Biology 1101 Week 4 Notes
Biology 1101 Week 4 Notes BIOLOGY 1101 - 0100
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BIOLOGY 1101 - 0100
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This 12 page Class Notes was uploaded by Alexa Notetaker on Friday February 5, 2016. The Class Notes belongs to BIOLOGY 1101 - 0100 at Ohio State University taught by Dr. Kristin Smock in Spring 2016. Since its upload, it has received 26 views. For similar materials see Biology in Biology at Ohio State University.
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Date Created: 02/05/16
Biology 1101 Week 4 Notes Cellular Respiration: • All organisms perform cellular respiration o Harvests energy stored in organic molecules (glucose) • Generates ATP for cellular work o ATP powers every activity that requires energy input in the cell o Explains constant need for food (= potential energy) Cycling: • Photosynthesis: o Sunlight + Water + Carbon Dioxide à Oxygen + Sugar § ENDERGONIC reaction • Cellular respiration o Oxygen + sugar à carbon dioxide + water + energy (ATP) § Opposite of photosynthesis § EXERGONIC reaction (releases energy) Cellular respiration model: Steps of cellular respiration: 1. Glycolysis a. Happens in the cytoplasm of cell b. Glycolysis- The breaking down of glucose i. Breaks glucose molecule in half 1. 3 carbon molecules (pyruvate) a. Then some ATP is released à multi-cellular eukaryotic cells, this glycolysis is not enough of energy • Can be for some bacteria cells NOTE: Glucose= C 6H12O 6 2. Krebs cycle a. Occurs in Mitochondria b. Pyruvate molecules are processed and broken down more (a little more ATP given of- maybe around 2) i. Carbon dioxide is produced and exhaled 3. Electron Transport Chain a. Occurs in Mitochondria b. Breathe in oxygen c. Concentration gradient- potential energy i. Takes energy to move from low concentration to high concentration ii. High concentration to low concentration does NOT take energy (kinetic energy) 1. Releases ADP and phosphate a. Creates ATP (average 28) 2. Oxygen is the final electron acceptor a. Attaches with Hydrogen on other side of membrane i. Creates 20 d. This process is very fast, particularly when a great amount of energy is needed e. “Hit the wall”- burned through glycogen stores and body must switch through different ways to get energy i. Could hit into fat stores, but not as easy People with Type 1 Diabetes do not produce enough insulin, a hormone that signals cells to take up glucose from the bloodstream. • A list of potential symptoms people with Type 1 diabetes may experience: o Fatigue- not able to convert glucose into pyruvate, stopping the entire cellular respiration cycle, which prevents the production of ATP (energy) o Extreme thirst- not able to create water from Electron Transport Chain, so they are constantly needing to take in H20 in order to make up for it; also, look at frequent urination o Loss of appetite o Weight issues- not able to break down glucose, so it stores it, causing weight issues o Frequent urination- build up of sugar in urine, which then pulls a lot of water into kidneys to help compensate, causing frequent urination What happens when there’s no oxygen? Anaerobic cellular respiration- cellular respiration without oxygen • In animals: End product is lactic acid o Muscles burn- lactic acid built up in muscles § Body is able to process lactic acid once back to aerobic respiration • In yeast: end product is ethanol o Yeast break down sugars in order to do this Anaerobic respiration/fermentation: • Animals o Switch to anaerobic respiration in absence of oxygen o Lactic acid builds up, causing burning in muscles o 2 ATP • Yeast: o Switch to anaerobic respiration in absence of oxygen o Production of ethanol § Beer/wine o Flavor depends on the sugars § Grapes= wine § Barely- beer § Potatoes- vodka § Agave- tequila Structure of DNA: • DNA is made of nucleotides o Phosphate group o Sugar (deoxyribose) o Nitrogenous base § Adenine (A) § Cytosine (C) § Thymine ( T ) § Guanine (G) Structure of DNA: • DNA is a double-helix o Sugar-phosphate backbone form “rails” o Nitrogenous bases form “rungs” • Complementary base pairing o A-T o