Transcript Biochemistry

Biochemistry
The study of the chemistry of life.
Textbook Chapter 2
1
Chemistry Review
• Atom – Basic unit of matter.
• Subatomic particles of atoms:
– electrons – negatively charged particle in
constant motion around the nucleus.
– protons – positively charged. (Equals atomic #)
– neutrons – No charge.
• *Protons & Neutrons
form the nucleus of
an atom.
2
It’s elemental…
• Element – a pure substance that
consists entirely of ONE type of
atom and more than 100 known
elements. There are only about 2
dozen found in living organisms.
• Compound – Substance formed by
the chemical combination of 2 or
more elements.
3
Bonding
• Ionic Bonds -When electrons are
transferred from one atom to
another.
– Involves a metal and a non-metal
4
Bonding, cont.
• Covalent Bonding – between two or
more non-metals. Electrons are
SHARED.
– Most of your compounds in biology are
covalently bonded!
5
Covalent Bonding in Water
Oxygen
shares its 6
electrons
Each hydrogen
shares 1
electron
Oxygen now has 8 electrons around it all
times!
6
Properties of Water
• Water is the single most abundant
compound in living things.
• Water has an unusually high boiling point
and freezing point
• Water expands when frozen and is less
dense as a solid
• Polarity – molecules in which the
charges are unevenly distributed that
attract like a magnet. This allows water
molecules to easily attract other water
molecules.
7
States of water
8
Adhesion and
Cohesion
• Water is attracted to other water. This is
called cohesion. Water can also be
attracted to other materials. This is called
adhesion.
• The oxygen end of water has a negative
charge and the hydrogen end has a
positive charge.
– The hydrogens of one water molecule are
attracted to the oxygen from other water
molecules. This attractive force is what gives
water its cohesive and adhesive properties.
9
Surface Tension
• Surface tension is the name we give
to the cohesion of water molecules
at the surface of a body of water.
– All the water molecules on the surface
of the bead are 'holding' each other
together or creating surface tension.
10
Capillary Action
• Capillary action is
related to the
adhesive properties of
water.
• You can see capillary
action 'in action' by
placing a straw into a
glass of water. The
water 'climbs' up the
straw.
• Plants use capillary
action to pull water
into themselves
11
Solutions and Suspensions
• Mixture – Materials composed of 2
or more elements or compounds
physically mixed together but not
chemically.
– Ex: salt and pepper: New substance
NOT formed.
12
Solutions
• Types of mixtures made with water:
1. Solutions – components are evenly
distributed.
a. Solute – substance that is
dissolved.
b. Solvent – substance which does
the dissolving.
Watch this flash movie!
*Water is the universal solvent.
13
Acids and Bases
• pH Scale – scale used to determine the
concentration of Hydrogen+ ions in a
solutions. Scale ranges from 0 – 14. 7 is
an equal # of H ions (balance). Below 7=
acidic/ Above 7= basic.
• Acid – high concentrations of H ions.
• Base – low concentrations of H ions.
14
15
More about pH
• Buffer – weak acid or base that can
react with strong acids or bases to
prevent sharp, sudden changes in
the pH level.
*Maintaining pH is essential to
maintaining homeostasis in living
things.
16
Suspensions
• Suspension – Mixtures of water
and no dissolved materials.
– Blood is an example of a
suspension. Can you name these
other examples?
17
Carbon Compounds
The basis of biochemistry
18
Organic Chemistry
– Is the study of compounds that contain
carbon atoms.
Carbon can:
1. Bond with many different elements.
2. Forms millions of different, large
complex structures.
*No other element comes close to the
versatility of carbon which is why it is
found in living things.
19
Molecule size
• Macromolecule – Giant molecules.
• Monomer – smaller molecules
• Polymer – many joined monomers.
20
Saturated vs. Unsaturated
• Saturated Fats – solid form of fats.
These fats do not break down easily.
They can cause hardening of the
arteries. Only found in animal
products.
• Polyunsaturated Fats – liquid at
room temperature. Ex: cooking oils,
such as corn, sesame, olive oil.
Found in plant products.
21
Nucleic Acids
• Nucleic Acids – macromolecule largest in the body. Forms and
transmits the genetic code.
• Nucleotides – polymers assembled
from individual monomers.
– 3 parts:
• Sugars/ Phosphates/ Nitrogen Bases.
22
Nucleotides
• 2 types of Nucleotides:
– a. DNA – deoxyribonucleic acid. The
master copy of the information code.
– b. RNA – ribonucleic acid. Makes
protein molecules.
23
4 Groups of Organic
Compounds
of Living Things
24
Carbohydrates
Carbohydrates – main source of energy in living
things. (starches/sugars)
– a. monosaccharides – single sugar
molecules. Glucose, galactose (milk), fructose
(fruits)
– b. polysaccharides – excess sugar stored in
animals & plants.
• 1. glycogen – sugar stored as in animal
tissues.
• 2. Cellulose – sugar stored in plant tissues.
The tough, flexible fibers found in plants.
25
Lipids
• Lipids – not soluble in water. Fats,
oils, waxes.
– Store energy,
– make up membranes
– coverings in living things
– Steroids are lipids too.
26
Proteins
• Proteins – polymer of molecules
called amino acids.
– Each protein has a specific job such as
cellular components and muscles and
bones.
27
Amino Acids
• Amino Acids – building blocks of
proteins. More than 20 types found
in nature.
28
Chemical Reactions &
Enzymes
*Everything that happens in an
organism. Growth, interactions with
the environment, movement, etc. are
based on chemical reactions.
• Chemical Reaction – process that
changes 1 set of chemicals into
another. Always involves change
and cannont be undone.
29
Chemical Reactions
• Energy exchanges – energy is
released anytime chemical bonds
form or break.
• Activation energy – energy needed
to get a reaction started.
• Enzymes – proteins that speed up
chemical reactions.
• Catalyst – substance that speeds
up the rate of chemical reactions
30
How do Enzymes Work?
1. Substrates – sites where reactions
can be brought together. Bonds to
the site on the enzyme which fits just
right like a lock and key.
2. Regulation – cells that contain
proteins that can turn “on” or “off”
enzymes when needed.
31