Advanced Biology Semester 1 Review Part II Chapters 5 - 9
Jan 03, 2016
Advanced Biology Advanced Biology
Semester 1 Review Part IIChapters 5 - 9
Semester 1 Review Part IIChapters 5 - 9
Chapter 5 The Working Cell
Chapter 5 The Working Cell
Things to know and Be Able To Do Types of energy Laws of Thermodynamics ATP Enzymes Membranes Cellular Transport
Review notes, study guides, and labs
Things to know and Be Able To Do Types of energy Laws of Thermodynamics ATP Enzymes Membranes Cellular Transport
Review notes, study guides, and labs
Energy is the Capacity to Perform Work
Energy is the Capacity to Perform Work
Kinetic Energy: Energy that is actually doing work Heat and Light
Potential Energy: Stored energy due to location or arrangement of matter Chemical energy is a form of potential
energy due to the arrangement of atoms in a molecule due to the chemical bonds
Kinetic Energy: Energy that is actually doing work Heat and Light
Potential Energy: Stored energy due to location or arrangement of matter Chemical energy is a form of potential
energy due to the arrangement of atoms in a molecule due to the chemical bonds
Laws of ThermodynamicsLaws of Thermodynamics 1st law: Energy can not be created or
destroyed. It can be transformed from one form to another. Cells do not make energy or consume energy, they
transform energy from one form to another. From the chemical energy of glucose to the
chemical energy of ATP
2nd Law: Energy transformations reduce the order of the universe Energy transformations are not 100% efficient In all energy transformations some energy is lost
in the form of heat.
1st law: Energy can not be created or destroyed. It can be transformed from one form to another. Cells do not make energy or consume energy, they
transform energy from one form to another. From the chemical energy of glucose to the
chemical energy of ATP
2nd Law: Energy transformations reduce the order of the universe Energy transformations are not 100% efficient In all energy transformations some energy is lost
in the form of heat.
Chemical Reactions Store or Release Energy
Chemical Reactions Store or Release Energy
Exergonic reactions release energy by breaking bonds.
Endergonic reactions store energy by forming new bonds
Energy Coupling: Cells use energy released by exergonic reactions to power essential endergonic reactions. Most energy released by exergonic reactions is
stored in the bonds of ATP ATP molecules shuttle this energy to places where
it is required for essential endergonic reactions
Exergonic reactions release energy by breaking bonds.
Endergonic reactions store energy by forming new bonds
Energy Coupling: Cells use energy released by exergonic reactions to power essential endergonic reactions. Most energy released by exergonic reactions is
stored in the bonds of ATP ATP molecules shuttle this energy to places where
it is required for essential endergonic reactions
EnzymesEnzymes Enzymes are proteins
Enzymes speed up chemical reactions by lowering the activation energy of the reaction but are not consumed in the chemical reaction (biological catalysts)
Enzymes are specific to the reactions they catalyze Active site: Region of the protein that binds to
the substrate Substrate: a reactant in the chemical reaction
that the enzyme acts on, must fit in the active site
Enzymes are proteins
Enzymes speed up chemical reactions by lowering the activation energy of the reaction but are not consumed in the chemical reaction (biological catalysts)
Enzymes are specific to the reactions they catalyze Active site: Region of the protein that binds to
the substrate Substrate: a reactant in the chemical reaction
that the enzyme acts on, must fit in the active site
Factors Affecting Enzyme Activity
Factors Affecting Enzyme Activity
pH, Temperature, and salinity can denature an enzyme
Inhibitors can block an enzymes active site Competitive: Sit in the active site and prevent
substrate from entering the active site Noncompetitive: Bind to the enzyme outside of
the active site, but cause the protein to change its overall shape, thus altering the active site.
Reversible: When inhibitors bind to the enzyme by weak H-bonds, can be easily be undone
Irreversible: When inhibitors bind to the enzyme with strong covalent bonds
pH, Temperature, and salinity can denature an enzyme
Inhibitors can block an enzymes active site Competitive: Sit in the active site and prevent
substrate from entering the active site Noncompetitive: Bind to the enzyme outside of
the active site, but cause the protein to change its overall shape, thus altering the active site.
