Podcast
Questions and Answers
What distinguishes organic compounds in biology?
What distinguishes organic compounds in biology?
Which of the following is NOT a type of carbohydrate?
Which of the following is NOT a type of carbohydrate?
What is the most common monosaccharide used for energy in the human body?
What is the most common monosaccharide used for energy in the human body?
Which of these statements about polysaccharides is true?
Which of these statements about polysaccharides is true?
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What is a key feature of lipids?
What is a key feature of lipids?
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Which of the following functions is NOT associated with lipids?
Which of the following functions is NOT associated with lipids?
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Which of the following types of carbohydrates is formed by two monosaccharides?
Which of the following types of carbohydrates is formed by two monosaccharides?
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What type of lipid is commonly known as fats and oils?
What type of lipid is commonly known as fats and oils?
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What is the percentage of total cell mass that water typically accounts for?
What is the percentage of total cell mass that water typically accounts for?
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Which of the following correctly describes the function of buffers in biological systems?
Which of the following correctly describes the function of buffers in biological systems?
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Which ion is NOT listed as an inorganic ion of the cell?
Which ion is NOT listed as an inorganic ion of the cell?
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What does the pH scale measure?
What does the pH scale measure?
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What role does water play in regulating internal body temperature?
What role does water play in regulating internal body temperature?
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Which of the following substances is considered an acid?
Which of the following substances is considered an acid?
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What is the neutral pH level on the pH scale?
What is the neutral pH level on the pH scale?
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Which function is NOT attributed to water in living organisms?
Which function is NOT attributed to water in living organisms?
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What is the primary function of hormones in the body?
What is the primary function of hormones in the body?
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Which of the following accurately describes the nucleotide structure in DNA?
Which of the following accurately describes the nucleotide structure in DNA?
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What distinguishes RNA from DNA?
What distinguishes RNA from DNA?
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Which of the following is NOT a function of water in living organisms?
Which of the following is NOT a function of water in living organisms?
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Which macromolecule is primarily involved in energy storage in human bodies?
Which macromolecule is primarily involved in energy storage in human bodies?
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What key difference between saturated and unsaturated fatty acids influences their physical properties?
What key difference between saturated and unsaturated fatty acids influences their physical properties?
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What makes buffers vital for living organisms?
What makes buffers vital for living organisms?
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Which nucleic acid primarily functions to carry genetic instructions for protein synthesis?
Which nucleic acid primarily functions to carry genetic instructions for protein synthesis?
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What type of fatty acid is characterized by having double bonds in its carbon chain?
What type of fatty acid is characterized by having double bonds in its carbon chain?
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Which component replaces the third fatty acid in a phospholipid?
Which component replaces the third fatty acid in a phospholipid?
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What is one of the primary functions of collagen in the human body?
What is one of the primary functions of collagen in the human body?
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Which statement accurately describes a steroid?
Which statement accurately describes a steroid?
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What type of proteins are responsible for speeding up chemical reactions in cells?
What type of proteins are responsible for speeding up chemical reactions in cells?
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Which of the following best describes saturated fatty acids?
Which of the following best describes saturated fatty acids?
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What is the primary structure of proteins composed of?
What is the primary structure of proteins composed of?
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Which protein is specifically known for transporting oxygen in the blood of animals?
Which protein is specifically known for transporting oxygen in the blood of animals?
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Study Notes
Course Information
- Subject/year: Medical Biology/1st year
- Lecturer: Inaam A. Abdulhameed
- Department: Anatomy
- Date: 17/11/2024
- University: University of Mosul
- College: College of Medicine
Lecture Aim
- Understand the structure and functions of molecular components of living organisms.
