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