Lect 3 Notes Cells Out of Control PDF

2023-09-20 CELLS OUT OF CONTROL Lecture Week 3: Chapters 3,4, and 6.1 1 BioA11 Introduction to the Biology of Humans • COURSE OBJECTIVES: INTRO Instructor: Karen Williams, PhD Office: SY210A Office hours: virtual::Thursday 11301200h ; in-person: Friday 1600h-1630h, or by appointment • • • ___...

2023-09-20 CELLS OUT OF CONTROL Lecture Week 3: Chapters 3,4, and 6.1 1 BioA11 Introduction to the Biology of Humans • COURSE OBJECTIVES: INTRO Instructor: Karen Williams, PhD Office: SY210A Office hours: virtual::Thursday 11301200h ; in-person: Friday 1600h-1630h, or by appointment • • • _______________ _______________ _______________ • See syllabus • Aim for this week: • 3. To understand the importance of cells, and to prepare to have effective group discussions Email: [email protected] 2 1 2023-09-20 BioA11 Introduction to the Biology of Humans Lecture week 3: Cells out of control • What are the components of cells? • Cell structure • Energy for cells to work • Cancer: cell growth out of control 3 3.2 Cell Structure (1 of 13) • Cytoplasm: includes cytosol and organelles (a) Animal cell Ribosomes Centriole Nucleolus Nucleus Cytoskeleton ‒ Organelles: perform specific jobs required by the cell and work with other organelles ‒ Cytosol: watery matrix with salts and enzymes; houses the organelles Nuclear envelope Plasma membrane Lysosome Mitochondrion Rough endoplasmic reticulum Golgi apparatus Cytosol Smooth endoplasmic reticulum 4 2 2023-09-20 3.2 Cell Structure (2 of 13) • Plasma membrane (a) Sugar chains ‒ Encloses all cells ‒ Defines outer boundary Phospholipid bilayer of cells ‒ Isolates cell contents from environment Protein 5 3.2 Cell Structure (3 of 13) Plasma membrane • Plasma membrane ‒ Determines materials to be allowed in or out ▪ Semipermeable: some molecules can cross and some are prevented from crossing Macromolecule Uncharged molecules such as CO2 and O2 Charged molecules and ions 6 3 2023-09-20 3.2 Cell Structure (4 of 13) • Membrane structure • Fluid properties (b) • Allow lipids and proteins to slide laterally Head ‒ Phospholipid bilayer Phospholipid ▪ Hydrophilic heads Tails maximize exposure to water ▪ Hydrophobic tails interact with each other; exclude water 7 3.2 Cell Structure (5 of 13) • Membrane structure ‒ Embedded proteins ▪ Carry out enzymatic functions ▪ Serve as receptors for outside substances ▪ Help transport substances throughout cell (a) Sugar chains Phospholipid bilayer Protein 8 4 2023-09-20 3.2 Cell Structure (6 of 13) • Cell structure (b) Plant cell (a) Animal cell Ribosomes Rough endoplasmic reticulum Centriole Nucleolus Nucleus Cytoskeleton Nucleus Nuclear envelope Ribosomes Cytoskeleton Nuclear envelope Plasma membrane Nucleolus Smooth endoplasmic reticulum Adjoining plant cell walls Cell wall Central vacuole Lysosome Mitochondrion Mitochondrion Golgi apparatus Rough endoplasmic reticulum Lysosome Golgi apparatus Cytosol Smooth endoplasmic reticulum Cytosol Plasma Chloroplast membrane 9 BioA11 Introduction to the Biology of Humans Describe these organisms’ cells ___ Dan Aamlid, Bugwood.org 1 Howard F. Schwartz, Colorado State University, Bugwood.org 2 Herbert A. 'Joe' Pase III, None, Bugwood.org 3 10 5 2023-09-20 3.2 Cell Structure (7 of 13) • Subcellular structures ‒ Cell wall: protection outside the plasma membrane for plants, fungi, and bacteria; provides structural support ‒ Nucleus: holds chromatin (DNA and proteins) in eukaryotic cells; surrounded by nuclear envelope ‒ Nucleolus: synthesizes ribosomes; inside nucleus Nuclear pore Nuclear envelope Nucleolus DNA Cellulose fibrils Plant 11 3.2 Cell Structure (8 of 13) • Subcellular structures ‒ Mitochondrion: produces energy for the cell through cellular respiration ‒ Chloroplast: produces sugars through photosynthesis in plant cells ‒ Lysosome: contains digestive enzymes to recycle molecules Outer membrane Intermembrane space Inner membrane Matrix Outer membrane Inner membrane Stroma Thylakoids Membrane Digestive enzymes and digested material 12 6 2023-09-20 3.2 Cell Structure (9 of 13) • Subcellular structures Ribosomes ‒ Ribosomes: assemble proteins; free floating or attached to ER ‒ Rough endoplasmic reticulum (rough ER): membrane network with ribosomes attached for protein