Anatomy & Physiology, 1e Chapter 4 PDF

Anatomy and Physiology, 1e Chapter 4: The Cellular Level of Organization Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023...

Anatomy and Physiology, 1e Chapter 4: The Cellular Level of Organization Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 1  Icebreaker Have you ever wondered, “What is the smallest living thing?”. What is a cell and how is it organized? How does cellular organization contribute to cellular function? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 2 The Cell Membrane and Its Involvement in Transport Section 4.1 Learning Objectives 4.1.1–4.1.8 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 3  Structure of the Cell Membrane Separates the cell’s internal environment from the external environment Regulates the movement of materials into and out of the cell Composed of phospholipids, cholesterol, carbohydrates, and proteins Flexible, dynamic structure Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 4  Think, Pair, Share Activity 1 Identify reasons for keeping a cell’s internal environment (i.e., intracellular fluid) separated from the external environment (i.e., extracellular fluid). Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 5 Think, Pair, Share Activity 1 Answer Identify reasons for keeping a cell’s internal environment (i.e., intracellular fluid) separated from the external environment (i.e., extracellular fluid). The separation of the internal and external environments allow the cell to organize the activities required to maintain life and regulate the movement of molecules into and out of the cell. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 6  Phospholipids (Figure 4.2) Major structural component of the cell membrane Amphipathic molecules Hydrophilic (“water- loving”) phosphate heads Hydrophobic (“water- fearing”) fatty acid tails Arranged into a bilayer (two layers) Phosphate heads face internal and external environments Fatty acid tails create hydrophobic region Elizabeth Co, within Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 7 bilayer  Phospholipid Structure (Figure 4.1) Amphipathic molecule Hydrophilic head contains a phosphate group and is attracted to water Hydrophobic tails are nonpolar and repelled by water Organized into a bilayer to form biological membranes Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 8 Cell Membrane Structure (Figure 4.3) Selectively permeable barrier Composed mainly of phospholipid bilayer Intracellular fluid (ICF) inside of cell Also called cytosol Extracellular fluid (ECF) outside of cell Proteins also associate with cell membrane Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 9  Membrane Proteins (1 of 2) Proteins associated with cell membrane add functionality Serve as channel proteins, receptors, enzymes, and in cell–cell recognition Transmembrane, or integral, proteins Span the entire width of the cell membrane Peripheral proteins Do not span the membrane Attached to the interior or exterior of the membrane Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 10  Membrane Proteins (2 of 2) Glycoproteins = proteins that have carbohydrate molecules attached Aid in cell recognition Glycocalyx is formed by numerous glycoproteins Only present in some cells Can serve as receptors for hormones and a means to bind to other cells Helps break down nutrients Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 11  Transport Across the Cell Membrane (Figure 4.4) Cell membrane is selectively permeable Allows only small, nonpolar molecules to pass freely Molecules able to pass will flow across the membrane if there is a gradient Flow occurs from high to low concentration unless prevented by resistance Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 12  Passive Transport Movement does not require energy Requires a concentration gradient Two forms: 1. Simple diffusion: molecules move from higher to lower concentration without the use of membrane proteins 2. Facilitated diffusion: molecules move from higher to lower concentration through membrane proteins Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 13  Examples of Diffusion (Figure 4.6) Everyday examples of diffusion: Perfume diffuses across a room Sugar molecules dissolve in coffee Dye diffuses through water Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 14  Simple Diffusion Across a Cell Membrane (Figure 4.5) Small, nonpolar molecules can pass through the cell membrane Diffusion continues until a net equilibrium is reached Diffusion occurs faster at higher temperatures Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 15  Facilitated Diffusion Across a Cell Membrane (Figure 4.7) Requires assistance of transmembrane proteins Molecules still move down concentration gradient Used for molecules that cannot diffuse through the cell membrane Such as polar or ionic molecules Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16  Osmosis The movement of water across the cell membrane Water moves from areas of lower solute to higher solute concentration Hypotonic solution—less solute outside of cell Water enters cells when they are in hypotonic solutions Hypertonic solution—more solute outside of cell