Download Biological Molecules

Biological Molecules
Part 2
Review of Reactions
• Condensation/Dehydration/Synthesis
– Monomers joined together
– One monomer releases H+, the other releases OH–
• Hydrolysis Reaction
– Polymers broken down
–
required
– H+ joins one
, OH- joins other
Dehydration reactions
Not Dehydration
Cells contain four major families of small carbon-based organic molecules
covalent bonds between
the building block
monomers create
polymeric
macromolecules
3:3
Proteins
• Large molecules (
) that form
some of the cytoplasm, hormones, globulins,
antibodies, and
• Provides structure (ex:
and cartilage)
• Composed of
group (NH2)
group
(COOH) and a common
attached to the side
chain R
• R group can be one H or as complex as a
system
R groups
amino acids in total
All have different R groups
Proteins
• Amino acids joined together through
reactions (water produced) to form polymer
and
.
• Polypeptide chains can be between 50 –
amino acids long are referred to as
.
• During the dehydration reaction, a
bond forms between N of
group of one
amino acid and the C of the
group of the
other amino acid
• The peptide bond is (slightly positive H and
slightly negative O)
Formation of Peptide Bond
Proteins
• Primary structure
– Amino acid sequence of a
linear chain of amino acids)
chain (a single
• Secondary structure
– Amino acids within the polypeptide chain
begins to form H-bonds
– H-bonds cause the
chain to either form a
,a
sheet, loops, or turns within
the same
chain
Proteins
Tertiary structure
– The different
structures within the
polypeptide chain come together and arrange
themselves to form a shape due to different
non-covalent interactions (H- bonding, ionic
interactions, van der waals forces, and
interactions)
– Once this globular shape is finalized, covalent
bonds form between two
(S-S) in
different R groups to
the proteins
shape together
Quantenary Structure
– More than one
chain comes together
to form this
– many, although not all engage in this type of
structure
hemoglobin
each red blood cell contains ~3x108
hemoglobin molecules
Proteins
• Tertiary structures can be changed or
denatured by heat,
, UV light or
pH.
• Denaturation can be temporary or
• What is denaturation?
Carbohydrates
• Can be classified as monosaccharides, disaccharides,
and
•
have carbon chains between 3-7 C’s in length
– Ex) 3C monosaccharides = triose
4C monosaccharides = pentose
6C monosaccharides =
• Two monosaccharides joined together through
reactions form a
• A disaccharide can be broken down through to form two
• Polysaccharides are long chains of
– Ex) cellulose or starch
Carbohydrates
Monosaccharides form disaccharides
3:9
Basic Photosynthesis
Works hand in hand
with cellular respiration
Glucose monomers linked by glycosidic bonds form storage carbohydrates
polysaccharides
starch in plants
glycogen in animals
Polysaccharides also play an important role in cell structure and cell signaling
3:10
Polysaccarides
Cellulose
•
•
•
Made up of
monomers
Makes up the cell
in plant cells
No
Glycogen
Starch
•
Made up of glucose
monomers
Glucose is stored in
this form in animal
cells
– Can be
into glucose
monomers if need
for cellular
•
Extensive branching
•
•
•
•
Made up of glucose
monomers
Glucose is stored in
this form in plant cells
– Can be
hydrolysed into
glucose
monomers if need
for cellular
respiration
branching
glycogen
Lipids
Lipids - Triglyceride
• contains C, H, and O
– no fixed ratio of atoms
• ex: fats and oils
• found in cell
• also used for
storage
• all
have two separate building blocks:
1) 1 glycerol
2) 3 fatty acids
* 3 fatty acids and one glycerol make 1 lipid molecule
Lipids
Oils:
– liquids at room temperature
– many
bonds in fatty acids
Fats:
– solid at room
– fewer
bonds
Waxes:
–
at room temperature
– longer carbon backbones
15
Lipids
• H from each OH of glycerol joins with OH from carboxyl group of
each fatty acid through a
reaction
– Results in the formation of
(neutral fat) + 3H2O
Glycerol
Saturated vs. Unsaturated
Lipids-Phospholipid
Phospholipids
– Lipid with a
group
– Usually a neutral fat with a phosphate on one
of the fatty
– Found in cell
(phospholipid bilayer)
– Polar end in high water concentration area
cytoplasm or
fluid
Phospholipids
3:12
Hydrophilic Molecules
2:17
Hydrophobic molecules
Nonpolar molecules and nonpolar
portions of molecules tend to
aggregate in water =
Water cannot form hydrogen bonds with
nonpolar substances
Water will form hydrogen bonds with
other water molecules and surround a
nonpolar molecule
The less hydrophobic surface, the more
energetically favorable it is for water to
surround nonpolar molecules
How is this accomplished?