synthesis ‒ Smooth endoplasmic reticulum (smooth ER): involved in lipid synthesis or detoxification; lacks ribosomes ‒ Golgi apparatus: modifies, sorts, Nuclear envelope Rough endoplasmic reticulum Ribosomes Vesicle Smooth endoplasmic reticulum Vesicle from ER arriving at Golgi apparatus Vesicle departing Golgi apparatus and packages proteins 13 3.2 Cell Structure (10 of 13) • Subcellular structures ‒ Centrioles: move chromosomes during animal cell division ‒ Cytoskeletal elements: form cytoskeleton for maintaining shape and structural support ‒ Central vacuole: stores water, sugars, and pigments in plant cells Microfilaments Intermediate filaments Microtubules Vacuole 14 7 2023-09-20 3.3 Transport Across Membranes (1 of 9) Plasma membrane • Membrane transport ‒ Substances must travel through the plasma membrane Macromolecule ▪ Food Uncharged molecules such as CO2 and O2 ▪ Supplements ▪ Substances able to cross reach equilibrium – equal concentrations on both sides of the membrane Charged molecules and ions 15 3.3 Transport Across Membranes (2 of 9) Plasma membrane • Membrane transport ‒ Plasma membrane: phospholipid bilayer is differentially permeable ▪ Hydrophobic substances pass more easily through the hydrophobic interior Macromolecule Uncharged molecules such as CO2 and O2 Charged molecules and ions 16 8 2023-09-20 3.3 Transport Across Membranes (3 of 9) • Passive transport: movement of molecules without energy ‒ Diffusion ‒ Facilitated diffusion ‒ Osmosis (a) Osmosis in an animal cell High concentration CO2 O2 O2 CO2 CO2 High concentration O2 O2 O2 O2 CO2 Glucose Amino acid Ca2+ Higher concentration of solute outside the cell Transport protein Shriveled cell CO2 CO2 Higher concentration of solute inside the cell Low CO2 concentration O2 Low concentration Burst cell 17 3.3 Transport Across Membranes (4 of 9) • Diffusion: passive transport from area of high concentration to low concentration ‒ Very small, hydrophobic molecules CO2 CO2 O2 O2 CO2 High concentration O2 O2 O2 O2 CO2 CO2 CO2 Low CO2 concentration O2 18 9 2023-09-20 3.3 Transport Across Membranes (5 of 9) • Facilitated diffusion: transport proteins help move hydrophilic and charged molecules across the membrane High concentration Glucose Amino acid Ca2+ Transport protein ‒ From high to low concentration ‒ Without using energy Low concentration 19 3.3 Transport Across Membranes (6 of 9) • Osmosis: diffusion of water across a membrane from high to low concentration (a) Osmosis in an animal cell Higher concentration of solute outside the cell Shriveled cell Higher concentration of solute inside the cell Burst cell 20 10 2023-09-20 3.3 Transport Across Membranes (7 of 9) • Active transport ‒ Uses proteins to move molecules from low to high concentration ‒ Powered by energy from ATP Active transport Low concentration High concentration 21 3.3 Transport Across Membranes (8 of 9) • Exocytosis: a membrane-bound vesicle fuses with the membrane and expels the large molecule outside the cell (a) Exocytosis 22 11 2023-09-20 3.3 Transport Across Membranes (9 of 9) • Endocytosis: a vesicle pinches the plasma membrane inward and brings a large molecule into the cell (b) Endocytosis 23 3.2 Cell Structure: • Cell structure (b) Plant cell (a) Animal cell Ribosomes Centriole Nucleolus Nucleus Cytoskeleton Nuclear envelope Plasma membrane Rough endoplasmic reticulum Nucleolus Nucleus Nuclear envelope Ribosomes Cytoskeleton Smooth endoplasmic reticulum Adjoining plant cell walls Cell wall Central vacuole Lysosome Mitochondrion Mitochondrion Golgi apparatus Rough endoplasmic reticulum Lysosome Golgi apparatus Cytosol Smooth endoplasmic reticulum Cytosol Plasma Chloroplast membrane 24 12 2023-09-20 BioA11 Introduction to the Biology of Humans Energy for the work of the cell • What are the components of cells? • Cell structure • Energy for cells to work • Cancer: cell growth out of control • Most energy comes from breaking down _____________ 25 3.1 Nutrients: Macronutrients (8 of 23) • Carbohydrates: main energy source • Possible structural composition: Fructose monomer • Single-unit simple sugars (monosaccharides) • Many sugar subunits (polysaccharides) • arranged in branching chains (complex carbohydrates) (a) Grape-flavored dietary supplement (b) Grapes 26 13 