Water will leave cells in hypertonic solutions Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 17 Water Molecule Concentration (Figure 4.8) Osmosis depends on the ratio of solute molecules to water Water will move from areas of lower solute concentration to areas of higher solute concentration Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 18  Osmosis Across a Membrane (Figure 4.9) Water moves across a semipermeable membrane toward the area with a higher solute concentration (i.e., lower water concentration) Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 19  Solution Comparisons (Figure 4.10) Isosmotic solutions have equal concentrations of solute A hyperosmotic solution contains more solute by comparison A hypoosmotic solution contains less solute by comparison Tonicity describes the osmolarity of the ECF comparedElizabeth to copied scanned, the or cytosol of to a publicly accessible website, in whole or in part. Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be duplicated, or posted 20  Effect of Tonicity on Cells (Figure 4.11) An isotonic solution has equal water concentration across the cell membrane Cell functions normally A hypertonic solution contains more solutes in the environment Cell shrinks A hypotonic solution contains fewer solutes in the environment Cell swells and may orburst Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, posted to a publicly accessible website, in whole or in part. 21  Active Transport Requires energy to move molecules against their concentration gradient From areas of lower concentration to areas of higher concentration Primary active transport—uses ATP as energy source Secondary active transport—uses electrochemical gradient as energy source Symporters—move two molecules in the same direction Antiporters—move two molecules in opposite directions Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 22  Sodium-Potassium Pump (Figure 4.12) Common example of primary active transport Uses ATP to move 3 sodium ions out of the cell and 2 potassium ions into the cell, against their concentration gradients Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 23  Polling Activity 1 The larger a cell is, the greater the demand it will have for nutrients. With this in mind, would you expect a larger cell or a smaller cell to have a greater number of membrane proteins? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 24  Polling Activity 1 Answer The larger a cell is, the greater the demand it will have for nutrients. With this in mind, would you expect a larger cell or a smaller cell to have a greater number of membrane proteins? The number of membrane proteins should be increased due to a greater need for nutrients. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 25  Endocytosis A form of active transport Uses the cell membrane to engulf materials Cell membrane pinches off to form a vesicle and material enters cell Three forms of endocytosis: 1. Phagocytosis 2. Pinocytosis 3. Receptor-mediated endocytosis Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 26  Forms of Endocytosis (Figure 4.13) 1. Phagocytosis: extends the cell membrane to bring in large molecules 2. Pinocytosis: membrane invagination brings in small amounts of fluid containing dissolved substances 3. Receptor-mediated endocytosis: more selective Ligand binds to membrane receptor foror posted to a publicly accessible website, in whole or in part. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, 27  Exocytosis (Figure 4.14) The process of a cell exporting material, or cell secretion Vesicle fuses with cell membrane Contents are released from cell Hormones and digestive enzymes secreted this way Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 28  Matching Activity 1 Match the form 1. Endocytosis A. Uses ATP as energy of membrane source 2. Simple diffusion transport to its 3. Exocytosis B. Molecules move from description. high to low 4. Facilitated concentration with diffusion the use of membrane 5. Primary active proteins transport C. Uses 6. Secondary active electrochemical transport gradient as energy source Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 29  Matching Activity 1 Answer Match the form of membrane transport to its description. 1. Endocytosis—A 2. Simple diffusion—none 3. Exocytosis—A 4. Facilitated diffusion—B 5. Primary active transport—A 6. Secondary active transport—C Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 30  The Cytoplasm and Cellular Organelles Section 4.2 Learning Objectives 4.2.1–4.2.5 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 31  Internal Components of Cells Major components of the inside of cells include: Cytoplasm—the fluid-like interior of cells including its compartments and organelles Organelles—membrane-bound structures that perform specific functions Cytosol – the gel-like substance within the cytoplasm Contains organelles and molecules needed by cell Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 32 A Model Human Cell (Figure 4.15) Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 33  Endoplasmic Reticulum (ER) (Figure 4.16) Endoplasmic Reticulum (ER)— series of channels continuous with the nuclear