molecules of life chapter 3. molecules inorganic compound nonliving matter salts, water organic...
TRANSCRIPT
Molecules of Life
Chapter 3
Molecules
Inorganic compound Nonliving matter Salts, water
Organic compound Molecules of life
Contains Carbon (C) and Hydrogen (H) Carbon backbone
Carbon Chemistry
Cell is mostly water The rest of the cell consists mostly of carbon-based molecules
Carbon is a versatile atom four electrons in an outer shell that holds eight can share its electrons with other atoms to form up to four
covalent bonds
Organic Molecules
Many molecules of life are macromolecules(macromolecules contain many molecules joined together)
Monomers: Simple organic molecules that exist individually
Polymers: Large organic molecules form by combining monomers
Polymer Monomer
Carbohydrate Monosaccharide
Protein Amino acid
Lipids Triglycerides
Nucleic acid Nucleotide
Molecules of Life
4 main classes of biological molecules 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids
Carbohydrates
Carbohydrates
Some Functions: Quick fuel Short-term energy storage Structure of organisms Cell to cell recognition
Consist of C, H, and O atoms 1:2:1 ratio
“Saccharides”3 major classes:
Monosaccharides Disaccharides Polysaccharides
Monosaccharides
“simple sugars”; “one monomer of a sugar” Dissolve easily in water
hydrophilic
Glucose C6H12O6
Fructose Form of glucose
Disaccharides
Short chain of two sugar monomers
Two Monosaccharides Lactose, sucrose, maltose Lactose = glucose + galactose
Polysaccharide
“Complex” carbohydrate Composed of many glucose molecules
Glycogen Polysaccharide of glucose Storage form of glucose in animals
Starch Storage form of glucose in plants
Cellulose Found in the cell walls of plants
Lipids
Lipids
Cells use lipids to store energy Hydrophobic Functions:
Energy Storage Cushioning and Insulation Found in the plasma membrane
3 main types: Fats & Oils Phospholipids Steroids
Fats
Dietary fat consists largely of the molecule triglyceride Combination of glycerol and three fatty
acids
Fats
Unsaturated fatty acids Have less than the maximum number of hydrogens
bonded to the carbons
Saturated fatty acids Have the maximum number of hydrogens bonded to the
carbons Most animal fats have a high proportion of saturated fatty
acids, which can be unhealthy Example: butter
Most plant oils tend to be low in saturated fatty acids Example: corn oil
Phospholipids
Glycerol, two fatty acids and a phosphate group
Plasma membrane Nonpolar tail Polar heads
Proteins
Why Proteins??
VERY important functions in cells Keratin and collagen have structural roles Enzymes speed up chemical reactions of
metabolism Responsible for transport of substances within
the body Transport substances across cell membranes Hormones that regulate cellular function
Insulin
Proteins
Made from amino acids 20 various kinds
Amino acids linked to one another by peptide bonds Two amino acids bound
by a peptide bond is a dipeptide
Three or more is a polypeptide chain
Protein
Polypeptide
Peptide / Dipeptide
Amino Acids
Protein Structure
Protein’s final shape and chemical behavior arise from it’s primary structure Chain bends, folds, coils,
etc.
Denaturing When proteins lose their
shape
Nucleic Acids
Nucleotides and Nucleic Acids
Nucleic acids Can be single stranded or double stranded
DNA Deoxyribonucleic acid genetic information
RNA Ribonucleic acid used to build proteins
Nucleotides and Nucleic Acids
Nucleic acids Built by nucleotides
Phosphate Pentose sugar Nitrogen-containing base
DNA Composition
DNA is built from four different kinds of nucleotides One of four bases determines the
nucleotide: A - Adenine G - Guanine T - Thymine C – Cytosine
DNA consists of two strands of nucleotides twisted into a double helix
GAGA….a nucleotide repeat!!
Base pairs Bases can only pair up with their corresponding “mate” 2 kinds:
A – T G – C
Amount of A = T Amount of G = C Can line up in any order
DNA Composition
Nucleotides linked together by covalent bonds
Bases of one strand linked to the other by hydrogen bonds
The two strands run in opposite directions
DNA into RNA
RNA a big player!! Single strand Sugar, phosphate group,
and a N-containing base Bases are:
A, C, G, and URACIL (U)