2023-09-20 4.1 Enzymes and Metabolism (1 of 7) Metabolism • All of the chemical reactions occurring in the body 27 4.1 Enzymes and Metabolism (2 of 7) Enzymes • Proteins that catalyze (speed up) chemical reactions • Named for the reaction catalyzed • End in suffix –ase • For example, sucrase breaks down sucrose Substrate: sucrose Glucose Fructose Bond is stressed Active site Enzyme: sucrase The shape of the substrate matches the shape of the enzyme's active site. Initial substrate binding to the active site changes the shape of the active site, inducing the substrate to fit even more snugly in the active site, stressing the bonds of the substrate. The shape change splits the substrate and releases the two subunits. The enzyme is able to perform the reaction again. 28 14 2023-09-20 4.1 Enzymes and Metabolism (3 of 7) Activation energy • Energy required to start a metabolic reaction • Amount required is decreased by enzymes (a) No enzyme present Reactants Products (b) Enzyme present Reactants Products 29 4.1 Enzymes and Metabolism (4 of 7) (a) No enzyme present Reactants Products (b) Enzyme present Reactants Products 30 15 2023-09-20 4.1 Enzymes and Metabolism (5 of 7) Induced fit model • Substrate: chemical being metabolized • Active site: enzyme region where substrate binds • Enzyme changes shape after substrate binds • stresses the substrate bonds Substrate: sucrose Glucose Fructose Bond is stressed Active site Enzyme: sucrase The shape of the substrate matches the shape of the enzyme’s active site. Initial substrate binding to the active site changes the shape of the active site, inducing the substrate to fit even more snugly in the active site, stressing the bonds of the substrate. The shape change splits the substrate and releases the two subunits. The enzyme is able to perform the reaction again. 31 4.1 Enzymes and Metabolism (6 of 6) Metabolic rate is influenced by many factors: • Genetics • Lower basal metabolic rates • Differences in fat storage and utilization 32 16 2023-09-20 4.2 Cellular Respiration (1 of 28) • Cellular respiration: series of metabolic reactions converting food energy into a usable form and releasing waste products Stored energy Toy dart Released energy Compressed spring 33 4.2 Cellular Respiration (3 of 28) Adenosine triphosphate (ATP) • Contains: • adenine • a sugar (ribose) • 3 phosphate groups Nitrogenous base (adenine) Sugar (ribose) 3 negatively charged phosphates 34 17 2023-09-20 4.2 Cellular Respiration (4 of 28) Phosphorylation • Phosphate group transferred from ATP to another molecule • Energy transferred • Adenosine diphosphate (ADP) produced ADP Enzyme Phosphorylated (energized) enzyme 35 4.2 Cellular Respiration (5 of 28) ATP and cellular work • Movement of cells • Active transport of substances across membranes • Making complex molecules (b) Transport work (a) Mechanical work (c) Chemical work Low concentration of solute Chlamydomonas Flagella Substrates Enzyme Product High concentration of solute 36 18 2023-09-20 4.2 Cellular Respiration (6 of 28) Regenerating ATP • Cellular respiration adds phosphate group to ADP • Makes ATP Energy from the breakdown of food ADP Phosphate High-energy currency 37 4.2 Cellular Respiration (7 of 28) Aerobic cellular respiration • Aerobic reactions – some steps require oxygen • Overall reaction: glucose + oxygen → water + carbon dioxide C6H12O6 + 6O2 → 6H2O + 6CO2 38 19 2023-09-20 4.2 Cellular Respiration (8 of 28) Breathing and cellular respiration Oxygen Carbon dioxide Breathing • Breathing: oxygen inhaled into lungs and delivered to cells; carbon dioxide exhaled Muscle cell Cellular respiration 39 4.2 Cellular Respiration (9 of 28) Breathing and cellular respiration • Breathing: oxygen inhaled into lungs and delivered to cells; carbon dioxide exhaled • Cellular respiration: requires oxygen from breathing; releases carbon dioxide for delivery to lungs for exhalation Oxygen Carbon dioxide Breathing Muscle cell Cellular respiration 40 20 2023-09-20 4.2 Cellular Respiration (10 of 28) Aerobic cellular respiration • Occurs mostly in the mitochondria • Series of complex reactions (a) Cross section of a mitochondrion (b) Mitochondrion Breakdown begins 41 4.2 Cellular Respiration (11 of 28) • Stages of cellular respiration • Occurs in 3 