membrane; provides passages for synthesis, transportation and storage Rough ER—contains ribosomes Involved in protein synthesis Smooth ER—lacks ribosomes Involved in lipid Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be synthesis scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 34  Golgi Apparatus (Figure 4.17) The Golgi Apparatus—series of flattened sacs Sorts and modifies products from rough ER for transport Cis-face receives products for modification Trans-face releases products after modification Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 35  Membranous Organelles for Detoxification and Energy Production Lysosomes—membrane-bound vesicles that contain digestive enzymes Used to break down wastes within cell Peroxisomes—contain enzymes used to produce hydrogen peroxide Used for detoxification and lipid metabolism Mitochondria—site of aerobic respiration Responsible for nutrient breakdown and ATP production Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 36  Mitochondria (Figure 4.18) “Energy transformer” of the cell Lined by 2 bilayers Outer membrane Inner membrane is folded into cristae More numerous in muscle and nerves Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 37  The Cytoskeleton (Figure 4.19) Helps maintain the structure of the cell Organizes cytoplasm Aids in separation during cellular division Composed of protein filaments that provide support 1. Microtubules—made of tubulin 2. Intermediate filaments—made of keratin 3. Microfilaments—made of1stactin Elizabeth Co, Anatomy and Physiology, Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 38  Dynamic Nature of the Cytoskeleton (Figure 4.20) Cytoskeleton is not fixed Cytoskeletal components form and can move depending on needs of the cell Helps move molecules and structures around interior of cell Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 39 Cell Surface Specializations (Figure 4.21) Microvilli help increase surface area of the cell Cilia aid in movement of the cell or movement across the surface of the cell Flagella are long appendages used for movement Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 40  Breakout Group Activity 1 Sketch a diagram of the cell and make sure to label all major organelles of the cell. Include the function of the organelle next to its name in your diagram. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 41  Breakout Group Activity 1 Answer Sketch a diagram of the Organelle functions should cell and make sure to include: label all major organelles Rough ER—protein synthesis of the cell. Include the function of the organelle Smooth ER—lipid synthesis next to its name in your Lysosomes—breakdown wastes diagram. within cell This answer should Peroxisomes—detoxification include a sketch of the Mitochondria—ATP production cell similar to figure Golgi apparatus—sorts and 4.15 of the text. modifies products from rough ER Nucleus—houses the DNA of the cell Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 42  Knowledge Check Activity 1 Loss of which of the following would lead to a lack of energy within the cell? A. Rough ER B. Smooth ER C. Golgi Apparatus D. Mitochondria Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 43  Knowledge Check Activity 1 Answer Loss of which of the following would lead to a lack of energy within the cell? D. Mitochondria Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 44  The Nucleus and DNA Section 4.3 Learning Objectives 4.3.1–4.3.2 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 45  Organization of the Nucleus (Figure 4.22) Nucleus houses the DNA of the cell Most human cells have a single nucleus. Nucleus is surrounded by a nuclear envelope. Nuclear pores allow small molecules to move into and out of nucleus. Nucleolus within nucleus is involved in ribosome production. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 46  Nucleic Acids Found in Human Cells (Table 4.1) Nucleic acids found in a healthy human cell include DNA, mRNA, tRNA, and rRNA DNA is storage form of genome mRNA is used in translation of proteins tRNA moves amino acids during translation rRNA is structural component of ribosomes Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 47  Nucleotide Bases of DNA (Figure 4.23) DNA has a double-helix structure formed by hydrogen bonds between nucleotide bases. The four nucleotide bases of DNA are: 1. Adenine (A) 2. Thymine (T) 3. Cytosine (C) and 4. Guanine (G) Adenine forms a double bond with thymine. Cytosine Elizabeth formsCo, aAnatomy triple bond1st with and Physiology, Edition. © 2023 Cengage. All Rights Reserved. May not be guanine. scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 48  Organization of DNA (Figure 4.24) DNA strands are wrapped around histone proteins for organization Chromatin is the loose form of DNA Chromatin is packaged during replication to form chromosomes Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 49  Breakout Group Activity 2 Practice forming complementary DNA strands using a series of DNA nucleotide bases given to you by a partner. You should also give your partner a series of nucleotide bases that you make up so that they can practice as well. