Unit%203%20and%204%20Biology%20Review

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Unit 3 and 4 Biology Review
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Building Molecules That Store Energy

• Metabolism involves either using energy to build
  molecules or breaking down molecules in which
  energy is stored.
• Photosynthesis process by which light energy is
  converted to chemical energy.
• Autotrophs organisms that use energy from
  sunlight of from chemical bonds in inorganic
  substances to make organic compounds.
• Most Autotrophs are photosynthetic organisms.

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Breaking Down Food For Energy

• Chemical energy in organic compounds can be
  transferred to other organic compounds or to
  organisms that consume food.
• Heterotrophs organisms that must get energy from
  food instead of directly from sunlight or
  inorganic substances. Heterotrophs get energy
  from food using cellular respiration.
• Cellular respiration a metabolic process that
  releases energy in food to make ATP which can
  provide the cell with the energy it needs.

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ATP

• ATP or Adenosine triphosphate is a nucleotide
  with two extra energy-storing phosphate groups.
• The phosphate groups store energy like a
  compressed springthe energy is released when the
  bonds holding the phosphate groups together is
  broken.
• The removal of a phosphate group from ATP makes
  ADP, or Adenosine diphosphate in the following
  reaction
• H20 ATP ? ADP P ENERGY!!!

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Photosynthesis Using the Energy in Sunlight

• There are three stages in Photosynthesis
• Stage 1 Absorption of Light EnergyEnergy is
  captured from sunlight.
• Stage 2 Conversion of Light EnergyLight energy
  is converted to chemical energy, which is
  temporarily stored in ATP and the energy carrier
  molecule NADPH.
• Stage 3 Storage of EnergyThe chemical energy
  stored in ATP and NADPH powers the formation of
  organic compounds, using carbon dioxide.
• Stages 1 and 2 of photosynthesis are
  light-dependent reactions.

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The Stages of Photosynthesis

• Stage 1 Absorption of Light EnergyEnergy is
  captured from sunlight.
• Stage 2 Conversion of Light EnergyLight energy
  is converted to chemical energy, which is
  temporarily stored in ATP and the energy carrier
  molecule NADPH.
• Stage 3 Storage of EnergyThe chemical energy
  stored in ATP and NADPH powers the formation of
  organic compounds, using carbon dioxide.

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Stage One Absorption of Light Energy

• Stage one is LIGHT DEPENDENT!
• Pigments structures that absorb light in certain
  wavelengths and reflect all others.
• Chlorophyll primary pigment involved in
  photosynthesis absorbs blue and red light and
  reflects green and yellow light. Two types
  chlorophyll a and chlorophyll b
• Cartenoids pigments that produce fall colors.

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Factors that Affect Photosynthesis

• Photosynthesis is directly affected by various
  environmental factors.
• The rate of photosynthesis increases as light
  intensity increases until all pigments are being
  used, when the Calvin cycle cannot proceed any
  faster
• The carbon dioxide concentration affects the rate
  of photosynthesis.
• Photosynthesis is also more efficient within a
  certain range of temperatures (enzymes are
  involved!)

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Cellular Energy

• Your cells transfer the energy in organic
  compounds, like glucose, to ATP through a process
  called cellular respiration.
• Oxygen you breath in air makes the production of
  ATP more efficient, although some ATP is made
  without oxygen.
• Aerobic metabolic processes that require oxygen
• Anaerobic metabolic process that do not require
  oxygen.

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The Stages of Cellular Respiration

• Stage 1 Glucose is converted to pyruvate,
  producing a small amount of ATP and NADH.
• Stage 2 Pyruvate an NADH are used to make a
  large amount of ATP in a process called aerobic
  respiration, occurring in mitochondria.
• Krebs cycle and electron transport chain take
  place, making more ATP.

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Respiration in the Absence of Oxygen

• If there is not enough oxygen for aerobic
  respiration to occur, there is no electron
  transport chain
• Under anaerobic conditions, fermentation occurs.
• Lactic Acid Fermentation
• Alcoholic Fermentation

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Production of ATP

• Total ATP Production
• Glycolysis 2 ATP
• Krebs Cycle 2 ATP
• Electron Transport Chain Up to 34 ATP

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The Path of Air

• Air enters the respiratory system through the
  nose or mouth. About 21 is oxygen gas.
• Air passes through the pharynx and continues to
  the larynx, or voice box.
• Air then passes into the trachea, or windpipe
  which divides into two smaller tubes called
  Bronchi, which branch into the lungs.
• Within the lungs, smaller tubes called
  bronchioles divide off.
• Finally, the smallest bronchioles reach air sacs
  called alveoli where gasses are actually
  exchanged.

