General Chemistry Quiz
49 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary distinction between isotopes of an element?

  • The number of neutrons. (correct)
  • The number of protons.
  • The number of electrons.
  • The number of valence electrons.

Which property of a radioisotope is used in radiometric dating?

  • The half-life of nuclear decay. (correct)
  • The potential energy of the electrons.
  • The total number of electrons.
  • The number of protons in the nucleus.

What is the relationship between an electron’s distance from the atomic nucleus and its potential energy?

  • The distance from the nucleus does not affect potential energy.
  • The closer the electron, the greater its potential energy.
  • Potential energy is influenced by half-life of the atom.
  • The further the electron, the greater its potential energy. (correct)

Which of the following primarily determines the chemical behavior of an atom?

<p>The valence electrons of an atom. (A)</p> Signup and view all the answers

Why are ions such as $Na^+$ considered to be dissociated in an aqueous environment?

<p>Because the polarity of water molecules interferes with ionic bonds. (A)</p> Signup and view all the answers

What is the optimal pH for human blood?

<p>7.4 (D)</p> Signup and view all the answers

Which buffer system is primarily responsible for maintaining blood pH?

<p>Carbonic Acid – Bicarbonate Buffer System (B)</p> Signup and view all the answers

If the blood becomes too basic, how does the carbonic acid-bicarbonate buffer system respond?

<p>By producing carbonic acid and hydrogen ions (B)</p> Signup and view all the answers

When blood becomes too acidic, what is one way the carbonic acid-bicarbonate buffer system works to raise the pH?

<p>By using excess hydrogen ions to produce carbonic acid (A)</p> Signup and view all the answers

What is the primary function of a base when dissolved in water?

<p>To produce hydroxide ions (C)</p> Signup and view all the answers

Why is carbon considered the 'best electron sharer' in organic molecules?

<p>It can form strong covalent bonds with four other atoms (A)</p> Signup and view all the answers

What characteristic makes molecules composed of only hydrogen and carbon (hydrocarbons) not very useful to living organisms in their pure form?

<p>They are non-polar and do not interact well with water (A)</p> Signup and view all the answers

What functional group is found in stearic acid which allows it to interact in biological systems?

<p>Carboxyl (C)</p> Signup and view all the answers

What characteristic of water allows it to dissolve many ionic and polar compounds?

<p>Its polarity which allows for interaction with other charged molecules (A)</p> Signup and view all the answers

What type of bond is formed by the unequal sharing of electrons?

<p>Polar covalent bond (B)</p> Signup and view all the answers

Which description best explains a molecule that is considered 'hydrophobic'?

<p>A molecule that is non-polar and does not dissolve in water (D)</p> Signup and view all the answers

What is the primary force that causes nonpolar molecules to group together in water?

<p>Hydrophobic interactions (B)</p> Signup and view all the answers

In the reaction of $HCl(g)$ with $H_2O(l)$ to form hydrochloric acid, what is the immediate product of the reaction in terms of ions?

<p>$H_3O^+$ and $Cl^-$ (C)</p> Signup and view all the answers

Which intermolecular force is characterized by a weak attraction between a hydrogen atom and a neighboring oxygen, nitrogen, or fluorine atom?

<p>Hydrogen bonding (A)</p> Signup and view all the answers

What is a neutralization reaction characterized by in basic terms?

<p>The reaction of an acid with a base to form water and a salt. (B)</p> Signup and view all the answers

If a molecule has polar covalent bonds, what other condition is essential for it to be a polar molecule?

<p>The molecule must have an asymmetrical arrangement of bonds. (A)</p> Signup and view all the answers

Which of the following best describes the role of dehydration synthesis in the formation of macromolecules?

<p>It links subunits together by removing a water molecule. (C)</p> Signup and view all the answers

A carbohydrate molecule with a carbonyl group on a terminal carbon is classified as which of the following?

<p>Aldose (A)</p> Signup and view all the answers

What type of linkage is formed during the creation of a disaccharide?

<p>Glycosidic linkage (C)</p> Signup and view all the answers

How does the structure of cellulose differ from that of starch and glycogen?

<p>Cellulose contains β 1-4 links, forming a straight chain structure, whereas starch and glycogen contain α 1-4 and α 1-6 links leading to branched structures. (D)</p> Signup and view all the answers

Which of the following is a primary function of lipids in living organisms?

<p>Long-term energy storage, cushioning, and insulation of cells (C)</p> Signup and view all the answers

What is the structural difference between an aldose and ketose monosaccharide?

