Four levels of protein structure

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Four levels of protein structure
1. Primary- the sequence of amino acids in a
protein. 2. Secondary- segments of polypeptide
folded or coiled to contribute to the overall
conformation. 3. Tertiary- further folding of
the polypeptide into its 3-D conformation. 4.
Quaternary- Only applies to proteins composed of
the aggregation of multiple polypeptides.
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Figure 5.18 The primary structure of a protein
Lysozyme
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Figure 5.20 The secondary structure of a protein
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Figure 5.22 Examples of interactions
contributing to the tertiary structure of a
protein
http//www.ncbi.nlm.nih.gov
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Keratin, the protein that forms hair
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Figure 5.23 The quaternary structure of proteins
(Conjugated protein)
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Figure 5.24 Review the four levels of protein
structure
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Figure 5.25 Denaturation and renaturation of a
protein
(Heat, pH, ionic environment)
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NUCLEIC ACIDS - THE ULTIMATE IN INFORMATION
TECHNOLOGY
Two Types -DNA (deoxyribonucleic acid) -RNA
(ribonucleic acid)
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Figure 5.28 DNA? RNA ? protein a diagrammatic
overview of information flow in a cell
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(Nucleic acid polymer)
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OH
Dehydration synthesis
H
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Dinucleotide
OH
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Inheritance is based on DNAs ability to
replicate.
Adenine hydrogen bonds with Thymine.
Guanine hydrogen bonds with Cytosine.
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Summary of differences between DNA and RNA
1. DNA incorporates nucleotides containing A, G,
C, T RNA incorporates nucleotides containing
A, G, C, U 2. DNA utilizes deoxyribose sugar.
RNA utilizes ribose sugar. 3. DNA is
double-stranded. RNA is single-stranded.
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Table 5.2 Polypeptide Sequence as Evidence for
Evolutionary Relationships
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Figure 7.0 Fluorescent stain of cell
How do we learn about cell structure and function?
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Figure 7.3 Cell fractionation
Differential Centrifugation - based on size
(pellet and supernatant) Density Gradient
Centrifugation - Rate Zonal- preformed density
gradients(size and shape) Equilibrium- Density
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Figure 7.0 Fluorescent stain of cell
How big is a cell?
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Figure 7.1 The size range of cells
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Figure 7.4 A prokaryotic cell
What are the two main types of cells?
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Common Components of all Cells
-molecular components -plasma membrane -DNA -cyto
plasm -ribosomes -metabolism
Animal
Plant
Bacteria (Prokaryotic)
(Eukaryotic)
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Figure 7.6 The plasma membrane
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Figure 7.10 Ribosomes
Ribonucleoprotein complex- rRNA and protein
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Figure 7.9 The nucleus and its envelope 
Nucleolus- site of ribosome synthesis
Lamina- net of intermediate filaments Matrix-
Structural fibers extending throughout nucleus
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Figure 7.11 Endoplasmic reticulum (ER)
Endomembrane System- internal membranes related
by physical continuity or vesicle transfer.
(nuclear envelope, E.R., golgi, lysosomes,and
various vacoules)
Smooth E.R.- Synthesis of lipids, carbo
metabolism(glycogen hydrolysis), detoxification
of poisons, Ca storage in muscles
R.E.R.- synthesis and modification of excreted
proteins, membrane proteins (glycoproteins).
Vesicle transport to golgi. Membrane production.
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Figure 7.12 The Golgi apparatus
Products from the E.R. modified, sorted, packaged
for shipping. Polysaccharide synthesis (pectins
in plants). Docking proteins in trans face
membrane.
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Figure 7.13 Lysosomes
Sac of hydrolytic enzymes for all
macromolecules. Bud from E.R. Acidic pH- H pumps
in membrane.
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Figure 7.14 The formation and functions of
lysosomes (Layer 1)
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Figure 7.14 The formation and functions of
lysosomes (Layer 2)
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Figure 7.14 The formation and functions of
lysosomes (Layer 3)
Digestion functions -Food -Cell
parts -Programmed cell death.
Lysosome storage diseases Tay-Sachs
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Figure 7.16 Review relationships among
organelles of the endomembrane system 
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Figure 7.19 Peroxisomes
Dehydrogenation reactions, formation of hydrogen
peroxide.
Peroxisomes not part of endomembrane system.
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Figure 7.17 The mitochondrion, site of cellular
respiration
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ENDOSYMIOTIC THEORY
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Figure 7.18 The chloroplast, site of
photosynthesis
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Figure 7.15 The plant cell vacuole 
Central vacuole storage of macromolecules,
inorganic ions, hydrostatic pressure.
Contractile vacuole Freshwater protists
Pigment storage Plastids
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Figure 7.20 The cytoskeleton
Structural support, cell motility, organelle
movement and anchoring, intra-cellular transport,
phagocytosis, regulation of biochemical
activities (signal transduction).
Not permanent, can disassemble and reassemble.
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Table 7.2 The structure and function of the
cytoskeleton
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Figure 7.21 Motor molecules and the cytoskeleton
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Figure 7.22 Centrosome containing a pair of
centrioles
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Figure 7.23 A comparison of the beating of
flagella and cilia
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Figure 7.24 Ultrastructure of a eukaryotic
flagellum or cilium
Basal body
(Structurally like centriole)
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Figure 7.25 How dynein walking moves cilia and
flagella
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Figure 7.26 A structural role of microfilaments
Increase surface area
Outer cytoplasmic area has gel consistancy.
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Figure 7.27 Microfilaments and motility
Distribution of nutrients and materials.
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Intermediate filaments permanent, reinforcing
cell shape, fix position of nucleus, nuclear
lamina, provide for characteristic shape of cells
like nerve cells.
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CELL SURFACES AND JUNCTIONS
Matrix of microfibrils(cellulose), other
polysaccharides and protein.
Pectins
(middle lamella)
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Figure 7.29 Extracellular matrix (ECM) of an
animal cell
fibronectin
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Figure 7.30 Intercellular junctions in animal
tissues
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Figure 7.31 The emergence of cellular functions
from the cooperation of many organelles