More biological molecules Flashcards
What does DNA stand for?
deoxyribonucleic acid
What does RNA stand for?
ribonucleic acid
What is the structure of a nucleotide?
pentose sugar, phosphate group and a nitrogenous base
What bond forms when nucleotides are joined together?
-Phosphodiester bond
-Ester bonds
Describe the structure of DNA
-Double helix
-Adenine and thymine, cytosine and guanine complementary
-H bonds between bases
-Antiparallel strands
-Sugar-phosphate backbone
What are the differences between RNA and DNA?
RNA:
-Ribose sugar
-Uracil, not thymine
-Single polynucleotide strand, not double
-Much shorter than DNA
Describe the process of semi-conservative replication
-DNA helicase unwinds and unzips the DNA, by breaking H bonds between bases
-Single strands act as a template, free nucleotides lined up and attached to CBP
-DNA polymerase catalyses the reaction joining nucleotides to template strand
-Each new DNA molecule contains one original strand and one new strand
What direction does DNA polymerase move in?
-3’ to 5’ direction
What does ATP stand for?
-Adenosine triphosphate
What did Meselson and Stahl’s experiment prove?
-Semi-conservative replication
What does ATP consist of?
-Adenine
-Ribose
-3 phosphate groups
What reaction does ATP hydrolase catalyse?
-The breakdown of ATP
What does ATP synthase catalyse?
-The synthesis of ATP
What are the 5 importances of water?
-It is a metabolite
-It is a solvent
-High latent heat of vaporisation
-High specific heat capacity
-Cohesive
Describe the structure of water
-H20
-H slightly positive, O slightly negative
-Polar molecule
-Hydrogen bonding
Why is water being a metabolite important?
-All hydrolysis and condensation reactions are metabolic reactions
-Energy from ATP is released during a hydrolysis reaction
Why is water being a good solvent important?
-One side of molecule is negative and one side is negative
-Ions will be entirely surrounded by water, so they will dissolve
-Useful substances can be taken up and dissolved in water and transported around the body
Why is water having a high latent heat of vaporisation important?
-Water requires a lot of energy to be turned from a liquid into a gas
-Can be used to cool organisms down without losing too much water
Why is water having a high specific heat capacity impoprtant?
-When water is heated, most of the energy is used to break the hydrogen bonds, so temperature doesn’t raise quickly
-Makes water a good habitat as temperature doesn’t experience rapid changes
-Helps organisms maintain a constant internal body temperature
Why is water being cohesive important?
-Good for transporting substances
-Water travelling up xylem
-High surface tension
-Allows sweat droplets to form
What is a cation?
-Ion with a positive charge
What is an anion?
-Ion with a negative charge
Why are iron ions important?
-In haemoglobin
-Oxygen binds to them
Why are hydrogen ions important?
-Control blood pH
-Affect enzyme-controlled reactions
Why are sodium ions important?
-Co-transport with glucose and amino acids
Why are phosphate ions important?
-In DNA, RNA and ATP
