Review of Last Class

Element vs. molecule Ionic bond vs. covalent bond Polar vs. nonpolar Hydrogen bond vs. van der Waals force Hydrophilic vs. hydrophobic vs. amphipathic Water – cohesion vs. adhesion solvent vs. solute acid vs. base vs. buffer

Biological Molecules

The hydrocarbon skeleton provides a basic framework: Biological Molecules Small and Large Figure 3-3 Saturated vs. unsaturated

Biological Molecules

The hydrocarbon skeleton provides a basic framework: Biological Molecules Small and Large Figure 3-3

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–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

三酸甘油酯

膽固醇

Four Classes of Building Blocks Lipids Sugars – polysaccharides Carbohydrate (C:H 2 O = 1:1) Nucleotides – nucleic acids Amino acids – proteins

One of the most biologically important carbo- hydrates is glucose. A six-carbon sugar, glucose is found almost exclusively in a geometric hexagonal form. Biological Molecules Small and Large

The molecule has carbon atoms found at intersections on the hexagon. CCC C C The sixth carbon is off the ring and one intersection has an oxygen rather than a carbon. OC Biological Molecules Small and Large

In this structure, there is a proportional relationship of one water molecule for each carbon atom. C C C C C OCH OH OH OH OHOH H2H2H2H2H H H H Biological Molecules Small and Large

C C C C C OCH OH OH OH OHOH H2H2H2H2H H H H The term carbohydrate is derived from this relationship. Glucose is the major building block of most polysachharides. Biological Molecules Small and Large

Biological Molecules Small and Large HOW DO SUGARS FORM POLYSACCHARIDES? Carbohydrates include sugars, starches and other compounds. Sugars include monosaccharides, with carbon chains of 3 to 6 carbons in length, or… chains of two to several monosaccharides in length, or oligosaccharides,

Here are two monosaccharides … and a disaccharide (sucrose) formed by a condensation reaction between the two mono- saccharides. Biological Molecules Small and Large Figure 3-11

Four Classes of Building Blocks Lipids Sugars – polysaccharides Nucleotides – nucleic acids Amino acids – proteins

Four Classes of Building Blocks Lipids Sugars – polysaccharides Nucleotides – nucleic acids Amino acids – proteins

The typical amino acid consists of two distinct groups, an amino group... H H N and a second group, a carboxylic acid. C O OH These two groups are joined by a central or alpha carbon. C Biological Molecules Small and Large

H H CCOON To the central Carbon, we find bonded an additional hydrogen atom. H There is a final unit bonded to the central carbon. This is known as the R group and it is this, more than anything else, that makes each amino acid unique. R Biological Molecules Small and Large

H H CCOOHN HRH H CCOON HR So, if we join these atoms to form water, we leave the carbon and nitrogen of the two amino acids joined by a condensation reaction. Biological Molecules Small and Large

H H CCO N HR CCOON HR + H 2 O H This new bond (-), is a peptide bond and since many of these bonds are needed to assemble a protein molecule, these large polymers are known as polypeptides. Biological Molecules Small and Large

Four Classes of Building Blocks Lipids Sugars – polysaccharides Nucleotides – nucleic acids Amino acids – proteins

Why are All Organisms Made of Cells?

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 bound organelles. –Bacteria and blue green algae are examples. –They are generally smaller than eukaryotic cells 0.4 to 5 micrometers (μm) vs μm Why Are All Organisms Made of Cells?

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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?