Transcript Ch 3-6 Review Lecture

Ch. 3-6 Review Lecture
1. Describe three properties of
water that make it useful for life.
Concept 3.2: Four emergent properties of water
contribute to Earth’s fitness for life
•
Four of water’s properties that facilitate an
environment for life are:
1.
2.
3.
4.
Cohesive behavior
Ability to moderate temperature
Expansion upon freezing
Versatility as a solvent
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Fig. 3-3
Adhesion
Water-conducting
cells
Direction
of water
movement
Cohesion
150 µm
2. Differentiate between bases and
acids. Give an example of each and
how their strength can change.
Effects of Changes in pH
• Concentrations of H+ and OH– are equal in
pure water
• Adding certain solutes, called acids and
bases, modifies the concentrations of H+
and OH–
• Biologists use something called the pH
scale to describe whether a solution is
acidic or basic (the opposite of acidic)
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Acids and Bases
• An acid is any substance that increases the
H+ (hydrogen ion) concentration of a solution
• A base is any substance that reduces the H+
concentration of a solution
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The pH Scale
• In any aqueous solution at
25°C the product of H+ and
OH– is constant and can be
written as
[H+][OH–] = 10–14
• The pH of a solution is
defined by the negative
logarithm of H+ concentration,
written as
pH =
–log [H+]
• For a neutral aqueous solution
[H+] is 10–7 = –(–7) = 7
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pH Scale
0
1
• Acidic solutions
have pH values
less than 7
• Basic solutions
have pH values
greater than 7
• Most biological
fluids have pH
values in the range
of 6 to 8
Gastric juice,
2 lemon juice
H+
H+
Battery acid
+
– H
H+ OH
OH– H+ H+
H+ H+
3 Vinegar, beer,
wine, cola
4 Tomato juice
Acidic
solution
5
Black coffee
Rainwater
6 Urine
OH–
H+
OH–
H+
OH–
OH– OH– +
H+ H+ H
Neutral
solution
Neutral
[H+] = [OH–]
Saliva
7 Pure water
Human blood, tears
8 Seawater
9
10
OH–
Milk of magnesia
OH–
OH–
H+ OH–
–
–
OH OH
–
H+ OH
Basic
solution
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11
Household ammonia
12
Household
13 bleach
Oven cleaner
14
3. What are hydrocarbons and how
are functional groups important for
them?
Hydrocarbons
• Hydrocarbons are
organic molecules
consisting of only carbon
and hydrogen
• Many organic molecules,
such as fats, have
hydrocarbon components
• Hydrocarbons can
undergo reactions that
release a large amount of
energy
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Concept 4.3: A small number of chemical groups
are key to the functioning of biological molecules
• Distinctive properties of organic molecules
depend not only on the carbon skeleton
but also on the molecular components
attached to it
• A number of characteristic groups are
often attached to skeletons of organic
molecules
• Functional groups are the components of
organic molecules that are most
commonly involved in chemical reactions
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4. List the four macromolecules and
their monomers for the three that
are polymers.
Concept 5.1: Macromolecules are polymers, built
from monomers
• A polymer is a long molecule consisting of
many similar or identical building blocks
• These small building-block molecules are
called monomers
• Three of the four classes of life’s organic
molecules are polymers:
– Carbohydrates
– Proteins
– Nucleic acids
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5. Define dehydration and
hydrolysis and the bonds that
form/break from them.
The Synthesis and Breakdown of Polymers
• When two monomers bond together through
the loss of a water molecule a
condensation reaction or more specifically a
dehydration reaction
• Enzymes are macromolecules that speed up
the dehydration process
• Polymers are disassembled to monomers by
hydrolysis, a reaction that is essentially the
reverse of the dehydration reaction
Animation: Polymers
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Fig. 5-2a
HO
1
2
3
H
Short polymer
HO
Unlinked monomer
Dehydration removes a water
molecule, forming a new bond
HO
1
2
H
3
H2O
4
H
Longer polymer
(a) Dehydration reaction in the synthesis of a polymer
Fig. 5-2b
HO
1
2
3
4
Hydrolysis adds a water
molecule, breaking a bond
HO
1
2
3
(b) Hydrolysis of a polymer
H
H
H2O
HO
H
6. What is the difference
between an aldose and a ketose?
Sugars
• Monosaccharides have molecular formulas
that are usually multiples of CH2O
• Glucose (C6H12O6) is the most common
monosaccharide
• Monosaccharides are classified by
– The location of the carbonyl group (as aldose
or ketose)
– The number of carbons in the carbon skeleton
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7. What is the difference between
starch, glycogen, and chitin?
Polysaccharides
• Polysaccharides, are polymers of hundreds and
thousands of monosaccharides, have storage and
structural roles
• The structure and function of a polysaccharide are
determined by its sugar monomers and the positions
of glycosidic linkages
• Starch, a storage polysaccharide of plants, consists
entirely of glucose monomers
• Plants store surplus starch as granules within
chloroplasts and other plastids. Animals that feed on
those plants have digestive enzymes that hydrolyze
the starch to glucose.
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8. List some specific examples of
lipids.
Concept 5.3: Lipids are a diverse group of
hydrophobic molecules
• Lipids are the one class of large biological
molecules that do not form polymers
• The unifying feature of lipids is having little
or no affinity for water
• Lipids are hydrophobic because they
consist mostly of hydrocarbons, which form
nonpolar covalent bonds
• The most biologically important lipids are
fats, phospholipids, and steroids
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9. Differentiate between saturated
and unsaturated fatty acids.
Fig. 5-12
Structural
formula of a
saturated fat
molecule
Stearic acid, a
saturated fatty
acid
(a) Saturated fat
Structural formula
of an unsaturated
fat molecule
Oleic acid, an
unsaturated
fatty acid
(b) Unsaturated fat
cis double
bond causes
bending
10. What are the main parts of
an amino acid?
