Chapter 2 – Discovering Life
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Transcript Chapter 2 – Discovering Life
Chapter 6
Biochemistry
Basic Chemistry
Living things are made
up of matter & all matter
is composed of atoms
Composition of Matter
Matter is anything that
has mass and takes up
space
All organisms are
composed of matter
Composition of Matter
Elements are made of
atoms
Elements bond to make
compounds
Atom
An atom is the basic unit of
matter.
They are composed of
subatomic particles
–
–
–
Protons (+)
Neutons (0)
Electrons (-)
Atoms
Horizontal rows are called periods.
Vertical columns are called groups.
Hydrogen
1
1.008
Hydrogen (element
name)
Atomic Number (equal
to the # of protons or #
of electrons)
Element Symbol
Atomic Mass (equal to
the number of protons,
neutrons & electrons in
a single atom)
Ions
An ions is an atom that has
gained or lost electrons.
Anions gain electrons
–
(ex. Cl-)
Cations lose electrons
–
(ex. Na+)
Chemical Bonds
Force that holds two or
more ions or atoms
together
Bond
–
Single, double, or
triple bonds
Ionic Bonds
Ionic
bonds form between
ions (ex. salt NaCl)
–
Metal + Nonmetal
Sodium Chloride – NaCl – Table
Salt
Covalent Bonds
Covalent
bonds form
between two nonmetals.
(ex. Water H2O
–
–
Nonmetal + Nonmetal
Forms when electrons
are shared
van der Waals Forces
Attractive
forces between
oppositely charged regions of
molecules.
Geckos Climbing Glass
Surface:
Attributed
to Van der Waal
forces
Between surface
and microscopic
projections on
their feet!
Molecules of Life
You Are
What
You Eat
“You Are What You Eat”
Nutrition
Facts label
– a summary of our
basic biochemistry
– Why do we need to eat
these?
Organic Molecules
Contain carbon
Molecules join to form
Macromolecules: large
molecules
Held together with
covalent bonds
Macromolecules are Polymers
Polymers
are molecules
held together by
covalent bonds
Made of monomers
Four classes of
macromolecules
Carbohydrates
Lipids
Proteins
Nucleic
Acids
Carbohydrates
Provide energy to cells
Subunit =
glucose
Contain carbon,
hydrogen
and oxygen.
Types of Carbohydrates
1. Simple
carbohydrates
mono- & di-saccharides
2. Complex carbohydrates
Starch, glycogen, and
cellulose
Known as polysaccharides
Simple Carbohydrates
Easy
to digest
Monosaccharide Examples:
– Glucose: simple sugar
– Fructose: fruit sugar
– Lactose: milk sugar
Monosaccharide’s:
Glucose
Fructose (isomer of glucose)
Galactose (isomer of glucose)
Ribose
Deoxyribose
Isomers:
Same
chemical formula but
different arrangement of
elements:
Glucose
Galactose
Disaccharides:
Sucrose
- Table sugar
Lactose - Milk sugar
Maltose - Malt sugar
Making Disaccharides:
Sucrose
= glucose + fructose
Lactose = glucose +
galactose
maltose = glucose + glucose
How to build a
disaccharide:
Done through a process called
dehydration synthesis
A.k.a. Dehydration reaction
Water (H2O) is lost
http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html
How to break down a
disaccharide:
You
break down a disaccharide
or a polysaccharide by
Hydrolysis
Water (H2O) is added!
Disaccharides must be broken
down or digested before
entering the cell.
Complex Carbohydrates
Longer
to digest
Long chains of
monosaccharides
so they are
polysaccharides
Complex Carbohydrates (cont.)
Starch
Glycogen:
energy storage
Cellulose: plant
structure
Starch:
Long
repeating chains of
monosaccharides.
It is called cellulosewhen found in
plant tissue (roots and grain)
It is called glycogen when found
in animal tissues (muscles and
liver)
Glycogen:
Used
for energy storage
so when the body needs
energy between meals or
during physical activity it
is broken down into
glucose.
Cellulose:
Provides
structural
support in plant cell walls.
Becomes fiber when we
eat plants; helps regulate
us!
Discussion Questions:
1. Why should we limit
some simple sugars?
2. Why do athletes eat
complex carbohydrates
before a long run / game?
Proteins
Subunits = amino acids
Amino acids are made up
of C, H, N, O, and
sometimes sulfur.
There are 20 amino acids!
Proteins
Proteins
Several
covalent bonds
called peptide bonds join
amino acids together to form
proteins.
Proteins a.k.a. polypeptides
Through what process? How do you
build a polymer?
Proteins
Proteins
differ in:
–#, type & the
arrangement of
amino acids
Protein Function:
Make
up 15% of your total
body mass
Affected by the order of the
amino acid chain.
Typically made up of 100 +
amino acids.
Protein Function:
Chains
combine to
form proteins or
polypeptides!
What do proteins do?
1.
Enzymes: speed up or
Increase rate of chemical
reactions / lowers
activation energy
Ex. Amylase converts
starch to simple sugar
Rates of Chemical Reaction
Energy
is needed to start
reaction: Activation Energy
Reactants
Products
What affects enzyme function?
pH
Temperature
What do proteins do? (cont.)
Transport: substances
inside the cell and between
cells
Ex. Hemoglobin (red blood
cell protein- carries Oxygen)
2.
What do proteins do?
(cont.)
Defense: Antibodies
which are used to
defend the body from
foreign invaders.
3.
What do proteins do? (cont.)
4. Structure: Collagen, Ligaments,
Tendons are made
up of proteins.
What do proteins do? (cont.)
5. Regulation: can be
Hormones
Ex. Insulin which regulates
glucose levels in the body!
What do proteins do? (cont.)
6.
Motion: muscle protein
which allows you to move!
Lipids
Subunit = Fatty Acids
Insoluble in water but
soluble in oil
Important for
homeostasis
Function of Lipids
1.Energy storage (Fat)
2.Regulate body functions
Steroids: Cholesterol,
Hormones (testosterone &
estrogen)
Function of Lipids (cont.)
3.
Provide structure:
in cells & waxy
coating on plants
Saturated Fats
Called
triglyceride
Hard & solid at room temp
Ex. Meat, Dairy, Butter,
Chocolate, Animal Fats
Unsaturated Fats
“Kinked”
carbon chain
Liquids at room temp
Ex. Peanuts, Fish, Olive Oil
Saturated v.s. Unsaturated
Trans Fats
Worst
type of fat
Increases risk of
heart problems
Discussion Questions
Which
type of fats
should we eat less of?
– Saturated & trans fats:
linked to heart disease
Discussion Questions
How
many calories must
you burn to lose 1 lb of
fat?
– 3,500 calories!!!
Nucleic Acids
Subunit
=
Nucleotide
Two types
DNA & RNA
DNA
Deoxyribonucleic
Store
genetic
information
Double helix
acid
RNA
Ribonucleic Acid
Helps synthesize
(create) proteins