Anatomy and Physiology Honors Midterm Exam Review Part 1 Chapters By Mrs. Shaw Digestion Circulation Movement Growth Respiration Absorption Responsiveness Excretion Assimilation Reproduction Opening Assignment Day 1 Chapter 1 Vocabulary review Characteristics of Life Match the correct term with the definition ____________1. Production of new organisms and new cells. ____________2. Movement of substances in body fluids. ____________3. Change in position of the body or of a body part, motion of an internal organ. ____________4. Increase in body size without change in shape. ____________5. Obtaining oxygen, removing carbon dioxide, and releasing energy from foods. ____________6. Removal of wastes produced by metabolic reactions. ____________ 7. Passage of substances through membranes and into body fluids. _____________8. Reaction to a change inside or outside the body. _____________ 9. breakdown of food substances into simpler forms that can be absorbed and used. _____________10. changing absorbed substances into chemically different forms. Digestion Circulation Movement Growth Respiration Absorption Responsiveness Excretion Assimilation Reproduction Chapter 1 Vocabulary review Characteristics of Life Match the correct term with the definition Reproduction1. Production of new organisms and new cells. Circulation__2. Movement of substances in body fluids. Movement__3. Change in position of the body or of a body part, motion of an internal organ. Growth_____4. Increase in body size without change in shape. Respiration__5. Obtaining oxygen, removing carbon dioxide, and releasing energy from foods. Excretion____6. Removal of wastes produced by metabolic reactions. Absorption __ 7. Passage of substances through membranes and into body fluids. Responsiveness_8. Reaction to a change inside or outside the body. Digestion ___ 9. breakdown of food substances into simpler forms that can be absorbed and used. Assimilation___10. changing absorbed substances into chemically different forms. Word Bank: ventral cavitythoracic cavitydiaphragm pelvic cavitydorsal cavityabdominal cavity cranial cavityabdominopelvic cavity vertebral cavity Practice: Look at the diagram on the right and list the cavity or muscle being identified. 1.___________________ 2.___________________ 3.___________________ 4.___________________ 5.___________________ 6.___________________ 7.___________________ 8.___________________ 9.___________________ Chapter 1 Diagram review 1._Ventral___________ 2.__Thoracic_________ 3.__Diaphragm______ 4.__Abdominopelvic__ 5._ Abdominal_______ 6.___Pelvic__________ 7.___Cranial_________ 8.___Vertebral_______ 9.__Dorsal___________ Chapter 1 Diagram review Create your Own Study Guide You will be allowed to bring 1 sheet of notebook or copy paper to use on the midterm exam. You will be using your previous tests and study guides to create your own midterm study guide based on your weaknesses. Go back over your tests and identify what you completely understand and remember. If you can answer the question off the top of your head, leave it off the study guide. If you struggle to remember it or totally have no idea, put that information on your study guide. Remember that the midterm is a compilation of the previous tests with NO NEW QUESTIONS. Use my website to review the powerpoints for each Chapter and review games. You will be using your study guide on exam day and turning it in for a grade. Please do not forget to bring it! Opening Assignment Day 2 Chapter 2 1. How many protons, neutrons, and electrons does one atom of Fluorine have? 2. The number of bonds an atom will make is determined by the number of _______________________. 3. The weak bond that holds two polar water molecules together is called a __________________________. 4. What are the 4 main macromolecules and their subunits in living organisms? Opening Assignment Day 2 Chapter 2 1. How many protons, neutrons, and electrons does one atom of Fluorine have? 9 protons 9 electrons 10 neutrons 2. The number of bonds an atom will make is determined by the number of __valence electrons______. 3. The weak bond that holds two polar water molecules together is called a __hydrogen bonds_______. 4. What are the 4 main macromolecules and their subunits in living organisms? Nucleic acids nucleotidesProteins amino acids Carbohydrates monosaccharides (sugars) Lipids fatty acids and glycerol Chapter 3 Match the organelle or cell part with its special function A. Uses enzymes to break down wastes B. Hair like projections that help cells move C. Made by the Golgi apparatus to be sent out of cell D. Makes RNA E. Contains enzymes that speed up chemical reactions F. Part of the cytoskeleton G. Create and transport lipids and proteins to the Golgi apparatus H. Makes ATP through cellular respiration I. Help distribute chromosomes in cell division J. Create proteins K. Packages proteins and lipids into vesicles 1. ______________Nucleolus 2. ______________Endoplasmic reticulum 3. ______________Golgi