Reversible: When inhibitors bind to the enzyme by weak H-bonds, can be easily be undone
Irreversible: When inhibitors bind to the enzyme with strong covalent bonds
MembranesMembranes Organize cellular activities Phospholipid Bilayer
Two layers of phospholipid molecules Polar heads face away from each other, nonpolar tails
face towards each other Allow small, nonpolar molecules to diffuse through
the membrane and into the cell Proteins
Embedded in the phospholipid bilayer Many functions depending on the type of protein
Enzymes, receptors, connnect cell to its surroundings, transport molecules into and out of the cell
Carbohydrates Cell ID tags to allow the cell to be recognized by other
cells that are part of the same organism
Organize cellular activities Phospholipid Bilayer
Two layers of phospholipid molecules Polar heads face away from each other, nonpolar tails
face towards each other Allow small, nonpolar molecules to diffuse through
the membrane and into the cell Proteins
Embedded in the phospholipid bilayer Many functions depending on the type of protein
Enzymes, receptors, connnect cell to its surroundings, transport molecules into and out of the cell
Carbohydrates Cell ID tags to allow the cell to be recognized by other
cells that are part of the same organism
Cellular TransportCellular Transport Diffusion: the movement of molecules
from areas where they are highly concentrated to areas where they are less concentrated Results from random motion of molecules Requires no work Molecules diffuse down their concentration
gradient, unaffected by the concentration of other molecules
Passive Transport: The diffusion of molecules across the membrane of a cell
Diffusion: the movement of molecules from areas where they are highly concentrated to areas where they are less concentrated Results from random motion of molecules Requires no work Molecules diffuse down their concentration
gradient, unaffected by the concentration of other molecules
Passive Transport: The diffusion of molecules across the membrane of a cell
OsmosisOsmosis The diffusion of water across a selectively
permeable membrane Water can diffuse easily across a biological
membrane Solute molecules can not diffuse across
biological membrane Water will diffuse until the concentration of
water is equal on both sides Hypertonic: Solutions with a high solute
concentration compared to another solution Hypotonic: Solutions with a low solute
concentration compared to another solution Water will move by osmosis from hypotonic
regions to hypertonic regions
The diffusion of water across a selectively permeable membrane Water can diffuse easily across a biological
membrane Solute molecules can not diffuse across
biological membrane Water will diffuse until the concentration of
water is equal on both sides Hypertonic: Solutions with a high solute
concentration compared to another solution Hypotonic: Solutions with a low solute
concentration compared to another solution Water will move by osmosis from hypotonic
regions to hypertonic regions
Osmoregulation
Osmoregulation In Hypotonic Solutions
Animal cells will lyse Plant cells become turgid but do not lyse, due to
rigid cell wall In Hypertonic Solutions
Animal cells will shrivel Plant cell membranes will shrivel, cell wall will not
change dimensions.
Osmoregulation: Organisms must use energy to control water loss or gain in their cells due to osmosis. They can not stop osmosis.
Example: Freshwater fish pee constantly Saltwater fish constantly drink, and concentrate urine in their tissues
In Hypotonic Solutions Animal cells will lyse Plant cells become turgid but do not lyse, due to
rigid cell wall In Hypertonic Solutions
Animal cells will shrivel Plant cell membranes will shrivel, cell wall will not
change dimensions.
Osmoregulation: Organisms must use energy to control water loss or gain in their cells due to osmosis. They can not stop osmosis.
