Download Topic 2.1-2.4 Carbs,Lipds, Protein and Water

Molecular Biology
Molecules to Metabolism
Topic 2.1
Molecular Biology
• Relatively new science
• Reductionism: the theory that every complex
phenomenon, especially in biology or
psychology, can be explained by analyzing the
simplest, most basic physical mechanisms
• Synthesis of Urea in 1720’s
• Falsified the theory of vitalism
Metabolism
• The web of all the enzyme catalyzed reactions
in a cell of an organism
• Either synthesis or digestion
Anabolism (synthesis)
• Synthesis of complex
molecules(macromolecules) from simpler
molecules (monomers).
• Condensation reaction (water is formed)
Catabolism (digestion)
• Breakdown of macromolecules into
monomers. (complex→simple)
• Hydrolysis reaction (water splits the molecule)
Inorganic Compounds
• Most inorganic compounds are compounds
that do not contain carbon. They are usually
small molecules(individual elements).
Examples:
– Carbon dioxide
– Water
Additional Necessary Elements for living
organisms
Element
Role in plant or animal
Sulfur
Stabilizes protein structure via the
formation of a sulfhydryl group.
Calcium
Needed to make the mineral that
strengthens bone and teeth. (nerve
transmission)
Phosphorous
Part of the phosphate group in ATP,
and DNA molecules. (phospholipids)
Iron
Needed to make hemoglobin which is
necessary for oxygen transport.
(myoglobin)
Sodium
Used in Neurons for the transmission
of impulses. (osmoregulation)
Organic Compounds
• Organic compounds are compounds that are
found in living things that contain Carbon
(C)and Hydrogen (H) .
– Examples :
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Carbohydrates
Lipids
Proteins
Nucleic acids
Carbon based life
• Carbon atoms can form 4 covalent bonds.
• Strongest type of bond so molecules are very
stable
• Can form single and/or double bonds with
more than one type of element
Chemical Elements and Water
Topic 2.2
Polarity
• Definition: (Campbell)
– A lack of symmetry, structural differences in
opposite ends of an organism or structure, such as
root end and shoot end of a plant.
• Application to molecules:
– Negative and positive poles
Opposites Poles Attract
Water Molecule = 2 Hydrogen's and 1 Oxygen
Because of water’s opposite
poles it is considered to be a
dipole or a polar molecule
Solvent Properties
• Property:
– Because of waters polarity is has the ability to dissolve both
organic and inorganic particles
• Example: (organic-glucose), (inorganic-sodium)
• Significance to living organism:
– This allows substances to be transferred via water in a
dissolved state.
• Example: sodium in blood, glucose in sap
• Water (a.k.a. universal solvent)
Cohesion
• Property:
– Water molecules attract to each other because of
hydrogen bonds that form between them.
– Surface tension is produced
by the cohesion of water
molecules. This makes
breaking the surface
of water difficult for small
objects.
Cohesion
• Significance to living organism:
– Transpiration, movement within plants
– Many organisms use the surface of water as their habitat.
Many organisms can remain afloat despite the fact that
they are in fact more dense than the water.
• Ex. Mosquito Larve
– Buoyancy : supports organisms
Thermal Properties: heat capacity
• Property:
– Large heat capacity. More energy needed to heat and
more energy given off when cooled.
• Significance to living organism:
– Water temperature tends to be very stable.
– Beneficial to aquatic organisms.
– Heat transfer in mammals.
Thermal Properties: boiling and freezing
points
• Property:
– Boiling point = 100°C
– Freezing point = 0°C
– Becomes less dense as it freezes causing ice to form first on
the surface
• Significance to living organism:
– Water rarely boils naturally
– Ice that forms first acts as an insulator
• Winter habitat
Thermal Properties: Cooling effects of
evaporation
• Property:
– Can evaporate at lower temperatures. Heat energy needed
to break the hydrogen bond is taken from the liquid water
cooling it down.
• Significance to living organism:
– Has useful cooling effects
• Sweat
Transparency
• Property:
– Light can pass through water
• Significance to living organism:
– Reach structures suspended within organisms.