<p>Aldoses have a carbonyl group at a terminal carbon, while ketoses have it at a central carbon. (D)</p> Signup and view all the answers

Which of the following best describes the process of hydrolysis?

<p>It is the addition of water molecules to break a larger polymer into subunits. (D)</p> Signup and view all the answers

Which polysaccharide is used for energy storage in animals?

<p>Glycogen (C)</p> Signup and view all the answers

What is the primary function of chitin?

<p>Form the hard exoskeletons of insects and crustaceans (C)</p> Signup and view all the answers

Compared to an equal mass of carbohydrates or proteins, how does the energy storage capacity of fats differ?

<p>Fats store approximately 9/4 the amount of energy. (A)</p> Signup and view all the answers

Which of the following types of molecules are primarily responsible for the formation of waterproof coatings on plant and animal parts?

<p>Waxes (D)</p> Signup and view all the answers

What type of bond is primarily involved in the formation of the alpha helix and beta-pleated sheet structures in proteins?

<p>Hydrogen bonds (B)</p> Signup and view all the answers

How many different amino acids are found in proteins and how many of them are considered essential for humans?

<p>20 different amino acids, 8 are essential (A)</p> Signup and view all the answers

In DNA, which nitrogenous base pairs with guanine (G)?

<p>Cytosine (C) (B)</p> Signup and view all the answers

What is the key characteristic of a protein that has undergone denaturation?

<p>It is unable to carry out its biological function (B)</p> Signup and view all the answers

What type of reaction is involved in joining two amino acids together to form a peptide bond?

<p>Dehydration synthesis (D)</p> Signup and view all the answers

An enzyme is specific to the reaction it catalyzes. This is due in part to what structural feature of the enzyme?

<p>The unique active site (A)</p> Signup and view all the answers

What structural change occurs to the enzyme during the induced fit model of enzyme-substrate interaction?

<p>The active site undergoes a slight conformational change (D)</p> Signup and view all the answers

The primary structure of a protein is ultimately determined by what component of a cell?

<p>The nucleotide sequence of a gene (B)</p> Signup and view all the answers

What is primarily responsible for the unique folding of polypeptide chains in the tertiary structure of a protein?

<p>Interactions between the amino acid side chains or 'R' groups (B)</p> Signup and view all the answers

What is the primary role of an enzyme in a catabolic reaction?

<p>To distort or stress the bonds of the substrates, encouraging bond breakage. (A)</p> Signup and view all the answers

Which of the following best describes the function of an enzyme in an anabolic reaction?

<p>It distorts bonds to encourage two substrates to form a new linkage. (D)</p> Signup and view all the answers

How does increasing the temperature, beyond the optimal range affect enzyme activity?

<p>It causes the enzyme to denature, thus decreasing its activity. (B)</p> Signup and view all the answers

What happens to the rate of an enzyme catalyzed reaction when the substrate concentration is increased beyond the saturation point?

<p>The reaction rate remains constant as all enzyme active sites are occupied. (C)</p> Signup and view all the answers

How does a competitive inhibitor affect an enzyme?

<p>It binds to the active site, blocking access for the regular substrate. (D)</p> Signup and view all the answers

What is the mechanism of action of a non-competitive inhibitor on an enzyme?

<p>It binds to an allosteric site, changing the enzyme's shape and preventing substrate binding. (B)</p> Signup and view all the answers

In feedback inhibition, how does a product of a metabolic pathway regulate an earlier step in the pathway?

<p>It binds to an enzyme earlier in the pathway, which induces a conformational change that prevents the catalytic action. (C)</p> Signup and view all the answers

What is the role of allosteric activators in enzyme regulation?

<p>They bind to allosteric sites and stabilize the active form of the enzyme. (A)</p> Signup and view all the answers

Flashcards

What are isotopes?

Two atoms with the same number of protons and electrons, but differing in the number of neutrons. This leads to a difference in their atomic mass.

What is a radioisotope?

A radioactive isotope is an isotope whose nucleus spontaneously decays. This decay is characterized by a specific half-life.

What is half-life?

The amount of time it takes for half of the nuclei in a radioisotope sample to decay.

What are valence electrons?

Electrons in the outermost energy level of an atom.

Signup and view all the flashcards

What is an ionic bond?

The force of attraction between opposite charges, created by the transfer of electrons between atoms. This creates ions with opposite charges that attract.

Signup and view all the flashcards

Polar Covalent Bond

A type of chemical bond where electrons are unequally shared between atoms, resulting in a partial positive (δ+) and partial negative (δ-) charge on each atom.

