Understanding macromolecules: The building blocks of life
This overview highlights the four categories of macromolecules essential to cellular function: carbohydrates, lipids, proteins, and nucleic acids. It explains how they are synthesized through dehydration reactions and broken down via hydrolysis. Carbohydrates provide quick energy, while lipids offer long-term storage. Proteins serve various functions, including enzymatic activity and transport. Nucleic acids, comprised of nucleotides, are crucial for genetic information. Dive into the specifics of each macromolecule to understand their roles and significance in biological systems.
Understanding macromolecules: The building blocks of life
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Presentation Transcript
Molecules of Life • Four categories of molecules are unique to cells (called macromolecules) • Carbohydrates • Lipids • Proteins • Nucleic acids • Synthesis of macromolecules involves a dehydration reaction • Breakdown of macromolecules involves a hydrolysis reaction
Carbohydrates • The ratio of hydrogen (H) atoms to oxygen (O) atoms is approximately 2:1 • Function for quick, short-term cellular energy
Carbohydrates • Simple carbohydrates • Low number of carbon atoms (3-7) • Monosaccharides • Glucose • Fructose – found in fruits • Galactose – found in milk • Disaccharides • Two monosaccharides joined together • Sucrose (table sugar) – formed when glucose joins with fructose • Lactose – formed when glucose joins with galactose
Carbohydrates • Complex carbohydrates • Contain many glucose (monosaccharide) units • Starch – storage form of glucose in plants • Glycogen – storage form of glucose in animals • Cellulose • Found in plant cell walls • Humans are unable to digest (passes through digestive tract as fiber)
Lipids • Contain more energy per gram than other biological molecules • Some function as long-term energy storage in organisms • Do not dissolve in water • Consist mostly of carbon and hydrogen atoms; contain few oxygen atoms
Lipids • Fats and Oils • Formed when one glycerol molecule reacts with three fatty acid molecules • Fats • Usually of animal origin • Solid at room temperature • Used for long-term energy storage, insulation, and cushioning • Oils • Usually of plant origin • Liquid at room temperature
Lipids • Emulsification – cause fats to mix with water • Saturated and Unsaturated Fatty Acids • Fatty acid (carbon-hydrogen chain ending with an acidic group –COOH • Saturated fatty acids have only single covalent bonds; lard and butter are examples • Unsaturated fatty acids have double bonds between carbon atoms wherever fewer than two hydrogens are bonded to a carbon atom; vegetable oils
Lipids • Steroids • Structure consists of four fused carbon rings with attached functional groups • Cholesterol • Structural component of animal cell membrane • Precursor of several other steroids
Proteins • Function of proteins • Fibrous structural proteins • Hormones • Muscle contraction • Transport • Protection • Enzymes
Proteins • Structure of proteins • Made of amino acid subunits • Amino group • Acid group • R (Remainder) group – differentiates amino acids • Dipeptide – two amino acids joined together • Polypeptide – three or more amino acids joined together
Nucleic Acids • Huge macromolecules composed of nucleotides • Nucleotides composed of 3 subunit molecules: • A phosphate • A pentose sugar • A nitrogen-containing base • Two classes of nucleic acids • DNA • RNA
Nucleic Acids • Two classes of nucleic acids • DNA • Make up genes • Contain pentose sugar deoxyribose • Nitrogen-containing bases • Adenine (A) • Thymine (T) • Guanine (G) • Cytosine (C) • Usually double stranded
Nucleic Acids • RNA • Intermediary in process of protein synthesis • Contain pentose sugar ribose • The nitrogen-containing base uracil (U) replaces thymine • Usually single stranded
