Nucleotides & Properties of Water
Nucleotides & Properties of Water 1330
Popular in Functional biology
verified elite notetaker
Popular in Life and Physical Sciences
This 5 page Class Notes was uploaded by Zaida Gomez on Friday September 23, 2016. The Class Notes belongs to 1330 at Texas State University taught by Aglaia Chandler in Fall 2016. Since its upload, it has received 6 views. For similar materials see Functional biology in Life and Physical Sciences at Texas State University.
Reviews for Nucleotides & Properties of Water
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 09/23/16
Chemical Level of Organization: Nucleotides Nucleotides & Nucleic Acids Nucleotides- composed of a nitrogen base, a sugar, and at least one phosphate group Nucleosides- composed of only a sugar and a base ATP/ADP Cycle - When adenosine triphosphate (ATP) gives up a phosphate group, adenosine diphosphate (ADP) forms - ATP can re-form when ADP binds to inorganic phosphate or to a phosphate group that was split from a different molecule - Regenerating ATP by this ATP/ADP cycle helps drive most metabolic reactions When one of the phosphates is removed, energy is released and can be used to do work in the cell - Builds or breaks down molecules - Moves materials into and out of cells High-Energy Compounds ATP is made by the cell using glucose (or fats) as fuel Nucleic Acids - Composed of nucleotides - Single or double stranded - Sugar phosphate backbone DNA and RNA Structure Basic unit: nucleotide; nucleoside Nitrogenous Bases: - Purines (A- adenine, G- Guanine) - Pyrimidines (C, cytosine, T- thymine—DNA, U- uracil—RNA) The structure of these nitrogenous bases differentiate nucleotides from each other The Double Helix- DNA secondary structure - Sugar phosphate backbone is the outside - Bases (hydrogen bonded) are inside - Backbone is antiparallel - Major/Minor grooves DNA Double-stranded Consists of four types of nucleotides A to T (2 hydrogen bonds) C to G (3 hydrogen bonds) RNA Usually single strands Four types of nucleotides Unlike DNA, contains the base Uracil in place of Thymine Sugar In RNA the pentose sugar is ribose In DNA the pentose sugar is deoxyribose Nucleic Acids DNA- large molecule that encodes the “blue prints” for an organism’s development and growth - Gene- segment of DNA containing the information for the synthesis of a functional biological product RNA- intermediate in the decoding of DNA into protein; genes in DNA are copied into an RNA molecule through a process called Transcription and the RNA is then decoded (translated) into amino acids that make protein 1. Ribosomal RNA (rRNAs): ribosome components 2. Messenger RNAs (mRNAs): carry genetic info from genes to ribosomes 3. Transfer RNAs (tRNAs): adapter molecules in translation of mRNA info into a specific sequence Denaturation - Refers to the melting of double stranded DNA to generate two single strands - Involves breaking of H bonds between bases in the duplex - Heating is the most common way When DNA is heated to 80+ degrees Celsius, the DNA double helix can unwind When T is lowered, the strands re associate Transcription/Translation Transcription- the copying of DNA into mRNA Translation- synthesis of a protein using MRNA strand Energy Reserves Glycogen makes up only about 1% of the body’s energy reserves Proteins make up 21% of energy reserves Fat makes up the 78% of reserves Carbohydrate Breakdown and Storage - Glucose is absorbed into blood - Pancreas releases insulin - Insulin stimulates glucose uptake by cells where it can be used for energy production or storage Making Glycogen - If glucose intake is high, ATP-making machinery goes into high gear - When ATP levels rise high enough, glucose is diverted into glycogen synthesis (mainly in liver and muscle) - Glycogen is the main storage, polysaccharide in animals Using Glycogen - When blood levels of glucose decline, pancreas releases glucagon - Glucagon stimulates liver cells to convert glycogen back to glucose and to release it to the blood - Muscle cells do not release their stored glycogen Dietary Fats Triacyglycerols (triglycerides) are the major energy input in the modern American diet 30-60% of the calories in the average American diet consequences include: increased obesity, diabetes, heart disease Energy from Proteins - Proteins are broken down to amino acids - Amino acids are broken apart - Amino group is removes, ammonia forms, is concerted to urea and excreted - Carbon backbones can enter