Example: Freshwater fish pee constantly Saltwater fish constantly drink, and concentrate urine in their tissues
Facilitated Diffusion and Active Transport
Facilitated Diffusion and Active Transport
Facilitated diffusion is the movement of molecules across a membrane by diffusion through transport proteins Transport proteins form channels that
allow large, polar, or charged molecules to cross the cell membrane
Active Transport uses energy and transport proteins to move molecules against their concentration gradient Active transport like all cellular work is
powered by ATP
Facilitated diffusion is the movement of molecules across a membrane by diffusion through transport proteins Transport proteins form channels that
allow large, polar, or charged molecules to cross the cell membrane
Active Transport uses energy and transport proteins to move molecules against their concentration gradient Active transport like all cellular work is
powered by ATP
Chapter 6Chapter 6
Things to Know and Be Able to Do: Overall chemical equation for aerobic
cellular respiration Inputs and outputs for all stages of cellular
respiration Location of each of the stages Fermentation
Review Chapter 6 notes, labs, and review packets
Things to Know and Be Able to Do: Overall chemical equation for aerobic
cellular respiration Inputs and outputs for all stages of cellular
respiration Location of each of the stages Fermentation
Review Chapter 6 notes, labs, and review packets
Aerobic Cellular Respiration
Aerobic Cellular Respiration
C6H12O6 + 6O2 ---> 6CO2 + 6H2O + 36-38 ATP
Glucose is broken down into Carbon dioxide and water
Requires oxygen Produces between 36 and 38 ATP molecules Has three major steps
Glycolysis Kreb’s Cycle Electron Transport Chain and Chemiosmosis
C6H12O6 + 6O2 ---> 6CO2 + 6H2O + 36-38 ATP
Glucose is broken down into Carbon dioxide and water
Requires oxygen Produces between 36 and 38 ATP molecules Has three major steps
Glycolysis Kreb’s Cycle Electron Transport Chain and Chemiosmosis
GlycolysisGlycolysis First stage of Aerobic cellular respiration
AND fermentation Takes place in the cytoplasm of all cells 2 molecules of pyruvic acid result from
the splitting of glucose 2 molecules of NADH shuttle electrons
and hydrogen ions to the Electron Transport Chain
2 molecules of ATP are made directly during glycolysis by substrate level phosphorylation
First stage of Aerobic cellular respiration AND fermentation
Takes place in the cytoplasm of all cells 2 molecules of pyruvic acid result from
the splitting of glucose 2 molecules of NADH shuttle electrons
and hydrogen ions to the Electron Transport Chain
2 molecules of ATP are made directly during glycolysis by substrate level phosphorylation
Chemical GroomingChemical Grooming Intermediate step between Glycolysis and
the Krebs Cycle 2 molecules of CO2 are produced; 1 from
each pyruvic acid 2 molecules of NADH shuttle electrons
and hydrogen ions to the Electron Transport Chain from the break down of pyruvic acid; 1 NADH from each pyruvic acid molecule
2 molecules of Acetyl CoA are formed from the break down of pyruvic acid
No ATP is made directly in this stage
Intermediate step between Glycolysis and the Krebs Cycle
2 molecules of CO2 are produced; 1 from each pyruvic acid
2 molecules of NADH shuttle electrons and hydrogen ions to the Electron Transport Chain from the break down of pyruvic acid; 1 NADH from each pyruvic acid molecule
2 molecules of Acetyl CoA are formed from the break down of pyruvic acid
No ATP is made directly in this stage
Kreb’s CycleKreb’s Cycle Second major step of aerobic cellular
respiration Occurs in the matrix of the mitochondria in
eukaryotic cells 4 molecules of carbon dioxide result from the
break down of the Acetyl CoA; 2 molecules from each Acetyl CoA
6 NADH and 2 FADH2 shuttle electrons from the breakdown of Acetyl CoA to the ETC; 3 NADH and 1 FADH2 from each Acetyl CoA
2 ATP are made directly by substrate level phosphorylation; 1 ATP from each Acetyl CoA
Second major step of aerobic cellular respiration
Occurs in the matrix of the mitochondria in eukaryotic cells
4 molecules of carbon dioxide result from the break down of the Acetyl CoA; 2 molecules from each Acetyl CoA
6 NADH and 2 FADH2 shuttle electrons from the breakdown of Acetyl CoA to the ETC; 3 NADH and 1 FADH2 from each Acetyl CoA
2 ATP are made directly by substrate level phosphorylation; 1 ATP from each Acetyl CoA
Electron Transport Chain and Chemiosmosis
Electron Transport Chain and Chemiosmosis
Final stage of aerobic Cellular respiration
