a1.2 nucleic acids

Flashcards on Nucleic Acids, DNA, RNA structure and function.

Deoxyribonucleic acid (DNA)

The molecule that allows storage of genetic information for all living things (viruses can use RNA).

Indicative of a common ancestor, otherwise it would have required all living things to develop the same molecule separately

Mutations in DNA are what allow for evolution to occur as we pass down genetic information to the next generation

all cells have the same DNA but expression of certain genes gives cells specialized functions

Mutations in DNA

Allow for evolution to occur as we pass down genetic information to the next generation.

Function of DNA

As genes to make proteins that have a certain function is shared by all living things.

Multicellular Organism & DNA

All cells have the same DNA, but expression of certain genes gives the cells their specialized function.

Nucleotides

Made up of a phosphate group, a five carbon pentose sugar (deoxyribose or ribose), and one of five nitrogenous bases.

DNA nitrogenous bases

Adenine, guanine, cytosine, & thymine.

RNA nitrogenous bases

Adenine, guanine, cytosine, & uracil.

Nucleic Acids

DNA & RNA are polymers made up of repeated nucleotides.

Condensation Reaction

The hydroxyl of one molecule and the hydrogen of another break off to form water and join the two smaller molecules or monomers together.

DNA & RNA Formation

Polymers Formed from Condensation of Nucleotide Monomers

Hydroxyl of one nucleotide and a hydrogen of another join to make water

this allows 2 nucleotides to join in a condensation reaction with water as a byproduct

3rd carbon in the sugar of one nucleotide is linked to the phosphate group on the 5th carbon in the sugar of another nucleotide

Directionality of DNA & RNA

During the processes of DNA replication & transcription, single nucleotides are added to a growing strand in a 5’ to 3’ direction.

First nucleotide of the new strand will be on the 5th end

Each subsequent nucleotide will attach its phosphate RO the third carbon of the previous nucleotides sugar forming a sugar phosphate backbone

last nucleotide of the new strand will have a hydroxyl on the third carbon of the sugar (3 end)

Complementary base pairing

Plays an important role in replication. A=T AND G=C

Pentose Sugar in DNA

Deoxyribose

Pentose sugar in RNA

Ribose

DNA - Number of strands

Double stranded (forms a double helix)

RNA - Number of strands

Single stranded

Messenger RNA (mRNA)

Synthesized from a section of DNA (a gene); genetic information necessary to make a polypeptide.

Transfer RNA (tRNA)

Synthesized from a segment of DNA; transfers the correct amino acid onto a growing chain of amino acids during the making of polypeptides.

Ribosomal RNA (rRNA)

Synthesized from a segment of DNA; combines with previously synthesized polypeptides to make ribosomes. Ribosomes are organelles that are the site of making polypeptides.

Adenosine triphosphate (ATP)

A single nucleotide and is used to transfer chemical energy throughout a cell or organism.

Chargaff’s Data on Base Pairs

The amount of Adenine equals the amount of Thymine, the amount of Guanine equals the amount of Cytosine, and the amount of purines equals the amount of pyrimidines.

Tetranucleotide Hypothesis

Data falsified tetranucleotide hypothesis of repeating sequence and equal amounts of the 4 bases.

Role of Complementary Base Pairing

Ensures that copies of DNA that will be in new cells are the same. Same DNA results in consistent protein synthesis and gene expression.

Purine-to-Pyrimidine Bonding

The tight packing of DNA would only be possible if equal sized bases paired together to make parallel strands (a purine paired with a pyrimidine) and if one strand were upside down (antiparallel).

Limitless Diversity & Storage Capacity of DNA Sequences

Various lengths and base sequences allows great storage in small space

Triplet Codon

Represents a meaningful bit of information by coding for a specific amino acid. There are 64 possible triplet codons. The sequence of these triplet codons determines the sequence of amino acids and the functionality of that piece of DNA.

Nucleosome

DNA around 8 histones with one histone to linker DNA. Supercoil chromosomes and help regulate transcription in eukaryotes

Hershey-Chase Experiment

Experiment showed DNA to be the genetic material by use of a virus infecting a bacterium.