• chloroplast,
• human eye
– Necessary characteristic for survival of aquatic
environments
Practice Problem 1
• 1. Outline the significance to organisms of the
different properties of water.
• Total 5-8 marks
Practice Problem 1 : Answer
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water is transparent / allows light to pass through for photosynthesis
cohesion of water molecules allow transport in plants
solvent – chemical reactions take place in water
many substances dissolve in water and can be transported
high boiling point making liquid water available to organisms / water is
liquid over a range of temperatures
water is most dense at 4°C so ice floats over water providing winter
habitat
high specific heat capacity so stable environment (internal/external)
high surface tension – supports (near) surface dwelling organisms
coolant – absorbs heat when it evaporates / changes states;
Carbohydrates
• subunit = simple sugars
• saccharides
• Function:
– Energy use (glucose)
– Energy Storage (glycogen)
–3 types found
3 Types of carbohydrates
Monosaccharides:
one sugar
glucose, ribose and
fructose
Disaccharides:
2 sugars linked together
maltose, lactose,
sucrose
Polysaccharides:
3 or more sugars linked
together
starch, glycogen,
cellulose
Glucose
Ribose
Sucrose
Glycogen
Condensation of Glucose and Fructose
Condensation of Glucose
Lipids
• Subunit = fatty acids + glycerol
• Functions of Lipids
– Energy Storage (fat in animals, oil in plants)
– Heat Insulation (subcutaneous fat)
– Buoyancy (lipids are less dense than water)
– Major component of cell membranes
Fatty Acids
Glycerol
Triglycerides
Triglyceride
Condensation Reactions Continued
Cis vs trans fat
Energy Storage Comparison
• Carbohydrates
– Digest easier than lipids
which makes releasing the
energy stored in them more
rapid
– Soluble in water making these
energy stores easier to
transport
– Short Term Energy Storage
– Stored as Glycogen
• Lipids
– Lipids contain more energy
per gram than carbohydrates
so stores of lipids are lighter
than stores of carbohydrates
that contain the same
amount of energy.
– Insoluble in water so they do
not cause problems with
osmosis in cells.
– Long Term Energy Storage
– Stored as fat
Proteins
• Subunit = amino acids (20 found in nature)
• Many different types of proteins found
• Functions:
enzymes (catalase)
transport (hemoglobin)
movement (actin/myosin in muscles)
structural ( collagen)
hormones (insulin)
receptors
immunity
Amino Acids
Amino acids
Condensation Reactions
• Condensation reactions
always yield water.
• This reaction is also
called dehydration
synthesis
• Water is removed and
creates new bonds
Polypeptides
• Most protein are made up
of groups of polypeptides
• Lysozyme (digests cell wall
of bacteria) is made up of
only one
• Hemoglobin (transport of
O2 and CO2) is made up of
only 4
Polypeptides
• Different species have a different
number of polypeptides that they
make
• Fruitflies make 14,000
• Humans make 23,000
Protein Functions
Rubisco:
• Found in plants (leaves)
• “fixes” atmospheric CO2
into a useable form for the
plant.
• Allows for photosynthesis
Protein functions
Insulin
• Hormone that regulates
blood sugar
• Secreted by pancreas
• Sends message to muscles
and liver
Protein Functions
Immunoglobins
• Antibodies that mark a
foreign invader for
destruction
• Many different antibodies
for different invaders
Protein functions
Rhodopsin
• Pigment that absorbs light
• Found in rod cells of eye
• Light causes a change in
shape of protein which
sends a signal to the brain
Protein Functions
Collagen
• Rope like proteins made up
of 3 polypeptides
• Connective tissue
• Skin, blood vessels,
ligaments
Protein Functions
• Spider silk
• Protein in spider
webs
• Stronger than steel
and tougher than
Kevlar
Proteins
• Sensitive to pH and temperature
• Most proteins have an optimum temperature
or pH that they function best
• Pepsin (stomach enzyme) works best at a pH
of 1.5
• In the presence of high temperatures or
extreme pH changes, a protein will denature
(lose its shapes)
Proteomes
• All of the proteins made in a particular cell
• Can be different for cells depending on their
function
• Genomes are all the genes in a cell; this is
fixed (same) for every cell
• Each person has a unique proteome