C-G • If you know the order of the bases on one strand of DNA, you will know the bases in the other strand • Hydrogen bonds hold the strands together o Weak bonds o Collectively, are strong • Double helix is stable • James Watson and Francis Crick o Came up with the physical structure of DNA o Happened in 1953 “It has not escaped our notice that the specific pairing we have postulated immediately suggests a potential copying mechanism for the genetic material” -Watson & Crick DNA Replication: • One of the most important properties of DNA is the fact that it can be copied • Stored information in a cell can be passed from: o Cell to cell o Generation to generation • The process of copying DNA molecule to form two identical DNA molecules • Complementary base pairing allows for each strand of the original DNA molecule to serve as a template for creating a new strand of DNA DNA Replication Steps: • DNA has not yet been replicated o Parent molecule has two strands (blue) • Unwinding- parent molecule “unzips” o Hydrogen bonds brake § Done by an enzyme § It’s a good thing that hydrogen bonds are so weak so that it does not require a ton of energy to break them • Complementary base pairing (A-T and C-G) • Joining- new nucleotides are linked together to form a new strand o New- yellow o Existing- blue Semi-conservative replication: • Daughter molecules- half new strand and half parent strand o Identical to each other and identical to parent molecule from which they came Mutation: • DNA polymerase (enzyme) “proofreads” as it adds new nucleotides o Makes a mistake 1 in 1 billion times § very efficient o Enzyme- protein that unzips and zips DNA nucleotides to form new strands • We call those mistakes mutations o Example: changes in the DNA sequence (A-G) • A mutation is any change in a cell’s DNA sequence • Can be caused by errors in replication, or by environmental factors o Examples: UV light, radiation, certain chemicals, viruses, etc. Cell Division: • Prokaryotes and single-celled eukaryotes reproduce asexually through cell division o Binary fission in prokaryotes o Mitosis in eukaryotes à Must first replicate DNA inside cell Mitotic Cell Division: • Multicellular eukaryotes use cell division for: o Growth o Development o Repair damaged tissues § Cut, broken bone, etc. Chromosome duplication: • Before cells divide, entire genome must be duplicated o Genome= all of the DNA information o Prokaryotes: single circular DNA molecule o Eukaryotes: genome is divided among chromosomes § Chromosomes are housed inside of the nucleus being replicated Eukaryotic chromosomes: • DNA plus packaging proteins • Barely visible when cell is not dividing o DNA loosely packed and accessible for cell • DNA condenses into visible chromosomes before cell division • Sister chromatids- pair of chromosomes with IDENTICAL DNA sequences o Physically attached to each other o Genetically identical from DNA replication • In most animal cells, all somatic cells (body cells) have two copies of each chromosomes o Diploid (2 sets of chromosomes) § One set came from egg cell § One set came from sperm cell • Homologous pairs o One from mom, one from dad o Pairs look similar but are NOT genetically identical § Look similar because chromosomes have the same genes for a certain trait (eye color, freckles, hair color, etc.) one from egg cell and one from sperm cell § Different because it encodes different information o Carry genes for the same trait o 23 pairs of chromosomes (23 from mom and 23 from dad) Human cells: • 46 Chromosomes in somatic cells o 23 from each parent Mitotic Cell Cycles: • Cell cycle- events between one cell division and the next • Two major stages o Interphase- cell not dividing but cell very active § Doing what the cell does to function properly o Cell division- mitosis and cytokinesis § Mitosis- division of nucleus § Cytokinesis- division of cytoplasm Interphase: • About 90% of the cell cycle, very active time o Cell grows, organelles double o Genetic material replicates o Chromosomes begin to condense Mitosis: Nuclear division: • Overall: daughter chromosomes sorted and separated • Two identical nuclei created à More to continue next week!