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Terms in this set (18)
What is nucleotide structure?
Pentose sugar, phosphate group and an N-conatining organic base
How are mononucleotides joined together?
Condensation reaction between sugar and phosphate group to form a phosphodiester bond
What is RNA structure?
A single, short polynucleotide chain, with ribose sugar and the bases A, G, C, U
What is DNA structure?
Deoxyribose sugar, the bases A, T, C and G, and two strands joined by H bonds between bases
How does a double helix form?
The uprights of phosphate and deoxyribose wind around one another to form a double helix which forms the structural backbone
Why is DNA stable?
The phosphodiester backbone protects the more chemically reactive organic bases in the double helix
H bonds form bridges between phosphodiester uprights (3 H bonds between C and G)
Base stacking- interactive forces
What is the function of DNA?
It is a hereditary material that passes genetic information from cell to cell, generation to generation
What are the adaptations of DNA?
Very stable- rarely mutates generation to generation
Only H bonds between strands- separate during DNA replication and protein synthesis
Large molecules- carries lots of genetic information
Base pairs in helical cylinder- genetic information isn't corrupted by outside chemical and physical forces
Base pairs- DNA can replicate and transfer information as mRNA
What are the requirements for semi-conservative replication?
Four types of nucleotide present
Both DNA strands template for attachment of nucleotides
Enzyme DNA polymerase
How does semi-conservative replication take place?
DNA helicase breaks H bonds linking base pairs of DNA so the double helix unwinds and strands separate. Each exposed polynucleotide strand acts as a template so complementary free nucleotides bind by specific base pairing. The nucleotides are joined in condensation reactions by DNA polymerase to form the missing polynucleotide strand on each of the two original polynucleotide strands of DNA. Each new DNA molecule has one original DNA strand, so half of the original DNA is saved
What facts helped figure out the semi-conservative model?
All bases contain N
N has two forms: lighter 14N and heavier 15N isotope
Bacteria incorporate N from growing medium to new DNA they make
How was the semi-conservative model figured out?
The original DNA is grown on 15N medium, then on 14N medium for a single generation. If centrifuged, the lighter DNA is at the top
What is the structure of ATP?
It's a phosphorylated macromolecule
Adenine- N containing organic base
Ribose- backbone other parts are attached to
Phosphates- chain of three phosphate groups
How does ATP store energy?
Bonds between phosphate groups are unstable so have a low activation energy, so they can be easily broken and release lots of energy
How is ATP synthesised?
Through a condensation reaction between ATP and an inorganic phosphate
How is ATP synthesised in organisms?
Chlorophyll containing plant cells during photosynthesis
Plant and animal cells in organisms
Plant and animal cells when phosphate groups are transferred from donor molecules to ADP
Why is ATP a good energy source?
It is an immediate energy store
What is the role of ATP?
Metabolic processes- energy to build up macromolecules from basic units
Movement- energy for muscle contraction
Active transport- energy to change the shape of carrier proteins
Secretion- form lysosomes for secretion of cell products
Activation of molecules- inorganic phosphate is released in hydrolysis of ATP can phosphorylate other compounds
OTHER SETS BY THIS CREATOR
Electrons and bonding