Transcript Chemistry of Life

Chemistry of Life
Matter…
Energy…
Life…
Objectives
Objectives:
A. Explain the nature of matter;
B. Discuss the importance of water and
solutions;
C. Break down the chemistry of cells, and
D. Recognize chemical reactions.
A: Nature of Matter
• Matter is made of atoms
Atom- smallest unit of matter that can not be
broken down by chemical means
Atoms consists of three kinds of particles
Protons- Positively Charged (+)
Neutrons- No Charged
Electrons- Negatively Charged (-)
A: Nature of Matter
• Nucleus – Core of an atom made of
protons (yellow) and neutrons (red)
• Electron cloud – The space around
the nucleus that electrons
(gray) may occupy at any
time
A: Nature of Matter
• Protons and electrons are oppositely
charged so they attract each other
• Typically atoms have no electrical charge
protons = electrons
• Element – substance made of only one
kind of atom, and is therefore a pure
substance
A: Nature of Matter
• Compound – Substance made of the joined
atoms of two or more different elements
• Every compound is identified by a chemical
formula that identifies the elements in the
compound and their proportions
• Example:
– Sodium (Na) joined with Chlorine (Cl) forms
Sodium Chloride (NaCl) or Table salt
– Two Hydrogen atoms (H2) joined with one
Oxygen atom (O) forms H20 or water
A: Nature of Matter
• Molecule – a group of atoms bonded together
• Types of bonds
– Covalent
– Hydrogen
– Ionic
A: Nature of Matter
• Covalent Bonds
– Atoms generally have a neutral charge
– Atoms are stable when they have eight electrons in
their outer energy level
– Atoms share electrons so that they have eight in their
outer energy level
A: Nature of Matter
• Hydrogen Bonds
– The shared electrons in a water molecule are attracted
more strongly by the oxygen nucleus than the hydrogen
nucleus
– The water molecule has partially positive and negative
ends, or poles
– The opposite poles of two water molecules form a weak
bond called a hydrogen bond (similar to opposing poles
on a magnet)
Hydrogen bond
A: Nature of Matter
• Ion – An atom or molecule that
has gained or lost an electron
• Ions may interact to form ionic
bonds
• Ions do not share electrons, but
one atom “gives” an electron to
the other so they have eight in
their outer energy level
• Na+ positive sodium ion & ClNegative chloride ion interact
to form NaCl
B: Water and Solutions
• Water is a major component of cells
– 70% of the human body is water
• Water stores heat efficiently
– Water helps regulate body temperature
• Water acts as a transport system for
nutrients and wastes for animals.
B: Water and Solutions
• Water bonds to its self and other
structures
– Cohesion – the polarity of water molecules
cause them to cling to one another like
magnets
– Caused by hydrogen bonds
B: Water and Solutions
–Adhesion – water molecules that
are attracted to another surface, ie:
water droplets stick to your skin
after a shower
–Adhesion and cohesion Causes
capillary action
B: Water and Solutions
• Compounds that dissolve in water
form solutions.
• Dissolved nutrients that are
transported along with the water
move to the places where they are
used.
B: Water and Solutions
• Solution: solute dissolved in a
solvent
• Solute: thing that gets dissolved
• Solvent: thing that does the
dissolving
B: Water and Solutions
• pH scale: indicates the concentration of
H+ ions in a solution
--------------------------------------------
0
7
14
Acid
Neutral
Base
B: Water and Solutions
• Acid: Contain higher concentrations of H+
ions than pure water and have a number
lower than 7
• Bases: Contain lower concentrations of H+
ions and have numbers greater than 7
• Neutral: Pure tap water
• Buffers: Weak acids or bases that react
with strong acids or bases to prevent a
sharp, sudden change in pH
C: Break Down Chemistry of Cells
• Carbon – most common substance found in all
living organisms
• Four Main Carbon Compounds: Carbohydrates,
Proteins, Lipids, Nucleic acids.
• Carbon has four electrons available for bonding
in its outer energy level
• Able to form single (sharing one electron) double
(sharing two electrons) or triple sharing (three
electrons) covalent bonds with other elements
C: Break Down Chemistry of Cells
• The variety of covalent bond types allows
carbon to form different shaped structures
• Isomers – Compounds with the same
simple formula but a different three
dimensional structure (ie. glucose and
fructose C6H12O6)
C: Break Down Chemistry of Cells
• Carbon compounds also vary greatly in size
• Polymer – Large molecule formed when two
smaller molecules bond together
• Condensation – Process through which
polymers are formed when the two smaller
molecules release an H and an OH group that
can form Water
• Hydrolysis – Process through which polymers
are broken apart by adding the H and OH group
from a water molecule
C: Break Down Chemistry of Cells
• Four basic types of carbon polymers
– Carbohydrates
– Lipids
– Proteins
– Nucleic acids
C: Break Down Chemistry of Cells
• Carbohydrates
– Used by the cell to store and release energy
– Composed of Carbon, Hydrogen, and Oxygen
at a ratio of 1:2:1
– Monosaccharide – Simplest type (glucose or
fructose)
– Disaccharide – Two monosaccharides
(sucrose or table sugar)
– Largest type: Polysaccharide (many
monosaccharides hooked together i.e. starch)
C: Break Down Chemistry of Cells
• Lipids (fats and oils)
– Used by the cell for energy storage,
insulation, and protective coating
– Important part of cell membrane
– Have a much larger ratio of C-H than 2:1 and
a much smaller ratio of C-O than 2:1
– Insoluble in water
– Nonpolar (no electrical charge)
C: Break Down Chemistry of Cells
• Lipids (fats and oils) cont:
• Saturated Fatty Acids
– Solid at room temperature
– The carbon atom can not bond with any more
hydrogen atoms
• Unsaturated Fatty Acids
– Liquid at room temperature
– The carbon atom can bond with more
hydrogen atoms
C: Break Down Chemistry of Cells
• Proteins
– Provide structure for tissue and organs, carry
out cell metabolism, help muscle tissue
contract, provide immunity, and regulate other
proteins
– Large complex polymer composed of carbon,
hydrogen, oxygen, nitrogen and usually sulfur
– Basic building blocks of proteins are called
amino acids
C: Break Down Chemistry of Cells
• Proteins cont.
– Twenty (20) common amino acids
– These 20 amino acids in different
combinations make thousands proteins
– Enzyme – Type of protein that speeds up
chemical reactions
C: Break Down Chemistry of Cells
• Nucleic acids
– Store cellular information in the form of a code
– DNA and RNA
– Made up of smaller subunits called
nucleotides
– Composed of Carbon, Hydrogen, Oxygen,
Nitrogen and Phosphorus arranged in three
groups, base, simple sugar, and phosphate
group
D. Recognize Chemical Reactions
• Chemical Reaction: a process that
changes or transforms one set of
chemicals into another
• The ------- in a chemical reaction is read
“changes to” or “forms”
• CO2 + H2O - H2CO3
• Carbon dioxide and water change to
carbonic acid
D. Recognize Chemical Reactions
• Catalyst: is a substance that speeds up
the rate of a chemical reaction
• Enzyme: are proteins that act as organic
catalysts.