Lesson 1: The Biology of You - BIOL 1441 PDF

Lesson 1: The Biology of You BIOL 1441 Cell & Molecular Biology  Learning Objectives (a.k.a. Study Guide) By the end of this lesson, students 5. List the 4 main macromolecules found in...

Lesson 1: The Biology of You BIOL 1441 Cell & Molecular Biology  Learning Objectives (a.k.a. Study Guide) By the end of this lesson, students 5. List the 4 main macromolecules found in the human body. will be able to: 6. Identify examples of each of the major 1. Explain how the human body is macromolecules. organized, from smallest (cells) to largest (organism). 7. Describe the function of each kind of macromolecule. 2. List the structures found in all types of cells. 8. Explain what happens in catabolic & anabolic reactions. 3. Explain how a prokaryotic cell is different from a eukaryotic cell, and give examples 9. Explain what happens in hydrolysis & of each. dehydration synthesis. 4. Describe the primary function of a cell’s plasma membrane.  What Happens When You Eat? The macromolecules in the food you eat The monomers from your food are are broken into monomers through the used to build macromolecules using process of hydrolysis. dehydration synthesis. Anabolism Catabolism + -  Each of your organs You are an has a specific job in Your body is made organism. its organ system. of 30 trillion cells! OUR CLASS IS HERE Your organ systems do complex Tissues (a.k.a. groups of cells) work functions to keep you alive. together to form organs.  Cells Lipids Cells are the smallest living things To be alive, a cell must: Be separate from its environment Be able to create energy from food Carbohydrates Be able to grow (processed here) Be able to reproduce The macromolecules that cells are built from help it do these things: Nucleic Acids Lipids form a plasma membrane barrier between inside & outside Carbohydrates are an easy energy source Proteins (working Proteins help the cell perform complex tasks inside here) Nucleic acids store genetic information to pass along to offspring Proteins  Classifying Cells Cells can be classified based on the location of their genetic information Some cells are prokaryotic cells Their genetic information is found in a nucleoid region (labeled D) Bacterial cells are prokaryotic cells Some cells are eukaryotic cells Their genetic information is stored in a membrane-enclosed nucleus (labeled B) Animal cells & plant cells are eukaryotic cells Let's Practice! Observe the cell on the left. This cell: DOES / DOES NOT have a membrane-enclosed nucleus. This cell would be considered: prokaryotic / eukaryotic Let's Practice! Observe the cells on the left. These cells : DO / DO NOT have a membrane-enclosed nucleus. These cells would be considered: prokaryotic / eukaryotic  Bacterial (Prokaryotic) Cells Cells Prokaryotic & eukaryotic cells can look very different Eukaryotic Human Cells Despite their many differences, all cells require some of the same structures to be alive: 1. DNA & RNA, a set of genetic information 2. Ribosomes, protein-building structures 3. A plasma membrane, a dividing line Other Eukaryotic Cells between inside & outside 4. Cytoplasm, a sugar & protein solution inside the cell Note: we may use cytoplasm and cytosol interchangeably this semester. Curious about the difference? See the short video on Fungus Plant Canvas.  All Cells Have: MACROMOLECULE: Nucleic Acids DNA & RNA DNA & RNA are the genetic information molecules of cells DNA is double-stranded, with 2 lines of genetic information wrapped around each other RNA is usually single-stranded, with just 1 line of information The monomers (a.k.a. pieces) used to build DNA & RNA are nucleotides Each nucleotide has a phosphate group, a sugar, and a nitrogenous base The nitrogenous base is what determines the identity of the nucleotide (A, T, G, C, or U)  MACROMOLECULE: All Cells Have: DNA & RNA Nucleic Acids The sugar in each nucleotide determines if it is found in DNA or RNA DNA nucleotides have deoxyribose sugar RNA nucleotides have ribose sugar The nucleotides found in DNA & RNA are different DNA: A, T, C, & G RNA: A, U, C, & G  DNA stores ALL the genetic information of a cell. Regions called genes contain the directions for building specific proteins. When a cell needs a specific protein, it makes an mRNA “copy” of the information stored in that gene. This mRNA is sent to ribosomes so they can build the protein.  Stop & Think It Through! Why do all cells (animal, plant, and bacterial) need to have DNA and RNA?  All Cells Have: Ribosomes Ribosomes are a cell’s protein-building "machines" In bacteria, ribosomes are found throughout the cytoplasm In animal & plant cells, ribosomes are also attached to the rough endoplasmic reticulum To build proteins, ribosomes need mRNA & monomers called amino acids First, they “read” the mRNA instructions Then, they connect amino acids in the correct order  MACROMOLECULE: Proteins Proteins Proteins (a.k.a. polypeptides) are long chains of amino acids After each chain is built, it folds into its 3D shape Sometimes, more than one folded chain connect, making a larger functional protein Proteins MUST be the correct 3D shape to be able to do their job in the cell Proteins lose their shape if the temperature or pH is too high or low, or if they are exposed to toxic chemicals If a protein permanently loses its 3D shape, it is denatured Denatured proteins CANNOT perform their functions  MACROMOLECULE: Functions of Proteins Proteins Proteins perform many different functions in cells Cytoskeleton proteins give cells their 3D shape Enzymes speed up chemical reactions Some reactions (anabolic reactions) build things Some reactions (catabolic reactions) break things Glycoproteins act like a name tag for cells (or viruses, like the one that causes COVID-19) Transport proteins move molecules across the plasma membrane of cells  Stop & Think It Through! Some antibiotics inactivate the ribosomes of bacterial cells. What effect would this have on bacterial cells? Why would this kind of antibiotic be a good way to treat a bacterial infection?  