Bio test 2 Flashcards
Deoxyribonucleic acid
consists of four types of nucleotide subunits, and two chains are held together by hydrogen bonds between the base portion of the nucleotides.
base pair
a purine-pyrimidine pair
complementary strand
when an A pairs with a T and a C with a G on the opposing strand of DNA
genome
the complete set of information in an organisms DNA
chromosomes
very long double-stranded DNA molecules are packaged into structures called chromosomes
Karyotype
the display of the full set of 46 human chromosomes.
gene
a segment of DNA that contains the instructions for making a particular protein.
Cell cycle
DNA molecule is replicated and the replicated copies must be separated and partitioned reliably into daughter cells at each cell division.
replication origin
where replication of the DNA begins
telomeres
contains repeated nucleotide sequences that enable the ends of the chromosomes to be replicated.
centromeres
allows one copy of each duplicated cell chromosome to be apportioned to each daughter cell
nucleolus
where the parts of the different chromosomes carrying genes for ribosomal RNA cluster together
chromatin
the complex of both classes of proteins with nuclear DNA
Histones and Nonhistones
the proteins that bind to the DNA to form eucaryotic chromosomes
nucleosome
the first and most fundamental level of chromatin packing
chromatin-remodeling complexes
machines that use the energy of ATP hydrolysis to change the position of DNA wrapped around nucleosomes.
heterochromatin
the most highly condensed form of interphase chromatin
euchromatin
the rest of the interphase chromatin.
eu means true or normal
epigenetic inheritance
depends on passing along specifically modified histone proteins
primase
the enzyme that synthesizes the RNA primer
RNA polymerase
primase is an example of this.
synthesizes RNA using DNA as a template
carries out transcription
telomerase
replenishes the nucleotides that are lost each time a eucaryotic chromosome is duplicated by adding multiple copies of the same short DNA sequence to the chromosome ends
mutations
permanent changes in the DNA
homologous recombination
genetic exchange between a pair of identical or vey similar DNA sequences, usually located on a pair of homologous chromosomes.
transcription
copy the neucleotide sequence of that gene into RNA
mRNA
codes for proteins
gene expression
the process by which the information encoded in a DNA sequence is translated into a product that has some effect on a cell or organism
promoter
contains a specific sequence of nucleotides indicating the starting point for RNA synthesis
rRNA
form the core of the ribosome and catalyzes proteins synthesis
miRNA
regulates gene expession
tRNA
serves as adaptors between mRNA and amino acids during protein synthesis
introns
noncoding region of a eucaryotic gene that is transcribed into an RNA molecule but is then excised by RNA splicing to produce mRNA
exons
segments of a eucaryotic gene that is transcribed inot RNA and expressed. dictates the amino acid sequence of part of a protein
RNA splicing
where the intron sequences are removed from the newly synthesized RNA and the exons are stitched together.
codon
each group of three consecutive nucleotides in RNA
reading frames
the set of successive triplets in which a string of nucleotide is translated into proteins.
anticodon
a set of three consecutive nucleotides that through base-pairing bind the complementary codon in an mRNA molecule
translation
the conversion of the RNA into proteins.
gene expression
the process by which a gene makes its effect on a cell or organism by directing the synthesis of a protein or an RNA molecule with a characteristic activity
DNA sequences
adjacent to the transcribed region of the gene have the role of binding proteins called “transcription factors” to either activate or repress transcription.
enhancers
These are sequences that bind transcription factors but differ from the first THREE in that they can be VERY far away from the place where transcription begins.