Takes place along a chain of protein molecules embedded in the inner mitochondrial membrane
Produces about 34 molecules of ATP using the NADH and FADH2 produced in previous stages; 3 ATP per NADH and 2 ATP per FADH2
Final stage of aerobic Cellular respiration
Takes place along a chain of protein molecules embedded in the inner mitochondrial membrane
Produces about 34 molecules of ATP using the NADH and FADH2 produced in previous stages; 3 ATP per NADH and 2 ATP per FADH2
Electron Transport Chain and Chemiosmosis
(continued)
Electron Transport Chain and Chemiosmosis
(continued) Electrons from NADH and FADH2 move down the Electron Transport Chain by redox reactions and release energy. Oxygen is the last electron acceptor in the chain
The released energy is used to actively transport H+ across the inner mitochondrial membrane from the matrix to the intermembrane space
H+ flows back into the matrix through ATP synthase which powers the phosphorylation of ADP to ATP
Electrons from NADH and FADH2 move down the Electron Transport Chain by redox reactions and release energy. Oxygen is the last electron acceptor in the chain
The released energy is used to actively transport H+ across the inner mitochondrial membrane from the matrix to the intermembrane space
H+ flows back into the matrix through ATP synthase which powers the phosphorylation of ADP to ATP
Alcoholic and Lactic Acid Fermentation
Alcoholic and Lactic Acid Fermentation Fermentation is an alternative to aerobic respiration when
oxygen supplies are limited or not present. Both use glycolysis to make ATP
Alcoholic Fermentation Breaks glucose down in to pyruvic acid Converts pyruvic acid into ethanol and CO2 to recycle
NAD+ Produces 2 ATP per glucose Common in yeast and bacteria, used to make beer and
wine Lactic Acid Fermentation
Breaks glucose down in to pyruvic acid Converts pyruvic acid into lactic acid to recycle NAD+ Produces 2 ATP per glucose Occurs in muscle cells, causes muscle soreness
Fermentation is an alternative to aerobic respiration when oxygen supplies are limited or not present.
Both use glycolysis to make ATP Alcoholic Fermentation
Breaks glucose down in to pyruvic acid Converts pyruvic acid into ethanol and CO2 to recycle
NAD+ Produces 2 ATP per glucose Common in yeast and bacteria, used to make beer and
wine Lactic Acid Fermentation
Breaks glucose down in to pyruvic acid Converts pyruvic acid into lactic acid to recycle NAD+ Produces 2 ATP per glucose Occurs in muscle cells, causes muscle soreness
Chapter 7Chapter 7
Things to know and be able to do: The overall equation and purpose of
photosynthesis The inputs and outputs of each stage of
Photosynthesis The location of each of these stages
Review all chapter 7 notes, labs, and review packets
Things to know and be able to do: The overall equation and purpose of
photosynthesis The inputs and outputs of each stage of
Photosynthesis The location of each of these stages
Review all chapter 7 notes, labs, and review packets
PhotosynthesisPhotosynthesis CO2 + H2O + light ---> C6H12O6 + O2 Organisms that can photosynthesize are called
autotrophs or producers Photosynthesis occurs in the chloroplasts of
eukaryotic cells and in green pigment molecules (chlorophyll) of some photosynthetic bacteria
Photosynthesis uses energy from sunlight to convert water and carbon dioxide into glucose. Oxygen gas is released as a by-product The glucose is used to make ATP by cellular respiration in
the mitochondria Excess glucose is stored as starch
Occurs in two major steps: Light reactions and Calvin Cycle
CO2 + H2O + light ---> C6H12O6 + O2 Organisms that can photosynthesize are called
autotrophs or producers Photosynthesis occurs in the chloroplasts of
eukaryotic cells and in green pigment molecules (chlorophyll) of some photosynthetic bacteria
Photosynthesis uses energy from sunlight to convert water and carbon dioxide into glucose. Oxygen gas is released as a by-product The glucose is used to make ATP by cellular respiration in
the mitochondria Excess glucose is stored as starch
Occurs in two major steps: Light reactions and Calvin Cycle
Light Reactions (PS I)Light Reactions (PS I) Occur in photosystems (PS I and PS II) that are
embedded in the thylakoid membranes of chloroplasts.
Photosystems are groups of chlorophyll molecules that absorb photons of light
Chlorophyll electrons in PS I are energized by sunlight, captured by a primary electron acceptor, and passed down an electron transport chain to NADP+ which becomes NADPH
NADPH shuttles these energy rich electrons to the Calvin cycle which occurs in the stroma of the chloroplast.
