nucleotide composition
sugar + phospahte group + single or double ringed nitrogenous base
Purines
nitrogeneous bases that have a double ring of carbon and nitrogen atoms such as adenine and guanine
Pyrimidines
nitrogenous bases that have a single ring of carbon and nitrogen atoms, such as cytosine, thymine, and uracil
# of genes in human body
20,000-50,000
centromere
area where the chromatids of a chromosome are attached
kinetochore
A specialized region on the centromere that links each sister chromatid to the mitotic spindle.
mRNA
template for protein synthesis: type of RNA that carries instructions from DNA in the nucleus to the ribosome
tRNA
The type of RNA that binds to specific amino acids and transports them to the ribosome during protein synthesis
rRNA
The most abundant type of RNA, which together with proteins froms the structure of ribosomes.
codon
three-nucleotide sequence on mRNA that codes for a single amino acid
transcription
process of copying genetic instructions from DNA to RNA
RNA polymerase
an enzyme that pries the 2 strands of DNA apart and hooks together the RNA nucleotides as they base pair along the DNA template
translation
process of converting nucleotide language into amino acids
anticodon
group of three bases on a tRNA molecule that are complementary to an mRNA piece
initiation
mRNA leaves nucleus and forms loop, tRNA comes to meet it, ribosomes attach along the loop
Elongation
subsequent tRNAs add more amino acids to the protein along the mRNA loop
Termination
Stop codon releases mRNA from ribosome
polyribosome
cluster of ribosomes all translating the same mRNA
DNA helicase
The enzyme that unzips and unwinds the double helix (2 DNA strands), breaks apart the hydrogen bonds between the complimentary base pairs.
DNA polymerase
enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
homologous pair
a pair of chromosomes, one from each parent, that have relatively similar structures and gene values
haploid
of a cell or organism having a single set of chromosomes
diploid
term used to refer to a cell that contains both sets of homologous chromosomes