apparatus 4. ______________Lysosome 5. ______________Ribosome 6. ______________Mitochondria 7. ______________Peroxisomes 8. ______________Centrosomes 9. ______________ Microtubules 10. ______________ Cilia 11. ______________ Vesicles Chapter 3 Match the organelle or cell part with its special function A. Uses enzymes to break down wastes B. Hair like projections that help cells move C. Made by the Golgi apparatus to be sent out of cell D. Makes RNA E. Contains enzymes that speed up chemical reactions F. Part of the cytoskeleton G. Create and transport lipids and proteins to the Golgi apparatus H. Makes ATP through cellular respiration I. Help distribute chromosomes in cell division J. Create proteins K. Packages proteins and lipids into vesicles 1. _____D_____ Nucleolus 2. _____G_____Endoplasmic reticulum 3. _____K_____Golgi apparatus 4. _____A_____Lysosome 5. _____J_____Ribosome 6. _____H____Mitochondria 7. _____E_____Peroxisomes 8. _____I_____Centrosomes 9. _____F____ Microtubules 10. _____B____ Cilia 11. _____C____ Vesicles Opening Assignment Day 3 Ch. 5 Tissues 1.What are the four types of human body tissue? 2.How are Epithelial cells classified? 3.What process allows nutrients to pass through the nonliving basement membrane at the bottom of epithelial tissue? Opening Assignment Day 3 Ch. 5 Tissues What are the four types of human body tissue? Epithelial - line and cover surfaces, lack direct blood supply Connective attach tissues, most have good blood supply Muscle allow for movement using contractions Nervous transmit impulses, made of neurons and neuroglial cells How are Epithelial cells classified? By number of layers (simple = 1; stratified = >1 and by shape (squamous scale like, cuboidal cube shaped, columnar column shaped) What process allows nutrients to pass through the nonliving basement membrane at the bottom of epithelial tissue? Diffusion the movement of substances from an area of high concentration to low concentration. Type of passive transport. Chapter 4 Labeling Label the Types of Epithelial TissueTissue A.B. C. D. E.F.G. Review of Chapter 1 Introduction into Anatomy and Physiology Ch. 1 Student Learning Goals: Students will be able to 1.1: Describe the early studies into the workings of the human body 1.2: Define anatomy and physiology and describe how they are related 1.3: Explain the biological levels of organization 1.4: List and describe the major characteristics of life 1.5: List and describe the main requirements of life including homeostasis and a mechanism to control it. 1.6: A. Describe the locations of the major body cavities. B. list the organs within each cavity C. Name the membranes associated within the thoracic and abdominopelvic cavities. D. List the main organ systems, know the organs in each system, and know the main function of each system. 1.7 Properly use the terms that describe relative positions, body sections, and body regions 1.1 Introduction Early interest in the human body probably developed as people became concerned about injuries and illnesses. Primitive doctors began to learn how certain herbs and potions affected body functions. As technology advanced practitioners began to identify and name body parts. They also described the function of each part which helped them understand how the body parts work together as a unit. 1.2 Anatomy and Physiology Anatomy is the branch of science that deals with the structure (morphology) of body parts their forms and how they are organized. Physiology is the branch that deals with the function of each body part (what they do and how they do it). These two things are difficult to separate because the structure is so closely related to the function. In other words a body parts function depends on how it is constructed. New understandings of anatomy and physiology of the human body are still being discovered today. 1.3 Levels of Organization 1. Atom 2. Molecule 3. Macromolecule 4. Organelle 5. Cell 6. Tissue 7. Organ 8. Organ system 9. Organism **Use the link on the textbook website to practice these levels. Match the correct term with the definition Digestion Circulation Movement Growth Respiration Absorption Responsiveness Excretion Assimilation Reproduction ____________1. Production of new organisms and new cells. ____________2. Movement of substances in body fluids. ____________3. Change in position of the body or of a body part, motion of an internal organ. ____________4. Increase in body size without change in shape. ____________5. Obtaining oxygen, removing carbon dioxide, and releasing energy from foods. ____________6. Removal of wastes produced by metabolic reactions. ____________ 7. Passage of substances through membranes and into body fluids. _____________8. Reaction to a change inside or outside the body. _____________ 9. breakdown of food substances into simpler forms that can be absorbed and used. _____________10. changing absorbed substances into chemically different forms. Match the correct term with the definition Digestion