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 50  Breakout Group Activity 2 Answer Practice forming complementary DNA strands using a series of DNA nucleotide bases given to you by a partner. You should also give your partner a series of nucleotide bases that you make up so that they can practice as well. For this activity students may practice creating using any sequence of the DNA nucleotide bases they create. Their partner should create the complementary strand using the base pairing of adenine to thymine and guanine to cytosine. For example, if the one partner creates the strand AGGTCCA, then the complementary strand should be TCCAGGT. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 51  Think, Pair, Share Activity 2 Identify potential benefits for housing DNA within the nucleus. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 52 Think, Pair, Share Activity 2 Answer Identify potential benefits for housing DNA within the nucleus. Benefits of containing DNA within the nucleus include additional protection for genetic material and control of reproduction. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 53  Protein Synthesis Section 4.4 Learning Objectives 4.4.1–4.4.3 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 54  Protein Synthesis within the Cell DNA contains the genetic code of the cell Genetic code provides the instructions to produce cellular proteins Protein production begins in the nucleus and ends in the cytoplasm Genes are transcribed into messenger RNA (mRNA) Gene is a segment of DNA that codes for a protein mRNA is then translated into proteins Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 55  Making Proteins from DNA (Figure 4.25) Proteome is a cell’s full complement of proteins Genes contain information necessary to make proteins DNA is transcribed to mRNA mRNA is then translated to proteins Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 56  Knowledge Check Activity 2 Which form of RNA is used to deliver amino acids to a ribosome? A. mRNA B. tRNA C. rRNA D. dRNA Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 57  Knowledge Check Activity 2 Answer Which form of RNA is used to deliver amino acids to a ribosome? B. tRNA Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 58  Transcription (Figure 4.26) Process of creating a strand of messenger RNA (mRNA) from a DNA template Occurs within the nucleus of the cell Complementary mRNA is made from a gene of one strand of DNA mRNA will leave the nucleus for translation Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 59  The Process of Transcription Three stages of transcription: 1. Initiation – DNA strands are separated and RNA polymerase begins to synthesize complementary RNA molecule 2. Elongation – RNA polymerase continues to add nucleotides to growing strand 3. Termination – RNA polymerase reaches end of gene and mRNA transcript is released Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 60  Creating a Mature mRNA Transcript (Figure 4.27) Before leaving nucleus, mRNA transcript is modified DNA contains regions that do not code for amino acids Called introns Regions that code for amino acids are called exons Introns must be removed before mRNA leaves nucleus Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 61  Translation (1 of 2) Process of creating a protein from a mRNA template Occurs in the cytoplasm of the cell Carried out by ribosomes Ribosomal RNA (rRNA)—component of ribosomes Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 62  Translation (2 of 2) Each three nucleotide sequences of mRNA is a codon. Ribosomes read codons. Transfer RNA (tRNA) brings amino acids to ribosomes. tRNA contains anticodons that match specific mRNA codons. Amino acids are linked by peptide bonds to form proteins. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 63  The Process of Translation (Figure 4.28) Initiation – ribosome subunits attach to start codon of mRNA transcript Elongation – tRNA molecules are attracted to the ribosome and deliver the corresponding amino acids to the growing polypeptide Termination – translation continues until ribosome reaches a “stop” codon that ends theElizabeth process scanned, Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be copied or duplicated, or posted to a publicly accessible website, in whole or in part. 64  Think, Pair, Share Activity 3 Identify advantages of relying on codons for protein formation. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 65 Think, Pair, Share Activity 3 Answer Identify advantages of relying on codons for protein formation. This is an advantage to the organism because if there is a mistake during translation via a mutation, there is a higher chance that the altered codon will still code for the same amino acid. