RNA, transcription, and translation study guide

differences between DNA and RNA
1) the sugar in RNA is ribose, sugar in DNA is deoxyribose
2)there is uracil in RNA instead of thymine in DNA
3)RNA is single stranded, DNA is double stranded
4) RNA molecules are smaller than DNA molecules
3 main types of RNA
mRNA: carries genetic information from DNA to ribosomes for the making of proteins
rRNA: combines with proteins in ribosmes
tRNA: smallest type of RNA, brings amino acids to the ribosome for making proteins
structure of RNA
acceptor stem: 3′ end with nucleotide sequence ACC, attaches to amino acid
Anticodon: a series of 3 bases that compliment 3 bases on mRNA
central dogma
DNA -> RNA -> Protein
gene activation
during gene activation histones are temporarily removed, and the portion of the DNA molecule containing the gene to be transcribed is uncoiled
transcription
The production of RNA from a DNA template, mRNA is necessary because DNA cannot leave the nucleus, it is a copy of one of the DNA strands to be carried out of the nucleus and used to produce protein
introns and exons
introns do not code for DNA exons do code for DNA
The genetic code
the genetic code consists of a series of 3 nucleotides in mRNA, each of these triplets is called a codon. Each codon in an mRNA specifies an amino acid
translation
The production of a protein from an mRNA template. codons are converted on mRNA into amino acids to build a protein
mRNA in translation
Binds with ribosomal subunits, the first codon AUG is the start codon
Epigenetics
the study of factors that affect gene expression in a heritable way but that do not alter the nucleotide sequence of DNA
epigenetic changes
alteration of a chromatin or DNA structure
Epigenetics: histone modification
histones can either stop or speed up transcription.
acetylation of histones loosens the folding of chromatin increasing transcription of those genes
Epigenetics: DNA Methylation
suppresses the expression of genes which means that transcription cannot occur
viruses
lack nucleotides and enzymes necessary to synthesize proteins and grow
retrovirus
virus that contains RNA as its genetic material. contains reverse transcriptase, which is an enzyme that uses viral RNA template to synthesize complementary strands of DNA. It also contains integrase which inserts the val DNA into the host cell DNA so that it can be replicated with the host DNA
reverse transcription
Viral DNA is incorporated into host DNA by integrase, the host cell replicates the viral DNA and viral proteins are synthesized and new virions are released
Mutations
permanent changes in the nucleotide sequence of DNA, they can be caused by errors that go uncorrected during the copying of DNA, exposure to x-rays or ultraviolet light, mutagens and some sviruses