Signup and view all the flashcards

Molecular Polarity

The overall distribution of charge within a molecule, which can be polar or non-polar. A polar molecule has a positive and negative end due to uneven electron distribution.

Signup and view all the flashcards

Hydrogen Bonding

A type of intermolecular force where a slightly positive hydrogen atom is attracted to a slightly negative oxygen, nitrogen, or fluorine atom on a neighboring molecule. It's the strongest type of intermolecular force.

Signup and view all the flashcards

Acid

A substance that produces hydrogen ions (H+) when dissolved in water, increasing the acidity of the solution.

Signup and view all the flashcards

Base

A substance that accepts hydrogen ions (H+) when dissolved in water, decreasing the acidity of the solution.

Signup and view all the flashcards

Buffer

A substance that helps to resist changes in pH by neutralizing both acids and bases, keeping the environment relatively stable.

Signup and view all the flashcards

Neutralization Reaction

A chemical reaction where an acid and a base react to form water and a salt. For example, hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form water (H2O) and sodium chloride (NaCl).

Signup and view all the flashcards

Hydrolysis

A chemical reaction where a molecule is broken down by adding water. For example, the breakdown of a disaccharide into two monosaccharides.

Signup and view all the flashcards

Dehydration Synthesis

The process of linking two subunits together by removing a water molecule.

Signup and view all the flashcards

Monosaccharide

A single sugar unit, the basic building block of carbohydrates.

Signup and view all the flashcards

Aldose

A type of monosaccharide with the carbonyl group on a terminal carbon.

Signup and view all the flashcards

Ketose

A type of monosaccharide with the carbonyl group on a central carbon.

Signup and view all the flashcards

Disaccharide

A carbohydrate composed of two monosaccharides linked together.

Signup and view all the flashcards

Polysaccharide

A carbohydrate composed of many monosaccharides linked together.

Signup and view all the flashcards

Starch

A polysaccharide that stores energy in plants. It is composed of amylose and amylopectin.

Signup and view all the flashcards

Glycogen

A polysaccharide that stores energy in animals. It is highly branched.

Signup and view all the flashcards

Cellulose

A structural polysaccharide found in plant cell walls. It is composed of β1-4 linked glucose units.

Signup and view all the flashcards

What is the optimal pH of human blood?

The ideal pH range for human blood is 7.35 to 7.45, with an optimal pH of 7.4. This is maintained by the buffering systems in the body.

Signup and view all the flashcards

What are buffers and what do they do in the body?

Buffers are molecules that resist pH changes by absorbing excess hydrogen ions (H+) or hydroxide ions (OH-) in a solution.

Signup and view all the flashcards

What is the primary buffering system in human blood?

The carbonic acid-bicarbonate buffer system is a major buffer in the body, keeping the pH of blood and extracellular fluid stable.

Signup and view all the flashcards

How does the carbonic acid-bicarbonate buffer system work when blood becomes too basic?

When blood becomes too alkaline (basic), carbon dioxide (CO2) and water (H2O) react to form carbonic acid (H2CO3). Carbonic acid then dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+), lowering the pH.

Signup and view all the flashcards

How does the carbonic acid-bicarbonate buffer system work when blood becomes too acidic?

When blood becomes too acidic, excess hydrogen ions (H+) combine with bicarbonate ions (HCO3-) to form more carbonic acid (H2CO3), thereby increasing the pH.

Signup and view all the flashcards

What is a base?

A substance that produces hydroxide ions (OH-) when dissolved in water.

Signup and view all the flashcards

Why is carbon so important in organic molecules?

Carbon is a key element in organic molecules because its ability to form four stable covalent bonds allows for the construction of complex and diverse structures.

Signup and view all the flashcards

What are hydrocarbons and how are they made more useful for living organisms?

Hydrocarbons are molecules composed of hydrogen and carbon atoms, forming non-polar structures. These structures store a lot of energy but lack water solubility. Adding polar functional groups to the carbon backbone improves their water solubility.

Signup and view all the flashcards

How do enzymes work in catabolic reactions?

In catabolic reactions, enzymes weaken bonds in the substrate to break them apart.

Signup and view all the flashcards

How do enzymes work in anabolic reactions?

In anabolic reactions, enzymes distort bonds in substrates to encourage the formation of new bonds.

Signup and view all the flashcards

What is the optimal temperature for an enzyme?

The optimal temperature for a given enzyme is the temperature at which its activity is the greatest.

