review of last class. element vs. molecule ionic bond vs. covalent bond polar vs. nonpolar hydrogen...

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Review of Last Class

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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 3-3Figure 3-3

Saturated vs. unsaturated

Biological Molecules

The hydrocarbon skeleton provides a basic framework:

Biological Molecules Small and Large

Figure 3-3Figure 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–

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:H2O = 1:1)

• Nucleotides – nucleic acids

• Amino acids – proteins

One of the most biologically important carbo-One of the most biologically important carbo-hydrates is hydrates is glucoseglucose..

A six-carbon sugar, glucose is found almostA six-carbon sugar, glucose is found almostexclusively in a geometric hexagonal form.exclusively in a geometric hexagonal form.

Biological Molecules Small and Large

The molecule has The molecule has carbon carbon atoms found atoms found at intersections on at intersections on the hexagon.the hexagon.

CC

CC

CC

CC CC

The sixth The sixth carboncarbon is isoff the ring and oneoff the ring and oneintersection has anintersection has anoxygenoxygen rather than rather thana a carboncarbon..

OO

CC

Biological Molecules Small and Large

In this structure, In this structure, there is a there is a proportional proportional relationship of one relationship of one water molecule for water molecule for each carbon atom. each carbon atom.

CC

CC

CC

CC CC

OO

CC

HH

OHOH

OHOH OHOH

OHOH

OHOHHH22

HH

HH

HHHH

Biological Molecules Small and Large

CC

CC

CC

CC CC

OO

CC

HH

OHOH

OHOH OHOH

OHOH

OHOHHH22

HH

HH

HHHH

The term The term carbohydratecarbohydrateis derived from this is derived from this relationship.relationship.

Glucose is the majorGlucose is the majorbuilding block of mostbuilding block of mostpolysachharides.polysachharides.

Biological Molecules Small and Large

Biological Molecules Small and Large HOW DO SUGARS FORM

POLYSACCHARIDES?

Carbohydrates include sugars, starches andCarbohydrates include sugars, starches andother compounds.other compounds.

Sugars include Sugars include monosaccharidesmonosaccharides, with , with carbon chains of 3 to 6 carbons in length, or… carbon chains of 3 to 6 carbons in length, or…

chains of two to several monosaccharides in chains of two to several monosaccharides in length, or length, or oligosaccharidesoligosaccharides,,

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

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 The typical amino acid consists of two distinct groups, an distinct groups, an amino groupamino group......

HH

HHNN

and a second group, a and a second group, a carboxylic acidcarboxylic acid..

CC

OO

OHOH

These two groups are joined by a central or These two groups are joined by a central or alpha carbonalpha carbon..

CC

Biological Molecules Small and Large

HH

HHCC CC

OO

OONN

To the central Carbon, we find bonded an To the central Carbon, we find bonded an additional hydrogen atom.additional hydrogen atom.

HH

There is a final unit bonded to the central There is a final unit bonded to the central carbon. This is known as the carbon. This is known as the R groupR group and it is and it is this, more than anything else, that makes each this, more than anything else, that makes each amino acid unique.amino acid unique.

RR

Biological Molecules Small and Large

HH

HHCC CC

OO

OHOHNN

HH

RRHH

HHCC CC

OO

OONN

HH

RR

So, if we join these atoms to form water, we So, if we join these atoms to form water, we leave the carbon and nitrogen of the two leave the carbon and nitrogen of the two amino acids joined by a condensation reaction.amino acids joined by a condensation reaction.

Biological Molecules Small and Large

HH

HHCC CC

OO

NN

HH

RR

CC CC

OO

OONN

HH

RR

+ + HH22OO

H

This new bond (This new bond (--), is a ), is a peptide bondpeptide bond and since and sincemany of these bonds are needed to assemblemany of these bonds are needed to assemblea protein molecule, these large polymers area protein molecule, these large polymers areknown as polypeptides.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 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?

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?