Circulation Movement Growth Respiration Absorption Responsiveness Excretion Assimilation Reproduction _Reproduction__1. Production of new organisms and new cells. _Circulation____2. Movement of substances in body fluids. _Movement___3. Change in position of the body or of a body part, motion of an internal organ. _Growth_____4. Increase in body size without change in shape. __Respiration_5. Obtaining oxygen, removing carbon dioxide, and releasing energy from foods. __Excretion___6. Removal of wastes produced by metabolic reactions. _Absorption__ 7. Passage of substances through membranes and into body fluids. _Responsiveness__8. Reaction to a change inside or outside the body. _Digestion____ 9. breakdown of food substances into simpler forms that can be absorbed and used. _Assimilation__10. changing absorbed substances into chemically different forms. Metabolism the sum total of all chemical reactions in the body that break down substances and build them up. It is a very complex mechanism that involves many different body systems. We will go into more detail on in Chapters 2, 3 & 4. Homeostasis If an organism is to survive, the conditions within its body fluids must remain relatively stable. Maintenance of a stable internal environment is called homeostasis. Homeostatic mechanisms help regulate body temperature, blood pressure, and many other things. Homeostatic mechanisms act through negative feedback. 1.6 Organization of the Human Body The human body is divided into 2 main sections; Axial portion: includes the head, neck, and trunk Appendicular portion: includes the arms and legs Body Cavities There are two main body cavities: Ventral: (Belly) Which is subdivided into. a) Abdominopelvic- which consists of the abdominal and pelvic regions, and contains the digestive and reproductive organs. b) Thoracic- which is the upper torso or chest region, and contains the heart and lungs. **The organs within these two cavities are called Viscera. Dorsal: (Back) Which is subdivided into.. a)Cranial- which contains the head and includes the brain. b)Vertebral- which includes the spinal column. Thoracic and Abdominopelvic Membranes Thoracic Membranes Parietal refers to the membrane attached to the wall of a cavity. Visceral refers to the membrane that is deeper toward the interior and usually covers an internal organ like the lung. While no actual space occurs between these specific membranes, the potential space between them is called the pleural cavity. Pleurisy is a condition where that pleural membrane gets inflamed. It can make breathing very painful. Abdominopelvic Membranes In the abdominopelvic cavity the lining membranes are called peritoneal membranes. A parietal peritoneum lines the wall and a visceral peritoneum covers each organ in the abdominal cavity. People with kidney failure use this membrane for dialysis. Table 1.1 (2 of 3) Table 1.1 (3 of 3) Body Planes There are three body planes: a)Transverse or Horizontal- divides the body into a top (superior) and bottom (inferior). b)Mid-Sagittal or Median- divides the body into an equal right and left side. c)Frontal or Coronal- divides the body into a front (anterior) and a back (posterior) side. Anatomy and Physiology Honors Chapter 2 The Chemical Basis of Life By Mrs. Shaw Resources Holes Essentials of Anatomy and Physiology 9 th Edition Learning Goals for Lessons 2.1 and 2.2 Students will be able to: Explain how the study of living things depends on the study of chemistry. Discuss how atomic structure determines how atoms interact. Describe the relationship between atoms and molecules. Explain how molecular and structural formulas symbolize the composition of compounds. Describe the three types of chemical reactions. Define pH. Chemistry is.... Chemistry is the branch of science that considers the composition of matter and how this composition changes. This is essential to the study of anatomy and physiology because body structures and functions result from chemical changes within cells. Atoms ATOM-the smallest complete unit of elements (matter) that maintain the characteristics of that element. Nucleus- The center of the atom, contains protons and neutrons Electron Cloud Region surrounding the nucleus containing the electrons The Nucleus Proton-A positively charged sub-atomic particle (+). Atomic Mass = 1 amu The number of protons is the same as the atomic number Li 3 7 The atomic mass The Atomic Symbol The Nucleus Neutrons A sub-atomic particle in the nucleus --Has a mass equal to 1 atomic mass unit --Neutron do not have a charge (0) To calculate the number of neutrons in an element Li 3 7 The atomic number The atomic mass -The atomic number The number of neutrons The Electron Cloud Electrons- The number of electrons equals the number of protons Sub-atomic particle with a negative charge (-) Electrons behave as if in a 3-D orbit Valence Electrons The outer most electrons Valence electrons are responsible for bonding Lets look at a few elements Hydrogen 1= Proton1= electron