biological molecules. the hydrocarbon skeleton provides a basic framework: biological molecules...
TRANSCRIPT
Biological Molecules
The hydrocarbon skeleton provides a basic framework:
Biological Molecules Small and Large
Figure 3-3Figure 3-3
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 4.5 Variations in carbon skeletons
HH H HH C
H H H HH
H
HH
H
H
H H H
H
H
H
H H H
H H H
H H
H
H
H
H
H
H
HH
H
H H H H
H H
H H
H H H H
H H
H H
HH
HH
H
H
H
C C C C C
C C C C C C C
CCCCCCCC
C
CC
C
C
C
C
CC
C
C
C
H
H
H
HH
H
H
(a) Length
(b) Branching
(c) Double bonds
(d) Rings
Ethane Propane
Butane 2-methylpropane(commonly called isobutane)
1-Butene 2-Butene
Cyclohexane Benzene
Functional Groups• Hydroxyl group R-OH
• Carbonyl group R-C-H (or R)
• Carboxyl group R-C
• Amino group R-N
• Sulfhydryl group R-SH
• Phosphate group R-O-P-O–
O
O
OH
H
H
O
O–
Four Classes of Building Blocks
• Lipids
• Sugars – polysaccharides
• Nucleotides – nucleic acids
• Amino acids – proteins
Condensation : monomer oligomer polymer
Four Classes of Building Blocks
• Lipids
• Sugars – polysaccharides
• Nucleotides – nucleic acids
• Amino acids – proteins
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.12 Examples of saturated and unsaturated fats and fatty acids
(a) Saturated fat and fatty acid
Stearic acid
(b) Unsaturated fat and fatty acidcis double bondcauses bending
Oleic acid
Hydrogenated oil
trans double bond
三酸甘油酯
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Hydrophilichead
WATER
WATER
Hydrophobictail
Figure 5.14 Bilayer structure formed by self-assembly of phospholipids in an aqueous environment
膽固醇
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Figure 4.9 A comparison of functional groups of female (estradiol) and male (testosterone) sex hormones
CH3
OH
HO
O
CH3
CH3
OH
Estradiol
Testosterone
Female lion
Male lion
Four Classes of Building Blocks
• Lipids
• Sugars – polysaccharides
Carbohydrate (C:H2O = 1:1)
• Nucleotides – nucleic acids
• Amino acids – proteins
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.4 Linear and ring forms of glucose
(b) Abbreviated ring structure. Each corner represents a carbon. The ring’s thicker edge indicates that you are looking at the ring edge-on; the components attached to the ring lie above or below the plane of the ring.
H
H C OH
HO C H
H C OH
H C OH
H C
O
C
H
1
2
3
4
5
6
H
OH
4 C
6 CH2OH 6 CH2OH
5 C
HOH
C
H OH
H
2 C
1C
H
O
H
OH
4 C
5 C
3 C
H
HOH
OH
H
2C
1 C
OH
H
CH2OH
H
H
OHHO
H
OH
OH
H5
3 2
4
(a) Linear and ring forms. Chemical equilibrium between the linear and ring structures greatly favors the formation of rings. To form the glucose ring, carbon 1 bonds to the oxygen attached to carbon 5.
OH3
O H OO
6
1
Here are twomonosaccharides …
and a disaccharide(sucrose) formed by a condensation reactionbetween the two mono-saccharides.
