Chapter 2 - Nucleic Acids Flashcards
What is the difference between DNA and RNA in all living organisms?
DNA is the genetic store of information, whereas RNA transfers this genetic information to the ribosomes
What are ribosomes made of?
They are made up of proteins and ribosomal RNA
What is a nulceotide and what is its structure?
Nucleotides are the monomers which DNA and RNA are formed of, and contain a backbone of an inorganic phosphate ion and deoxyribose sugar (ribose sugar in RNA) and one of four different nitrogenous bases.
What are the 4 nitrogenous bases, what do they bond to and how is this different in RNA
Adenine bonds to thymine and cytosine bonds to guanine in DNA, however in RNA, uracil replaces thymine and instead bonds to adenine.
How is DNA formed from nucleotides?
The nucleotides are bonded together by DNA polymerase in a condensation reaction, forming a phosphodiester bond
What is the semi-conservative model of replication?
It is where between each generation one of the original strands of the DNA is kept and copied perfectly, which forms 2 double stranded helices each with one new strand and one original strand.
What were the two alternative suggested models?
Conservative and dispersive replication. Conservative where the both strands of the original DNA would be conserved and another DNA would be made, and dispersive is where different parts of each strand were cut up and replaced with new DNA.
How does semi conservative replication occur in the nucleosome?
The double helix is unwound by DNA helicase, exposing both strands of DNA. The free nucleotides will then base pair and form a new strand of complementary DNA to each strand, and these new strands are bonded together by phosphodiester bonds by DNA polymerase
What is the structure of ATP?
It is adenosine triphosphate, or an adenine base bonded to a ribose sugar which is bonded to a chain of 3 different phosphate groups.
Why and how is ATP broken down?
ATP is broken down by ATP hydrolase, and turns from ATP to ADP which is a very energetically favourable process, releasing large amounts of energy which is required for some reactions. Also the released phosphate group can be used to phosphorylate molecules which makes them much more reactive.
How is ATP formed?
ATP is formed from ADP and an inorganic phosphate ion (Pi) by ATP synthase suring photosynthesis and respiration, however substrate level phosphorylation can also occur which doesn’t require ATP synthase.
Why is water so useful in animal cells?
It is often used as a metabolite in basic cell processes, such as hydrolysis and condensation reactions.
It is a buffer, meaning that cells don’t heat up or cool down too quickly which is essential for proteins.
It is the “universal solvent” and therefore is able to facilitate the majority of reactions as the medium.
Why is the properties of water so useful to plants?
It is cohesive, or “sticky”, to itself, meaning it can be transported in columns of water without metabolic energy being expended in xylems.
What are some examples of inorganic ions and their uses in organisms?
Calcium is essential for bone development and muscle contraction
Sodium and potassium are necessary for nerve impulses, as well as sodium being used in co transport
Hydrogen ions are used for pH balancing and digestive enzymes.