Lets look at a few elements Helium 2=protons2=neutrons 2=electrons Electrons and bonding Think about having two magnets. The closer they are to each other the stronger the attraction is. There is a similar attraction between the negatively charged electrons and the positively charged nucleus. The outermost electrons (valence electrons) can be attracted to the nucleus of other atoms. This attraction is what causes a chemical bond. Types of Chemical Bonds There are three types of chemical bonds we will discuss: ionic bonds, covalent bonds, and hydrogen bonds. Covalent Bonds Covalent bonds happen when atoms share electrons. For example: Chlorine needs one electron to have a full outer shell so it can share 2 electrons with another Chlorine atom and become stable. Ionic Bonds Ionic bonds happen when electrons are transferred from one atom to another, causing the atom to become either positively charged or negatively charged. Na + Cl = Na Cl Table Salt Polarity and Hydrogen Bonds Different types of chemical bonds share electrons to different degrees. An ionic bond gains or loses electrons. A covalent bond shares electrons. A molecule formed when electrons are not shared equally. This results in the formation of a polar molecule hydrogen bond All compounds can be classified in 2 broad categories: Organic compounds- Contain carbon and hydrogen atoms Inorganic compounds- Can have one or the other, but do not contain both carbon and hydrogen atoms Macromolecules are built from small organic compounds the same way a railroad train is built, by linking a lot of smaller units together into long chains. Monomers and Polymers Large carbon compounds are built up from smaller simpler molecules called monomers (mono = one ) Monomers can bind to one another to form complex molecules known as polymers (poly = many) A polymer consists of repeated, linked units, which can also bind forming large polymers called Macromolecules. (macro = large ) Dehydration Synthesis Monomers link to form polymers through a chemical reaction called condensation reaction or dehydration synthesis. During the formation of polymers, Water (H 2 O), is released or is by-product of the reaction. Hydrolysis or Decomposition The breakdown of some complex molecules, such as polymers, occurs through a process known as hydrolysis. (decomposition) Hydrolysis is the reverse of a condensation reaction. The addition of water, to some polymers can break the bonds that hold them together 4 Main Macromolecules There are four main types of macromolecules found in living organisms: Carbohydrates Lipids Proteins Nucleic Acids Carbohydrates Composed of carbon, hydrogen, and oxygen atoms in the proportion of 1 : 2 : 1 General formula: (CH 2 O) n where n is the number of carbon atoms. Example: The sugar glucose is a small carbohydrate; its n equals 6. Therefore its chemical formula is C 6 H 12 O 6. The building blocks (or monomers) of carbohydrates are monosaccharides. Lipids Lipids (include fats, oils, waxes, etc.) Class of macromolecules that do not dissolve in water Lipids usually serve one of three functions: Energy storage structural support in cell membranes (phospholipids) serve as reactants ( starting materials) for metabolic reactions Fatty acids are the building blocks (or monomers) that make up most lipids. Fatty acids are classified as either saturated or unsaturated. Proteins Proteins are organic compounds composed mainly of carbon, hydrogen, and nitrogen atoms. Proteins are the construction materials for body parts such as hair, skin, nails, and blood. Proteins Amino acids are the building blocks (or monomers) that make up most proteins There are 20 different kinds of amino acids that humans use. One important group of proteins - enzymes - help control chemical reactions by acting as catalysts. Catalysts speed up reactions by lowering activation energy. Nucleic Acids Nucleic Acids are complex organic molecules that store genetic information in the cell. Nucleotides are the building blocks (or monomers) that make up most nucleic acids. Nucleotides consist of a sugar (pentose) + base (nitrogenous) + phosphate. Anatomy and Physiology Honors Chapter 3 - Cells Chapter 3 Learning Goals Students will be able to: Explain how cells differ from one another based on their primary function. (3.1) Describe the structure of a eukaryotic cell and the main function of the organelles. (3.2) Explain how substances move through cell membranes. (3.3) Describe the cell cycle and how cancer develops from malfunctions within the cycle. (3.4) How Cells Differ The human body is made of over 75 trillion cells! Cells in different tissues vary in size, shape, and function. 