<<***Unit 1: Chemistry of life (8-11%)***<< * Water is a polar molecule, meaning it has a partial positive charge on one end (the hydrogen atoms) and a partial negative charge on the other end (the oxygen atom). This polarity allows water molecules to form hydrogen bonds with each other, giving water its unique properties such as high surface tension and the ability to dissolve many substances. * Hydrogen bonds are formed when a hydrogen atom with a partial positive charge is attracted to an electronegative atom with a partial negative charge, such as oxygen or nitrogen. The hydrogen atom forms a weak electrostatic bond with the electronegative atom, resulting in a hydrogen bond. Hydrogen bonding is a type of intermolecular force that occurs when a hydrogen atom is bonded to a highly electronegative atom such as nitrogen, oxygen, or fluorine. The hydrogen atom becomes partially positively charged, while the electronegative atom becomes partially negatively charged. This creates a strong electrostatic attraction between neighboring molecules, resulting in higher boiling and melting points compared to similar molecules that do not exhibit hydrogen bonding. Examples of substances that exhibit hydrogen bonding include water, ammonia, and DNA. * Water is a unique substance with several important properties. Some of the key properties of water include: * High surface tension: Water molecules are attracted to each other, creating a strong surface tension that allows insects to walk on water and causes water droplets to form beads on surfaces. * High heat capacity: Water can absorb a lot of heat energy without a significant increase in temperature, making it an effective coolant in many applications. * High boiling and freezing points: Water has a high boiling point (100°C) and a high freezing point (0°C), which allows it to exist as a liquid over a wide range of temperatures. * Universal solvent: Water is an excellent solvent, meaning it can dissolve a wide variety of substances, including salts, sugars, and gases. * High density: Water is denser than air, which allows aquatic organisms to float and provides buoyancy for boats and ships. * CHNOPS is an acronym that stands for the six most important elements found in living organisms: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur. These elements are essential for the formation of biological molecules such as carbohydrates, lipids, proteins, and nucleic acids. * Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen atoms. They serve as a primary source of energy for living organisms and play important structural roles in cells. The basic unit of carbohydrates is a monosaccharide, which can be linked together to form disaccharides and polysaccharides. Carbohydrates can also be modified with functional groups, such as amino or phosphate groups, to perform specific biological functions. \ ![](https://knowt-user-attachments.s3.amazonaws.com/4b4532b805a74522a76b3bf0424ebfcc.jpeg =741x433) * **Lipid Structure and Function** Lipids are a diverse group of biomolecules that are insoluble in water but soluble in organic solvents. They are composed of fatty acids and glycerol, and their functions include energy storage, insulation, and cell membrane structure. The structure of lipids varies depending on the type of lipid, but they all contain hydrophobic and hydrophilic regions that allow them to interact with both water and other lipids. Some common types of lipids include triglycerides, phospholipids, and cholesterol. \ ![](https://knowt-user-attachments.s3.amazonaws.com/21811fd557a44cd4ba15c0847dc8ce3f.jpeg =741x417) * Proteins are complex molecules made up of amino acids that are folded into specific three-dimensional structures. The structure of a protein determines its function, which can range from catalyzing chemical reactions to providing structural support for cells. There are four levels of protein structure: primary, secondary, tertiary, and quaternary. The primary structure is the linear sequence of amino acids, while the secondary structure refers to the local folding of the polypeptide chain into alpha helices or beta sheets. The tertiary structure is the overall three-dimensional shape of the protein, and the quaternary structure refers to the arrangement of multiple protein subunits. \ ![](https://knowt-user-attachments.s3.amazonaws.com/a0ba98ee182043e5994aad7c150c2de0.jpeg =741x1677) * **Nucleic Acid Structure and Function** Nucleic acids are macromolecules that store and transmit genetic information. They are made up of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. The two types of nucleic acids are DNA and RNA. DNA is a double-stranded helix that stores genetic information in the sequence of its nitrogenous bases: adenine, thymine, guanine, and cytosine. RNA is a single-stranded molecule that plays a key role in protein synthesis by carrying genetic information from DNA to ribosomes. The function of nucleic acids is to store and transmit genetic information, which is essential for the growth, development, and reproduction