Cellular Respiration PDF

Cellular Respiration: Process of breaking down macromolecules (glucose) to produce ATP (energy). Understanding Adenosine Triphosphate (ATP)  ATP is a special molecule that carries energy throughout the cell. It is made up of Adenine (nitrogenous base), ribose (sugar), and 3 phosphates....

Cellular Respiration: Process of breaking down macromolecules (glucose) to produce ATP (energy). Understanding Adenosine Triphosphate (ATP)  ATP is a special molecule that carries energy throughout the cell. It is made up of Adenine (nitrogenous base), ribose (sugar), and 3 phosphates.  Energy is held in its chemical bonds and released when ONE phosphate molecule breaks off to form ADP (Adenine Diphosphate).  ATP captures chemical energy obtained from the breakdown of food molecules and releases it to fuel other cellular processes, such as cell division and muscle contraction. ________________________________________________________________________________________________________________________________ Two types of cellular respiration:  Anaerobic respiration: occurs when there is no oxygen to aid the breakdown of molecules to form ATP.  Aerobic respiration: occurs when oxygen is available to aid the breakdown of molecules to form ATP. ___________________________________________________________________________________________________________________________________________ Glycolysis: - This is the first step in breaking down glucose. - Glucose is broken down to form 2 pyruvate molecules, 2 ATP and 2 NADH+H+ - Occurs in the cytoplasm. - Requires energy. - Does not require oxygen. __________________________________________________________________________________________________________________________________________ Carrier Molecules: - NAD+ and FAD are carrier molecules. Throughout the stages of aerobic respiration, they come into play to collect Hydrogen molecules to form: NADH+H+ and FADH2, these molecules are carried to the electron transport chain where the hydrogen ions are used to make the most ATP. - Enzyme coA: carrier molecule that carries acetyl (2C) from oxidation of pyruvate to the Krebs cycle. Stages of Aerobic respiration (with oxygen):  Occurs only when there is oxygen.  After Glycolysis, the pyruvate molecules diffuse into the mitochondria where it is further broken down to release more energy. o Two steps:  Kreb’s cycle  Electron Transport Chain  Before a Pyruvate molecule can enter the Kreb’s cycle, it must first undergo oxidation! Oxidation of ONE Pyruvate molecule (occurs in the mitochondria’s matrix). o Each pyruvate molecule (3C) undergoes oxidation where the carboxyl group is detached to form CO2. This allows a Coenzyme A to attach to the oxidized molecule to form Acetyl CoA (2 C). One NADH+H+ is also formed. NOTE: Pyruvate must undergo oxidation because: (1) it cannot enter the Kreb’s Cycle as a 3C molecule. (2) Oxidation allows the attachment of Coenzyme A, which functions to carry the oxidized molecule to the Kreb’s cycle. 1) Kreb’s cycle: o Acetyl CoA (2C) enters the Kreb’s cycle where it bonds to an oxaloacetate molecule (4C) to form Citrate (6C).  How? CoA breaks off allowing oxaloacetate to bond to the Acetyl molecule. CoA returns to carry another oxidized pyruvate molecule. o In the Kreb’s cycle, Citrate undergoes a series of chemical reactions where the following is produced (per pyruvate molecule):  2 CO2  3 NADH+H+  1 FADH2  1 ATP  2) Electron Transport Chain (ETC) (occurs at the Cristae of the mitochondria). o This is where all the NADH+H+ and FADH2 produced from Glycolysis, Oxidation of Pyruvate, and the Kreb’s cycle is USED to make the MOST energy (~30-34 ATP molecules!). - Special protein molecules are located along the inner membrane fold, these molecules function as Natural pumps that takes Hydrogen ion from the mitochondrial matrix to the intermembrane space. - Increase of hydrogen in the intermembrane space results in an increase in Hydrogen ion concentration. o Recall: molecules naturally want to move from an area of high concentration to low concentration (Diffusion) - The only way hydrogen molecules can move from a high concentration (the intermembrane space) to an area with low concentration (matrix) is through a special protein called the ATP synthase. o When molecules move through this protein, ADP is converted back to ATP. Additional Info (YOU WILL NOT BE TESTED ON THIS ADDITIONAL INFO):  Complex I: Takes electrons from NADH+H+ allowing it to generate power to pump H+ into the intermembrane space.  Complex II: Takes electrons from FADH molecules. Complex II does not act as a pump!  CoQ: Receives electrons from Complex 1 and II.  Complex III: Electrons from CoQ are transferred to Complex III. Complex III, acts like a pump, pumping H+ molecules from the matrix to the intermembrane space.  Cyt C: Receives electrons and passes it onto Complex IV.  