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 66  Cell Replication Section 4.5 Learning Objectives 4.5.1–4.5.5 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 67  The Cell Cycle (Figure 4.29) Three phases: Interphase, mitosis, and cytokinesis The cell spends most of its time in interphase Interphase is split into: 1. G1 phase—cell grows, makes proteins, and carries out cellular functions 2. S phase—cell replicates its DNA 3. G2 phase—cell prepares for mitosis Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 68  Cellular Replication Cellular replication occurs as the parent cell divides to form two daughter cells Mitosis occurs in somatic cells Daughter cells are identical to parent cell Cells contain 46 chromosomes or the diploid number Meiosis occurs for reproductive cells Resulting cells have half the amount of genetic material from one parent and half from the other parent Cells contain 23 chromosomes or the haploid number Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 69  DNA Replication (1 of 2) (Figure 4.30) The process of copying DNA Occurs during the S phase of the cell cycle Three phases: 1. Initiation: the DNA strands are separated by helicase 2. Elongation: the DNA polymerase synthesizes a new strand 3. Termination: the DNA replication stops Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 70  DNA Replication (2 of 2) (Figure 4.31) Chromatin—the linear form of DNA Condensed into chromosomes during replication Replicated copy is called a sister chromatid Sister chromatids are attached at a centromere Chromatids separate during mitosis Makes sure each daughter cell has a complete copy of DNA Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 71  Phases of Nucleic Acid Processes (Table 4.2) Transcription, translation, and replication are each divided into 3 steps: Initiation Elongation Termination Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 72  Mitosis (1 of 2) Cell replication consists of four major phases, followed by cytokinesis: Prophase: Chromatin condenses into chromosomes and the centrioles migrate to opposite sides of the cell. Metaphase: Chromatids align in the middle of the cell. Anaphase: Chromatids separate and move toward the opposite sides of the cell. Telophase: Nucleoli and nuclear membranes start to form, and chromosomes return to chromatin form Cytokinesis: Cleavage furrow divides cell into two distinct scanned, cells. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be copied or duplicated, or posted to a publicly accessible website, in whole or in part. 73 Mitosis (2 of 2) (Figure 4.32) Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 74  Factors That Regulate Cell Division (Figure 4.34) Cellular division is regulated by: Growth factors like hormones Contact inhibition If cell is surrounded, it won’t divide Increasing efficiency Larger cells are less efficient Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 75  Breakout Group Activity 3 Divide the phases of mitosis among your group members. Have each member do a sketch of their phase and then, as a group, present your sketches and have each member explain their phase of mitosis. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 76  Breakout Group Activity 3 Answer Divide the phases of mitosis among your group members. Have each member do a sketch of their phase and then, as a group, present your sketches and have each member explain their phase of mitosis. The sketches should resemble the phases of mitosis presented in figure 4.32. The descriptions of the phases are seen in the image below: Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 77  Think, Pair, Share Activity 4 What role does meiosis play, if any, in the process of evolution? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 78 Think, Pair, Share Activity 4 Answer What role does meiosis play, if any, in the process of evolution? Meiosis reduces a cell's chromosome number by half, while also creating new genetic combinations within daughter cells. This genetic reshuffling creates variability leading to evolution. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 79 Cellular Differentiation Section 4.6 Learning Objectives 4.6.1–4.6.2 Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 80  Cellular Differentiation (Figure 4.35) The cells of the human body develop from a single cell. Cells become specialized for a specific function through differentiation. Stem cells are undifferentiated yet can become required cell types. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 81  Stem Cells Stem cells can differentiate into specific cell types. Specific genes are turned on during differentiation. Transcription factors turn on necessary genes. Turning specific genes on in stem cells produces certain proteins needed for the differentiated cell’s function. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 82  Think, Pair, Share Activity 5 What advantages does having stem cells offer to an adult human body? Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 83 Think, Pair, Share Activity 5 Answer What advantages does having stem cells offer to an adult human body? Stem cells can offer the ability to replace differentiated cells should they become damaged or die. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 84  Summary After finishing this chapter, you should be able to: Describe the structure of the cell membrane. Describe the structures within the cytoplasm of a cell. Describe the functions of cellular organelles. Discuss the process of protein synthesis. Elizabeth Co, Anatomy and Physiology, 1st Edition. © 2023 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 85