Protein Folding and Structure

• Organic molecules all contain carbon.

Protein Folding and Structure

• Chaperonins help proteins fold correctly and refold misfolded ones.
• Hydrogen bonds between backbone atoms stabilize the secondary structure of proteins, including alpha helices and beta sheets.
• The four levels of protein structure are primary, secondary, tertiary, and quaternary.
• Protein denaturation occurs when proteins lose their structure and function due to extreme conditions
• Denatured proteins lose their functional shape and may become inactive after their structure is disrupted.
• Temperature changes disrupt hydrogen bonds and other interactions, leading to protein denaturation and loss of function.
• Understanding protein structure is crucial for determining how proteins function and interact in biological systems.
• R groups determine the properties of amino acids, influencing protein folding, stability, and function.
• The specific sequence of amino acids determines a protein's three-dimensional structure and, consequently, its function.
• The primary structure of a protein is the linear sequence of amino acids in a peptide chain.
• Lysine is a positively charged amino acid that forms additional peptide bonds and participates in various biochemical reactions.

Nucleic Acids

• The primary functions of DNA include information storage, replication, and transmission.
• Complementary base pairing ensures accurate replication and transcription of genetic information.
• Hydrogen bonds between complementary bases stabilize the double helix structure of DNA.
• Purines (adenine and guanine) have a two-ring structure, while pyrimidines (cytosine, thymine, and uracil) have a single-ring structure.
• The backbone of nucleic acids consists of alternating sugar and phosphate molecules linked by covalent bonds.
• RNA contains ribose sugar and uracil, and is primarily single-stranded, unlike DNA.
• mRNA carries genetic information from DNA to ribosomes, while rRNA is a component of the ribosome itself, aiding in protein synthesis.
• The main types of RNA are mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA), each serving roles in protein synthesis.

Enzymes and Biochemical Reactions

• Enzymes catalyze biochemical reactions by lowering the activation energy required for the reaction.
• Enzymes reduce activation energy by stabilizing the transition state and bringing reactants closer together.

Protein Synthesis

• Protein synthesis occurs through transcription of DNA to mRNA and translation of mRNA to a polypeptide chain.
• Ribosomes facilitate the translation of mRNA into a polypeptide chain during protein synthesis.
• tRNA carries specific amino acids to the ribosome and matches them to the codons in the mRNA.

Amino Acids and Peptide Bonds

• Only L-amino acids are used in proteins across all life forms, suggesting a common evolutionary origin.
• Optical isomers, or enantiomers, can have different biological activities.
• A peptide bond is formed between the amino group of one amino acid and the carboxyl group of another, releasing water.
• Hydrophobic amino acids repel water and tend to be buried in the protein core, while hydrophilic amino acids attract water and are often found on the protein surface.

Water

• Water's critical traits include being a polar molecule capable of hydrogen bonding and acting as a universal solvent.
• Pure water has all the following properties except the ability to dissolve lipids.
• The property that the elemental formula of the molecule is (CH2O)n gives "Carbohydrate" its name.

Phospholipids and Cell Membranes

• Phospholipids form a bilayer that serves as the fundamental structure of cell membranes, creating a barrier between the interior of the cell and its environment.
• Phospholipids are the molecule types that can form a cellular membrane.

Other Key Points

• A polar covalent bond results in slight positive and negative charges on different parts of the molecule, creating the potential for hydrogen bonding.
• Atoms can be combined into new, distinct molecules by covalent bonding.
• Helium is not commonly used by living things.
• The function of a buffer is to stabilize the pH of a solution to a particular level.
• The catalysis of chemical reactions of a cell is NOT a function of carbohydrates.
• When writing out chemical reactions, one must balance both the atoms and electrons on each side of the arrows.
• Phosphorylation can modify protein structure and function, often regulating enzyme activity and signaling pathways.

Explore protein folding with chaperonins, hydrogen bonds, and levels of structure. Learn about protein denaturation, temperature effects, amino acid R groups, and their impact on protein function and stability. Understand how protein structure determines function in biological systems.