Signup and view all the flashcards

What happens to an enzyme when the temperature is too high or too low?

Enzymes lose their function and shape when the temperature is too high or too low, becoming non-functional.

Signup and view all the flashcards

How does pH affect enzyme activity?

Enzymes work best within a narrow pH range. Outside this range, their shape changes, rendering them inactive.

Signup and view all the flashcards

How does substrate concentration affect enzyme activity?

Enzymes work by binding to a substrate at their active site. As more substrate is added, the reaction rate increases until all active sites are occupied.

Signup and view all the flashcards

What is a competitive inhibitor?

Competitive inhibitors resemble the substrate and bind to the active site, blocking the substrate's access.

Signup and view all the flashcards

What is a non-competitive inhibitor?

Non-competitive inhibitors bind to a different site on the enzyme, causing a shape change that prevents substrate binding to the active site.

Signup and view all the flashcards

Beeswax

A type of wax derived from honeycombs and used in various products. It's a long-chain fatty acid ester with a hydrophobic nature.

Signup and view all the flashcards

Paraffin

A type of wax derived from petroleum. It's also hydrophobic and used in many applications like candles and cosmetics.

Signup and view all the flashcards

Cutin

A waxy, water-repellent substance found on the surface of plant leaves and stems. It's also a fatty acid ester and serves as a protective barrier.

Signup and view all the flashcards

Nucleotides

The building blocks of DNA and RNA. They consist of three parts: a nitrogenous base, a five-carbon sugar, and a phosphate group.

Signup and view all the flashcards

Amino Acids

The basic units of proteins. Each amino acid has a specific side chain (R group) that determines its properties.

Signup and view all the flashcards

Primary Structure of Protein

The sequence of amino acids in a polypeptide chain. This sequence determines the protein's shape and function.

Signup and view all the flashcards

Secondary Structure of Protein

Localized folding patterns within a polypeptide chain. Two main types: α-helix and ß-pleated sheets. These folds are formed by hydrogen bonds.

Signup and view all the flashcards

Tertiary Structure of Protein

The overall three-dimensional shape of a protein. Determined by interactions between amino acid side chains.

Signup and view all the flashcards

Quaternary Structure of Protein

The arrangement of multiple polypeptide chains in a larger protein complex. This occurs when two or more polypeptide chains interact and assemble.

Signup and view all the flashcards

Protein Denaturation

The process of a protein unfolding and losing its functional shape. This can be caused by changes in temperature, pH, or other factors.

Signup and view all the flashcards

Study Notes

Chemical Fundamentals

  • Molecules like lipids, nucleic acids, proteins, and carbohydrates are crucial for living things
  • Biochemistry studies the chemistry of these biologically important molecules
  • Isotopes are atoms with the same number of protons and electrons but a different number of neutrons
  • Atomic mass varies between isotopes
  • Radioisotopes spontaneously decay and have a half-life
  • Half-life is the amount of time it takes for half of the nuclei in a sample to decay
  • Radiometric dating and radioactive tracers use radioisotopes

Chemical Behaviour

  • Electrons orbit the nucleus at distances determined by their energy levels
  • Higher energy levels are further from the nucleus
  • Valence electrons are in the outermost energy level and affect the chemical behaviour of an atom

Chemical Bonding

  • Intramolecular forces occur between atoms, including bonds like ionic and covalent
  • Intermolecular forces happen between molecules, such as hydrogen bonds and other weak forces

Intramolecular Forces

  • Ionic bonds are attractive forces between positive and negative charges (e.g., NaCl)
  • Covalent bonds form when atoms share one or more pairs of valence electrons (e.g., Hâ‚‚O)

Intermolecular Forces - Polarity

  • Polar covalent bonds occur when electrons are unequally shared, creating partial positive and negative charges on atoms
  • Electronegativity differences lead to partial charges
  • Water is a polar molecule with unique properties

Molecular Polarity

  • Polar molecules have asymmetrical bond arrangements
  • Water's polarity makes it a good solvent for ionic and polar compounds
  • Hydrogen bonding is a strong intermolecular force in water

Importance of Water - Solubility of Molecules in Cells

  • Cells operate in aqueous environments, making water crucial for life
  • Polar molecules readily dissolve in water
  • Non-polar molecules are hydrophobic and don't mix with water
  • Several intermolecular forces affect water's behaviour, including hydrogen bonding and hydrophobic interactions

Biochemical Reactions

  • Neutralization reactions occur when acids and bases react to form water and salts

