Biology Topic 2 Molecular Biology

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11th grade Biology Flashcards on Biology Topic 2 Molecular Biology, created by Hannah Hercher on 29/07/2017.
Hannah Hercher
Flashcards by Hannah Hercher, updated more than 1 year ago
Hannah Hercher
Created by Hannah Hercher over 7 years ago
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Topic 2 Molecular Biology
2.1 Molecules to metabolism Molecule smallest part of a compound, which has the chemical properties of that compound !! Elements exist in ionic compounds!!
anions and cations anion - negatively charged -> gained electron cation - positively charged -> lost electron
electrophilic atom electrophilic - loves water
Bonding ionic - looses electrons ionic bonds - one atom looses e- the other gains the e- covalent - shares electrons polar covalent binding - sharing electrons. The atom that's more electrophilic pulls other atom closer
Polar Covalent bonds (eg)
Glycerol
Types of carbon - based compounds polymers - many units monomers - one unit many attached monomers make up one polymer
Anabolism vs Catabolism Anabolism - synthesis of new compounds (make macromolecules from monomers) A+B->AB Catabolism - makes smaller molecules from macromolecules AB->A+B
Glucose Alpha vs Glucose Beta
Condensation reaction Names for it: Condensation reaction, synthesis reaction or dehydration reaction looses/produces one water molecule
Hydrolisis break- down of water
dimer and tetramer two( monomers) up to ten then it's a polymer tetramer - 4
Hydrolysis reaction Names for it: Hydrolysis reaction or decomposition reaction (water included in reaction)
Polypeptide many AA's (amino acids) attached to another also: polypeptide - many smaller molecules that make up proteins/long chains of AA's.
Difference polypeptide and protein usually (not always) a protein is made of several polypeptides hence: monomer of proteins - > AA's
Proteomics Functions of proteins - Defense -Communication - Structure -Enzymes -Transport -storage
Proteome a collection of proteins produced by a cell, tissue or organism - tells you what you are predisposed to e.g. breast cancer
Enzymes Most enzymes are proteins They are biological catalysts (speeding up reactions) AND are not changed by the reaction
Structure of DNA & RNA - DNA & RNA molecules are polymers - their monomers are called: nucleotides
Nucleotides consist of: * a pentose sugar (Deoxyribose in DNA) * a phosphate group (acidic + negatively charged) * a nitrogenous base - Adenine (A) -Guanine (G) -Cytosine (C) -Thymine (T)
DNA base pairing Guanine and Cytosine
DNA base pairing Adenine and Thymine
DNA replication, transcription and translation
Replication DNA copying -happens in the synthesis (s phase) of interphase
Experiment: Meselson & Stahl Background - carried out in 1958 which supported the hypothesis that DNA replication was semiconservative - when the double stranded DNA helix is replicated, each of the two new double-stranded DNA helices consisted of one strand from the original helix and one new one - nitrogen is found in the nitrogenous bases of each nucleotide, they decided to use an isotope of nitrogen to distinguish between parent and newly copied DNA. The isotope of nitrogen had an extra neutron in the nucleus, which made it heavier.(N15) E. coli was grown for several generations in a medium containing NH4Cl with 15N. When DNA is extracted from these cells and centrifuged on a salt (CsCl) density gradient, the DNA separates out at the point at which its density equals that of the salt solution. The DNA of the cells grown in 15N medium had a higher density than cells grown in normal 14N medium. After that, E. coli cells with only 15N in their DNA were transferred to a 14N medium and were allowed to divide; the progress of cell division was monitored by microscopic cell counts
Experiment: Meselson & Stahl Procedure - nitrogen is found in the nitrogenous bases of each nucleotide, they decided to use an isotope of nitrogen to distinguish between parent and newly copied DNA. The isotope of nitrogen had an extra neutron in the nucleus, which made it heavier.(N15) E. coli was grown for several generations in a medium containing NH4Cl with 15N. When DNA is extracted from these cells and centrifuged on a salt (CsCl) density gradient, the DNA separates out at the point at which its density equals that of the salt solution.
Experiment: Meselson & Stahl Results The DNA of the cells grown in 15N medium had a higher density than cells grown in normal 14N medium. After that, E. coli cells with only 15N in their DNA were transferred to a 14N medium and were allowed to divide; the progress of cell division was monitored by microscopic cell counts
Experiment: Meselson & Stahl Results cont. DNA was compared to pure 14N DNA and 15N DNA. After one replication, the DNA was found to have intermediate density. Since conservative replication would result in equal amounts of DNA of the higher and lower densities (but no DNA of an intermediate density), conservative replication was excluded. However, this result was consistent with both semiconservative and dispersive replication. Semiconservative replication would result in double-stranded DNA with one strand of 15N DNA, and one of 14N DNA DNA from cells after two replications had been completed was found to consist of equal amounts of DNA with two different densities, one corresponding to the intermediate density of DNA of cells grown for only one division in 14N medium, the other corresponding to DNA from cells grown exclusively in 15N medium. This was consistent with semi conservative replication
Replication (detail) DNA-> DNA - starts at origin of replication site - Helicase unwinds DNA helix (unzips) creating a fork - single strand binding proteins stabilize 2 separate strands of DNA. Needed because of: elastic potential energy -> snaps back when released - Primase - adds primer where DNA Polymerase can start - DNA polymerase adds nucleotides
Replication Fork
Lagging strand vs Leading strand lagging strand - 3' - 5' direction leading strand - 5' - 3' direction
Transcription DNA->RNA - similar to replication - RNA polymerase unwinds the DNA strand so that the base sequence can be copied -RNA polymerizes the RNA nucleotides in order for those two things to BE POSSIBLE RNA polymerase must first combine with a promoter - RNA (which includes mRNA) is a single stranded molecule hence, only ONE of the two DNA strands will be used as a template to create the mRNA molecule
Transcription visualized
Complementary Base pairing differences! everything remains the same binding EXCEPT: Adenine (A) on the DNA is now paired with Uracil (U) on the newly forming mRNA molecule
IMPORTANT -> Transcription only one of the two strands of DNA is copied the other strand is not used
Cell respiration (book definition) making energy in the form of ATP by mitochondria takes place in EVERY cell in our body!
Cell respiration (syllabus definition) controlled release of energy from organic compounds to produce ATP
ATP Adenosine Tri Phosphate - negatively charged
Aerobic respiration Produces: 36 ATP/Gluc net: 2ATP/Gluc WITH oxygen
Anaerobic respiration WITHOUT oxygen Alcoholic Fermentation Glucose-> ethanol + CO2 Lactic Acid Fermentation Glucose-> lactic acid (causes oxygen debt) - regulated breathing needs oxygen to break down the lactic acid (oxidizing) lactic acid ->> HARMFUL
Glycolysis breaks down glucose into pyruvate Glyco - glucose lysis - break- down Needs to happen in order for respiration to take place
Bioethanol - bacteria used to ferment wastes - ethanol produced - renewable energy source
Bioreactor manufactured or engineered device or system that supports a biologically active environment
Photosynthesis production of carbon compounds in cells using light energy
Chlorophyll (photosynthesis) - chlorophyll absorbs red and blue light most effectively and reflects green light more than other colours
Visible light visible light has a range of wavelengths with violet being the shortest and red the longest wavelength
Photolysis of water break - down of water to give oxygen (to provide for electrons) happens from energy of photons
Gaffron's Experiment
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