3 Basic Parts of the Cell Cell Membrane, Nucleus, Cytoplasm Cell Membrane Cytoplasm Nucleus Cell Boundaries Cell membrane thin, flexible, selectively permeable membrane that surrounds the cell and protects the inside of a cell from the environment outside. Controls what enters and leaves the cell. Made of phospholipids bilayer, proteins, and some carbohydrates. Two layers! Cell Membrane Phospholipids have two ends, one of which is hydrophilic, or attracted to water, and one of which is hydrophobic, or repelled by water. Cell Membrane Smaller molecules, like oxygen and carbon dioxide, can pass through this membrane easily on their own because they are soluble in lipids, but larger ones like amino acids, sugars, proteins, etc. cannot. Cell Membrane Proteins in the cell membrane act as receptors and form channels for the passage of ions and molecules. (See Genetics connection pg. 53) Patterns of surface carbohydrates associated with the membrane proteins enable certain cells to recognize one another. (Genetics connection pg. 53) Cytoplasm Cytoplasm contains membranes, organelles, and the rods and tubules of the cytoskeleton, suspended in cytosol. Cell activities occur mainly in the cytoplasm, where nutrients are received, processes, and used. Organelles in the Cytoplasm Endoplasmic reticulum Function: Helps to create and then transport lipids and proteins to the Golgi apparatus; breaks down toxic material. Rough ER has ribosomes Smooth ER no ribosomes Organelles in the Cytoplasm Rough ER Smooth ER Ribosomes Ribosomes Function: Synthesize (Create) Proteins! Found in a cells cytoplasm or attached to the endoplasmic reticulum (E.R) Ribosome Golgi Apparatus Golgi Apparatus (Golgi bodies)- refines, packages, and delivers proteins (glycoproteins) synthesized on ribosomes into ball-like structures called vesicles Golgi apparatus and Secretion Golgi are composed of stack of six membranous stacks. As the proteins travel through the Golgi apparatus, sugars are added or removed. The vesicles that come out may bind with the cell membrane to transport nutrients out of the cell as a secretion. Mitochondria Mitochondria converts chemical energy stored in food into energy(ATP) for the cell to function. Powerhouse of the Cell! Converts glucose and oxygen into ATP, Carbon Dioxide (CO2) and Water (Cellular Respiration) ATP- the fuel for cellular processes such as growth, cell division, and material transportNotes Lysosomes Lysosomes small organelles filled with enzymes that help break down nutrient molecules or foreign particles and recycle cellular components. Notes Perioxysomes Perioxysomes house enzymes that catalyze (speed up) a variety of biochemical reactions. For example: Synthesis of bile acids, hydrogen peroxide degradation, lipid breakdown, and detoxification of alcohol. Notes Microfilaments and Microtubules Microfilaments and microtubules aid cellular movements and support and stabilize the cytoplasm and organelles. Together these two things form the cytoskeleton the framework inside a cell that helps cell to maintain shape, move, and move organelles.. Notes Centrosome The centrosome contains centrioles that aid in distributing chromosomes during cell division. Notes Cell Appendages Cell appendages are often used for movement. Flagella- long, tail- like appendage that whip back and forth and move a cell. Cilia- short hair like structures that can move a cell or move molecules away from a cell. Notes The Nucleus Nucleus large membrane-enclosed structure that contains the cells genetic information and directs cell activities Nuclear Envelope membrane that surrounds the nucleus that consists of an inner and outer membrane. Nuclear Envelope Notes The Nucleolus small, dense body composed largely of RNA and protein. Ribosomes form in the nucleolus. Chromatin loosely coiled fibers of DNA and protein called chromosomes. The Nucleus Nucleolus Chromatin Notes Chapter 3 Match the organelle or cell part with its special function A. Uses enzymes to break down wastes B. Hair like projections that help cells move C. Made by the Golgi apparatus to be sent out of cell D. Makes RNA E. Contains enzymes that speed up chemical reactions F. Part of the cytoskeleton G. Create and transport lipids and proteins to the Golgi apparatus H. Makes ATP through cellular respiration I. Help distribute chromosomes in cell division J. Create proteins K. Packages proteins and lipids into vesicles 1. ______________Nucleolus 2. ______________Endoplasmic reticulum 3. ______________Golgi apparatus 4. ______________Lysosome 5. ______________Ribosome 6. ______________Mitochondria 7. ______________Peroxisomes 8. ______________Centrosomes 9. ______________ Microtubules 10. ______________ Cilia 11. ______________ Vesicles Chapter 3 Match the organelle or cell part with its special function A. Uses enzymes to break down wastes B. Hair like projections that help cells move C. Made by the Golgi apparatus to be sent out of cell D. Makes RNA E. Contains enzymes that speed up chemical reactions F. Part of the cytoskeleton G. Create and transport lipids and proteins to the Golgi apparatus H. Makes ATP through cellular respiration I. Help distribute chromosomes in cell division J. Create proteins K. Packages proteins and lipids into vesicles 1. _____D_____ Nucleolus 2. _____G_____Endoplasmic reticulum 