Occur in photosystems (PS I and PS II) that are embedded in the thylakoid membranes of chloroplasts.
Photosystems are groups of chlorophyll molecules that absorb photons of light
Chlorophyll electrons in PS I are energized by sunlight, captured by a primary electron acceptor, and passed down an electron transport chain to NADP+ which becomes NADPH
NADPH shuttles these energy rich electrons to the Calvin cycle which occurs in the stroma of the chloroplast.
Light Reactions (PS II)Light Reactions (PS II) Electrons lost from PS I are replaced by
electrons from PS II. Electrons from chlorophyll molecules in PS II are
energized by photons of sunlight, captured by a primary electron acceptor, and passed down an electron transport chain to reach PS I.
As the electrons move down the electron transport chain the energy lost is used to pump H+ across the thylakoid membrane, from the stroma into the thylakoid compartment.
The H+ then flow through ATP synthase to power the production of ATP
Electrons lost from PS I are replaced by electrons from PS II.
Electrons from chlorophyll molecules in PS II are energized by photons of sunlight, captured by a primary electron acceptor, and passed down an electron transport chain to reach PS I.
As the electrons move down the electron transport chain the energy lost is used to pump H+ across the thylakoid membrane, from the stroma into the thylakoid compartment.
The H+ then flow through ATP synthase to power the production of ATP
Products of the Light Reactions
Products of the Light Reactions
Electrons lost from PS II are replaced by electrons that come from the splitting of water at PS II using the energy absorbed from sunlight.
Splitting water makes O2 which is released from the stomata of plant leaves
ATP and NADPH made during the light reactions are used in the Calvin Cycle
The Calvin cycle also requires CO2 which the plant brings in through the stomata of its leaves
Electrons lost from PS II are replaced by electrons that come from the splitting of water at PS II using the energy absorbed from sunlight.
Splitting water makes O2 which is released from the stomata of plant leaves
ATP and NADPH made during the light reactions are used in the Calvin Cycle
The Calvin cycle also requires CO2 which the plant brings in through the stomata of its leaves
Calvin CycleCalvin Cycle Occurs in the stroma of the chloroplast 3 molecules of CO2 enter the Calvin Cycle
and form a chemical intermediate This chemical intermediate is phosphorylated
by ATP and reduced by NADPH G3P is formed and leaves the Calvin cycle. This process is repeated, producing a second
molecule of G3P. The two molecules of G3P combine to form 1
molecule of glucose ADP and NADP+ are recycled back to the
thylakoids
Occurs in the stroma of the chloroplast 3 molecules of CO2 enter the Calvin Cycle
and form a chemical intermediate This chemical intermediate is phosphorylated
by ATP and reduced by NADPH G3P is formed and leaves the Calvin cycle. This process is repeated, producing a second
molecule of G3P. The two molecules of G3P combine to form 1
molecule of glucose ADP and NADP+ are recycled back to the
thylakoids
Chapter 8: Cellular Basis of Reproduction and
Inheritance
Chapter 8: Cellular Basis of Reproduction and
Inheritance Things to know and be able to do: Binary Fission Chromosomes vs. chromatin Cell cycle stages and control mechanisms Stages of Mitosis and its purpose in organisms Cell division and relationship to cancer Meiosis
Purpose in organisms Stages How meiosis causes genetic variation Potential accidents during meiosis
Review all notes, labs, review packets and study guides
Things to know and be able to do: Binary Fission Chromosomes vs. chromatin Cell cycle stages and control mechanisms Stages of Mitosis and its purpose in organisms Cell division and relationship to cancer Meiosis
Purpose in organisms Stages How meiosis causes genetic variation Potential accidents during meiosis
Review all notes, labs, review packets and study guides
Cell DivisionCell Division Binary Fission
Occurs in bacteria Results in exact clones of bacteria cells The single bacterial chromosome is copied and the
cell divides in half Mitosis
Occurs in Eukaryotes Results in 2 daughter cells that are genetically
identical to each other and the parent cell Used for growth, repair and development in
multicellular organisms Meiosis
Occurs only in the ovaries and testes of Eukaryotes. Makes 4 haploid daughter cells called gametes
Binary Fission Occurs in bacteria Results in exact clones of bacteria cells The single bacterial chromosome is copied and the
cell divides in half Mitosis
Occurs in Eukaryotes Results in 2 daughter cells that are genetically