Complex IV: Also pumps H+ molecules to the intermembrane space. In addition, it releases the electrons that were collected to form water molecules.  ATP synthase: A special molecule that allows H+ to move from the intermembrane space to the matrix (high to low concentration). When H+ molecules move through, it can take ADP (used energy molecule) and convert into ATP.  - NAD+ and FAD molecules return to the cytoplasm and Kreb’s cycle to carry more Hydrogen to bring back to the ETC. ___________________________________________________________________________________________________________________________________________ Aerobic respiration summary:  1 Glucose molecule = ~38 ATP o 2 ATP- Glycolysis o 2 ATP- Kreb Cycle (1 from each pyruvate) o 30-34 ATP- Electron Transport Chain. __________________________________________________________________________________________________________________________________________ Stage of Anaerobic respiration (without oxygen):  Occurs only when there is little-to-no oxygen. NOTE:  After Glycolysis, the pyruvate molecules are broken down further to form Lactic acid (in animals) OR  1 glucose molecule can alcohol and carbon dioxide (in yeast or plant cells) produce 4 ATP (in o This process occurs in the cytoplasm. animals) o In animals, pyruvate is broken to form lactic acid; a toxic chemical molecule that causes o 2 from Glycolysis muscle fatigue or spasm (painful). The body can remove lactic acid when oxygen is made o 2 from producing available again. How? by transporting lactic acid to the liver where it is converted back to lactic acid. pyruvate and then to glucose again.  Anaerobic respiration is also known as fermentation. o Recall some microbes, like yeast, can undergo fermentation. Fermentation process in yeast is used to make bread and alcoholic beverages. o Another microbe that undergoes fermentation is lactic acid bacteria. Fermentation process of lactic acid bacteria is used to make yoghurt. ___________________________________________________________________________________________________________________________________________ Anaerobic respiration summary: Cell Compounds:  Cells are largely composed of carbon molecules.  3 main groups of carbon molecules: 1. Carbohydrates. 2. Lipids. 3. Proteins. ___________________________________________________________________________________________________________________________________________ Carbohydrates: sugar molecules.  Function: o Main source of energy, store energy (starch and glycogen), is the structural base for most animals (cellulose- plants, chitin- exoskeleton).  Carbohydrates can be classified further into 2 types of groups: (1) Simple Carbohydrates, (2) Complex Carbohydrates. ___________________________________________________________________________________________________________________________________________ Simple carbohydrates: Has one or two sugar molecules. Complex carbohydrates: Has more than two sugar molecules - These sugars are easily/quickly digested and converted. - These sugars are digested and converted much slowly.  Monosaccharides (glucose)- one sugar  Polysaccharides (starch, glycogen (stored molecule glucose), cellulose (fibre), chitin).  Disaccharides (sucrose)- two sugar molecules bonded together. ___________________________________________________________________________________________________________________________________________ Lipids: Fatty acids that make Fats, Oils, waxes and hormones.  Function: o Cell membrane, long-term energy storage, insulation, hormone formation (eg. estrogen and testosterone).  Lipids and Proteins- Cell membranes.  Cholesterol: Allow cell membranes to be more flexible.  Fatty acid: Monomer  Saturated fat  Unsaturated Fat - Hydrophobic o Solid (Straight chain) o liquid (not a straight - Long carbon chain of carboxylic acid. o tightly bonded chain) o Has more covalent Glycerol: bonds (double bonds) o Loosely packed - Compound with 3 alcohol groups. ___________________________________________________________________________________________________________________________________________ Proteins: Chain of Amino acids bonded together by a peptide bond.  Function: o Cell transport (think proteins located on cell membranes and haemoglobin), forms enzymes, hormones (Insulin), form antibodies, structural base (collagen, keratin). Amino Acid Peptides Polypeptides  C, H, N, O, S (some)  Short chain of amino acids (2-50).  A chain of many amino acids.  Amino group- R Group- Carboxyl  Amino acids are held together by bonds group. called ‘peptide bonds. ___________________________________________________________________________________________________________________________________________ Enzymes: large protein molecules that function as a biological catalyst.  Catalyst: a substance that controls the speed of a chemical reactions without affecting/changing itself or being used up in the process.  