Biology Chapter 2 Review

Exploring the Building Blocks

A fascinating journey into the fundamental components that make up life's intricate tapestry.

Building Blocks of Life

• Proton: Found in the nucleus, carries a positive charge.
• Electron: Found in electron shells, carries a negative charge.
• Neutron: Found in the nucleus, carries no charge.
• Covalent Bond: Formed by sharing electrons between atoms.
• Ionic Bond: Formed by the transfer of electrons between atoms.
• Isotope: Atoms of the same element with different numbers of neutrons.
• Van der Waal Forces: Weak attractions between molecules.
• Example: London dispersion forces.
• Importance: Contribute to molecular interactions and properties.

Multiple Choice

Which type of bond is formed by sharing electrons between atoms?

• Proton bond

• Ionic bond

• Covalent bond

• Van der Waal Forces

Covalent Bond

Trivia: Covalent bonds are formed by sharing electrons between atoms. This type of bond is the strongest and most common in nature. It is responsible for holding together molecules like water, DNA, and proteins. Covalent bonds play a crucial role in chemical reactions and the formation of complex structures.

Building Blocks of Life

• Why does water expand when it freezes? Water molecules form a crystalline structure when frozen, with each molecule forming hydrogen bonds with four neighboring molecules. This arrangement creates open spaces, causing the volume to increase.
• What makes a molecule polar? A molecule is polar if it has a positive and negative end due to an uneven distribution of electrons. This occurs when there is a significant difference in electronegativity between atoms.
• Example of hydrogen bonding: Water molecules form hydrogen bonds with each other, creating cohesive forces.
• Are hydrogen bonds stronger or weaker than ionic or covalent bonds? Hydrogen bonds are weaker than both ionic and covalent bonds.
• Define cohesion: Cohesion is the attraction between molecules of the same substance.
• Define adhesion: Adhesion is the attraction between molecules of different substances.
• Example of cohesion: Water forming droplets on a leaf due to cohesive forces.
• Example of adhesion: Water sticking to the sides of a glass due to adhesive forces.
• Two parts of a solution: A solution consists of a solvent (the substance in which solutes dissolve) and solutes (the substances being dissolved).
• What is pH a measurement of? pH is a measurement of the acidity or alkalinity of a solution.
• Range of the pH scale: The pH scale ranges from 0 to 14, with 7 being neutral, values below 7 acidic, and values above 7 alkaline.
• Difference between water and an acidic solution: An acidic solution has a higher concentration of hydrogen ions (H+) than water, making it more acidic.
• Difference between water and a basic (alkaline) solution: A basic solution has a higher concentration of hydroxide ions (OH-) than water, making it more alkaline.

Multiple Choice

What is the range of the pH scale?

• 0 to 7

• 7 to 14

• 1 to 14

• 0 to 14

pH Scale Range

• pH scale ranges from 0 to 14
• 0-6 is acidic, 7 is neutral, and 8-14 is alkaline
• pH 7 is the pH of pure water
• pH below 0 or above 14 is not possible

Building Blocks of Life

Covalent Bonds: Carbon can form single, double, or triple covalent bonds. Single bond: 4 electrons shared. Double bond: 8 electrons shared. Triple bond: 12 electrons shared. Polymers: Large molecules made of repeating subunits called monomers. Formed through polymerization, where monomers join together. Monomers: Small molecules that can join together to form polymers. Carbohydrates: Organic compounds made of carbon, hydrogen, and oxygen. Provide energy and structural support. Lipids: Hydrophobic molecules that store energy and form cell membranes. Nucleic Acids: Carry genetic information and control cellular activities. Proteins: Perform various functions in cells. Reactants: Found on the left side of the arrow in a chemical equation. Products: Found on the right side of the arrow. Catalyst: Substance that speeds up a chemical reaction without being consumed.

Multiple Choice

What are the building blocks of life?

• Covalent Bonds

• Polymers

• Carbohydrates

• Lipids

Building Blocks: Polymers

Polymers are the building blocks of life. They are large molecules made up of repeating subunits called monomers. Examples include DNA, proteins, and carbohydrates. Polymers play a crucial role in the structure and function of living organisms, making them essential for life as we know it.

Exploring Life's Building Blocks

• Catalyst: Found in a chemical equation
• Law of Conservation of Mass: Matter cannot be created or destroyed
• Endothermic Reaction: Absorbs energy to occur
• Exothermic Reaction: Gives off energy when it occurs
• Activation Energy: Energy required to start a reaction
• Active Site: Region on an enzyme where substrates bind
• Enzyme: Biological catalyst that speeds up chemical reactions
• Biological Importance: Enzymes regulate and control metabolic processes
• Substrate: Reactant that binds to an enzyme
• Variables Affecting Enzyme Rate: Temperature, pH, substrate concentration

Multiple Choice

Which of the following variables affect the rate of an enzyme?

• Catalyst

• Activation Energy

• Temperature

• pH

pH and Enzyme Rate

pH is a crucial factor that affects the rate of an enzyme. Enzymes have an optimal pH at which they function best. Deviating from this pH can denature the enzyme, rendering it ineffective. Maintaining the correct pH is essential for enzyme activity and overall biological processes.