3. _____K_____Golgi apparatus 4. _____A_____Lysosome 5. _____J_____Ribosome 6. _____H____Mitochondria 7. _____E_____Peroxisomes 8. _____I_____Centrosomes 9. _____F____ Microtubules 10. _____B____ Cilia 11. _____C____ Vesicles 3.3 Movements Through Cell Membranes Review of Cell Membrane The exchange of materials between a cell and its environment takes place at the cell membrane. A cell membrane is semipermeable- it allows only certain substance to enter or leave a cell 2 Types of Transport across a Cell Membrane PASSIVE MECHANISMS ACTIVE MECHANISMS Movement of substances through cell membrane with no energy from cell required. Types: Diffusion, Facilitated Diffusion, Osmosis, Filtration Movement of substances through cell membrane with energy from cell required. Types: Active Transport, Endocytosis, Exocytosis, Types of Passive Transport Diffusion movement of particles from an area of high to low concentration. Diffusion continues until the concentration of a substance is the same on both sides of a membrane. (equilibrium)/animation__how_diffusion_works.html Facilitated Diffusion: when substances use the help of special protein carrier molecules to move into or out of a cell. Types of Passive Transport/animation__how_facilitated_diffusion_works.html Osmosis: when water molecules diffuse from a region of higher water concentration to a region of lower water concentration. Types of Passive Transport/animation__how_osmosis_works.html Filtration: when molecules are forced through membranes using pressure. Used to separate solids from water. Types of Passive Transport **We will go into more detail on this when we discuss the Cardiovascular and Urinary systems. Types of Active Transport Active Transport- The movement of materials across a cell membrane from an area of low concentration to an area of high concentration with the use of energy a.Exocytosis a cells vesicles releases their contents outside of the cell. b.Endocytosis the cell surrounds a large particle and brings it into the cell Types of Endocytosis Pinocytosis: cell drinking Phagocytosis: cell eating Receptor Mediated Endocytosis: Protein molecules extend through a portion of the cell membrane to the outer surface where they form receptors to bind with specific molecules (ligands). Transcytosis: Combines both endocytosis and exocytosis to transport across the cell membrane. We will again go into a lot more detail when we discuss the Cardiovascular, Urinary and Immune system. Practice with Transport Match the type of transport with the correct definition A.A cells vesicle releases their contents outside the cell. B.Pressure is used to force substances across the cell membrane C.the cell surrounds a particle and brings it into the cell D.carrier proteins are used to transport substances E.movement of substances from an area of high concentration to low concentration F.movement of water across a cell membrane 1. ______________ Diffusion 2. ______________ Facilitated diffusion 3. ______________ Filtration 4. ______________ Osmosis 5. ______________ Exocytosis 6. ______________ Endocytosis Practice with Transport Match the type of transport with the correct definition A.A cells vesicle releases their contents outside the cell. B.Pressure is used to force substances across the cell membrane C.the cell surrounds a particle and brings it into the cell D.carrier proteins are used to transport substances E.movement of substances from an area of high concentration to low concentration F.movement of water across a cell membrane 1. _____E_________ Diffusion 2. _____D_________ Facilitated diffusion 3. _____B_________ Filtration 4. _____F_________ Osmosis 5. _____C_________ Exocytosis 6. ______A________ Endocytosis 3.4 The Cell Cycle & Cell Differentiation Most cells in an organism go through a cycle of growth, development, and division called the cell cycle. The cell cycle allows organisms : to grow and develop replace old or damaged cells produce new cells. The Cell Cycle There are two main phases of the cell cycle: 1.Interphase 2.Mitotic phase Phases Of The Cell Cycle Interphase 2. Replication of DNA. (S stage) The cell replicates its strands of chromatin Sister chromatids are the two identical strands of DNA that make up the duplicated chromosome. They are held together by a structure called a centromere. When DNA is copied or replicated during this phase mutations can occur Cell Differentiation Cells come from preexisting cells by the process of mitosis. These trillions of cells that are created this way change into at least 260 specialized types by the process of differentiation. Stem cells vs. Progenitor cells Cells that retain the ability to divide repeatedly without specializing are called stem cells. Progenitor cells are specialized cells that come from stem cells. Cell Death A cell that does not divide or specialize may die. Apoptosis is a form of cell death that is a normal part of development. Cancer and the Cell Cycle Cancer is a disease characterized by abnormal cell growth.