Enzymes control the speed of chemical reactions that occurs in the body (i.e. they control metabolic pathways) Metabolism: the sum of all chemical reactions occurring within a living organism. o Catabolism: Breaking down large molecules into simpler molecules by releasing energy (exothermic). Example: Respiration. o Anabolism: Small molecules combine to form a larger molecule by utilizing energy (endothermic). Example: Photosynthesis. Two types of enzymes: o Intracellular enzymes: located within’ the cells. o Extracellular enzymes: located outside the cell where they do special tasks such as digestion. ___________________________________________________________________________________________________________________________________________ How enzymes function: o Enzymes are highly specific, meaning they cannot catalyse just any reaction.  For an enzyme to catalyse a reaction, it must have the correct reactants (this is also called the substrate). o The part of the enzyme the bind to the substrate is called the active site.  The active site is shape specific. If a substrate does not match its shape, then a reaction cannot take place. o Enzyme work to lower the activation energy (AE) needed by a reaction.  AE= The minimum amount of energy needed to start a reaction. Enzyme models: o Lock and Key model:  The active site on the enzyme is unique to its substrate.  If an enzyme attaches perfectly to its substrate, a chemical reaction occurs.  If an enzyme’s active shape is different from its substrate, a chemical reaction cannot occur. o Induced fit model:  The active site on the enzyme can change its shape slighting to fit a substrate.  Altering the active site allows enzyme and substrate to attach perfectly, resulting in a chemical reaction. ___________________________________________________________________________________________________________________________________________  Example of enzymes and their functions: Enzyme Function 1. Amylase (mouth) Breaks down carbs into smaller sugars. 2. Pepsin (Stomach) Breaks down proteins to polypeptides. 3. Lipase (Small Intestine) Breaks down lipids into fatty acids and glycerol Factors that affect enzyme activity: ***See next page for additional dets.  FACTOR EXPLANATION 1) Temperature - Increase in temperature increases the rate of reaction. However, if temperature increases beyond an optimum temperature (enzyme’s preferred temperature), this can cause bonds within the enzyme molecule to break changing the shape of the protein. In other words, the active site changes and substrates will not be able to bond. - Different enzymes have different optimum temperatures. The majority of enzymes in our body works best at temperatures 37-45 °C - Enzymes that are no longer able to catalyse reactions are said to be denatured. 2) pH (acidity) - Different enzymes work best in different pH ranges. Change in pH can slow down the rate of reaction. - Extreme pH changes can also result the enzyme being denatured. - Changes in pH changes the presence of H+ and OH- ions, this affects the bonding of Amino acids (proteins) which overall causes the protein molecule to change shape i.e denature. 3) Enzyme - Increase in enzymes concentration will increase the rate of reaction. Reaction will occur as long as there are concentration substrates available. 4) Substrate - The rate of reaction can increase if there is an increased number of reactants (substrates). concentration - The rate of reaction can become constant if the concentration of substrates continues to increase. When this occurs, a saturation point is reached. (The point in which all available enzymes are occupied with substrates.) Cell transport: crucial to maintain a stable internal environment and receive substances/material in the correct amount. - There are two ways in which materials move in-and-out, and throughout the cell: 1. Active transport 2. Passive transport. ___________________________________________________________________________________________________________________________________________ Active transport: - Energy (ATP) is needed to move molecules/substances from an area of low concentration to high concentration (against concentration gradient). o Examples:  The uptake of glucose in the intestine.  The uptake of potassium ions from the soil to the root hair cell. Passive transport: - Does not require energy to move substances/molecules. o Examples:  Simple Diffusion: the net movement of particles from an area of high concentration to low concentration (occurs naturally; along the concentration gradient).  Facilitated Diffusion: Uses specialized proteins (channels or carriers) to help move molecules down the concentration gradient (high to low).  Osmosis: specialized diffusion where molecules diffuse through a semi permeable membrane (selective membrane that only allows certain molecules to pass through).  