Transcript SHOW Biochemistry- atoms, acids,macro

BIOCHEMISTRY
THE NATURE OF MATTER
• REMEMBER…
• Atoms are made up of electrons (-),
neutrons (neutral), and protons (+)
• Proton number = atomic number = type
of element
Bonds
• Ionic bond – when electrons
are transferred from one
atom to another
– Example NaCl
• Covalent bond – electrons are
shared between atoms
– Example H2O
PROPERTIES OF WATER
• Polarity – uneven distribution of
electrons between the hydrogen and
oxygen atoms
– Oxygen is bigger and attracts the
electrons more than hydrogen
• Hydrogen bonds – slightly positive,
polar H atoms are attracted to polar
negative atoms like O
•
Acids
–
–
•
Acids and Bases
Compounds that form hydrogen ions ( H+) when
dissolved in water
Ex. Lemon juice
Bases
–
–
Compounds that reduce the amount of
hydrogen ions in a solution. Usually bases form
hydroxide ions (OH -) instead of hydrogen ions
when dissolved in water.
Ex. Ammonia
MACROMOLECULES
• Monomers (smaller units)
join to make polymers or
macromolecules
– Carbohydrates
– Lipids
– Proteins
– Nucleic acids
CARBOHYDRATES
• Organic compounds composed
of carbon, hydrogen and oxygen
with a ratio of two hydrogen
atoms to every one oxygen atom
• Made up of sugars
USE OF CARBOHYDRATES
• Source of energy for many
living things
• Examples: sugar and
starch
TYPES OF CARBOHYDRATES
• Monosaccharides
• Disaccharides
• Polysaccharides
MONOSACCHARIDES
• Only one sugar molecule
• Examples -glucose,
fructose, and galactose
• All three are C6H12O6, but
they are isomers
• Draw Glucose
DISACCHARIDES
• Double sugars (two
monosaccharides combined)
• Examples: sucrose, lactose, and
maltose
• All are isomers with the chemical
formula C12H22O11
POLYSACCHARIDES
• Long chains of monosaccharides
joined together
• Examples: starch, glycogen,
and cellulose
• Plants store excess sugar as
starch, and break it down for
energy
• Humans store excess
sugar as glycogen, &
break it down for energy
• Cellulose used by plants
to build cell walls.
Carbohydrates and Nutrition
• Beware of low carbohydrate diets
– Low carbohydrates cause your body to
break down muscle (protein)
– Low carbohydrates can cause your
appetite to increase (your body thinks it
is starving)
• Eat whole grains!
– Whole grains provide fiber and help to
prevent heart disease and cancer.
DEHYDRATION SYNTHESIS
• Two molecules join together
by losing a molecule of water
• DRAW
HYDROLYSIS REACTION
• Larger molecules broken
down into smaller molecules
by the addition of water
• Draw
LIPIDS
• Include fats, oils, steroids &
waxes
• Composed of carbon, hydrogen
and oxygen, but the # of H atoms
per molecule is much greater
then the # of O atoms
• An example, C57H110O6
USES OF LIPIDS
• Stored for energy
• Form basic structure of cell
membranes
• Protection
• Insulation
• Waterproof coverings
THE STRUCTURE OF SOME FATS
• Fatty Acids (a common
type of fat):
–a long carbon chain with
a -COOH (carboxyl
group) at one end
• Different types of fatty acids:
–Saturated - all single, covalent
bonds in between carbons in
chain
–Unsaturated - one double bond
between carbons in chain
–Polyunsaturated - many
double bonds between
carbons in chain
• Steroids include:
– Cholesterol -made by animals
and is both helpful & harmful
– Testosterone/Estrogen –
male/female hormones
– Cortisone – medicine used to
reduce swelling/itching
Fats and Nutrition
• Unsaturated fat is better for you
than saturated fat. Double bonds are
easier to break than single bonds.
• High fat diet actually increases
appetite.
• To increase fat break down, you must
increase physical activity.
• Good fats are found in some fish,
olives, and nuts and actually help to
prevent heart disease.
PROTEIN
• Made up of amino acids
linked together
• Composed of C, H, & O as
well as nitrogen, N, and
possibly sulfur
USES OF PROTEINS
• Build living materials like muscle
• Act as enzymes to help carry out
chemical reactions
• Fight disease
• Transport particles into or out of
cells
• Act as markers on cells
AMINO ACID STRUCTURE
• Have a central C that is
bound to:
–carboxyl group (-COOH)
–a hydrogen atom
–a amino group (-NH2)
–an “R” group (Draw)
General structure
Alanine
Serine
• There are 20 main amino acids.
• Each has same basic structure
with the only difference being
the “R” group
• Amino acids are linked by
peptide bonds (formed by
dehydration synthesis)
• Peptide bond is between
two amino acids
• Polypeptide – (a protein)
many amino acids joined
Protein and Nutrition
• Proteins help to suppress appetite so
eat a little at every meal.
• Proteins help build lean body mass.
• Increased lean body mass increase
your BMR (basal metabolic rate).
– This means that you burn more calories.
• Yo-yo dieting decreases BMR and
makes your body store fat.
NUCLEIC ACIDS
• Composed of nucleotides
• Nucleotides consist of a
sugar, a nitrogenous base,
and a phosphate
• Nucleic acids include: DNA,
RNA, ATP, and NAD
Figure 16.5 The double helix
CHEMICAL REACTIONS
• Chemical reactions always involve
breaking bonds in reactants and
making bonds in products
• Some reactions release energy and
therefore usually occur
spontaneously
• Other reactions need energy to
happen
• Activation energy – the minimum
amount of energy needed to start any
reaction
• Enzymes are catalysts which speed up
chemical reactions
• Enzymes are proteins that lower
activation energy and allow reactions to
occur at normal temperatures
• Without enzymes, too much energy would
be needed to start all of the thousands of
reactions your body performs all of the
time!
Reaction pathway Activation energy
without enzyme without enzyme
Activation energy
with enzyme
Reaction pathway
with enzyme
• Each enzyme is specific and
has a specific shape
• Enzymes are not
permanently changed and
are not used up in the
reaction
• Most enzyme names end in -ase
• Reactants are called substrates.
• Enzymes work on substrates (either
breaking them down or adding
something to them.
• Example: Lactase (enzyme) breaks
down lactose (substrate), which is the
sugar in milk.
Factors that affect enzyme
activity
• Enzymes are made of protein and
there are certain factors that affect
protein shape
• If the proteins shape is altered it will
no longer work
• Factors
– pH
– Temperature
– Salt concentration