A1 Molecules Flashcards

Question

Ribose / deoxyribose (Pentose sugar)

Answer 1

5 carbons, 1 oxygen C to the right of O is C₁, the carbons following in a clockwise manner are C₂, C₃ and C₄ connecting back to O C₅ comes off of C₄ connecting to the phosphate group

Answer 2

Phosphorous connected to 2 O⁻ molecules with a single bond, one -OH group, and double bonded to one O One of the O⁻ molecules loses the - when connected to sugar

Answer 3

DNA: - Adenine - Thymine - Guanine - Cytosine RNA: - Adenine - Uracil - Guanine - Cytosine Purines (double rings): A, G Pyrimidines (single rings): T, U, C

Answer 4

Removal of water to create a bond

Answer 5

2 nucleotide molecules can join together with a phosphodiester bond -OH on the phosphate group and the -OH coming off of C₃ of the ribose can condense, leaving an O between them in covalent bonds Water (H₂O) comes off as a byproduct

Answer 6

Strands are parallel, but run in opposite directions Van der Waals (intermolecular forces) i.e. hydrogen bonds connect between bases of different strands

Answer 7

A-T (U in RNA) and G-C A-T have 2 hydrogen bonds G-C have 3 hydrogen bonds

Answer 8

longer polymer of nucleotides double stranded deoxyribose sugar adenine pairs with thymine

Answer 9

shorter polymer of nucleotides single stranded ribose sugar adenine pairs with uracil

Answer 10

Each resulting copy is made of one parents strand and one new strand

Answer 11

Using the codes in DNA to synthesise a protein

Answer 12

DNA -> RNA -> protein These steps follow rules of complementary base paring

Answer 13

DNA molecules can vary in length Many possibilities for unique sequences DNA is only 2 nm in diameter, so cells can store long lengths of DNA 1 nm = 1×10⁻⁹ m (0.000000001 m)

Answer 14

Same codons (3 base pairs) on RNA code for same amino acids in almost every organism Universal genetic code Evidence that all life arose from a universal common ancestor

Answer 15

5' end and 3' end 5' is where phosphate of same nucleotide is connected (C₅) 3' is where phosphate of different nucleotide attaches (C₃) Antiparallel: 5'-3' vs 3'-5' New nucleotides can only be attached to 3'

Answer 16

DNA wrapped twice around a core of 8 histone proteins Additional H1 histone stabilises the nucleosome and helps condense the DNA Joined by linker DNA Eukaryotes have nucleosomes Prokaryotes have naked DNA and no histone proteins

Answer 17

1950s Knew chromosomes were made of DNA and protein and that they carried genetic information Which was responsible for transmitting hereditary information: DNA or protein? Viruses are also made up of DNA and protein

Answer 18

Bacteriophages Marked some with sulphur which adheres to proteins - radioactive protein coat Marked others with phosphorous which adheres to DNA Allowed marked viruses to infect bacterial cells Viruses inject genetic information Mixture of bacteriophage remnants and infected cells were placed into centrifuge, which spun them around and separated them by weight Cells are heaviest and go towards the bottom They noticed the marked DNA was the one in the cell

Answer 19

Tetranucleotide hypothesis: DNA consisted of a repeating sequence of 4 nucleotides in equal amounts and proteins were the genetic material Tested the nucleotide composition of several species Variation across different life forms (falsification of tetranulceotide hypothesis) Complementary base pairing