Alveoli tiny air sacs in the lungs where oxygen
and carbon dioxide gases are exchanged.
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Gas Transport Oxygen Transport

1. Oxygen reaches lungs.
2. Oxygen diffuses from alveoli to capillaries (tiny
   blood vessels surrounding alveoli).
3. Oxygen rich blood travels to the heart.
4. Oxygen diffuses from the blood into the cells for
   aerobic respiration.
5. Carbon dioxide diffuses to the blood from cells.
6. Most carbon dioxide travels to the heart.
7. The heart pumps blood to lungs. Carbon dioxide
   is released to the alveoli.
8. Carbon dioxide is expelled in exhalation.

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Gas Transport Carbon Dioxide Transport

• Carbon dioxide is also taken in by blood in three
  forms.
• 7 is dissolved in blood plasma.
• 23 is attached to hemoglobin molecules inside
  red blood cells.
• 70 is carried in the blood as bicarbonate ions
  (H2CO3).

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Is a Virus Alive?

• Living things are made of cells, are able to grow
  and reproduce, and are guided by information
  store in their DNA.
• Virus segments of nucleic acids contained in a
  protein coat.
• Viruses are not cells and are even smaller than
  prokaryotes.
• Viruses replicate by infecting cells and using
  the cell to make more viruses.
• Pathogens agents that cause disease.
• Viruses are pathogens.
• Viruses do not have all the properties of life,
  and are subsequently not considered to be living.
• Viruses do not grow, do not have homeostasis, and
  do not metabolize.

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Discovery of Viruses

• Scientists trying to find the cause of the
  tobacco mosaic disease found that if they
  strained infected sap, they could still infect
  plants. This told scientists that the pathogen
  was smaller than a bacterium.
• For many years, viruses were thought to be tiny
  cells.
• Eventually, Wendell Stanley concluded that TMV is
  a chemical rather than an organismeach particle
  is composed of RNA or DNA and a protein.

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Viral Structure

• Capsid virus protein coat, which contains RNA or
  DNA.
• Envelope structure surrounding capsid which
  allows viruses to enter cells. Made of
• Proteins, Lipids, and Glycoproteins
• Bacteriophage a virus that enters bacteria that
  has a complex structures.

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Viral Replication

• Viruses lack the enzymes necessary for metabolism
  and have no structures to make protein.
• Viruses must rely on living cells (host cells)
  for replication. Before a virus and replicate,
  it must infect a living cell.
• An animal virus enters its host through
  endocytosis.
• Bacteriophages punch holes in cell walls and
  inject DNA

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Lytic Cycle

• Lytic Cycle the cycle of viral infection,
  replication, and cell destruction.
• After viral genes have entered the cell, they use
  the cell to replicate viral genes and to make
  viral proteins which are then assembled to make
  complete viruses. The host cell is broken open
  and releases newly made viruses.

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Lysogenic Cycle

• Lysogenic Cycle the viral genome replicates
  without destroying the host cell.
• Provirus a virus that stays inside a cell but
  does not make new viruses instead the viral gene
  is inserted into the chromosomes of a host cell,
  making a provirus. Whenever the cell divides,
  the provirus also divides.

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HIV Structure

• Many viruses such as Influenza and HIV have an
  envelope.
• In many cases the envelope is composed of a lipid
  bilayer derived from the membrane of the host
  cells with glycoproteins embedded within the
  envelope.
• Within the envelope lies the capsid, which
  encloses the genetic material.
• Viruses are often restricted to certain kinds of
  cells. This may be due to viruses origin.
• Viruses may have originated from fragments of
  host genes escaped or were expelled from cells.
• There are many kinds of virusespossibly as many
  kinds of viruses as kinds of organisms!

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HIV Infection

• HIV entry is a two-step process. The viruses
  attaches to the cell and then the envelope fuses
  with the membrane.
• Attachment spikes composed of a glygoprotein
  fits a human cell receptor and binds to human
  cells.
• Entry into Macrophages HIV binds to a receptor
  and a co-receptor which allows the capsid to
  enter the cell.
• Replication Once inside, the HIV capsid comes
  apart and releases its components including viral
  RNA. New viruses are assembled and released by
  exocytosis.
• AIDS HIV continues to replicated and take over
  cells they could not before. HIV starts to
  reproduce in T Cells and destroy them.

