Chapter 01

A Singular Theme

• Basic structures and mechanisms that sustain life are common to all living creatures

• All forms of life are connected to one another and to their predecessors

Homologous Patterns

• Common patterns in bones are signs of biological unity

Cells

• Basic structural unit of all living things

• Gather fuel and building materials

• Produce usable energy

• Grow and duplicate

Cells

• Every living thing is a cell or is made of cells

• All cells contain nearly the same molecules and undergo similar interactions

Size and Speed

• The smaller an object is, the faster it can move

• Life depends on frequent and vigorous collisions of molecules

Relative Sizes

Relative Sizes

Atoms

• Elemental units of which everything is made

• Atomic Diameters: one to a few hundred millionths of an inch

Molecules

• Atoms bonded together

• CO2: source of life’s carbon atoms

• O2: crucial to energy generation in most life forms

• H2O: aids chemical events inside cells

Molecules

Simple Molecules

• Sugars, nucleotides, amino acids

• Food and/or building materials

Chain Molecules

• Long strings of simple molecules linked together

• Protein: amino acid chain

• DNA and RNA: nucleotide chains

Molecular Structures

• Chain molecules fit together in complex architectural arrangements

• Form cell’s infrastructure

Cell

• Nucleus: contains most of DNA

• Cytoplasm: surrounds nucleus; site of most active cell processes

Animal Cell

Microscopy

• Mid 1600s: first evidence of existence of things smaller than the unaided eye could see

• Robert Hooke: viewed a cork slice with a magnifying lens; named densely-packed empty chambers “cells”

Measurement Units

• Meter: standard metric system unit of length

• Centimeter = 1 x 10-2 meter

• Millimeter = 1 x 10-3 meter

• Micrometer = 1 x 10-6 meter

• Nanometer = 1 x 10-9 meter

Light Microscope

• Magnifies and focuses image formed when light passes through an object

• Can’t distinguish objects smaller or closer together than the shortest wavelength of visible light (200 nm)

Transmission Electron MicroscopeScanning Electron Microscope

• Use beam of electrons controlled by electric or magnetic fields

• Possible to see details of cell surfaces and rough shapes of large molecular structures

Scanning Electron

Micrograph• The

mitochondrion (M) is about the same size as a common bacterium (E. coli)

Electron Micrograph

• View of the nucleus (N), Golgi bodies (G), and vesicles (V)

X-ray Diffraction

• Used to study structural details of individual proteins

• Technique contributed to discovery of DNA double helix structure and structure of hemoglobin

X-ray Diffraction• Protein molecules isolated and crystallized so

they stack regularly in a three-dimensional lattice• Beam of x-rays focused on protein crystal –

regularly repeating atoms in crystal structure deflect x-rays at certain angles

• X-rays produce pattern of exposure spots on photographic film placed behind protein sample

X-ray Diffraction

• X-ray diffraction pattern of DNA captured by Rosalind Franklin

• The X is an indicator of a helical molecular shape

Scientific Process

• Observe an interesting event or phenomenon

• Identify a particular aspect of it that can be stated as a problem

• Produce an hypothesis that explains the event

• Test the hypothesis by experiment

Scientific Method

• Conclusions scientists arrive at after testing many hypotheses are statements that have probability of reflecting reality; they are never certainties

• An idea becomes substance only if it fits into a dynamic accumulating body of knowledge

Ultracentrifuge

• Used to separate and compare sizes of cell components

• A rotor spins tubes containing materials from broken cells at speeds of up to 80,000 rpm

• Cell components separate out according to size

The Way Life WorksCentral Characters

• DNA: information

The Way Life WorksCentral Characters

• Protein: machinery

Your ItineraryPatterns

Energy and Information

Machinery and Feedback

Community and Evolution