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The Scope of Life
– Biology is the scientific study of
life.
ATOMS
• Life is structured on a
size scale ranging from
the molecular to the
global.
• Biology’s scope stretches
across the enormous
diversity of life on Earth.
Ionic Bonds
Covalent Bonds
Hydrogen Bonds
Chemical Reactions
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Biological Molecules
Biological Molecules
– There are four categories of large molecules in
cells:
– There are four categories of large molecules in
small
cells:
sugar
molecules
• Carbohydrates
• Carbohydrates
• Lipids
• Lipids
• Proteins
• Proteins
• Nucleic acids
• Nucleic acids
Polysaccharides
L-O-N-G
starch
molecules
The Overall Equation for Cellular Respiration
– A common fuel molecule for cellular
respiration is glucose.
• The overall equation for what happens to
glucose during cellular respiration
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Adding Up the ATP from Cellular Respiration
Biological Molecules
– There are four categories of large molecules in
cells:
–fats
• Carbohydrates
• Lipids
–steroids
• Proteins
• Nucleic acids
–Lipids are hydrophobic.
•They do not mix with water
The Versatility of Cellular Respiration
– Cellular respiration can “burn” other kinds
of molecules besides glucose:
A Panoramic View of Eukaryotic Cells
– The lipids belong to a special category
called phospholipids.
– Phospholipids form a two-layered
membrane, the phospholipid bilayer.
Osmosis and Water Balance
in Cells
– Osmosis is the passive transport of water
across a selectively permeable membrane.
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Membrane Function
– Working cells control the transport of materials to
and from the environment with membranes.
– They do this with the aid of membrane proteins.
Biological Molecules
– There are four categories of large molecules in
cells:
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids
The Versatility of Cellular Respiration
– Cellular respiration can “burn” other kinds
of molecules besides glucose:
Protein
Shape
Proteins
– A protein is a polymer constructed from
amino acid monomers.
– Proteins perform most of the tasks the
body needs to function.
Structural Proteins
Receptor Proteins
Storage Proteins
Enzymes
Contractile Proteins
Hormonal Proteins
Transport Proteins
Sensory Proteins
Defensive Proteins
Gene Regulatory
Proteins
– Enzymes can function over and over again.
– Proteins
have four
levels of
structure.
How Enzymes Work
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Adding Up the ATP from Cellular Respiration
– The molecules of electron transport chains are
built into the inner membranes of mitochondria.
• The chain functions as a chemical machine that uses
energy released by the “fall” of electrons to pump
hydrogen ions across the inner mitochondrial
membrane.
• These ions store potential energy.
A review of photosynthesis
Biological Molecules
– There are four categories of large molecules in
cells:
• Carbohydrates
DNA, deoxyribonucleic acid
• Lipids
• Proteins
• Nucleic acids
RNA, ribonucleic acid
How DNA Controls the Cell
– Two strands of DNA
join together to form a
double helix.
– DNA controls the cell by transferring its coded
information into RNA.
• The information in the RNA is used to make proteins.
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The Cell
Figure 4.4
The Cell Cycle and Mitosis
– Almost all of the genes of a eukaryotic cell
• Are located on chromosomes in the cell
nucleus.
Eukaryotic Chromosomes
– Each eukaryotic
chromosome
contains one very
long DNA molecule,
• Typically bearing
thousands of genes.
– The number of
chromosomes in a
eukaryotic cell
• Depends on the
species.
– Chromosomes
• Are made of chromatin, a combination of DNA
and protein molecules.
• Are not visible in a cell until cell division occurs.
– The DNA in a
cell is packed
into an
elaborate,
multilevel
system of
coiling and
folding.
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– Before a cell
divides, it
duplicates all of
its chromosomes,
resulting in two
copies called
sister chromatids.
– When the cell
divides, the sister
chromatids
separate from
each other.
• From movie folder play:
–
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–
MitosisOverview.html
LateInterphase.html
Prophase.html
Prometaphase.html
Metaphase.html
Anaphase.html
Telophase.html
Cytokinesis.html
• To wrap it all up play:
– MitosisAllPhases.html
The Cell Cycle
– Eukaryotic cells that divide undergo an
orderly sequence of events called the cell
cycle.
– The cell cycle consists of two distinct
phases:
• Interphase
• Mitotic phase
Figure 8.7
Mitosis and Cytokinesis
– Mitosis
• Is the division of the chromosomes.
