BIOL207 Lecture Notes - Lecture 3: Glycerol, Cholesterol, Chno-Fm
27 May 2018
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September 10, 2013
PEDS 101 – Human Physiology
Chapter 2: Molecular Interactions
Levels of organization and the related fields of study:
Chapter 2 Overview:
• Biomolecules, Electrons (bonds) → Covalent (create molecules), Non-covalent (facilitate
reversible reaction), Proteins (most abundant and diverse biomolecule)
Biomolecules:
• Oxygen (O2), hydrogen (H), carbon (C) make up more than 90% of body mass. (major
essential elements).
• Molecules that contain carbon are known as organic molecules. Organic molecules
associated with living organisms are also called biomolecules.
• Biomolecule groups* (4):
1. Lipids (C, H)
2. Carbohydrates (C, H, O)
3. Protein (C, H, O, N, S)
4. Nucleotides (C, H, O, N)
→ The body uses the first 3 groups for energy & building blocks for cellular components.
→ Nucleotides include DNA, RNA, ATP and cyclic ATP. DNA and RNA are the structural
components of genetic material. ATP (adenosine triphosphate) and related molecules carry
energy, while cyclic AMP (adenosine monophosphate; cAMP) and related compounds
regulate metabolism.
- Lipids are biomolecules made mostly of carbon and hydrogen. Most lipids have a backbone
of glycerol and 1-3 fatty acids. An important characteristic of lipids is that they are nonpolar
and therefore not very soluble in water. Lipids can be divided into 2 broad categories (fats,
oils)
- Carbohydrates are the most abundant biomolecule. They get their name from their
structure, literally carbon with water. The general formula for a carbohydrate is (CHnO)n,
shoig that for eah aro there are to hdroge’s ad oe oge. Carohdrates a
be divided into 3 categories: monosaccharides, disaccharides, and complex glucose
polymers called polysaccharides.
- Proteins are polymers of smaller building-block molecules called amino acids. Amino acids
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have a carboxyl group (-COOH) and amino group (-NH2) and hydrogen attached to the same
aro. The fourth od of the aro attahes to ariale R group.
- Nucleotides are biomolecules that play an important role in energy and information
transfer. Single nucleotides include the energy-transferring compounds ATP and ADP
(adenosine diphosphate) as well as cyclic AMP, a molecule important in the transfer of
signals between cells. Nucleic acids (or nucleotide polymers) such as RNA and DNA store and
transmit genetic information.
• *Review structure Fig 2.1-2.4 (do’t eorize
→
just know difference) PAGE 33
• Fig 2.1 → Lipids are mostly carbon and hydrogen
• Fig 2.2 → Carbohydrates are primarily carbon, hydrogen, and oxygen in the ratio CH2O
• Fig 2.3 & 2.4 → Proteins and nucleotides contain nitrogen in addition to carbon, hydrogen
and oxygen. Two amino acids, the building blocks of proteins, also contain sulfur.
Other info about molecules:
• Types:
- Conjugated proteins (Ex: lipoproteins) → carriers of fat in circulation (digestion) lipo=lipids
- Glycosylated (Ex: glycoprotein, glycolipid) → glycoprotein=carb mixed with protein
• Not all biomolecules are pure proteins, pure carbohydrate, or pure lipid → Conjugated
proteins are protein molecules combined with another kind of biomolecule. Lipoproteins
are found in cell membranes and in blood, where they act as carriers for less soluble
molecules like cholesterol.
• Glycosylated molecules are molecules to which a carbohydrate has been attached. Proteins
combined with carbohydrates form glycoproteins. Lipids bound to carbohydrates become
glycolipids. Glycoproteins and glycolipids, like lipoproteins, are important components of cell
membranes.
Mostly present around proteins *FUNCTIONS
→ Many biomolecules are polymers, large molecules
made up of repeating units. Ex: glycogen and starch are
both glucose polymers. They differ in the way the glucose
molecules attach to each other.
