Biology Study PDF

pH Acidic → pH < 7 = Neutral → pH = 7 Basic → pH > 7 Macromolecules Class: Carbohydrates Monomer: Monosaccharides ○ Simple sugars, such as glucose, fructose, and galactose, serve as the building blocks for carbohydrates. ○ Each monosaccharide contains a...

pH Acidic → pH < 7 = Neutral → pH = 7 Basic → pH > 7 Macromolecules Class: Carbohydrates Monomer: Monosaccharides ○ Simple sugars, such as glucose, fructose, and galactose, serve as the building blocks for carbohydrates. ○ Each monosaccharide contains a backbone of carbon atoms bonded to hydrogen and hydroxyl groups Elements: Carbon (C), Hydrogen (H), Oxygen (O) Function: The primary source of energy for cells, providing quick and accessible fuel. They also serve structural roles in the cell walls of plants (cellulose) and exoskeletons of arthropods (chitin) Polymer:  Polysaccharides: Long chains of monosaccharides, such as starch (energy storage in plants), glycogen (energy storage in animals), and cellulose (structural component in plant cell walls) Class: Lipids Monomer: Fatty acids: Long hydrocarbon chains with a carboxyl group at one end Glycerol: A three-carbon molecule with hydroxyl groups Elements: Carbon (C), Hydrogen (H), Oxygen (O); sometimes Sulfur (S), and Phosphorus (P) in phospholipids Function: Energy storage (triglycerides), insulation, protection, and forming cell membranes (phospholipids). Some lipids also act as signaling molecules (steroids) Polymer: Triglycerides: Consist of one glycerol molecule bonded to three fatty acids, used primarily for long-term energy storage Class: Nucleic acids Monomer: Nucleotides (Each nucleotide is composed of three components) A nitrogenous base (adenine, thymine, cytosine, guanine, or uracil) A five-carbon sugar (ribose in RNA, deoxyribose in DNA)  A phosphate group Elements: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P) Function: Storage and transmission of genetic information (DNA and RNA), energy transfer (ATP), and catalysis of biochemical reactions (ribozymes) Polymer: DNA (Deoxyribonucleic Acid): A double-helix structure formed by two strands of nucleotides bonded together by hydrogen bonds between complementary bases. ○ DNA stores genetic information crucial for the development and functioning of living organisms Class: Proteins Monomer: Amino acids: Organic compounds containing an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (R group) all attached to a central carbon atom. Elements: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N); sometimes Sulfur (S) in certain amino acids Function: Structural support (collagen & keratin) Catalysis of biochemical reactions (enzymes)  Transport of molecules (hemoglobin), defense (antibodies), and regulation (hormones) Polymer: Polypeptides: Long chains of amino acids linked by peptide bonds, which fold into specific three-dimensional structures to form functional proteins. Protein Structures: 1. Primary (Polypeptide Chain): Exact ordering of amino acid sequence. This determines the end shape and function of the protein. 2. Secondary (Local Folding): α - helices and β - pleated sheets. Covalent hydrogen bonding occurs between amino and carboxyl groups. 3. Tertiary (3D Shape): Further folding of the secondary stage, forming the overall 3D shape of the protein via H-bonds, ionic bonds, disulphide bridges, and Vander Waals interactions. 4. Quaternary (Multiple Polypeptides): This is the final assembly of multiple polypeptides, bringing the protein together into it’s full shape and function. Water Potential: 屮 = 屮S + 屮P Water moves from high 屮 to low 屮 Solute Potential: 屮S = -iCRT The more negative the number is, the lower the water potential due to higher solute concentration. 屮S = -(ionization constant)(molar concentration)(pressure constant)(temperature in Kelvin) 屮S = -(1 for sugar or 2 for salt)(given in M)(0.0831 liter bars⁄mole-K)(273°K+#°C) Other Notes:  Movement is always high to low water potential Solutions ○ Hypotonic: Low concentration of sugar in the solution; solute moves into the cell (high water potential) ○ Isotonic: Same concentration; equal moving ○ Hypertonic: High concentration of sugar in solution; solute moves out of the cell (low water potential) Cell Respiration C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP The mitochondria is able to efficiently transfer energy. Cells generated from nutrients (primarily Glucose) in the form of ATP.  In aerobic respiration, we start with the equation C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP. C6H12O6, or glucose, a 6-carbon sugar, first goes through the cellular process known as glycolysis. This process takes place in the cytoplasm, oxidizing the glucose and resulting in: NAD+ picks up hydrogen (H+) and electrons, resulting in NADH 2 ATPs go through hydrolysis and is broken down into 2 ADPs + Pi (Phosphate Intermediate) 4 ADPs are turned into 4 ATPs through substrate-level phosphorylation (different from oxidative phosphorylation because making ADP + Pi form into ATP does not involve a proton gradient); however, only a net 2 ATP is created as 2 ATPs are used during glycolysis. Glycolysis then breaks down the 6-carbon glucose sugar into 2 pyruvates, two 3-carbon molecules. These pyruvates then move into the mitochondrial matrix and undergo pyruvate oxidation. In the mitochondrial matrix, pyruvate oxidation oxidizes the two 