• Is preceded by interphase.
From movie folder play:
- AnimalMitosis_SV.mpg
- SeaUrchinTimeLapse_SV.mpg
Figure 8.8.1
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– Mitosis consists of four distinct phases:
• Prophase
• Metaphase
Figure 8.8.2
• Anaphase
• Telophase
Figure 8.8.3
– Cytokinesis
• Typically occurs during telophase.
• Is the division of the cytoplasm.
• Is different in plant and animal cells.
From movie folder play:
- Cytokinesis.html
Figure 8.9a
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Fighting Cancer
Figure 8.9b
Meiosis, The Basis of Sexual
Reproduction
– Sexual reproduction depends on
• Meiosis.
• Fertilization.
Homologous Chromosomes
– Different organisms of the same species
have the same number and types of
chromosomes.
Copyright © 2007 Pearson Education, Inc. publishing as Pearson Benjamin Cummings
– A somatic cell
• Is a typical human body cell.
• Has 46 chromosomes.
– A karyotype is an orderly arrangement of
chromosomes.
– Homologous chromosomes are matching
pairs of chromosomes.
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– Humans have
• Two different sex chromosomes, X and Y.
• Twenty-two pairs of matching chromosomes,
called autosomes.
Figure 8.13
Gametes and the Life Cycle of
a Sexual Organism
– The life cycle of a multicellular organism is
the sequence of stages leading from the
adults of one generation to the adults of the
next.
Figure 8.14
– Humans are diploid organisms.
• Their cells contain two sets of chromosomes.
• Their gametes are haploid, having only one set
of chromosomes.
– Fertilization
• Is the fusion of sperm and egg.
• Creates a zygote, or fertilized egg.
– Sexual life cycles involve an alternation of
diploid and haploid stages.
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The Process of Meiosis
– In meiosis,
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•
•
Haploid daughter cells are produced in diploid organisms.
Two consecutive divisions occur, meiosis I and meiosis II,
preceded by interphase.
Crossing over occurs.
From movie folder play:
MeiosisOverview.html
Interphase.html
ProphaseI.html
MetaphaseI.html
AnaphaseI.html
TelophaseICytokin.html
ProphaseII.html
MetaphaseII.html
AnaphaseII.html
TelophaseIICytokin.html
Figure 8.15
Figure 8.16.1
Figure 8.16.2
Review: Comparing Mitosis
and Meiosis
– All the events unique to meiosis occur
during meiosis I.
Figure 8.16.3
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The Origins of Genetic
Variation
– Offspring of sexual reproduction are
genetically different from their parents and
from one another.
Figure 8.17
Independent Assortment of
Chromosomes
– In independent assortment, every
chromosome pair orients independently of
the others during meiosis.
From the movie folder play:
- GeneticVariation.html
Figure 8.18
Random Fertilization
– The human egg cell is fertilized randomly
by one sperm, leading to genetic variety in
the zygote.
Crossing Over
– In crossing over,
• Homologous chromosomes exchange genetic
information.
• Genetic recombination occurs.
From the movie folder play:
- CrossingOver.html
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When Meiosis Goes Awry
– What happens when errors occur in meiosis?
Figure 8.19
How Accidents During Meiosis
Can Alter Chromosome Number
– In nondisjunction,
• The members of a chromosome pair fail to separate
during anaphase.
• Gametes with an incorrect number of chromosomes
are produced.
Figure 8.20
Copyright © 2007 Pearson Education, Inc. publishing as Pearson Benjamin Cummings
– The result of nondisjunction
Down Syndrome: An Extra
Chromosome 21
– Down Syndrome
• Is a condition where an individual has an extra
chromosome 21.
• Is also called trisomy 21.
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– The incidence of Down Syndrome
increases with the age of the mother.
Figure 8.22
Abnormal Numbers of Sex
Chromosomes
– Nondisjunction
• Also affects the sex chromosomes.
Evolution Connection:
New Species from Errors in Cell
Division
– Errors in meiosis may have been
instrumental in the evolution of many
species.
Copyright © 2007 Pearson Education, Inc. publishing as Pearson Benjamin Cummings
– Polyploids
• Are new species.
• Have more than two sets of homologous
chromosomes in each somatic cell.
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