Amino Acid Monomers
• Amino acids are organic molecules with
carboxyl and amino groups
• Amino acids differ in their properties due to
differing side chains, called R groups
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Fig. 5-UN1
carbon
Amino
group
Carboxyl
group
Fig. 5-18
Peptide
bond
(a)
Side chains
Peptide
bond
Backbone
(b)
Amino end
(N-terminus)
Carboxyl end
(C-terminus)
11. Describe the four structures
of a protein.
Four Levels of Protein Structure
• Primary structure, the
sequence of amino acids
in a protein, is like the
order of letters in a long
word
• Primary structure is
determined by inherited
genetic information
• Consists of hydrogen and
disulfide bonds.
• Even a slight change in
the primary structure can
affect a protein’s ability to
function
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Fig. 5-21c
Secondary Structure
 pleated sheet
Examples of
amino acid
subunits
 helix
Fig. 5-21f
Hydrophobic
interactions and
van der Waals
interactions
Polypeptide
backbone
Hydrogen
bond
Disulfide bridge
Ionic bond
Fig. 5-21e
Tertiary Structure
Quaternary Structure
Fig. 5-22a
Normal hemoglobin
Primary
structure
Val His Leu Thr Pro Glu Glu
1
2
Secondary
and tertiary
structures
3
4
5
6
7
subunit
Quaternary
structure
Normal
hemoglobin
(top view)
Function
Molecules do
not associate
with one
another; each
carries oxygen.
Fig. 5-22b
Sickle-cell hemoglobin
Primary
structure
Secondary
and tertiary
structures
Val His Leu Thr Pro Val Glu
1
2
3
Exposed
hydrophobic
region
Quaternary
structure
Sickle-cell
hemoglobin
Function
Molecules
interact with
one another and
crystallize into
a fiber; capacity
to carry oxygen
is greatly reduced.
4
5
6
7
subunit
12. List the five nitrogenous
bases and their groupings.
Fig. 5-27c-1
Nitrogenous bases
Pyrimidines
Cytosine (C)
Thymine (T, in DNA)
Uracil (U, in RNA)
Purines
Adenine (A)
Guanine (G)
(c) Nucleoside components: nitrogenous bases
13. Compare and contrast
eukaryotic and prokaryotic cell
structure.
• Prokaryotic cells are
characterized by having
– No nucleus
– DNA in an unbound
region called the
nucleoid
– No membrane-bound
organelles
– Cytoplasm bound by the
plasma membrane
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• Eukaryotic cells are characterized by
having
– DNA in a nucleus that is bounded by a
membranous nuclear envelope
– Membrane-bound organelles
– Cytoplasm in the region between the plasma
membrane and nucleus
• Eukaryotic cells are generally much larger
than prokaryotic cells
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14. Compare and contrast
animal and plant cell structure.
Fig. 6-9a
Nuclear
envelope
ENDOPLASMIC RETICULUM (ER)
Flagellum
Rough ER
NUCLEUS
Nucleolus
Smooth ER
Chromatin
Centrosome
Plasma
membrane
CYTOSKELETON:
Microfilaments
Intermediate
filaments
Microtubules
Ribosomes
Microvilli
Golgi
apparatus
Peroxisome
Mitochondrion
Lysosome
Fig. 6-9b
NUCLEUS
Nuclear envelope
Nucleolus
Chromatin
Rough endoplasmic
reticulum
Smooth endoplasmic
reticulum
Ribosomes
Central vacuole
Golgi
apparatus
Microfilaments
Intermediate
filaments
Microtubules
Mitochondrion
Peroxisome
Chloroplast
Plasma
membrane
Cell wall
Plasmodesmata
Wall of adjacent cell
CYTOSKELETON
15. Differentiate between free
and bound ribosomes.
Ribosomes: Protein Factories
• Ribosomes are particles made of ribosomal
RNA and protein
• Ribosomes carry out protein synthesis in
two locations:
– In the cytosol (free ribosomes)
– On the outside of the endoplasmic reticulum or
the nuclear envelope (bound ribosomes)
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16. Differentiate between
smooth and rough ER.
Functions of Smooth ER
• The smooth ER
– Synthesizes lipids
– Metabolizes carbohydrates
– Detoxifies poison
– Stores calcium
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Functions of Rough ER
• The rough ER
– Has bound ribosomes, which secrete
glycoproteins (proteins covalently bonded to
carbohydrates)
– Distributes transport vesicles, proteins
surrounded by membranes
– Is a membrane factory for the cell
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17. Explain why mitochondria and
chloroplasts are NOT considered to
be part of the endomembrane
system.
• Mitochondria and chloroplasts
– Are NOT part of the endomembrane system
– Have a double membrane
– Have proteins made by free ribosomes
– Contain their own DNA
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18. Compare and contrast the
structure of chloroplasts and
mitochondria.
Mitochondria: Chemical Energy Conversion
• Mitochondria are in nearly all eukaryotic
cells
• They have a smooth outer membrane and
an inner membrane folded into cristae
• The inner membrane creates two
compartments: intermembrane space and
mitochondrial matrix
• Some metabolic steps of cellular respiration
are catalyzed in the mitochondrial matrix
• Cristae present a large surface area for
enzymes that synthesize ATP
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Fig. 6-17
Intermembrane space
Outer
membrane
Free ribosomes
in the
mitochondrial
matrix
Inner
membrane
Cristae
Matrix
0.1 µm
• Chloroplast structure includes:
– Thylakoids, membranous sacs, stacked to form
a granum
– Stroma, the internal fluid
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Fig. 6-18
Ribosomes
Stroma
Inner and outer
membranes
Granum
Thylakoid
1 µm