identical to each other and the parent cell Used for growth, repair and development in
multicellular organisms Meiosis
Occurs only in the ovaries and testes of Eukaryotes. Makes 4 haploid daughter cells called gametes
Chromatin and ChromosomesChromatin and Chromosomes
Refers to the DNA of all organisms when it is in thin threadlike fibers during interphase
Prokaryotic DNA forms a single circular chromosome
Eukaryotes form numerous chromosomes made of DNA densely coiled around proteins Always found in the nucleus At the beginning of cell division chromosomes
consist of 2 identical copies of DNA called sister chromatids joined together by a centromere
Refers to the DNA of all organisms when it is in thin threadlike fibers during interphase
Prokaryotic DNA forms a single circular chromosome
Eukaryotes form numerous chromosomes made of DNA densely coiled around proteins Always found in the nucleus At the beginning of cell division chromosomes
consist of 2 identical copies of DNA called sister chromatids joined together by a centromere
Stages of the Cell CycleStages of the Cell Cycle Interphase
G1: Cell grows, copies organelles, makes proteins, carries out its function in the organism
S: Cell replicates (copies) its DNA G2: Cell continues growing and makes
proteins involved in cell division Mitotic Phase:
Mitosis: Nucleus and chromosomes are divided
Cytokinesis: The rest of the cell including the cell membrane organelle copies and cytoplasm divides
Interphase G1: Cell grows, copies organelles, makes
proteins, carries out its function in the organism
S: Cell replicates (copies) its DNA G2: Cell continues growing and makes
proteins involved in cell division Mitotic Phase:
Mitosis: Nucleus and chromosomes are divided
Cytokinesis: The rest of the cell including the cell membrane organelle copies and cytoplasm divides
Stages of Mitosis (PMAT)Stages of Mitosis (PMAT) Prophase
Chromatin coils and condenses into chromosomes Spindle fibers form and attach to kinetochores on each sister
chromatid Nuclear membrane breaks up
Metaphase Spindle fibers align chromosomes on the metaphase plate
Anaphase Spindle fibers pull sister chromatids apart and move them towards
the poles of the cell Telophase
Chromatids uncoil New nuclear membranes begin to form Cytokinesis begins during the end of mitosis
Prophase Chromatin coils and condenses into chromosomes Spindle fibers form and attach to kinetochores on each sister
chromatid Nuclear membrane breaks up
Metaphase Spindle fibers align chromosomes on the metaphase plate
Anaphase Spindle fibers pull sister chromatids apart and move them towards
the poles of the cell Telophase
Chromatids uncoil New nuclear membranes begin to form Cytokinesis begins during the end of mitosis
CytokinesisCytokinesis The process that divides cells Eukaryotic Animal Cells
Microfilaments form a ring around the center of the cell
Microfilaments begin to contract and pinch the center of the cell together forming a cleavage furrow
Eukaryotic Plant cells Vesicles containing cellulose line up in the
center of the cell Vesicles fuse with each other and the edges of
the cell forming a membrane covered cell wall down the middle of the cell
The process that divides cells Eukaryotic Animal Cells
Microfilaments form a ring around the center of the cell
Microfilaments begin to contract and pinch the center of the cell together forming a cleavage furrow
Eukaryotic Plant cells Vesicles containing cellulose line up in the
center of the cell Vesicles fuse with each other and the edges of
the cell forming a membrane covered cell wall down the middle of the cell
Control of the Cell CycleControl of the Cell Cycle
Density Dependent Inhibition As cell density increases, cell division
slows down and eventually stops Anchorage Dependence
Most cells must be attached to other cells in order to continue dividing
Growth factor Proteins secreted by neighboring cells that
stimulate cell division in surrounding cells. As cell density increases the volume of
growth factor declines and cell division slows
Density Dependent Inhibition As cell density increases, cell division
slows down and eventually stops Anchorage Dependence
Most cells must be attached to other cells in order to continue dividing
Growth factor Proteins secreted by neighboring cells that
stimulate cell division in surrounding cells. As cell density increases the volume of
growth factor declines and cell division slows
Control of the Cell Cycle (checkpoints)
Control of the Cell Cycle (checkpoints)
Cells do not proceed through the cell cycle unless they get “go-ahead” signals at key check points End of G1: Growth factors signal go ahead if
the cell is large enough, has copied organelles and made enough proteins. Most important.
