Download Anatomy I - Unit 3: Basic Biochemistry

Basic Biochemistry
What is Biochemistry?


Biochemistry is the study of the chemical
interactions of living things.
Biochemists study the structures and
physical properties of biological
molecules.

Often are involved in the manufacture of new
drugs and medical treatments
Biochemistry: where chemistry and
biology meet head-on



Living things require millions of chemical
reactions within the body, just to survive.
Metabolism = all the chemical reactions
occurring in the body.
Organic molecules:




usually associated with living things.
always contain CARBON.
are “large” molecules, with many atoms
always have covalent bonds (share electrons)
Composition of an Atom



Protons: Nucleus, positive charge
Neutrons: Nucleus, no charge
Electron: Energy levels, negative
charge
Isotopes



Atoms of the same element with a
different number of neutrons.
Benefits: the radiation given off of
some isotopes can be used to treat
cancer and kill bacteria that cause
food to spoil.
Can also be used as “tracers” to
follow the movement of substances
thru the body.
Bonding



There are 2 main types of bonds:
Ionic: When atoms transfer
electrons
Covalent: When atoms share
electrons
Acids & Bases





Acids have a pH of 0-6
Bases have a pH of 7-14
Neutral = 7
What is the optimal pH of human
blood?
7.4
Buffers


Substances that can absorb or
release H+ as levels fluctuate within
living systems to help maintain a
constant pH
Example: Carbonic Acid Bicarbonate
(buffer that helps maintain pH of
the blood)
Macromolecules of Cells


Macro = large
4 types of macromolecules in cellular
biology
1.
2.
3.
4.
Carbohydrates
Lipids
Proteins
Nucleic Acids
Macromolecule #1: Carbohydrates

Sugars and groups of sugars

Purposes: energy and structure

Includes three types:



Monosaccharide (1 sugar – quick energy)
Disaccharide (2 sugars – short storage)
Polysaccharide (many sugars – energy
long storage & form structures)
Macromolecule #1: Carbohydrates

Polysaccharide Examples:



Glycogen—glucose polymer stored for future
energy needs. Found in liver, muscle and
sperm, etc.
Cellulose—glucose polymer used to form
fibers for plant structures. Humans can’t
digest (fiber). Most abundant organic
molecule.
Chitin—glucose polymer for exoskeletons of
some crustaceans & insects.
Polysaccharides
Polysaccharides
Macromolecule #2: Lipids
Insoluble in water (think oil & water)
4 types:


1-triglycerides (fats & oils)



2-phospholipids (primary component of cell
membrane)
3-steroids (cell signaling)


(long-term energy storage, insulation)
cholesterol molecules modified to form sex
hormones. (e.g. testosterone, estrogen, etc.)
4-waxes (protection, prevents water loss)

Used mainly by plants, but also bees, some
furry animals and humans.
Triglycerides
Phospholipids
Steroids
Waxes
Macromolecule #3: Proteins


Support
Probably the most complicated of all biological
molecules.
Serve the most varied purposes, including:
structural proteins (e.g., keratin, collagen)
Enzymes
speed up chemical reactions
Transport
cell membranes channels, transporters in blood
(e.g., Hemoglobin)
Defense
antibodies of the immune system
Hormones
cell signaling (e.g., insulin)
Motion
contractile proteins (e.g., actin, myosin)
Collagen
Antibodies
Cellular Transport
Motion
actin & myosin
fibers in muscles
Macromolecule #3: Proteins



The building blocks of proteins are
AMINO ACIDS. There are only 20
types of Amino Acids.
There are millions of different
proteins, and they are all built from
different combinations of the 20
amino acids.
Amino acids join together to form
peptides, polypeptides, and
polypeptide chains.
Enzymes



Act as a lock and key
Specific: One substrate fits one
enzyme
Reusable: One enzyme can break
down many substrates
Competitive Inhibition

In competitive inhibition, the
inhibitor binds to the same active
site as the normal enzyme
substrate, without undergoing a
reaction.
Induced Fit Model

In this model, the
enzyme changes
shape on
substrate binding.
The active site
forms a shape
complementary to
the substrate only
after the substrate
has been bound
Macromolecule #4: Nucleic Acids

Nucleotides: building blocks of nucleic acids.


Each nucleotide contains
 (a) phosphate molecule,
 (b) nitrogenous base, and
 (c) 5-carbon sugar
Several types of nucleic acids, including:



DNA: deoxyribonucleic acid
 Genetic material, double stranded helix
RNA: ribonucleic acid
 Genetic material, single stranded
ATP: adenosine triphosphate
 High energy compound
DNA
Nucleotide Structure
THE BIG PICTURE
Chemistry is essential for life…