Biological Molecules Small and Large
Figure 3-11Figure 3-11
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Figure 5.6 Storage polysaccharides of plants and animals
Mitochondria Giycogen granulesChloroplast Starch
Amylose Amylopectin
1 m
0.5 m
(a) Starch: a plant polysaccharide (b) Glycogen: an animal polysaccharide
Glycogen
Four Classes of Building Blocks
• Lipids
• Sugars – polysaccharides
• Nucleotides – nucleic acids
• Amino acids – proteins
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.25 DNA RNA protein: a diagrammatic overview of information flow in a cell
1
2
3
Synthesis of mRNA in the nucleus
Movement of mRNA into cytoplasm
via nuclear pore
Synthesisof protein
NUCLEUSCYTOPLASM
DNA
mRNA
Ribosome
AminoacidsPolypeptide
mRNA
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Figure 5.27 The DNA double helix and its replication3 end
Sugar-phosphatebackbone
Base pair (joined byhydrogen bonding)Old strands
Nucleotideabout to be added to a new strand
A
3 end
3 end
5 end
Newstrands
3 end
5 end
5 end
C G
C G
AT
C G
A T
A T
G C
A T
A T
T A
G
AC
C
C
G G
T
A
A
T
C
G
A
T
G
C
A
T
A
T
T
A
C
GA
T
A
T
G
C
T
AA
TT
A
C
G
A
T
T
A
C
G
T
A
C
GG
C
T
CG
5 end
Four Classes of Building Blocks
• Lipids
• Sugars – polysaccharides
• Nucleotides – nucleic acids
• Amino acids – proteins
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
S
Figure 5.17 The 20 amino acids of proteins
O
O–
O
O–
H
H3N+ C C
O
O–
H
CH3
H3N+ C
H
C
O
O–
CH3 CH3
CH3
C C
O
O–
H
H3N+
CH
CH3
CH2
C
H
H3N+
CH3
CH3
CH2
CH
C
H
H3N+ C
CH3
CH2
CH2
CH3N+
H
C
O
O–
CH2
CH3N+
H
C
O
O–
CH2
NH
H
C
O
O–
H3N+ C
CH2
H2C
H2N C
CH2
H
C
Nonpolar
Glycine (Gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile)
Methionine (Met) Phenylalanine (Phe)
C
O
O–
Tryptophan (Trp) Proline (Pro)
H3C
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O–
OH
CH2
C C
H
H3N+
O
O–
H3N+
OH CH3
CH
C C
HO–
O
SH
CH2
C
H
H3N+ C
O
O–
H3N+ C C
CH2
OH
H H H
H3N+
NH2
CH2
OC
C C
O
O–
NH2 O
C
CH2
CH2
C CH3N+
O
O–
O
Polar
Electricallycharged
–O O
C
CH2
C CH3N+
H
O
O–
O– O
C
CH2
C CH3N+
H
O
O–
CH2
CH2
CH2
CH2
NH3+
CH2
C CH3N+
H
O
O–
NH2
C NH2+
CH2
CH2
CH2
C CH3N+
H
O
O–
CH2
NH+
NHCH2
C CH3N+
H
O
O–
Serine (Ser) Threonine (Thr)Cysteine
(Cys)Tyrosine
(Tyr)Asparagine
(Asn)Glutamine
(Gln)
Acidic Basic
Aspartic acid (Asp)
Glutamic acid (Glu)
Lysine (Lys) Arginine (Arg) Histidine (His)
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Figure 5.18 Making a polypeptide chain
Carboxyl end
(C-terminus)
DESMOSOMES
OH
DESMOSOMESDESMOSOMES
OH
CH2
C
N
H
C
H O
H OH OH
Peptidebond
OH
OH
OH
H H
HH
H
H
H
H
H
H H
H
N
N N
N N
SH Side chains
SH
OO
O O O
H2O
CH2 CH2
CH2 CH2CH2
C C C C C C
C CC C
Peptidebond
Amino end(N-terminus)
Backbone
(a)
(b)
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Figure 5.20 Exploring Levels of Protein Structure: Tertiary structure
Figure 5.20 Exploring Levels of Protein Structure: Tertiary structure
CH2
OH
O
COH
CH2
CH2 NH3+ C-O CH2
O
CH2SSCH2
CH
CH
CH3
CH3
H3C
H3C
Hydrophobic interactions and van der Waalsinteractions
Polypeptidebackbone
Hydrogenbond
Ionic bond
Disulfide bridge
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Polypeptidechain
Collagen
Chains
ChainsHemoglobin
IronHeme
Figure 5.20 Exploring Levels of Protein Structure: Quaternary Structure
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Exposed hydrophobic region
Figure 5.21 A single amino acid substitution in a protein causes sickle-cell disease
Primary structure
Secondaryand tertiarystructures
Quaternary structure
Function
Red bloodcell shape
Hemoglobin A
Molecules donot associatewith oneanother; eachcarries oxygen
Normal cells arefull of individualhemoglobinmolecules, eachcarrying oxygen
10 m 10 m
Primary structure
Secondaryand tertiarystructures
Quaternary structure
Function
Red bloodcell shape
Hemoglobin S
Molecules interact with one another tocrystallize into a fiber, capacity to carry oxygen is greatly reduced
Fibers of abnormalhemoglobin deform cell into sickle shape
subunit subunit
1 2 3 4 5 6 7 3 4 5 6 721
Normal hemoglobin Sickle-cell hemoglobin. . .. . .Val His Leu Thr Pro Glu Glu Val His Leu Thr Pro Val Glu
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.16 The catalytic cycle of an enzyme
Substrate(sucrose)
Enzyme (sucrase)
Glucose
OH
H O
H2O
Fructose
1 Active site is available for a molecule of substrate, the
reactant on which the enzyme acts.