Some combinations of elements, known as functional
groups, occur repeatedly in biological molecules. The
atoms in a functional group tend to move from molecule
to molecule as a single unit. Ex: hydroxyl groups (-OH)
common in many biological molecules are added and
removed as a group rather than as single hydrogen or
oxygen atoms. Amino groups (-NH2) are the signatures of
amino acids. The phosphate group, (-H2PO4) plays a role
in many important cell processes, such as energy transfer and protein regulation.
Biomolecule Functions:
• 1. Energy and structural building blocks (lipids, CHO, protein)
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• 2. Store/transmit genetic information (nucleic acids DNA/RNA) and energy transfer
(nucleotides ATP, ADP, cAMP)
Bonds and shapes (Fig 2.6) Page 42:
• Covalent (create molecules) → sharing electrons
- Polar (Ex: H2O) → regions of particle charge (The larger and stronger oxygen atoms pulls
the hydrogen electrons towards itself. This pull leaves the two hydrogen atoms of the
molecule with a partial positive charge, and the single oxygen atom with a partial negative
charge from the unevenly shared electrons).
- Nonpolar (Ex: fatty acids) → An even distribution of electrons (molecules composed of
mostly C and H)
→
Phospholipids have polar heads and nonpolar tails
→
characteristic = bilayers
• Noncovalent (facilitate reversible reactions, help establish pH, molecule shape) → transfer
of electrons
- Ionic (anions - → gain e-, cations + → lose e-) NaCl → Na+ + Cl- (electrostatic attraction
between ions)
- Hydrogen (surface tension in H2O)
- Van der Waals forces (between atoms) → weak bonds
• Covalent and ionic bonds are strong bonds because they require significant amounts of
energy to make or break. Hydrogen bonds and Van der Waals forces are weaker bonds that
require much less energy to break.
• Some molecules develop regions of partial positive and negative charge when the electron
pairs in their covalent bonds are not shared evenly between the linked atoms. When
electrons are shared unevenly the atom with the stronger attraction for electrons develops a
slight negative charge (S-) and the atoms with the weaker attraction for electrons develops a
slight positive charge (S+).
• A hydrogen bond is a weak attractive force between a hydrogen atom and a nearby oxygen,
nitrogen, or fluorine atom. No electrons gained, lost or shared; instead oppositely charged
regions in a polar molecule are attracted to each other.
Molecular Interactions (in solution) Fig 2.8:
• Solubility (solute + solvent = solution) → the degree to which a molecule is able to dissolve
in a solvent (the more easily it dissolves, the higher the solubility)
- hydrophilic (Ex: NaCl) ater loig dissolve easily in water
→
if chemicals can get into
cell or if they need a carrier
- hydrophobic (Ex: Cholesterol) ater hatig
→
fat is’t solule
→
usually nonpolar that
a’t for H ods ith H2O
• Molecular shape and function are related
→ Covalent bond angles, ionic bonds, hydrogen bonds, and van der Waals forces all interact
to create the distinctive shape of a complex biomolecule. (Proteins have most complex and
varied shape of all biomolecules).
• Hydrogen ions alter pH (molecular shape; Fig 2.9)
→
**when we change pH (more acidic, more alkaline) we change function in proteins. (Ex:
activate certain enzymes)
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Document Summary
Levels of organization and the related fields of study: Chapter 2 overview: biomolecules, electrons (bonds) covalent (create molecules), non-covalent (facilitate reversible reaction), proteins (most abundant and diverse biomolecule) Biomolecules: oxygen (o2), hydrogen (h), carbon (c) make up more than 90% of body mass. (major essential elements), molecules that contain carbon are known as organic molecules. Organic molecules associated with living organisms are also called biomolecules: biomolecule groups* (4), lipids (c, h, carbohydrates (c, h, o, protein (c, h, o, n, s, nucleotides (c, h, o, n) The body uses the first 3 groups for energy & building blocks for cellular components. Nucleotides include dna, rna, atp and cyclic atp. Dna and rna are the structural components of genetic material. Atp (adenosine triphosphate) and related molecules carry energy, while cyclic amp (adenosine monophosphate; camp) and related compounds regulate metabolism. Lipids are biomolecules made mostly of carbon and hydrogen. Most lipids have a backbone of glycerol and 1-3 fatty acids.