3-carbon pyruvates causing: The two 3-carbon pyruvates go through pyruvate oxidation one at a time. ○ During this process, you lose 1-carbon from both 3-carbon pyruvates, resulting in 2CO2 that is removed during the cellular process (waste). ○ After oxidizing through this process, we are left with two 2-carbon molecules, both attaching to acetyl-coenzyme. + NAD is also present in this stage of aerobic respiration and just like glycolysis, the NAD+ picks up hydrogen (H+) and electrons, resulting in NADH After the 2 pyruvates are converted into acetyl coenzymes after pyruvate oxidation, these acetyl coenzymes enter the citric acid cycle (Krebs Cycle). In the Krebs Cycle, a series of reactions occur from the oxidation of these coenzymes: NAD+ picks up hydrogen (H+) and electrons, resulting in NADH FAD is introduced, which also picks up hydrogen (H+) and electrons, but more effectively than NAD+, resulting in FADH2 2 ADPs are turned into 2 ATPs through substrate-level phosphorylation. The two 2-carbons acetyl coenzymes produce 4 CO2 (waste). After the Krebs Cycle, glucose is completely oxidized. After all this, we enter oxidative phosphorylation, a stage that involves the electron transport chain and Chemiosmosis (The process where H+ is powered by proton motive force into ATP Synthase to create 26-28 ATPs). All the electron carriers NADH and FADH2 made from the other cellular processes donate their collected electrons to the ETC. ○ The e- goes from the matrix into the ETC (inner membrane) and is accepted by oxygen (final electron acceptor), powering the proton pumps (proteins), and allowing them to go through facilitated diffusion (passive transport). ○ H+ is also combined with O2 (- charge) to create H2O (waste)  These proton pumps then pump the donated H+ into the intermediate space of the inner membrane. ○ The H+ protons flow back into the mitochondrial matrix through the ATP synthase (protein), driving the synthesis of ATP from ADP and phosphorous intermediate through a process called Chemiosmosis, producing 26-28 ATPs In the end, the breakdown per glucose molecule is about 30-32 ATPs in total. Glycolysis: 2 ATPs (net) Pyruvate Oxidation: 0 ATP Citric Acid Cycle: 2 ATPs Oxidative Phosphorylation: 26-28 ATPs Photosynthesis 6CO2 + 6H2O+sunlight → C6H12O6 + 6O2 Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose (a sugar). It takes place mainly in the chloroplasts of plant cells. The process can be divided into two main stages: the light-dependent reactions and the light-independent reactions (also called the Calvin cycle). 1. Light-dependent reactions (Occur in the thylakoid membranes of the chloroplasts) These reactions require light to produce energy carriers, ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), which are used in the second stage of photosynthesis. Steps of Light-Dependent Reactions: Absorption of Light: Chlorophyll, the green pigment in the thylakoid membranes, absorbs light energy, primarily from the blue and red wavelengths. Water Splitting (Photolysis): The absorbed light energy splits water molecules into oxygen (O₂), protons (H⁺), and electrons. The oxygen is released as a byproduct. Electron Transport Chain (ETC): The excited electrons from chlorophyll are passed along a series of proteins embedded in the thylakoid membrane. As they move down the chain, they release energy used to pump protons (H⁺) into the thylakoid lumen, creating a proton gradient. ○ Electrons flow down the ETC without energy because it is driven by electrochemical potential from a high to low energy level gradient. ATP Synthesis: The proton gradient drives the synthesis of ATP through an enzyme called ATP synthase. This process is known as photophosphorylation (ADP + Pi). NADPH Formation: At the end of the electron transport chain, the electrons reduce NADP⁺ to form NADPH. In summary, light-dependent reactions convert light energy into ATP and NADPH, while also producing oxygen as a byproduct. 2. Light-Independent Reactions / Calvin Cycle (Occur in the stroma of the chloroplasts) This is also known as the dark reactions or carbon fixation stage because it does not require light directly, but it uses the energy (ATP and NADPH) generated in the light-dependent reactions to synthesize glucose. Steps of the Calvin Cycle:  1. Carbon Fixation: The enzyme RuBisCO incorporates carbon dioxide (CO₂) from the atmosphere into an organic molecule called ribulose-1,5-bisphosphate (RuBP), forming an unstable 6-carbon compound that quickly splits into two molecules of 3-phosphoglycerate (3-PGA). 2. Reduction: ATP and NADPH are used to convert 3-PGA into glyceraldehyde-3-phosphate (G3P), a 3-carbon sugar. One G3P molecule exits the cycle to help form glucose and other carbohydrates. 3. Regeneration of RuBP: The remaining G3P molecules are used to regenerate RuBP, which allows the cycle to continue. This step also requires ATP. The overall output of the Calvin cycle is glucose (C₆H₁₂O₆ or 2 G3Ps), which can be used by the plant for energy or stored as starch. CO₂: Carbon dioxide (from the air) H₂O: Water (from the soil) C₆H₁₂O₆: Glucose (a sugar used as energy) O₂: Oxygen (released as a byproduct) Summary: Light-Dependent Reactions: Convert solar energy into chemical energy (ATP and NADPH). Light-Independent Reactions (Calvin Cycle): Use ATP and NADPH to convert CO₂ into glucose. Multiple Choice Quiz: