohydrates can be broken down to provide energy.

Monosaccharides and Disaccharides

• Monosaccharides are simple sugars with 3-7 carbon atoms, like glucose and galactose.
• Disaccharides are two simple sugars joined by dehydration synthesis. Dehydration synthesis is the process of removing a water molecule to join the molecule; this forms a bond between two molecules.

Monosaccharides and Disaccharides

• Dehydration synthesis joins molecules to form disaccharides, removing a water molecule in the process.

Polysaccharides

• Polysaccharides are chains of simple sugars (e.g., glycogen).
• The term 'poly' indicates many units.

Protein Structure

• Proteins are the most abundant and important organic molecules.
• Their basic elements are carbon, hydrogen, oxygen, and nitrogen.
• Proteins have 20 amino acids as fundamental building blocks.

Protein Functions

• Proteins have many functions, impacting support, movement, transport, buffering (regulation of metabolic regulation, coordination, defense.

Amino Acids

• Amino acids are the building blocks of proteins.
• They consist of a central carbon, hydrogen, an amino group (-NH₂), a carboxyl group (-COOH), and a variable side chain (R group.

Peptides

• Peptide bonds form between amino acid's amino and carboxyl groups, via a dehydration reaction.

Shape and Function

• Protein function depends on shape, determined by its amino acid sequence.
• Denaturation is the loss of shape and function due to heat or pH.

Primary Structure

• Polypeptides are long chains of amino acids.
• The sequence of amino acids is considered the primary structure.

Secondary Structure

• Hydrogen bonds create spirals or pleats in the secondary structure of proteins.
• Dotted lines represent hydrogen bonds binding segments of protein molecules (polypeptide chains)

Tertiary Structure

• The secondary structure folds into a unique shape in the tertiary protein structure stage.
• There are different shapes a protein can take, resulting in their various functions; the tertiary structure is important to describe the final shape of the protein.

Quaternary Structure

• Several tertiary structures can come together to form the final protein shape, known as the quaternary protein structure.

Protein Structure Levels

• Hierarchical organization of protein structure levels is summarized with descriptions.