End of G2: Growth factors signal go ahead if cell has correctly replicated DNA during S phase
Metaphase of Mitosis: Growth factors signal go ahead if chromosomes are correctly aligned at metaphase with spindle fibers attached
Cells do not proceed through the cell cycle unless they get “go-ahead” signals at key check points End of G1: Growth factors signal go ahead if
the cell is large enough, has copied organelles and made enough proteins. Most important.
End of G2: Growth factors signal go ahead if cell has correctly replicated DNA during S phase
Metaphase of Mitosis: Growth factors signal go ahead if chromosomes are correctly aligned at metaphase with spindle fibers attached
Cancer is a Disease of the Cell Cycle
Cancer is a Disease of the Cell Cycle
Cancerous cell divide out of control. They do not respond to density
dependence and continue to grow to much higher densities than normal cells thus creating a tumor
Some cancer cells, those in malignant tumors, do not respond to anchorage dependence and can metastasize. In other words they can break free from the tumor and begin growing even when not attached to other tissues, thus spreading the cancer through the organism
Cancerous cell divide out of control. They do not respond to density
dependence and continue to grow to much higher densities than normal cells thus creating a tumor
Some cancer cells, those in malignant tumors, do not respond to anchorage dependence and can metastasize. In other words they can break free from the tumor and begin growing even when not attached to other tissues, thus spreading the cancer through the organism
Life CyclesLife Cycles Somatic (non-reproductive) cells are diploid.
They contain pairs of homologous chromosomes.
Gametes (reproductive cells) are haploid. Meiosis divides diploid cells in the testes or
ovaries to produce haploid gametes Gametes contain one chromosome from each
homologous pair in an organisms diploid cells
Fertilization is the union of gametes from two different individuals as the result of sexual reproduction. Fertilization produces diploid zygotes. Zygotes develop into offspring through repeated
rounds of mitosis
Somatic (non-reproductive) cells are diploid. They contain pairs of homologous chromosomes.
Gametes (reproductive cells) are haploid. Meiosis divides diploid cells in the testes or
ovaries to produce haploid gametes Gametes contain one chromosome from each
homologous pair in an organisms diploid cells
Fertilization is the union of gametes from two different individuals as the result of sexual reproduction. Fertilization produces diploid zygotes. Zygotes develop into offspring through repeated
rounds of mitosis
MeiosisMeiosis Meiosis is the process that makes
haploid gametes from diploid cells in reproductive organs.
Meiosis involves two consecutive rounds of cell division
Meiosis results in four haploid daughter cells with different genetic combinations in each daughter cell.
Meiosis has 8 stages divided between meiosis I and meiosis II
Meiosis is the process that makes haploid gametes from diploid cells in reproductive organs.
Meiosis involves two consecutive rounds of cell division
Meiosis results in four haploid daughter cells with different genetic combinations in each daughter cell.