of all living organisms. \ ![](https://knowt-user-attachments.s3.amazonaws.com/8050f1128be947379e07545e5a704334.jpeg =775x620) * Dehydration synthesis is a chemical reaction that involves the loss of a water molecule from the reacting molecules to form a new product. Hydrolysis, on the other hand, is a chemical reaction that involves the addition of a water molecule to break down a compound into its constituent parts. These reactions are important in many biological processes, such as the synthesis of proteins and the breakdown of carbohydrates. \ ![](https://knowt-user-attachments.s3.amazonaws.com/743cd495c2c348e787606fe81d327617.jpeg =741x618) <<***Unit 2: Cell Structure and Function (10-13%)***<< * There are many different types of cells in the human body, each with a specific function. Some examples of cell types include: * Red blood cells: These cells carry oxygen throughout the body. * White blood cells: These cells are part of the immune system and help fight off infections. * Neurons: These cells transmit signals throughout the nervous system. * Muscle cells: These cells are responsible for movement. * Epithelial cells: These cells line the surfaces of organs and tissues. * Stem cells: These cells have the ability to develop into many different types of cells. There are many other types of cells as well, each with their own unique characteristics and functions. * The surface area is commonly used in biology and chemistry to understand the efficiency of diffusion and other processes that occur across a membrane or surface. The ratio is calculated by dividing the surface area of an object by its volume (SA/V). *Objects with a high surface area to volume ratio have a greater surface area relative to their volume, which allows for more efficient exchange of materials*. * **Organelle Structure and Functions** \ ![](https://knowt-user-attachments.s3.amazonaws.com/0b3a2bca6ddb4c45bbb8bfc83326a7f9.jpeg =741x519) ![](https://knowt-user-attachments.s3.amazonaws.com/e322fe022306457b9ce24238db273bf1.jpeg =775x375) * The endomembrane system is a group of organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins. It includes the endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and vacuoles. The endoplasmic reticulum is responsible for protein and lipid synthesis, while the Golgi apparatus modifies and packages these molecules for transport. Lysosomes and peroxisomes are involved in breaking down and recycling cellular waste, and vacuoles are used for storage. * Endosymbiosis theory which posits that eukaryotic cells arose from prokaryotic cells. The theory further articulates that the mitochondria found in today's eukaryotes evolved from aerobic bacteria and that the chloroplasts found in today's plant cells arose from cyanobacteria. * Active transport requires energy for the movement of molecules whereas passive transport does not require energy for the movement of molecules. In active transport, the molecules move against the concentration gradient whereas in passive transport, the molecules move along the concentration gradient. \ ![](https://knowt-user-attachments.s3.amazonaws.com/5d75dec9b77c4620bbb5b9020e3223f2.jpeg =775x531) * A concentration gradient is when particles or solutes move from a highly concentrated area of particles to a less concentrated area of particles. This process is aided by proteins located on the plasma membrane (membrane proteins) such as transport proteins: Channel proteins and carrier proteins. \ ![](https://knowt-user-attachments.s3.amazonaws.com/e8921bd875e34c019573082a65dc3738.jpeg =684x455) * Water potential is a measure of the differences in potential energy between a water sample with solutes and pure water. Water moves via osmosis from an area of higher water potential (more water molecules, less solute) to an area of lower water potential (less water, more solutes). ![](https://knowt-user-attachments.s3.amazonaws.com/87a0e337c1f640929d3e87ca89c25975.jpeg =775x535) ![](https://knowt-user-attachments.s3.amazonaws.com/4229f9793f5e415ebd0d92e6411f8dbc.jpeg =775x606) * Endocytosis occurs when the cell engulfs an external substance and takes it into the cell by the infolding of the cell membrane. Exocytosis occurs when the cell secretes a substance outside the cell. \ ![](https://knowt-user-attachments.s3.amazonaws.com/16b5e4cf8536459294ee13fdf6589dd6.jpeg =741x389) <<***Unit 3: Cellular Energetics (12-16%)***<< * Enzymes are the molecules formed mostly of proteins that help to catalyze the biochemical reactions in the body. They have an active site where the substrate can bind and the reaction is catalyzed. \ ![](https://knowt-user-attachments.s3.amazonaws.com/dc31bf79b55244699f1254e1a3dc9b6c.jpeg =741x494) ![](https://knowt-user-attachments.s3.amazonaws.com/2a6725b1e846492484ee95267b2efe60.jpeg =741x417) ![](https://knowt-user-attachments.s3.amazonaws.com/7068f422b26241c6835f81f380bbfaf2.jpeg =474x324) * PHOTOSYNTHESIS: ![](https://knowt-user-attachments.s3.amazonaws.com/10366a54be5a4b678f616e2c53e7f2f5.jpeg =741x607) \

AP Bio SPEED REVIEW