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HIV Infection
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Viral Diseases
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Emerging Viruses

• Newly recognized viruses or reappearing viruses
  are called emerging viruses.
• In 1999 a mosquito-borne virus called West Nile
  began to spread across the U.S., probably brought
  by infected birds.
• People who are infected typically experience mild
  flulike symptoms. However, sometimes fatal
  inflammation of the brain may occur.

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Prions and Viroids

• In addition to viruses and bacteria, scientists
  are now recognizing new classes of pathogens.
• Prions composed of proteins but have no nucleic
  acid.
• A disease-causing prion is folded into a shape
  that does not allow the prion to function.
  Contact with a prion causes a normal version of
  the protein to misfold, too. This causes a chain
  reaction.
• Prions are linked to Mad Cow disease and the
  human Creutzfeldt-Jakob.
• Virod a single strand of RNA with no capsid.
• Important infectious agents in plants.

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Change in Chromosome Structure

• Mutations changes in an organisms chromosome
  structure.
• Breakage of a chromosome can lead to four types
  of mutation.
• Deletion a piece breaks off completely, the new
  cell will lack a set of genes.
• Duplication a chromosome fragment attaches to
  its homologous chromosome, which will then carry
  two copies of genes.
• Inversion chromosome reattaches to the original
  chromosome in reverse.
• Translocation chromosome reattaches to a
  nonhomologous chromosome.

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Primary Tissue Layers

• There are three primary tissue layers, described
  in the table below.
• The cells of all animals except sponges are
  organized into units called tissues, which are
  cells with a common structure that work together
  to perform a function.

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The Cell Cycle

• Cell Cycle a repeating sequence of cellular
  growth and division during the life of an
  organism. A cell spends ninety percent of its
  time in the first three phases, known together as
  interphase.
• The cell will enter the last phases
• of interphase only if the cell is about
• to divide. There are five phases of
• the cell cycle, listed below and
• summarized on the next slide
• 1. First growth 2. Synthesis, 3. Second growth
  4. Mitosis 5. Cytokinesis.

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When Control is Lost Cancer

• Certain genes contain the information to make
  proteins that regulate cell growth and division.
• If one of these genes is mutation, the protein
  may not function, and regulation of cell growth
  and division can be disrupted.
• Cancer the uncontrolled growth and division of
  cells.
• A disorder of cell division cancer cells do not
  respond normally to the bodys control
  mechanisms.
• Some mutations cause cancer by over-producing
  growth-promoting molecules, speeding up the cell
  cycle.
• Others cause cancer by inactivating control
  proteins.

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Mitosis
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Mitosis

• 1. Prophase Chromosomes coil up and become
  visible during prophase. The nuclear envelope
  dissolves and a spindle forms.
• 2. Metaphase Chromosomes move to the center of
  the cell and line up along the equator. Spindle
  fibers link the chromatids of each chromosome to
  opposite poles.
• 3. Anaphase Centromeres divide during anaphase.
  The two chromatids (now called chromosomes) move
  toward opposite poles as spindle fibers shorten.
• 4. Telophase A nuclear envelope forms around the
  chromosomes at each polechromosomes are now at
  opposite poles.

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A Winding Staircase

• Watson and Crick determined that DNA is a double
  helix. Each strand is made of linked
  nucleotides, the subunits that made up DNAmade
  of a sugar (deoxyribose), a nitrogen base, and a
  phosphate group.

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Purines and Pyrimidines

• The sugar and the phosphate group are the same
  for each nucleotide. However, there are four
  different nitrogen bases adenine, guanine,
  thymine, and cytosine.
• Adenine and guanine are Purines.
• Thymine and Cytosine are Pyrimidines.
• Nitrogen bases of nucleotides face each other in
  the double helix and are held together by weak
  hydrogen bonds.

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Pairing Between Bases

• A Purine on each strand (A or G) is always paired
  with a pyrimidine on the other strand (C or T)
• A pairs with T
• G pairs with C
• Two strands contain complementary base pairsthe
  sequence of bases on one strand determines the
  sequence on the other strand.

Determine the complementary strand for the
following sequences TCGAACT CCAGATTG
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Roles of Enzymes in DNA Replication

• DNA Replication The process of making a copy of
  DNA
• DNA Helicases open the double helix by breaking
  the hydrogen bonds that link the complementary
  nitrogen bases between the two strands
• Replication Fork The area where the double helix
  separates
• DNA Polymerase enzymes that move along the
  strands of DNA and add new nucleotides to the new
  nitrogen bases
• When replication is complete, there are two
  identical DNA molecules, each made of a new
  strand and an old strand.

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Steps of DNA Replication
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