okazaki fragment

tRNA

reads mRNA to be complementary to it. (3' -5') -90 nucleotides long. -undergoes POST-TRANSCRIPTIONAL MODIFICATION -raw tRNA contains introns which must be excised Functions: 1. Covalently Bonds to its specific A.A. at one end (CCA stem) with amino acid -acyl tRNA synthetase 2. Conects to ribosomes 3. Base pairs w/ mRNA (codon; tRNA= anti codon)

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome. "workbench"

intron

sequence of a eukaryotic gene's DNA that is not translated into a protein. CALLED SPACERS

Primer

strand of nucleic acid that serves as starting point for DNA synthesis on lagging strand

chromosome

a single package of DNA that contains many genes, regulator elements and other nucleotide sequences including HISTONE PROTEINS.

DNA polymerase III

adds nucleotide, only in 5' - 3' direction (can add only)

Holandric Traits

carried only on the Y chromosome

Bar Bodies

number of X chromosomes minus 1

Okazaki fragment

A short segment of DNA synthesized on a template strand during DNA replication. Many Okazaki fragments make up the lagging strand of newly synthesized DNA. 100-200 nucleotides long in Eukaryotes.

Start Codon

AUG = methionine

Pre Natal Diagnosis (birth defects)

Amniocentesis- 14th to 16th week gestation Chronic Villi Method- 10th to 12th week of gestation. Risk of spontaneous abortion=1%

transcription

(genetics) the organic process whereby the DNA sequence in a gene is copied into mRNA.

translation

(genetics) the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm

Aneuploidy

Cells that have extra chromosomes or chromosomes missing. Monosomy (2n-1) =45 chromosomes Trisomy (2n+1) 47 chromosomes

mRNA

Messanger RNA. messanger from DNA to cytoplasm to make polypeptides (amino acid sequences). (mRNA= 5' to 3')

Translocation

Ribosomes move 3 nucleotides to the right along the mRNA. mRNA moves through the groove between the two sub units like a tape recorder. Movement is really dependent upon random motion and accidental, but predictable collisions.

Stop Codons

UAG, UGA, UAA