Title: Four levels of protein structure
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2Four 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.
3 Figure 5.18 The primary structure of a protein
Lysozyme
4 Figure 5.20 The secondary structure of a protein
5 Figure 5.22 Examples of interactions
contributing to the tertiary structure of a
protein
http//www.ncbi.nlm.nih.gov
6Keratin, the protein that forms hair
7 Figure 5.23 The quaternary structure of proteins
(Conjugated protein)
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10 Figure 5.24 Review the four levels of protein
structure
11 Figure 5.25 Denaturation and renaturation of a
protein
(Heat, pH, ionic environment)
12NUCLEIC ACIDS - THE ULTIMATE IN INFORMATION
TECHNOLOGY
Two Types -DNA (deoxyribonucleic acid) -RNA
(ribonucleic acid)
13 Figure 5.28 DNA? RNA ? protein a diagrammatic
overview of information flow in a cell
14(Nucleic acid polymer)
15OH
Dehydration synthesis
H
16Dinucleotide
OH
17Inheritance is based on DNAs ability to
replicate.
Adenine hydrogen bonds with Thymine.
Guanine hydrogen bonds with Cytosine.
18Summary 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.
19 Table 5.2 Polypeptide Sequence as Evidence for
Evolutionary Relationships
20Figure 7.0 Fluorescent stain of cell
How do we learn about cell structure and function?
21Figure 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
22Figure 7.0 Fluorescent stain of cell
How big is a cell?
23Figure 7.1 The size range of cells
24Figure 7.4 A prokaryotic cell
What are the two main types of cells?
25Common Components of all Cells
-molecular components -plasma membrane -DNA -cyto
plasm -ribosomes -metabolism
Animal
Plant
Bacteria (Prokaryotic)
(Eukaryotic)
26Figure 7.6 The plasma membrane
27Figure 7.10 Ribosomes
Ribonucleoprotein complex- rRNA and protein
28Figure 7.9 The nucleus and its envelopeÂ
Nucleolus- site of ribosome synthesis
Lamina- net of intermediate filaments Matrix-
Structural fibers extending throughout nucleus
29Figure 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.
30Figure 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.
31Figure 7.13 Lysosomes
Sac of hydrolytic enzymes for all
macromolecules. Bud from E.R. Acidic pH- H pumps
in membrane.
32Figure 7.14 The formation and functions of
lysosomes (Layer 1)
33Figure 7.14 The formation and functions of
lysosomes (Layer 2)
34Figure 7.14 The formation and functions of
lysosomes (Layer 3)
Digestion functions -Food -Cell
parts -Programmed cell death.
Lysosome storage diseases Tay-Sachs
35Figure 7.16 Review relationships among
organelles of the endomembrane systemÂ
36Figure 7.19 Peroxisomes
Dehydrogenation reactions, formation of hydrogen
peroxide.
Peroxisomes not part of endomembrane system.
37Figure 7.17 The mitochondrion, site of cellular
respiration
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39ENDOSYMIOTIC THEORY
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41Figure 7.18 The chloroplast, site of
photosynthesis
42Figure 7.15 The plant cell vacuoleÂ
Central vacuole storage of macromolecules,
inorganic ions, hydrostatic pressure.
Contractile vacuole Freshwater protists
Pigment storage Plastids
43Figure 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.
44Table 7.2 The structure and function of the
cytoskeleton
45Figure 7.21 Motor molecules and the cytoskeleton
46Figure 7.22 Centrosome containing a pair of
centrioles
47Figure 7.23 A comparison of the beating of
flagella and cilia
48Figure 7.24 Ultrastructure of a eukaryotic
flagellum or cilium
Basal body
(Structurally like centriole)
49Figure 7.25 How dynein walking moves cilia and
flagella
50Figure 7.26 A structural role of microfilaments
Increase surface area
Outer cytoplasmic area has gel consistancy.
51Figure 7.27 Microfilaments and motility
Distribution of nutrients and materials.
52Intermediate filaments permanent, reinforcing
cell shape, fix position of nucleus, nuclear
lamina, provide for characteristic shape of cells
like nerve cells.
53CELL SURFACES AND JUNCTIONS
Matrix of microfibrils(cellulose), other
polysaccharides and protein.
Pectins
(middle lamella)
54Figure 7.29 Extracellular matrix (ECM) of an
animal cell
fibronectin
55Figure 7.30 Intercellular junctions in animal
tissues
56Figure 7.31 The emergence of cellular functions
from the cooperation of many organelles