BIOL 120 LECTURE, Week 4 Notes
BIOL 120 LECTURE, Week 4 Notes Biol 120
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This 14 page Class Notes was uploaded by Michelle Noratel on Friday September 23, 2016. The Class Notes belongs to Biol 120 at Towson University taught by Jennifer M Wenzel in Fall 2016. Since its upload, it has received 13 views. For similar materials see Principles of Biology in Biology at Towson University.
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Date Created: 09/23/16
"How Living Things Live: Digestion and Metabolism" Lecture Three Flashcards Digestion is the bodily process of breaking down food into contents that our body can use Digestion is completed by use of both What is Digestion? mechanical (e.g., chewing) and chemical (e.g., enzymes) processes What are the Processes of 1. Ingestion 2. Digestion Digestion? 3. Absorption (hint: there are five!) 4. Assimilation 5. Egestion/Elimination Ingestion is the process of digestion that takes place in the mouth when we eat and What is Ingestion? swallow things in the mouth are the salivary glands which help break down the macromolecules of food, as well as mastication (chewing) which literally break the food down What is Digestion? Digestion is the chemical and mechanical breakdown of food by the enzymes in our stomach Absorption is the process done by the cells where they take in soluble matter via What is Absorption? cellular transport (the taking in of smaller molecules into the cells) "How Living Things Live: Digestion and Metabolism" Lecture Three Flashcards Assimilation is the use of digestive molecules by cells in order to absorb What is Assimilation? molecules for energy, metabolism, and functions of the cell, such as growth, repair, and multiplication Egestion is the process of eliminating What is Egestion? undigested or undigestible material from the body What is Another Word For the The alimentary canal! "Digestive System"? 1. Salivary glands 2. Esophagus What Are the Main Organs of 3. Liver 4. Stomach the Digestive System? 5. Gallbladder (in order) 6. Pancreas 7. Small intestine 8. Large intestine 9. Appendix 10. Anus The mouth is the site of ingestion! This is where we break down the food by What Happens in the Mouth? chewing (mastication) and spit/saliva (our salivary glands secrete salivary amylase, which is an enzyme that breaks down starch into sugar "How Living Things Live: Digestion and Metabolism" Lecture Three Flashcards The esophagus is the tube from the mouth to the stomach that moves the bolus (literally chunk or globs of chewed food) What Happens in the Esophagus? to our stomach by way of peristalsis (muscle contractions that push the food down) Our stomach does so much for us! With pepsin, our stomach helps us to digest protein With HCl, our stomach kills bad bacteria What Happens in the Stomach? With mucus, our stomach protects itself from acidic stomach acids (which at 1.52pH could really burn our stomach!) Our stomach is like a big mixing bowl, or blender, mixing all of the food we've eaten by peristalsis, which (as you remember) move food via muscular contractions and digest the protein we've eaten It only takes about an hour or two for our chyme (partially disgusted foodstuffs) to get to its next stop–the small intestine!) Lots of absorption occurs here sugars, amino acids, and fatty acids are released from breakdown of food and are sent into the bloodstream Our small intestine is 23' long! What Happens in the Small The villi (little fingerlike protrusions Intestine? along the lining of the SI) and microvilli (even smaller little fingers attached to the villi) grab as many nutrients that they can so that our gut bacteria can get all that they need The enzymes that digest carbs are primarily produced by the SI walls "How Living Things Live: Digestion and Metabolism" Lecture Three Flashcards The liver produces bile, which neutralizes stomach acids that work together to cause fat molecules to What Happens in the Liver? form droplets for absorption Bile is more basic than stomach acid at around 56.5 pH, so it neutralizes those harsh acids! The gallbladder stores our bile (aka gall) When food enters the small intestine, contractions of the gallbladder release that bile into the small intestine What Happens in the When the gallbladder malfunctions, Gallbladder? bile can turn into a hard rock because it is held instead of released into the SIthis can cause pain or obstructions, and food may be unable to be digested and bile backs up! The pancreas is the spot where