Intended Learning Outcomes
- Determine the functions of water in living organisms
- Summarize the structure of the pH scale and the importance of buffers to biological systems
- Describe the four major types of biological molecules
- Understand the functions of the four major types of molecules
The Molecular Composition of Cells
- Cells are composed of water, inorganic ions, and organic molecules
- Water is the most abundant molecule in cells, accounting for 70% or more of total cell mass
Functions of Water in the Body
- Water is the primary building block of cells
- Regulates internal body temperature by sweating and respiration
- Carbohydrates and proteins are metabolized and transported in the bloodstream by water
- Assists in flushing waste, mainly through urination
- Acts as a shock absorber for the brain, spinal cord, and fetus
- Forms saliva
- Lubricates joints
Acids and Bases
- Acids dissociate in water, releasing hydrogen ions (H+)
- Hydrochloric acid (HCl) dissociates into H+ and Cl-
- Bases either take up hydrogen ions (H+) or release hydroxide ions (OH-)
- Sodium hydroxide (NaOH) dissociates into Na+ and OH-
pH Scale
- Used to indicate the acidity and basicity of a solution
- Ranges from 0 to 14
- 0 is most acidic, 14 is most basic
- pH 7 is neutral
Buffers
- Resist changes in pH when small amounts of acid or base are added
- Crucial for maintaining stable pH levels in biological systems, essential for proper cellular function and metabolic processes
Inorganic Ions
- Inorganic ions (Na+, K+, Mg2+, Ca2+, HPO42-, Cl-, HCO3-) constitute 1% or less of cell mass
- Involved in various aspects of cell metabolism
- Play critical roles in cell function
Organic Compounds
- In biology, "organic" refers to molecules containing carbon (C) and hydrogen (H) and is associated with living organisms
- Classified into four types: carbohydrates, lipids, proteins, and nucleic acids
1- Carbohydrates
- Almost universally used as an energy source for living organisms
- Some organisms use them for structural function
- Composed of carbon, hydrogen, and oxygen, with a typical hydrogen to oxygen ratio of 2:1
- Subtypes: monosaccharides, disaccharides, and polysaccharides
Monosaccharides
- Simple sugars
- Glucose is the most common, providing immediate energy to the body
- Other common monosaccharides include fructose and galactose
Disaccharides
- Formed by the covalent bonding of two monosaccharides
- Important disaccharides: maltose, sucrose, and lactose
Polysaccharides
- Long chains of monosaccharides linked by covalent bonds
- Examples: starch, glycogen, and cellulose
- Starch is the stored form of sugars in plants
- Glycogen is the stored form of glucose in the human liver
2- Lipids
- Diverse in structure and function
- Do not dissolve in water
- Composed mostly of carbon and hydrogen atoms
- Functions: energy storage, hormone components, and cellular membrane constituents
- Types: fats, oils, waxes, phospholipids, and steroids
Fats and Oils (Triglycerides)
- Formed when glycerol reacts with three fatty acid molecules
- A fatty acid is a carbon-hydrogen chain ending with an acidic group (COOH)
- Fatty acids categorized as saturated or unsaturated based on the presence of double bonds
Saturated Fatty Acids
- Have no double bonds between carbon atoms
- Solid at room temperature
Unsaturated Fatty Acids
- Have double bonds between carbon atoms
- Liquid at room temperature
Phospholipids
- Similar to fats, but the third fatty acid is replaced by a phosphate group
- Hydrophilic ("water-loving") phosphate end and hydrophobic ("water-fearing") fatty acid end
- Major components of cell membranes
Steroids
- Lipids with a unique structure of four fused carbon rings
- Cholesterol is a major steroid, a component of animal plasma membranes
- Precursor to other steroids, including sex hormones
3- Proteins
- Macromolecules with amino acid subunits
- Primary structure: a sequence of amino acids linked together; a chain
- Secondary structure: the chain twists or folds
- Tertiary structure: the final 3D shape of the protein
- Quaternary structure: how multiple polypeptide chains interact
Protein Functions
- Support (e.g., keratin in hair and nails, collagen in tissues)
- Enzymes (catalyzing biochemical reactions)
- Transport (e.g., hemoglobin in blood)
- Defense (e.g., antibodies)
- Hormones (e.g., Insulin regulating blood sugar)
- Motion (e.g., actin and myosin in muscle contraction)
4- Nucleic Acids
- Key macromolecules for the continuity of life
- Carry genetic blueprints and instructions for cell functioning
- Two main types: DNA and RNA
- Composed of monomers called nucleotides
- Nucleotides have three components: a nitrogenous base, a pentose sugar, and a phosphate group
- DNA is double-stranded, forming a double helix
- RNA is single-stranded
Nucleic Acids in DNA and RNA
- Nucleotides in DNA contain deoxyribose sugar; in RNA, ribose sugar
- DNA bases: adenine (A), thymine (T), guanine (G), and cytosine (C)
- RNA bases: adenine (A), uracil (U), guanine (G), and cytosine (C)
Summary of Lecture
- Water is the most abundant molecule in organisms, essential for many functions
- pH reflects acidity/basicity
- Buffers regulate pH
- Carbohydrates, lipids, proteins, and nucleic acids are important organic molecules with specific roles in cells
Quiz Questions
- An example of a polysaccharide used for energy storage in humans is glycogen
- Saturated and unsaturated fatty acids differ in the number of carbon-to-carbon double bonds
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