Meiosis has 8 stages divided between meiosis I and meiosis II
Meiosis I (PMAT I)Meiosis I (PMAT I)Prophase I: Pairs of homologous chromosomes, each consisting of
identical sister chromatids, attach to each other and form tetrads
Crossing over between non-sister homologous chromosomes
Metaphase I: Tetrads line up along the imaginary metaphase plate
Anaphase I Tetrads separate, homologous chromosomes in each
tetrad get pulled to opposite poles of the cell. Each chromosome still consists of 2 connected sister chromatids
Telophase I Chromosomes may or may not unwind and new nuclei
may or may not form depending on the species. Occurs simultaneously with cytokinesis, which divides the
parent cell into two haploid daughter cells
Prophase I: Pairs of homologous chromosomes, each consisting of
identical sister chromatids, attach to each other and form tetrads
Crossing over between non-sister homologous chromosomes
Metaphase I: Tetrads line up along the imaginary metaphase plate
Anaphase I Tetrads separate, homologous chromosomes in each
tetrad get pulled to opposite poles of the cell. Each chromosome still consists of 2 connected sister chromatids
Telophase I Chromosomes may or may not unwind and new nuclei
may or may not form depending on the species. Occurs simultaneously with cytokinesis, which divides the
parent cell into two haploid daughter cells
Meiosis II (PMAT II)Meiosis II (PMAT II) Prophase II
Spindle fibers reform in each daughter cell and begin moving chromosomes towards the center of the cell
Metaphase II Chromosomes line up at the metaphase plate of each
daughter cell Anaphase II
Sister chromatids separate and are pulled to opposite poles of each cell
Telophase II New nuclei form around the groups of sister chromatids Cytokinesis begins dividing each cell into two daughter cells,
for a total of four daughter cells at the end of meiosis II.
Prophase II Spindle fibers reform in each daughter cell and begin moving
chromosomes towards the center of the cell Metaphase II
Chromosomes line up at the metaphase plate of each daughter cell
Anaphase II Sister chromatids separate and are pulled to opposite poles
of each cell Telophase II
New nuclei form around the groups of sister chromatids Cytokinesis begins dividing each cell into two daughter cells,
for a total of four daughter cells at the end of meiosis II.
Sources of Genetic Variation
Sources of Genetic Variation Independent Orientation: Homologous pairs
of chromosomes can line up in two different orientations. Each pair orients itself independently of all other pairs.
Crossing Over: Non sister homologous chromosomes can exchange pieces with each other during synapsis of prophase I. This leads to new combinations of traits not seen in either parent
Random fertilization: The two processes above produce varied gametes in all parents. Which male gamete fertilizes a specific female gamete during sexual reproduction between 2 parents is due to random chance
Independent Orientation: Homologous pairs of chromosomes can line up in two different orientations. Each pair orients itself independently of all other pairs.
Crossing Over: Non sister homologous chromosomes can exchange pieces with each other during synapsis of prophase I. This leads to new combinations of traits not seen in either parent
Random fertilization: The two processes above produce varied gametes in all parents. Which male gamete fertilizes a specific female gamete during sexual reproduction between 2 parents is due to random chance
Accidents During MeiosisAccidents During Meiosis Nondisjunction
Homologous chromosomes fail to separate during meiosis IResults in 4 gametes with abnormal chromosome #
(2 with extra, 2 with less) Sister chromosomes fail to separate in Meiosis II
Results in 2 gametes with normal chromosome #, and 2 with abnormal chromosome # (1 with extra, 1 with less)
Usually results in miscarriage if nondisjunction occurs between autosomes, but there are exceptions (down syndrome)
More survivable if nondisjunction occurs between sex chromosomes (Turners, Klienfelter)
Nondisjunction Homologous chromosomes fail to separate
during meiosis IResults in 4 gametes with abnormal chromosome #
(2 with extra, 2 with less) Sister chromosomes fail to separate in Meiosis II
Results in 2 gametes with normal chromosome #, and 2 with abnormal chromosome # (1 with extra, 1 with less)
Usually results in miscarriage if nondisjunction occurs between autosomes, but there are exceptions (down syndrome)
More survivable if nondisjunction occurs between sex chromosomes (Turners, Klienfelter)
Accidents During MeiosisAccidents During Meiosis Alterations of chromosomes: Results from
chromosomes breaking during meiosis Deletions: missing a piece altogether, usually
the most serious Duplication: When a piece of one chromosome
breaks off and is added to its homolog, Resulting in 2 copies of the genetic information
Inversion: When a piece breaks off of one chromosome and then is reattached upside down to the same chromosome
Translocation: When a piece breaks off and attaches to another non-homologous chromosome
Alterations of chromosomes: Results from chromosomes breaking during meiosis Deletions: missing a piece altogether, usually
the most serious Duplication: When a piece of one chromosome
breaks off and is added to its homolog, Resulting in 2 copies of the genetic information
Inversion: When a piece breaks off of one chromosome and then is reattached upside down to the same chromosome
Translocation: When a piece breaks off and attaches to another non-homologous chromosome