Example of osmosis: o Kidney Dialysis/hemodialysis:  The dialyzer removes waste from a patient’s blood through a dialyzing membrane (semipermeable membrane). Reb blood cells are separated from the waste. New dialysis fluid it pumped with the red blood cells back to the body. Important terms: - Concentration gradient: when two solutions of different concentrations are separated by a membrane. - Concentrated solution: A solution with many solute particles dissolved in a volume of solution. - Dilute solution: A solution with a few solute particles dissolved on a volume of solution. - Osmoregulation: the control of water inside a cell or organism. - Hypotonic solution: a dilute solution with few dissolved solute particles. - Hypertonic solution: a concentrated solution with many dissolved solute particles. - Isotonic solution: two solutions with the same concentration of particles (solute and water). SURFACE AREA TO VOLUME RATIO (credit: Mrs. Mulitalo) ___________ Genetics: the study of heredity and variations.  Heredity: concerned with how genes are transferred from one generation to another.  Variation: the differences that exist between individuals, i.e., Every individual or organism is unique (including identical twins). o Continuous variation: differences are not distinct i.e., ca (example, height, length of finger) o Discontinuous variation: differences are distinct (can be categorized) (example, ability to roll tongue, has a widow peak). Genetic material: contains genetic information that controls the function and structure of cells. Cell division: Process in which cells divide to form new cells. Two types of cell division:  Mitosis: cell division for growth and repair (somatic cells).  Meiosis: cell division for creating gametes (sex cells) ___________________________________________________________________________________________________________________________________________  Important terminology: o Somatic cells: all body cells except for gametes. o Gametes: a term given to sex cells (sperm and ovum) o Chromosome: condensed or coiled up DNA molecule. o Diploid cells (2N): cell containing 46 chromosomes (23 paternal and 23 maternal chromosomes). o Haploid cells (1N): cell containing 23 chromosomes. o Chromatid: a single strand chromosome (before DNA replication). o Sister chromatids: two pairs of identical chromatids held together at the centromere (result of DNA replication). o Centromere: the most constricted region of a chromosome. o Homologous chromosomes: Identical chromosomes (same height and gene placement) with slight variations of alleles. o Parent cell: cell that has or will undergo cell division. o Daughter cell: resulting cells from cell division.  Mitosis: o Only somatic cells undergo mitosis. o This cell division Is where one single cell, called the parent cell, divides to form 2 identical cells, called the daughter cells. o The four stages of mitosis are: Prophase, Metaphase, Anaphase and Telophase (PMAT).  Prophase: Chromosomes condenses making them more visible and nucleus begins to disappear.  Metaphase: Nucleus fully disappears and chromosomes line up in the middle of a cell.  Anaphase: Centrioles go to opposite ends of a cell and create spindles to pull apart chromosomes o Spindles are thread-like structures (microtubules). o Chromosomes are pulled apart to opposite sides of the cell.  Telophase: Once chromosomes have been pulled apart to opposite poles, the cytoplasm starts to divide before the cell membrane divides to form 2 new 100% identical cells. o Before a cell can undergo the four stages of mitosis, they undergo Interphase.  Cells spend 90% of it’s lifetime in interphase.  In this phase, cells are carrying out their normal cellular functions, growing bigger in size.  DNA is also being copied to form 2 sister chromatids. *1 chromatid= 1 chromosome *2 chromatid= 1 chromosome  Meiosis: o Only gametes (sex cells) undergo meiosis. Definitions:  Sperm: male sex cell  Ovum or egg: female sex cell o Cell division occurs two times resulting in two stages: Meiosis I and Meiosis II. In other -Crossing over: when homologous words, PMAT occurs two times: chromosomes pair up and sit over each  Prophase 1: Starts with a Diploid cell. Homologous chromosomes pair up to other. swap genes (crossing over and recombination). As a result, genetically distinct chromosomes are formed. Nucleus also disappears in this phase. -Recombination: When alleles from each  Metaphase 1: Homologous Chromosomes line up in the middle. homologous chromosomes swap to form  Anaphase 1: Homologous Chromosomes are pulled apart by centrosomes. a chromosome with new combination of  Telophase 1: Cytoplasm divides and two daughter cells are formed. alleles  Prophase 2: No crossing over occurs.  Metaphase 2: Chromosomes line up in the middle and spindle fibers form again.  Anaphase 2: Chromosomes are pulled apart.  Telophase 2: Cytoplasm divides and nuclear membrane form around the chromosomes. After, membrane pulls apart to form a total of 4 cells. (Haploid cells). 