stages • Involves electrons • Removed from glucose in early stages • Used to make ATP in final stage • Transported by electron carriers • Nicotinamide adenine dinucleotide (NAD+) 42 21 2023-09-20 4.2 Cellular Respiration (12 of 28) Nicotinamide adenine dinucleotide (NAD+): taxicab for electrons Electron transport chain Citric acid cycle 2-carbon fragment 2 ATP produced by citric acid cycle and 26 from electron transport chain Pyruvic acid Glycolysis 2 43 4.2 Cellular Respiration (13 of 28) Nicotinamide adenine dinucleotide (NAD+): taxicab for electrons Electron transport chain • Empty taxicab (NAD+) • Picks up electrons and hydrogen ions (H+) • Becomes full taxicab (NADH) • Carries electrons to final destination 2-carbon fragment Pyruvic acid Glycolysis 2 Citric acid cycle 2 ATP produced by citric acid cycle and 26 from electron transport chain • Empty taxicab returns for more electrons. 44 22 2023-09-20 4.2 Cellular Respiration (14 of 28) Stages of cellular respiration • Stage 1: Glycolysis • Stage 2: Citric acid cycle • Stage 3: Electronic transport chain and ATP synthesis 3-carbon pyruvic acid Citric acid cycle 2-carbon molecule Matrix Citric acid cycle enzymes Mitochondrion 45 4.2 Cellular Respiration (19 of 28) • Electrons from glycolysis and citric acid cycle • Dropped off by NADH​ • Move toward mitochondrial matrix • Combine with oxygen to form water Outer mitochondrial membrane Cytosol Electron transport chain proteins Inner mitochondrial membrane Intermembrane space Matrix 46 23 2023-09-20 4.2 Cellular Respiration (20 of 28) • Hydrogen ions (H+) • Concentration decreases in mitochondrial matrix • Concentration increases in intermembrane space • Charged ions can’t diffuse across the membrane • Escape through protein channel, ATP synthase Outer mitochondrial membrane Cytosol Electron transport chain proteins Inner mitochondrial membrane Intermembrane space Matrix 47 4.2 Cellular Respiration (21 of 28) • Hydroelectric Dam Analogy • Water passes through turbine • Mechanical energy converted to electricity • H+ and ATP synthase • H+ ions pass through ATP synthase protein channels • 26 ATP molecules synthesized Outer mitochondrial membrane Inner mitochondrial membrane Cytosol Electron transport chain proteins Intermembrane space Matrix 48 24 2023-09-20 4.2 Cellular Respiration (22 of 28) Metabolism of other nutrients • If carbohydrates and fats are unavailable, proteins may be used • Amino group is removed • Other components enter the citric acid cycle Fatty acids Glycerol Carbohydrates Glucose Proteins Amino acids Glycolysis Pyruvic acid 2-carbon fragment Mitochondrion NH3 Cytosol 49 4.2 Cellular Respiration (24 of 28) (a) Human muscle Anaerobic respiration • Metabolic process to generate energy without oxygen • Possible in certain cells • E.g., Muscle cells Regeneration Glycolysis Fermentation 2 50 25 2023-09-20 4.2 Cellular Respiration (27 of 28) (a) Human muscle Oxygen debt • Body needs to replace oxygen • Heavy breathing continues after exercise stops • Liver needs oxygen to convert lactic acid to pyruvic acid • Muscles shut down if oxygen debt too large Regeneration Glycolysis Fermentation 2 51 4.2 Cellular Respiration (28 of 28) Fermentation (b) Yeast • Microbes transform milk sugars into lactic acid • Yogurt • Sour cream • Cheese • Yeast cells convert glucose to ethyl alcohol Regeneration • Beer • Wine Glycolysis Fermentation 2 52 26 2023-09-20 BioA11 Introduction to the Biology of Humans What in these items is important for fermentation? • Yoghurt e.g. ___ https://flic.kr/p/9m93Ji • Rum e.g. Screech rum: https://flic.kr/p/GYTNzX • Sourdough bread: e.g.__ https://flic.kr/p/ayq7pr 53 6.1 What Is Cancer? (1 of 10) Mitosis: type of cell division • One parent cell divides into two daughter cells • Regulated to occur only when more cells are needed Cancer: cells replicate when they shouldn’t • Results when regulation fails 54 27 2023-09-20 6.1 What Is Cancer? (2 of 10) Unregulated cell division forms a lump of cells Cyst: fluid-filled lump with no function; not cancerous Tumor: a solid mass of cells with no apparent function • Benign tumor: doesn’t affect surrounding tissues • Malignant tumor: invades surrounding tissues; cancerous • Metastasis: malignant cells break away and start new cancers at