Biology - freshman year - second semester

DNA:

  • DNA stands for deoxyribose, nucleic acid

  • by the late 1800’s they knew that genes contained genetic information

  • by the early 1900’s they were pretty sure that chromosomes contained genes

  • chromosomes consist of both protein and DNA

  • genes carry info from 1 generation to the next, and can be replicated, or copied, easily

  • DNA is the “blueprint of life”

  • Dna contains the instructions for making proteins within the cell

  • located inside the nucleus in eukaryotic cells.

  • DNA is made of two nucleotide chains that twisr around to form a structure similar to a twisted ladder

  • The dna structure is made up of 4 different types of nitrogen bases:

guanine

cytosine

adenine

thymine

  • guanine ans cytosine always pairs together

  • adenine and thymine always pair together

  • the three parts of nucleotide is the phosphate group, deoxyribose sugar, and nitrogen bases.

DNA vs RNA

  • the job of the RNA in the cell is to make proteins

  • RNA stands for ribose nucleic acid

  • the nitrogen base that RNA has that DNA does not is Uracil

  • Uracil replaces Thymine

  • mRNA is the type of RNA that carries the DNA sequence that it copied from the DNA to the ribosomes to make the protiens

  • rRNA is the type of RNA that holds the structural components of ribosomes

  • tRNA is the type of RNA that provides linkage between mRNA and amino acids and brings amino acids to ribosomes.

  • tRNA = transfer RNA

  • rRNA = ribosomal RNA

  • mRNA = messenger RNA

DNA → RNA → Protein → trait

  • transcription between DNA and RNA

  • RNA processing between RNA and DNA

  • Translation between RNA and Protein

  • RNA forms base pairs within a single strand, but RNA is not a perfect straight line

  • transcription is the first process in gene expression, in which transcription is when an RNA (specifically mRNA) makes a copy of DNA

  • Transcription MUST occur in the nucleus because thats where the DNA is stored

  • for transcription, the first part is when the enzme RNA polymerase opens the DNA strands by bonding to the beginning of the gene. The second part is when the RNA polymerase adds complementary RNA Nucleotides to one side of the DNA

  • the third step is that the chain of RNA begins to grow

  • finally, once RNA ploymerase reaches a STOP signal, the copying will stop and the mRNA will detach from the DNA