enzymes for digesting fats and What Happens in the proteins (lipase and peptidase, Pancreas? respectively) are secreted into the small intestine Meeting place of the small and large intestinessmall tube about 4 inches long The crazy thing is that we don't know What Happens in the what the appendix does! Some say it's a vestigial organ, some say it's useless Appendix? now that we've evolved from whatever it was useful for, and some think it's a place to store good bacteria so that we can quickly reboot our digestive system after a diarrheal illness "How Living Things Live: Digestion and Metabolism" Lecture Three Flashcards The large intestine absorbs water and What Happens in the Large dehydrates our chyme from the small intestinethis becomes feces Intestine? The anus is the site of egestion, or elimination, of feces (solid waste) What Happens in the Anus? It's our gut bacteria! Also known as gut flora, gut microbiota, or gut microbes These are inside of the small intestine, which help you to digest foodthey Anything Else? are a complex microbiotic species (hint: the "forgotten organ") They help synthesize vitamins B and K The assist in immune functions by attacking harmful bacteria There are 10x more bacteria in your digestive tract than total amount of human cells in your entire body! Diseases and disorders in the brain are What About Gut Microbes and being treated by altering the microbiome! Your Brain? These little bacteria have big implications in the body "How Living Things Live: Digestion and Metabolism" Lecture Three Flashcards Metabolism is the set of chemical reactions that produce energy in the What is the Metabolism? body by breaking down chemical bonds in our food 33% food's "energy" is used for digestion 55% is used by basal metabolism (keeping body at body temperature, keeps heartbeat/respiration regular) 13% is left over for activity, which we store for later Hormone produced by the pancreas that What is Insulin? removes glucose from the blood by assisting uptake into the cells When we eat, the food gets broken down How Do Cells Get Glucose? and glucose enters the bloodstream along with insulin Glucose in blood → high blood sugar → pancreas releases insulin to combat Cycle of Blood Sugar it → insulin and glucose meet and enter the cells Glucagon (another pancreatic hormone) converts glycogen to glucose Unused glucose can be converted into ShortTerm Energy Storage glycogen for shortterm storage in the liver and muscles "How Living Things Live: Digestion and Metabolism" Lecture Three Flashcards Energy is stored as fat (lipids) in LongTerm Energy Storage adipose (fatty) tissue Fat is converted into glucose for energy use Diabetes mellitus ("passing honey") named because doctors tasted urine What is Diabetes? and people with diabetes had very sweet urine The pancreas stops producing insulin, and takes in sugars that can't get into the cells What is Type I Diabetes? because there is no insulin to pair up withunable to use sugar, which can lead to chronic high blood sugar The body becomes so used to producing insulin after eating a lot of sugary foods that eventually insulin What is Type II Diabetes? production stops, and can lead to chronic high blood sugar The pancreas wants to regulate blood sugar and keeps trying to produce eventually exhausts itself What we eat ends up getting absorbed by So What? (What Are the the cells and the food we eat becomes a Ramifications of Eating? Why part of our living body! Isn't that cool? When they say "we are what we eat," it's Does it Matter?) really true! "Cells!" Lecture Four Flashcards What is Abiogenesis? An early scientific belief that life spontaneously springs from nothing A Flemish scientist of the early 17th century who believed in abiogenesis. He Who is Jan Baptista van Helmont? "proved" this by "creating mice." In his attic was a pile of dirty clothes and a bag of surplus wheat. After three weeks, mice were "created," so abiogenesis was real! (Very anecdotal evidence) The first to challenge abiogenesis. He performed an experiment, filling three glasses with raw meat–one open, one corked, and one with gauze on top. The Who is Francesco Redi? open container had meat with flies and maggots on top, the corked had neither flies nor maggots, and the gauzed had flies and maggots lying on top of the gauze. He theorized that the flies came from the outside and laid their eggs there. Ever hear of pasteurization? Pasteur theorized that all life must come from other life, and he proved this with an experiment in 1859. He put