Chapter 2: Chemical Level of Organization Flashcards

Comprehensive practice flashcards covering basic chemical principles, elements, chemical bonds, reactions, inorganic molecules, and major organic macromolecules from Chapter 2.

What is the definition of chemistry as presented in the lecture notes?

Chemistry is the science that studies the composition and properties of substances (matter).

What percentage of total body mass is made up of the four major chemical elements?

The four major chemical elements make up about $96\%$ of total body mass.

What are the four major chemical elements in the body and their percentage contributions to total body mass?

Oxygen ($65.0\%$), Carbon ($18.5\%$), Hydrogen ($9.5\%$), and Nitrogen ($3.2\%$).

What is the primary function and charge of the ionized form of sodium ($Na^+$) in the human body?

It is the most plentiful cation in extracellular fluid (ECF), essential for maintaining water balance, and needed to generate action potentials.

Which element's ionized form ($Cl^-$) serves as the most plentiful anion in extracellular fluid?

Chlorine (Cl).

What role does potassium ($K^+$) play in the human body?

It is the most plentiful cation in intracellular fluid (ICF) and is needed to generate action potentials.

What subatomic particles are located in the nucleus of an atom, and what are their respective charges and masses?

Protons (charge: $+$, mass: $1\,\text{AMU}$) and neutrons (charge: neutral/$o$, mass: $1\,\text{AMU}$).

How many electrons fill the first, second, and third electron shells according to the notes?

The 1st shell is full with $2\,e^-$; the 2nd shell is full with $8\,e^-$; the 3rd shell is "full" with $8$ valence $e^-$ (holds up to $18$).

How is the number of neutrons in an atom calculated?

$$\text{Number of Neutrons} = \text{Atomic Mass} - \text{Atomic Number}$$

What is an isotope?

Isotopes are atoms of the same element that have a different number of neutrons.

What is a free radical or superoxide?

A particle with an unpaired electron in its outer shell that is very reactive and damaging to the body.

How is a molecule distinguished from a compound?

A molecule results when two or more atoms chemically combine, whereas a compound is a molecule containing two or more different elements.

How is an ionic bond formed, and with what type of molecules is it typically associated?

An ionic bond is formed when atoms give up or accept electrons; it is associated with inorganic molecules.

What is the difference between non-polar covalent bonds and polar covalent bonds?

In non-polar covalent bonds, electrons are shared equally between atoms; in polar covalent bonds, electrons are shared unequally.

What is a hydrogen bond?

A weak attraction found between molecules, such as between water molecules and within DNA.

What is energy of activation?

The energy needed to initiate a chemical reaction.

How do synthesis and decomposition reactions differ in terms of metabolic categorization and energy flow?

Synthesis reactions are anabolic (building up) and endergonic (more energy in); decomposition reactions are catabolic (breaking down) and exergonic (more energy out).

What general features distinguish inorganic compounds from organic compounds?

Inorganic compounds are associated with non-living matter, smaller, usually ionic, and lack carbon bound to hydrogen; organic compounds are associated with living matter, larger, held by covalent bonds, and feature a carbon backbone with hydrogen.

What proportion of cell volume and body fluids consists of water?

Approximately $55\%$ to $60\%$ water.

What is the difference between a dehydration reaction and a hydrolysis reaction?

In a dehydration reaction, water is released as an output to build a polymer (synthesis); in a hydrolysis reaction, water is added as an input to break down a polymer (decomposition).

How are inorganic acids, bases, and salts defined based on their dissociation in water?

An acid releases hydrogen ions ($H^+$); a base releases hydroxide ions ($OH^-$); a salt releases cations and anions other than $H^+$ or $OH^-$.

How does hydrogen ion concentration ($[H^+]$) change with each unit change on the pH scale?

A change of one pH unit represents a 10-fold ($10\times$) change in $[H^+]$ concentration (inversely proportional to pH).

What is the primary function of a chemical buffer?

A buffer helps resist changes in pH to maintain homeostasis.

What are the three monosaccharides highlighted in the notes and their specific biological roles?

Glucose (hexose, used for quick energy), Deoxyribose (pentose, sugar base of DNA), and Ribose (pentose, sugar base of RNA).

Which monosaccharides combine to form sucrose, lactose, and maltose?

Sucrose = Glucose + Fructose; Lactose = Glucose + Galactose; Maltose = Glucose + Glucose.

What are isomers?

Molecules that have the same chemical formula but different structural arrangements.

What are the three complex carbohydrates (polysaccharides) described in the notes and their functions?

Glycogen (stores energy temporarily in liver and skeletal muscle), Starch (plant polysaccharide easily digested for energy), and Cellulose (plant polysaccharide not digestible, provides fiber in diet).

How do saturated fats differ structurally and physically from unsaturated fats?

Saturated fats have no double bonds in their fatty acid chains and are solid at room temperature; unsaturated fats contain double bonds ($C=C$) in their fatty acid chains and are liquid at room temperature.

What does it mean for a phospholipid to be amphipathic?

It possesses both a polar, hydrophilic head (phosphate group) and non-polar, hydrophobic tails (fatty acid chains).

What are the basic biological functions of vitamins A, D, E, and K?

Vitamin A is for sight; Vitamin D is for calcium absorption; Vitamin E is for skin and acts as an antioxidant; Vitamin K is for blood clotting.

What four basic chemical groups compose the structure of an amino acid?

An amino group, a carboxyl group (acid), a central carbon bonded to hydrogen, and a remainder ('R') group.

What is the specialized covalent bond that links amino acids together during dehydration synthesis?

A peptide bond.

What is denaturation and what environmental factors can induce it?

Denaturation is the process where a protein loses its 3-D shape and functionality; it can be caused by changes in temperature, pH, and ion concentration.

What three structural components make up a nucleotide?

A nitrogenous base (C, A, G, T, or U), a pentose sugar (deoxyribose or ribose), and a phosphate group.

Which nitrogenous bases are purines and which are pyrimidines?

Purines are Adenine (A) and Guanine (G); Pyrimidines are Cytosine (C), Thymine (T), and Uracil (U).

How do DNA and RNA differ in pentose sugar, nitrogenous bases, and strandedness?

DNA contains deoxyribose, bases A, G, C, T, and is double-stranded; RNA contains ribose, bases A, G, C, U, and is single-stranded.

How many total ATP molecules can be generated from one glucose molecule through complete cellular respiration?

Up to $36$ ATP molecules total ($2$ ATP net from the anaerobic phase/glycolysis, and up to $34$ ATP from the aerobic phase/Krebs & ETS).

Which enzyme breaks down ATP into ADP in an exergonic reaction, and which enzyme recharges ADP back to ATP in an endergonic reaction?

ATPase breaks down ATP; ATP Synthase recharges ADP back to ATP.