Download Nucleic acid

Biomolecules
Nucleic Acids
Lipids
Biomolecules
Learning Objectives
• Analyze how nucleic acid structure relates to its functions
• Analyze how lipid structure relates to its functions
• Distinguish between the structures and functions of carbohydrates,
proteins, nucleic acids, and lipids
Nucleic Acids
• Nucleic acid – polymer
responsible for the
reproduction of genetic
materials and proteins
– Nucleotide – a monomer
of a nucleic acid
• Composed of a
phosphate group, a 5carbon sugar, and a
nitrogenous base
– Nitrogenous bases:
adenine, guanine,
cytosine, thymine, and
uracil
Nucleic Acids
Characteristic
Shape
Sugar present
Bases present
DNA
Usually double-stranded
Deoxyribose
Adenine, Guanine
Cytosine, Thymine
RNA
Usually single-stranded
Ribose
Adenine, Guanine
Cytosine, Uracil
Nucleic Acids
• Structure vs function
– Structure: nitrogenous bases protrude from the nucleotide chain
• Information is stored in the specific order of nitrogenous bases
– Functions:
• DNA: create proteins and transmit information from one generation to
the next
• RNA: act as a DNA messenger during protein synthesis
Lipids
• Lipid – a molecule that
is insoluble in water
– Not composed of
specific polymers
– Includes fats, oils, and
steroids
– Hydrophobic – insoluble
in water
• Due to large presence of
nonpolar, hydrocarbon
chains
Lipids
• Fats and oils
– Triglyceride – a fat or oil
consisting of one
molecule of glycerol
bonded to three fatty
acids
• Glycerol – 3-carbon chain
bonded to hydrogen
atoms and alcohol groups
• Fatty acid – a long
hydrocarbon chain with a
carboxyl group on one
end
Lipids
• Saturated fats
– Butter and lard
– Saturated fatty acid – a
fatty acid in which all
carbon atoms are bonded
to other carbon and
hydrogen atoms
– Solid at room
temperature
Lipids
• Unsaturated fats
– Vegetable oil and olive oil
– Unsaturated fatty acid – a
fatty acid in which some
carbons are bonded via
double bonds to other
carbon atoms
• Double bonds create
kinks in the molecule
– Liquid at room
temperature
Lipids
• Saturated vs. unsaturated fats
Lipids
• Phospholipids
– Hydrophilic head – glycerol, phosphate, and a charged molecule
– Hydrophobic tail – two fatty acids
– Hydrophilic – soluble in water
Lipids
• Phospholipids
– Important component of the cell membrane
– Phospholipid bilayer forms when hydrophobic tails aggregate on
the inside and hydrophilic heads form outer membrane
Lipids
• Steroid – a type of lipid
consisting of a
backbone of 4 carbon
rings
– Cholesterol – important
component of cell
membrane
Lipids
• Structure vs. function
– Structure – large amount of C-H bonds
– Functions
• Long term energy storage
• Cushioning and insulation
• Chemical messengers
Biomolecule comparison
Macromolecule
Structure
(Building Blocks)
Function
Examples
Carbohydrate
Starch
Monosaccharides
Energy storage in plants
Potatoes
Glycogen
Monosaccharides
Energy storage in animals
Liver product
Cellulose
Monosaccharides
Structural support
Paper, celery strings
Chitin
Monosaccharides
Structural support
Spider’s exoskeleton
Protein
Globular
Amino acids
Catalysis; transport
Enzymes; hemoglobin
Fibrous
Amino acids
Support
Collagen, elastin
Nucleotides
(thymine, guanine, adenine,
cytosine)
Nucleotides
(uracil, guanine, adenine,
cytosine)
Genetic code
Chromosomes
Protein synthesis
Messenger RNA
Ribosomal RNA
Glycerol + 3 fatty acids
Energy storage
Butter and vegetable oil
Phospholipids
Glycerol + 2 fatty acids +
phosphate group
Cellular boundary
Cell membrane
Steroids
Carbon rings
Messengers;
membrane fluidity
Prostaglandins;
cholesterol
Nucleic Acid
DNA
RNA
Lipid
Triglycerides
Biomolecules
Polymers
Carbohydrates
Proteins
Biomolecules
Learning Objectives
•
•
•
•
Explain the building block idea of monomers and polymers
Analyze how carbohydrate structure relates to its functions
Explain the four levels of protein structure
Analyze how protein structure relates to its functions
Polymers
• Macromolecule – a large molecule composed of smaller
molecules joined together
• Polymer – a large molecule composed of similar subunits
joined via covalent bonds (poly means many)
– Monomer – a small subunit that composes polymers (mono means
one)
– Dimer – two monomers bonded together (di means two)
Polymers
Carbohydrates
• Carbohydrate – a sugar composed of monosaccharides,
disaccharides, or polysaccharides
– Composed of carbon, hydrogen, and oxygen atoms
• Monosaccharide – the simplest sugar (saccharide means
sugar)
– Can exist on its own or as a monomer in a carbohydrate polymer
Carbohydrates
• The formation of isomers allows monosaccharides to have
great diversity
Carbohydrates
• Disaccharide – a substance composed of two
monosaccharides bonded together
– Ex) glucose + fructose = sucrose (table sugar)
Carbohydrates
Disaccharide
Building Blocks
(Monosaccharides)
Maltose
Glucose + Glucose
Sucrose
Glucose + Fructose
Lactose
Glucose + Galactose
Carbohydrates
• Polysaccharide – a group of
several monosaccharides bonded
together
Carbohydrates
• Structure vs. function
– Structure: abundant
carbon-hydrogen (C-H)
bonds
– Function: energy storage
– C-H bonds release
energy when broken
Carbohydrates
• Structure vs. function
– Structure: rigid
polysaccharides
– Function: protection
Proteins
• Protein – a polymer composed of amino acid monomers
– Amino acid – a monomer of a protein
• Consists of a central carbon, a hydrogen atom, an amino group, a
carboxylic acid, and a variable R group
• 20 different R groups
Proteins
• Dipeptide – a compound composed of two amino acids
bonded together
• Polypeptide – a group of several amino acids bonded
together
• A protein is can be composed of one polypeptide chain or
several chains folded together
Proteins
• Protein specificity
– Changing the R group
changes the protein
– Changing the sequence
of amino acids changes
the protein
– Each protein has a
specific shape that gives
it a specific function
Proteins
• Protein structure
– Primary structure –
sequence of amino acids
– Secondary structure –
hydrogen bonding in the
polypeptide backbone
– Tertiary structure –
interactions between the
R groups of amino acids
– Quaternary structure –
interactions between
polypeptide chains
Proteins
• Protein function:
structure
– Fibrous proteins – a
group of long, fiber-like
proteins that form
structural parts of cells
and body tissues
Proteins
• Protein function:
chemical messengers,
protection, transport
– Globular proteins – a
compact, spherical
variety of protein