distant locations 55 6.1 What Is Cancer? (3 of 10) Tumor Normal cell Potentially cancerous cell Normal cell division Unregulated cell division Malignant if tumor invades surrounding tissue (cancerous) Benign if tumor has no effect on surrounding tissue (noncancerous) Metastatic if individual cells break away and start a new tumor elsewhere (cancerous) 56 28 2023-09-20 6.1 What Is Cancer? (4 of 10) Cancer cells • Differ from normal cells • Replicate when they shouldn’t • Invade surrounding tissues • Move to other locations in the body 57 6.1 What Is Cancer? (5 of 11) Cancer cells • Travel anywhere in the body via specific body systems • the circulatory system • Blood • the lymphatic system • Lymph – fluid lost from blood vessels • Lymph nodes – filter fluids from blood vessels • Analyzed for presence of metastatic cells 58 29 2023-09-20 6.1 What Is Cancer? (6 of 10) Risk factors: behaviors or conditions that increase the chance of developing a disease • Inherited cancer risk • Carried in genes • E.g., mutated BRCA1 gene Long arm BRCA1 Centromere • breast cancer • ovarian cancer Short arm 59 6.1 What Is Cancer? (7 of 10) Risk factors: behaviors or conditions that increase the chance of developing a disease • Environmental exposures • Exposure to carcinogens (cancer-causing agents) • Cigarette smoking • Alcohol consumption • Ultraviolet (UV) light exposure 60 30 2023-09-20 6.1 What Is Cancer? (8 of 10) Synergistic risk factors: enhance the activity of other carcinogens • Tobacco • Alcohol • Together, smoking tobacco and drinking alcohol have a greater risk than each activity alone. Increased risk of cancer of the esophagus (%) 60 50 40 30 20 10 0 Tobacco users Alcohol users Alcohol and tobacco users 61 6.1 What Is Cancer? (9 of 10) Decreasing cancer risk Table 6.1 Decreasing Your Cancer Risk Risk-Reducing Behavior Specific Risk Reduction Information Biological Mechanism of Risk Reduction Don’t Use Tobacco. The use of tobacco of any type, whether delivered via cigarettes, cigars, pipes, or chewing tobacco, increases your risk of many cancers. Electronic cigarettes, which contain nicotine only, are new enough that risks from their use have not yet been determined. Tobacco and tobacco cigarette smoke contain more than 20 known cancercausing substances. Chemicals present in tobacco and cigarette smoke have been shown to increase cell division, damage DNA, inhibit a cell’s ability to repair damaged DNA, and prevent cells from dying when they should. Limit Alcohol Consumption. Men who want to decrease their cancer risk should have no more than two alcoholic drinks a day, and women one or none. When harmful chemicals dissolve in alcohol, they are able to traverse cell membranes and can damage DNA. 62 31 2023-09-20 6.1 What Is Cancer? (10 of 10) [Table 6.1 continued] Risk-Reducing Behavior Specific Risk Reduction Information Biological Mechanism of Risk Reduction Eat a Low-Fat, High-Fiber Diet. Eat at least 5 servings of fruits and vegetables every day as well as 6 servings of food from other plant sources, such as breads, cereals, grains, rice, pasta, or beans. Fruits and vegetables are rich in antioxidants which help prevent DNA damage. Exercise Regularly. Engage in physical activity for at least 30 minutes 5 days a week. Exercise keeps the immune system functioning effectively, allowing it to recognize and destroy cancer cells. Maintain a Healthy Weight. Avoid becoming obese. If you are obese, consult a physician for a weight loss program. Because fatty tissues can store hormones, the abundance of fatty tissue has been hypothesized to increase the risk of hormone-sensitive cancers such as breast, uterine, ovarian, and prostate cancer. 63 BioA11 Introduction to the Biology of Humans Lecture week 3: Cells out of control • What are the components of cells? ________________ • Cell structure • Animal cells have ____; plant cells have ______. • Energy for cells to work • Use this reaction ________________ • Cancer: _______out of control • Next week and for tutorial: • Read chapter 18 section 18.2 and watch video in Fig.18.8 (eText Study area Bioflix ch 18 “Homeostasis”) • What is an organ? What is a tissue? • _____________________________________________________ _____________________________________________________ 64 32