By nonpolar molecules
aggregating
C-C and C-H bonds are the most common
nonpolar bonds in biological systems
2:18
Hydrophobic Effect
2:19
Hydrophobic
effect is not an
attraction
between particles
but an avoidance
of an energetically
unfavorable state
Hydrophobic effect
2:20
A lipid bilayer prevents the diffusion of polar substances
solutes spontaneously diffuse from
a region of high concentration to a
region of low concentration
a lipid bilayer prevents the
diffusion of polar substances out of
the inner compartment (also
prevents the inward diffusion of
polar substances)
3:13
Types of Lipids
steroids:
1.
:
• a. component of cell membranes that affects
stiffness
• b.
to synthesize other steroids/hormones
– e.g. testosterone & estrogen
2. hormones:
•
growth/functioning of specific cells
• chemical messengers between cells
– e.g.
stimulates sperm production
Nucleic Acids
Purines
Adenine
Pyriminadines
Cytosine
Nucleic Acids
• Are formed of subunits called
• Nucleotide are composed of a base, a
sugar, and a
acid
• In DNA the nitrogenous base may be one of 4:
– adenine, guanine
Pyrimidines –
,
DNA
• DNA (Deoxyribonucleic
Acid) is
sided
with H-bonds between
the
bases
holding it together
• Purines have two
bonds between
them while
have three hydrogen
bonds
RNA
• RNA (Ribonucleic
acid) is
stranded
• RNA contains the
base
instead of
thymine
ATP
• ATP (Adenosine
Triphosphate) is a
containing an
adenine, a ribose
sugar, and 3
groups (instead of one)
• Between each
phosphate group are
rich bonds
• This is where the cell
obtains its
ATP
ADP + phosphate + energy
By the end of this section
you should know:
• Demonstrate knowledge of dehydration synthesis and hydrolysis as
applied to organic monomers and polymers
• Differentiate among carbohydrates, lipids, proteins, and nucleic
acids with respect to chemical structure
• Recognize the following molecules in structural diagrams: ATP,
DNA, disaccharide, glucose, glycerol, hemoglobin, monosaccharide,
neutral fat, phospholipids, polysaccharide (starch, glycogen, and
cellulose), ribose, RNA, saturated and unsaturated fatty acids,
steroids
• Recoginze the empiracle formula of a monosaccharide as CnH2nOn
• List the main functions of carbohydrates
• differentiate among monosaccharides (e.g., glucose), disaccharides
(e.g., maltose), and polysaccharides
• differentiate among starch, cellulose, and glycogen with respect to:
function, type of bonding, level of branching
• describe the location, structure, and function of the following in the
human body: neutral fats, steroids, and phospholipids
• compare saturated and unsaturated fatty acids in terms of molecular
structure
• list the major functions of proteins
• draw a generalized amino acid and identify the amine, acid
(carboxyl), and R-groups
• identify the peptide bonds in dipeptides and polypeptides
• differentiate among the following levels of protein organization with
respect to structure and types of bonding: primary, secondary (alpha
helix, beta pleated sheet), tertiary, quaternary (e.g., hemoglobin)
• list the major functions of nucleic acids (RNA and DNA)
• name the four nitrogenous bases in ribonucleic acid (RNA) and
describe the structure of RNA using the following terms: nucleotide
(ribose, phosphate, nitrogenous base, adenine, uracil, cytosine,
guanine), linear, single stranded, sugar-phosphate backbone
• name the four nitrogenous bases in DNA and describe the structure
of DNA using the following terms: nucleotide (deoxyribose,
phosphate, nitrogenous base, adenine, thymine, cytosine, guanine),
complementary base pairing, double helix, hydrogen bonding, sugarphosphate backbone
• compare the general structural composition of DNA and RNA
• relate the general structure of the ATP molecule to its role as the
“energy currency” of cells