Neutralization Reaction

  • Acids release hydrogen ions in water
  • Bases release hydroxide ions in water
  • Reactions form water and salts
  • Buffers maintain a stable pH level
  • Carbonic acid—bicarbonate buffer system is crucial for human blood pH regulation

Organic Molecules React

  • Condensation reactions create larger molecules by combining smaller ones, releasing water
  • Energy is absorbed into the newly formed bonds
  • Hydrolysis reactions break down large molecules into smaller ones, requiring water
  • Common biological linkages include: ether and ester

Building Hydrocarbons

  • Hydrocarbons are compounds of hydrogen and carbon
  • Many are nonpolar but store energy
  • For them to be useful to living things, functional groups have to be attached to carbon backbone

Functional Groups

  • Functional groups change a hydrocarbon's properties dramatically and are key to organic reactions
  • Hydroxyl, carboxyl, amino, sulfhydryl, and phosphate groups each have specific functions.

Carbohydrates

  • Carbohydrates are used for energy, structure, and cell signaling
  • Classified as monosaccharides, oligosaccharides, and polysaccharides
  • Monosaccharides are the basic units
  • Oligosaccharides contain multiple monosaccharides
  • Polysaccharides are long chains of monosaccharides
  • Two types: aldoses and ketoses based on carbonyl group's location
  • Disaccharides are formed by linking two monosaccharides
  • Polysaccharides like starch, glycogen, cellulose, and chitin serve varied functions in organisms

Lipids

  • Lipids are hydrophobic and insoluble in water
  • Includes fats, phospholipids, steroids, and waxes
  • Fats are energy-storage molecules
  • Phospholipids form cellular membranes
  • Steroids have multiple roles in the body

Steroids

  • Steroids are a type of lipid with a distinctive structure
  • Involved in many important biological functions
  • Includes hormones like estrogen, testosterone, and progesterone

Waxes

  • Waxes are hydrophobic, waterproof coatings found in plants and animals

Nucleic Acids

  • Nucleic acids store and transmit genetic information
  • DNA and RNA are constructed of nucleotides
  • Nucleotides contain a nitrogenous base, sugar, and phosphate group
  • Nucleotides are connected via a phosphodiester bond
  • DNA and RNA differ in their nitrogenous bases and sugar
  • Nucleic acids have a structure with two strands in double helix form

Proteins

  • Proteins perform numerous functions, from transport and structural support to catalysis
  • Proteins are made up of amino acids
  • Different amino acids have different properties.
  • 20 different amino acids exist

Amino Acids

  • Amino acids are monomers for building proteins
  • They are categorized by their R group properties
  • Some are acidic and some are basic

Protein Structure

  • Proteins have four levels of structure: Primary, Secondary, Tertiary, and Quaternary
  • Primary structure: Sequence of amino acids
  • Secondary structure: Regular, repeating folding patterns (alpha helix, beta sheet)
  • Tertiary structure: 3D folding determined by interactions between amino acid side chains
  • Quaternary structure: Multiple polypeptide chains interacting to form a functional protein
  • Proteins can be denatured, losing their structure and function by changes in temperature or pH.
  • Denaturation is a process of breaking of bonds within the protein.

Enzymes

  • Enzymes are protein catalysts that speed up biological reactions
  • They lower the activation energy, making reactions easier to occur
  • Enzyme activity is affected by several factors including temperature, pH, and substrate concentration.
  • Enzymes can be inhibited by molecules that block their active site, preventing the substrate from binding

Factors That Affect Enzyme Activity

  • Temperature and pH are important factors affecting enzymes
  • Temperature increases reaction rates, but very high temperatures can cause denaturation
  • pH affects the ionization of amino acid side chains, impacting enzyme function
  • Substrate concentration and enzyme concentration impact reaction rate, but with limited saturation capacity

Inhibition

  • Competitive inhibitors compete with substrate to bind to the active site
  • Non-competitive inhibitors bind to another site away from active site, changing enzyme's shape
  • Feedback inhibition stops production of a product when levels are high

Allosteric Regulation

  • Cells control enzyme activity using allosteric regulators
  • Activators and inhibitors bind to allosterically controlled enzymes and change their structure, affecting function
  • This modification regulates activity and maintains cells' proper function
  • Cofactors and coenzymes are nonprotein components necessary for enzyme function

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

All Notes 1.1-1.4 PDF

Description

Test your knowledge on key concepts in general chemistry, including isotopes, radioisotopes, chemical behavior, pH levels, and buffer systems. This quiz encompasses various fundamental principles that are essential for understanding chemistry in biological systems.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser