BIOLOGY

• The endoplasmic reticulum is a network of membranes involved in the synthesis of proteins and lipids, as well as the detoxification of drugs and toxins.
• What is the main focus of biochemistry?

  Biochemistry deals with biological molecules and their chemical reactions.
• What are the four fundamental kinds of biological molecules?

  Carbohydrates, proteins, lipids, and nucleic acids.
• What are the dehydration-synthesis and hydrolysis reactions?

  • Dehydration synthesis: Joins monomers by removing water to form polymers.
  • Hydrolysis: Breaks down polymers into monomers by adding water.
• What properties of water make it essential for life?

  High polarity, hydrogen bonding, high specific heat, high heat of vaporization, cohesion, hydrophobic exclusion, ionization, and lower density of ice.
• What is the empirical formula for monosaccharides?

  C$n$H$2n$O$n$
• What are the roles of monosaccharides?

  Monosaccharides serve as energy sources and building blocks for more complex carbohydrates.
• How do isomers and stereoisomers of glucose differ?

  Isomers have the same molecular formula but different structures, while stereoisomers differ in spatial arrangement.
• What is a glycosidic bond?

  A glycosidic bond is a type of covalent bond that links monosaccharides in disaccharides and polysaccharides.
• What are the properties and roles of disaccharides?

  Disaccharides consist of two monosaccharides and serve as energy sources and transport forms of carbohydrates.
• What are the properties and roles of polysaccharides?

  Polysaccharides are long chains of monosaccharides that serve as energy storage and structural components.
• What are the molecular structures of starch, glycogen, cellulose, and chitin?

  Starch is a storage polysaccharide in plants, glycogen is a storage polysaccharide in animals, cellulose is a structural component in plant cell walls, and chitin is a structural component in fungal cell walls and exoskeletons of arthropods.
• Why are laboratory-manufactured sweeteners considered "left-handed" sugars?

  They are "left-handed" sugars that cannot be metabolized by "right-handed" enzymes in the body.
• What are proteins made of?

  Proteins are made of amino acids.
• What is the structural formula of an amino acid?

  An amino acid consists of a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a variable R group.
• What is the process of peptide linkage synthesis and breakage?

  • Synthesis: Amino acids join via dehydration synthesis to form peptide bonds.
  • Breakage: Peptide bonds are broken through hydrolysis, releasing individual amino acids.
• Why is the sequence of amino acids significant in proteins?

  The sequence of amino acids determines the protein's structure and function, as exemplified by sickle cell hemoglobin.
• How are proteins classified?

  Proteins are classified as globular and fibrous proteins.
• What are examples of structural and functional proteins?

  Examples of structural proteins include collagen and keratin; functional proteins include enzymes and antibodies.
• What are lipids and their roles?

  Lipids are organic molecules that provide energy storage, insulation, and make up cell membranes.
• What are the properties and roles of acylglycerols, phospholipids, terpenes, and waxes?

  Acylglycerols store energy, phospholipids form cell membranes, terpenes have various biological roles, and waxes provide waterproofing.
• What is the molecular structure of acylglycerols, phospholipids, and terpenes?

  • Acylglycerols: Composed of glycerol and fatty acids.
  • Phospholipids: Composed of glycerol, two fatty acids, and a phosphate group.
  • Terpenes: Composed of isoprene units.
• What are steroids and prostaglandins, and what roles do they play?

  Steroids are lipids that function as hormones, while prostaglandins are involved in signaling processes in the body.
• What are nucleic acids and nucleotides?

  Nucleic acids are polymers made of nucleotides, which are the monomers of nucleic acids.
• What is the molecular structure of a nucleotide?

  A nucleotide consists of a phosphate group, a sugar, and a nitrogenous base.
• What are the nitrogenous bases found in nucleotides?

  The nitrogenous bases include adenine, thymine, cytosine, guanine, and uracil.
• What are examples of a mononucleotide and a dinucleotide?

  An example of a mononucleotide is ATP, and an example of a dinucleotide is NAD.
• What is the double helical structure of DNA as proposed by Watson and Crick?

  The double helical structure of DNA consists of two strands of nucleotides twisted around each other, held together by hydrogen bonds between complementary bases.
• What is a gene?


  A gene is a sequence of nucleotides in DNA that codes for the formation of a polypeptide.
• What is the general structure of RNA?

  RNA is a single-stranded molecule composed of nucleotides, with ribose sugar and nitrogenous bases.
• What are the three types of RNA and how do they differ in structure and roles?

  The three types of RNA are mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA), each with distinct structures and functions in protein synthesis.
• What are conjugated molecules and their roles?

  Conjugated molecules are complexes of biomolecules, such as glycolipids, glycoproteins, lipoproteins, and nucleoproteins, that play various roles in cellular functions.
• What is the importance of water in biological systems?

  • Water is a major component of cells (70%).
  • It acts as a solvent for biochemical reactions.
  • It helps regulate temperature due to high specific heat.
  • It facilitates transport of substances in organisms.
• What is the significance of the proportions of biomolecules in bacterial and mammalian cells?

  • Water: 70%
  • Protein: 15% (bacterial), 18% (mammalian)
  • Carbohydrates: 3% (bacterial), 4% (mammalian)
  • Lipids: 2% (bacterial), 3% (mammalian)
  • DNA and RNA proportions vary.
• How much heat is required to raise the temperature of 1g of water by 1°C?

  1 Calorie (4.18 Joules)
• Why does water have a high heat capacity?

  Due to its hydrogen bonding, which absorbs heat without significantly raising temperature
• How does water's high heat capacity benefit organisms in hot environments?

  It stabilizes temperature and protects living material against sudden thermal changes
• What is the heat of vaporization of water?

  574 calories per gram
• What does high heat of vaporization mean for animals?

  A large amount of heat can be lost with minimal loss of water from the body
• How does sweating help cool an animal?

  Body heat is used to vaporize the sweat, thus cooling the animal