broth in two swanneck flasks and boiled the broth in them. He broke the thin neck on one of the Who is Louis Pasteur? flasks and left the other intact. In the unbroken flask, there was no growth, but in the broken flask, there was small, microbial growth. He said that when liquid is exposed to air, mold and bacteria grows. The closed swan neck flasks are still not growing mold! "Cells!" Lecture Four Flashcards 1660s – Hooke – first described cells (cork, like the cork tree) 1660s – Redi experiment Cell Timeline 1670s – von Leeuwenhoek visualized living cells 1830s – Cell Theory begins to form 1850s – Pasteur's experiment 1850s – golden age of microbiology, and germ theory of disease Matthias Shleiden – plant theorist, who said that all plants are made of cells Who Are the Big Players in Theodore Schwann – animal theorist, Cell Theory? who said that all animals are made of cells Rudolf Virchow – said that all cells came from preexisting cells 1830s1850s: post microscope, pre germ theory 3 tenets: Three Tenets of Cell Theory 1. The cell is the basic unit of life 2. All living things are made of cells 3. Cells arise from preexisting cells Prokaryotic: Singlecelled organisms Don't have nuclei (e.g., bacteria and archaea) Cell Categories Eukaryotic: Usually multicellular organisms Cells that have nuclei (e.g., plants, animals, fungi, protists (protists are complicatedly singlecelled) "Cells!" Lecture Four Flashcards Components in Prokaryotic Cells No nucleus, floating DNA/RNA Cell wall: structural wall and protection for the cell (an exoskeleton) Plasma membrane: controls what gets in and out Components in Eukaryotic Cells (Plant) Cell Wall: Support and structure Cell Membrane: Controls what comes in/out Cytoplasm: Water, salt, proteins inside the cell Nucleus: Contains DNA Chloroplast: Site of Photosynthesis Mitochondria: Make energy ("powerhouse "Cells!" Lecture Four Flashcards Components in Eukaryotic Cytoskeleton: Skeleton of the cell Cytoplasm: Water, salt, proteins inside the Cells (Animal) cell Endoplasmic Reticulum: ribosomes live on ER and make proteins Mitochondrion: Change glucose to ATP (energy) Golgi Body: Packages proteins in vesicles for transport around the cell Nucleus: Contains DNA Lysosomes: Contains enzymes to degrade food, waste, invaders, etc The membrane is the "gatekeeper" of the cell, controlling what can and can't get in The membrane has many membranes What Makes the Plasma Phospholipid layer: phosphate + lipid (fat) arranged in two layers Membrane So Special? Phosphates are polar (hydrophillic), so they allow water in Lipids are hydrophobic, so they keep water out The two aren't glued together, however, so some molecules could sneak into the cell "Cells!" Lecture Four Flashcards How Do Molecules Get Into or 1. Simple diffusion 2. Facilitated diffusion Out of the Cell? 3. Active transport (hint: there are five ways!) 4. Endocytosis 5. Exocytosis Small molecules (like oxygen and water) can pass through the cell membrane, from areas of high concentration to areas of low concentration (concentration gradient) What is Simple Diffusion? For larger molecules that can't pass through cracks in the membrane Passive = does NOT require energy What is Facilitated Diffusion? "Cells!" Lecture Four Flashcards For moving molecules from areas of high concentration to areas of low concentration through channels Active = requires energy Cell pulls in molecules through the channel Moves against the concentration gradient What is Active Transport? Takes energy by the cell Cells absorb materials by engulfing them Cell forms pit (like a little mouth) and pulls in molecules How the cell takes in molecules too big to fit through the protein channel (proteins, bacteria, fluids, cholesterol, etc) What is Endocytosis? "Cells!" Lecture Four Flashcards Push vesicle up to cell membrane; joins it, pushes molecules on the inside of the vesicles out of it (proteins and chemical messengers that head to communicate with other cells) Seen a lot in the brain (with neutotransmitters)exocytosed from brain cells one neuron (brain cell) to another What is Exocytosis? Exocytoses chemical messenger, makes contact with another neuron on the receiver how messages are passed on The "pleasure" signal/reward center of the brain, a neurotransmitter Dopamine is exocytosed by the brain What is Dopamine? when organisms experience pleasure, like when eating something really good, when having sex, when getting a surprise reward, or when taking drugs!
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