the energy producing reactions Properties of Water (Acids, Bases, pH and Buffer) 1. Polarity 2. Temperature-Stabilizing 3. Solvent 4. Cohesive Water Is a Polar Covalent Molecule - Molecule has no net charge - Oxygen end has a slight negative - Hydrogen end has a slight positive charge Water is a Good Solvent - mammalian cells are 70% water 2/3 of our water is inside our cells 1/3 is outside our cells - Water is the solvent for biological systems - Hydrophilic compounds interact (dissolve) with water Polar compounds Ionic compounds Hydrogen bond with water Ex. sugar - Hydrophobic compounds do not interact with water Non polar compounds Repelled by water Ex. oil Hydrophobic Interactions A nonpolar substance does not dissolve in water The H-bond network of water reorganizes to accommodate the non-polar solute Non-polar substances tend to aggregate Amphipatic Molecules -molecules that contain both polar and non-polar groups The Addition of Solute Affects the Properties of Water A solute is a compound that is added to a solvent The physical properties of water are affected by the number of solutes added - Not mass or chemical property of solute - The effective concentration of water is lowered If water is separated by a semi-permeable membrane, water moves form the higher to lower concentration (osmosis- the diffusion of water through a cell membrane) - Osmotic pressure- pressure applied to solution to prevent the influx of water; the higher the solute concentration of a solution, the higher its osmotic pressure When a cell is in a solution with the same solute concentrate… Osmotic pressure is equal on both sides of the membrane No net movement of water through the membrane Temperature-Stabilizing Effects Liquid water can absorb much heat before its temperate rises (high heat capacity) Much of the added energy disrupts hydrogen bonding rather than increasing the movement of molecules Evaporation of Water Large energy input can cause individual molecules of water to break free into the air As molecules break free, they carry away some energy (lowering temperature) Evaporative water loss is used by mammals to lower the body temperature Ice Hydrogen bonds lock molecules in a lattice Water molecules in lattice are spaced farther apart than those in liquid water Ice is less dense than water, therefore, floats Water Cohesion Cohesion- attraction between like molecules Hydrogen bonding holds molecules in liquid water together Creates surface tension Surface tension-holds drops of water together in a round shape. It allows both water striders and paperclips to float on water even though they are denser. It also allows you to fill a cup slightly over the brim with water Allows water to move as continuous column upward through stems of plants Capillary Action Adhesion- the attraction between unlike object such as the attraction between water and another object (glass) Surface tension is also responsible for capillary actions. Capillary action- occurs when water climbs upward through a small space, defying gravity due to the forces of adhesion and surface tension The pH Scale - Measures of H+ concentration of fluid - Change of 1 on scale means 10x change in H+ concentration Examples: Pure water is neutral with pH of 7.0 Acidic- stomach acid (1.0-3.0) Lemon juice (2.3) Basic- Sea water (7.8-8.3) Baking soda (9.0) pH: symbol p means “negative logarithm of” “take the negative log (base 10) of the next thing that follows” pH= -log [H+] (the smaller the number the bigger the p) (the log of 1 is zero) Acids and Bases Acids- - Donate H+ when dissolved in water - pH<7 Bases- - Accept H+ when dissolved in water - when dissolved in pure water, base molecules will accept a hydrogen ion from a water molecule leaving behind an increased concentration of OH- ions in the solution - pH>7 Weak/Strong Acids Weak- Reluctant H+ donors, can accept H after giving it up (ex. Carbonic acid) Strong- completely give up H+ when dissolved (ex. Hydrochloric acid) Salts Compounds that release ions other than H+ and OH- when dissolved in water (NaCl) Ex. NaCl releases Na+ Cl- Many salts dissolve into ions that play important biological roles Buffer Systems Minimize shifts in pH Partnership between weak acid and base forms when dissolved Two work as a pair to counter shifts in pH Carbonic Acid-Bicarbonate Buffer System - When blood pH rises, carbonic acid dissociates to form bicarbonate and H+ - When blood pH drops, bicarbonate binds H+ to form carbonic acid