AP Bio Notes

Elements

Elements

Substances that cannot be broken down into simpler substances by chemical means; 92 natural elements, with 96% of living things' mass composed of oxygen (O), carbon (C), hydrogen (H), and nitrogen (N).

Trace elements

Elements needed in small quantities by organisms, such as iron (Fe), iodine (I), and copper (Cu).

Atom

The smallest unit of an element that retains its properties, composed of protons, neutrons, and electrons.

Isotopes

Atoms with the same number of protons but different neutrons, sharing similar chemical properties but differing in mass.

Chemical compound

Combination of two or more elements in a fixed ratio, with properties different from its elements.

Ionic bond

Formed by electron transfer between atoms, resulting in oppositely charged ions.

Covalent bond

Formed by electron sharing between atoms, can be nonpolar or polar depending on electron distribution.

Hydrogen bonds

Weak bonds between hydrogen atom and electronegative atom, important in water properties like cohesion and adhesion.

Cohesion

Attraction between molecules of the same substance, contributing to surface tension in water.

Adhesion

Attraction between molecules of different substances, seen in capillary action.

Surface tension

Tension at the surface of water due to cohesion, allowing objects to float.

Acids and Bases

Acids release hydrogen ions (H+), while bases release hydroxide ions (OH-), measured on the pH scale.

Organic compounds

Contain carbon atoms covalently bonded to hydrogen and other elements, essential for life.

Polymers

Macromolecules formed by chains of monomers, linked by dehydration synthesis and broken down by hydrolysis.

Carbohydrates

Organic compounds with carbon, hydrogen, and oxygen, classified as monosaccharides, disaccharides, or polysaccharides.

Proteins

Essential for cell structure and function, composed of amino acids with unique R-groups, forming polypeptides and higher structures.

Hydrophobic amino acids

Amino acids that repel water and are typically found in the interior of proteins.

Disulfide bond

A covalent bond formed between two cysteine amino acids, stabilizing the tertiary structure of proteins.

Quaternary structure

Structure formed when multiple polypeptide chains interact to create a final protein.

Chaperone proteins (chaperonins)

Proteins that assist other proteins in folding correctly and efficiently.

Triglycerides

Lipids composed of one glycerol molecule and three fatty acids, serving as a major energy storage form.

Fatty acids

Long chains of carbons with hydrogen atoms, having a carboxyl group at one end.

Lipid Saturation

The degree of saturation in lipids affecting their structure and function, influencing their physical state.

Phospholipids

Lipids with hydrophobic tails and hydrophilic heads, crucial components of cell membranes.

Cholesterol

A lipid molecule with a four-ringed structure, important for membrane fluidity and hormone synthesis.

Nucleic acids

Organic compounds containing nucleotides, including DNA and RNA, essential for genetic information storage and protein synthesis.

Peroxisomes

Organelles that detoxify substances and produce hydrogen peroxide (H2O2) as a byproduct, containing enzymes to break down hydrogen peroxide into oxygen and water.

Cytoskeleton

Network of protein fibers determining cell shape, including microtubules and microfilaments.

Microtubules

Structures made of tubulin protein, essential for cellular division and movement, part of centrioles, cilia, and flagella.

Microfilaments

Thin rod-like structures composed of actin protein, crucial for movement and involved in processes like cytokinesis and muscle contraction.

Cilia and Flagella

Threadlike structures aiding in locomotion, found in organisms like Euglena and Paramecium.

Plant Cells

Cells with a cell wall (cellulose), chloroplasts, and a central vacuole, lacking centrioles found in animal cells.

Passive Transport

Movement of substances down a concentration gradient without energy, including simple and facilitated diffusion.

Osmosis

Diffusion of water across a semipermeable membrane from high to low concentration, influenced by tonicity and water potential.

Active Transport

Energy-requiring movement of molecules against a concentration gradient, exemplified by the sodium-potassium pump.

Enzymes

Catalysts speeding up reactions by lowering activation energy, with specificity for substrates and an active site for binding.

Enzyme Inhibitors

Compounds that alter the shape of enzymes, preventing them from catalyzing reactions effectively.

Adenosine Triphosphate (ATP)

A molecule storing energy in phosphate bonds, crucial for cellular processes.

ATP Hydrolysis

The process where ATP is converted to ADP, releasing energy used in cellular activities.

Exergonic Reactions

Processes releasing energy, like ATP hydrolysis, to fuel endergonic reactions.

Photosynthesis

The process in autotrophs converting light energy into chemical energy to produce glucose and oxygen.

Chloroplast Structure

Organelles where photosynthesis occurs, containing thylakoids and stroma.

Light Reactions

Initial phase of photosynthesis converting light energy into ATP and NADPH.

Absorption Spectrum

Shows the wavelengths of light absorbed by pigments like chlorophyll.

Calvin Cycle

Light-independent reactions using ATP and NADPH to fix carbon dioxide into glucose.

Photorespiration

Wasteful process in plants using ATP and oxygen without producing sugars efficiently.

Aerobic Respiration

Cellular process producing ATP in the presence of oxygen through glycolysis, Krebs cycle, and oxidative phosphorylation.

Glycolysis

First stage of aerobic respiration breaking down glucose to pyruvic acid, generating ATP and NADH.

Acetyl-CoA Formation

Conversion of pyruvic acid to acetyl-CoA in the mitochondria for the Krebs cycle.

Krebs Cycle

Citric acid cycle in mitochondria producing ATP, NADH, and FADH2 from acetyl-CoA.

Oxidative Phosphorylation

Final stage of aerobic respiration where electron transport chain generates ATP.

Electron Transport Chain

Process where carrier molecules pass electrons down a chain until reaching the final electron acceptor, oxygen.

Chemiosmosis

Simultaneous process during electron transport chain where ions are pumped and diffuse to create ATP.

ATP Synthase

Channels allowing hydrogen ions to diffuse across the inner membrane, producing ATP by combining ADP and Pi.

Aerobic Respiration

Process involving glycolysis, formation of Acetyl-CoA, Krebs cycle, and oxidative phosphorylation to produce ATP using oxygen.

Anaerobic Respiration

Respiration occurring without oxygen, leading to reduced ATP production and halting of electron transport chain.

Photosynthesis vs

Both processes involve ATP production driven by a proton gradient created by an electron transport chain.

Krebs Cycle

Series of reactions in mitochondria matrix producing NADH, FADH2, and ATP from Acetyl-CoA.

Calvin Cycle

Series of reactions in chloroplasts using light to reduce CO2 to carbohydrates, opposite goal of Krebs cycle.

Mitosis

Cell division process involving stages like prophase, metaphase, anaphase, and telophase to produce two identical daughter cells.

Meiosis

Cell division process in sex cells involving two rounds of division to produce haploid gametes for sexual reproduction.