All Cells Have: MACROMOLECULE: Lipids A Plasma Membrane The cell’s plasma membrane is also known as its phospholipid bilayer Phospholipid molecules have two regions Their head group, which loves water (making it hydrophilic) Their fatty acid tails, which hate water (making them hydrophobic) The head The bilayer structure of the plasma membrane protects (the hydrophilic part) the phospholipid's tails from water It also makes it semipermeable (a.k.a. “picky” about what The tails can & cannot cross it) (the hydrophobic parts) All Cells Have: Cytoplasm Cytoplasm is the soupy solution inside a cell’s plasma membrane 80% of this is water It includes all of cell's organelles Cytoskeleton It also includes dissolved salts & macromolecules Macromolecules in the cytoplasm Cytoskeleton proteins, giving the cell its (with carbohydrates) shape Enzymes, speed up chemical reactions Carbohydrates, providing energy to the cell  MACROMOLECULE: Carbohydrates Carbohydrates Carbohydrates are a cell’s “favorite food” The energy stored in carbohydrates are released through catabolic (a.k.a. breaking) reactions Carbohydrates are classified by size Monosaccharides (like glucose) are made of one sugar molecule Disaccharides (like sucrose) are made of two sugar molecules Polysaccharides (like starch) are made of many sugar molecules  MACROMOLECULE: Carbohydrates Carbohydrates Not all carbohydrates are the same Some carbohydrates (pentoses) have 5 carbons (6 carbons) (5 carbons) while others (hexoses) have 6 carbons Some carbohydrates are linear while others form rings Monosaccharides & disaccharides provide energy quickly Polysaccharides store energy Glycogen is used by animal cells for short-term energy storage Starches are used by plant cells for short-term energy storage  MACROMOLECULE: Fats Lipids Simplified triglyceride structure Fats are used for long-term energy storage The most common fat in animal cells is triglycerides Triglycerides are made of a glycerol head & three fatty acid tails Detailed triglyceride structure The energy of fats is stored in the chemical bonds (connections) in the fatty acid tails The longer the fatty acid tail, the more energy that is stored in it  MACROMOLECULE: Fats Lipids Fatty acid tails can be saturated or unsaturated Saturated fatty acids have carbons attached to as many hydrogens as possible This creates straight fatty acid tails that can pack together closely This kind of fat is solid at room temperature Unsaturated fatty acids have double bonds (extra connections) between carbons This creates bent fatty acid tails that can’t squeeze as closely together This kind of fat is liquid at room temperature  Stop & Think It Through! Why is it good for human skeletal muscle cells to store extra energy in the form of glycogen, not triglycerides?  Let's Practice! Omega-6 fatty acids are a type of unsaturated fatty acid used by the human body to grow. (Interestingly, our bodies cannot make them!) Which chemical structure is MOST LIKELY to represent an omega-6 fatty acid? How do you know?  Let's Practice! Phospholipids are the type of lipid used to build a cell's plasma membrane. Each phospholipid has 2 fatty acid tails. Fatty Acid #1 is a: Fatty Fatty saturated / unsaturated Acid #1 Acid #2 fatty acid. Fatty Acid #2 is a: saturated / unsaturated fatty acid  MACROMOLECULE: Cholesterol Lipids Cholesterol is a lipid made of 4 attached carbon rings Cholesterol can be obtained through diet Cholesterol is also made by the liver when it metabolizes saturated fatty acids Excessive cholesterol can clog blood vessels, but the human body requires a moderate level of it Cholesterol maintains the stability of the plasma membrane Cholesterol is used to make sterol hormones (like testosterone, estrogen, and cortisol)  Types of Chemical Reactions Catabolic reactions occur when large Anabolic reactions occur when molecules (like lipids) are broken down smaller pieces are used to build a into smaller pieces large molecule Large molecules store energy in their Building new connections between chemical bonds (a.k.a. smaller pieces requires energy connections) between smaller pieces Cells use anabolic reactions to store Catabolic reactions release the stored energy for later use energy for a cell to use  Terminology: Cortisol Synthesis / genesis = building Lysis / release = breaking Cortisol is a sterol hormone released by the body during stress Cortisol changes the metabolic processes (a.k.a. chemical reactions) of the body It increases breakdown of glycogen (stored release of fatty acids & triglycerides release of fatty acids energy) in the body storage of triglycerides Cortisol decreases the building of new proteins Notice that the effects of cortisol on metabolism are opposite of the effects of insulin on metabolism  Terminology: Let’s Synthesis / genesis = building Lysis / release = breaking Apply It! release of fatty acids & release of fatty acids triglycerides storage of triglycerides Based on its effects in the body, would Based on its effects in the body, would cortisol be an anabolic hormone or a insulin be an anabolic hormone or a catabolic hormone? catabolic hormone?  Water & Chemical Reactions Water (H2O) is often involved in the breaking & building of chemical bonds In hydrolysis, water is used to break a chemical bond A water molecule is split into H & OH, each part attaching to a different side of the chemical bond Result: the monomers detach from one another Hydrolysis is a type of catabolic reaction In dehydration synthesis, water is made (along with a new chemical bond) H & OH are removed from the monomers Result: a chemical bond forms between them Dehydration synthesis is a type of anabolic reaction  So… What Happens When You Eat? The macromolecules in the food you eat The monomers from your food are are broken into monomers through the used to build macromolecules using process of hydrolysis. dehydration synthesis. Anabolism Catabolism + -  Let’s Practice! The Macromolecules: A Summary Type of Function Examples Macromolecule Lipids  To Prepare for Next Class…  Review your class notes Use the eTextbook & Other Helpful Resources to supplement your lecture notes  Complete the homework assignment Review what you didn’t understand and make another attempt. You can complete the homework as many times as you want!  Print the slides for Lesson #2 – The Great Divide  Take some deep breaths… this moves oxygen directly into your cells and reduces stress!