2 Substrate binds toenzyme.
4 Products are released. 3 Substrate is convertedto products.
Four Classes of Building Blocks
• Lipids
• Sugars – polysaccharides
• Nucleotides – nucleic acids
• Amino acids – proteins
Why are All Organisms Made of Cells?
• All Organisms Are Made of Cells
• Cell Theory– All organisms are composed of one or more
cells.– Cells are the basic unit of organization of all
organisms.– All cells come from existing cells.
Every Cell Consists of a Boundary, a Cell Body, and a Set of Genes
– The Plasma Membrane • The boundary of the cell which serves to define the limits of the cell and selectively admit and excrete specific molecules.
– A set of Genetic Instructions• It is contained in one or more molecules of DNA.• Nucleus/nucleoid
– The Cell Body• The cytoplasm, which is the portion of the cell outside the nucleus but inside the membrane.
• Cytosol, organelles, cytoskeleton
Why Are All Organisms Made of Cells?
• Every Cell Consists of a Boundary, a Cell Body, and a Set of Genes
• Two Major Cell Types• Prokaryotic Cells
– pro = before, Karyo = nucleus – Prokaryotic cells lack a nucleus and other membrane bou
nd organelles.
– Bacteria and blue green algae are examples.
– They are generally smaller than eukaryotic cells
0.4 to 5 micrometers (μm) vs. 10-100 μm
Why Are All Organisms Made of Cells?
How Are Cells Alive?How Are Cells Alive?Cells are the fundamental living units of life Cells are the fundamental living units of life and all contain the characteristics of life and all contain the characteristics of life discussed in Chapter 1.discussed in Chapter 1.
organizationorganization chemical transformationschemical transformationsenergy transformationsenergy transformations changechangeresponsivenessresponsiveness continuitycontinuity
reproductionreproduction
Copyright 2001 by Harcourt, Inc.
Why Are All Organisms Made of Cells?Why Are All Organisms Made of Cells?
6
Copyright 2001 by Harcourt, Inc.
Individual Cells May Specialize for Different TasksIndividual Cells May Specialize for Different Tasks
Cellular organization allows organisms to make a division Cellular organization allows organisms to make a division of labor among specialized cells.of labor among specialized cells.
If you were one big cell, organizing your body to perform If you were one big cell, organizing your body to perform all its different jobs would be difficult.all its different jobs would be difficult.
MulticellularityMulticellularity allows individual specialization.allows individual specialization.For example, your red blood cells specialize in carrying oxygen For example, your red blood cells specialize in carrying oxygen and your heart cells function to pump blood throughout your bodyand your heart cells function to pump blood throughout your body..
Why Are All Organisms Made of Cells?Why Are All Organisms Made of Cells?
3-D Animation of Vessel Trafficking© 1995 Robert Ezzell
Traffic Through the Golgi Apparatus© 1997 The Mona Group LLC
The Endomembrane System in Action© 1997 The Mona Group LLC
Lysosome and Mitochondria Transport© Mark Cooper
Golgi Bodies© 1994 Cytographics
Endoplasmic Reticulum Extension© Mark Cooper
Videos and AnimationsChapter 9: Protein Sorting and Transport: The Endoplasmic Reticulum,
Golgi Apparatus, and Lysosomes
Dynamic mitochondria
Microtubule Assembly and Breakdown© 1997 The Mona Group LLC
Organization of a Thin Filament in Skeletal Muscle© 1997 The Mona Group LLC
Assembly of an Actin Filament© 1997 The Mona Group LLC
Gelsolin Catalyzes the Breakdown of Actin Filaments© 1997 The Mona Group LLC
A Flagellum© 1997 The Mona Group LLC
Kinesin is a Motor Protein© 1997 The Mona Group LLC
Videos and AnimationsChapter 11: The Cytoskeleton and Cell Movement
Ca2+ Wave at Fertilization of Xenopus Egg© L. Jaffe and Linda Runft
Neuronal Growth Cone Motility© Paul Forscher Laboratory, Dept. Molecular, Cellular & Developmental Biology, Yale University
Cell Locomotion in a Flagellate,Part 2© Sidney Tamm
Cell Locomotion in a Flagellate,Part 1© Sidney Tamm
Proteus Swarm Cells© 1995 James Shapiro[swarm_cells.mov]
Slime Mold Morphogenesis© 1991 John Bonner[slimemold.mov]
Videos and AnimationsChapter 12: The Cell Surface
WHAT DO MEMBRANES DO?
– Membranes are essential boundaries that separate the inside from the outside;
– Membranes regulate the contents of the spaces they enclose;
– Membranes serve as a “workbench” for a variety of biochemical reactions;
– Membranes participate in energy conversions.
Why Are All Organisms Made of Cells?
membrane