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DNA polymerases
Most proteins localized in mitochondria, such as the mitochondrial RNA and ________, are synthesized on cytosolic ribosomes and are imported into the organelle by processes.
Pulse
________ labeling with 3H- uridine and autoradiography have shown that most transcription occurs in regions of euchromatin and the nucleolus.
Barbara McClintock
________ discovered the first mobile elements while doing classical genetic experiments in maize (corn) during the 1940s.
multicellular animals
Most genes in ________ and plants contain introns, which are removed during RNA processing.
genetic material
During interphase, when cells are not dividing, the ________ exists as a nucleoprotein complex called chromatin, which is dispersed through much of the nucleus.
15 kb DNA sequence
The ________ encoding chicken lysozyme constitutes a simple transcription unit containing four exons and three introns.
major cytoskeletal
Invertebrates, the ________ proteins are the actins, tubulins, and intermediate filament proteins like the keratins.
Encodes rRNAs
diploid
In the mating by fusion of haploid yeast cells, both parents contribute equally to the cytoplasm of the resulting ________; thus inheritance of mitochondria is biparental.
lineages
In ________ leading to higher eukaryotes, homologous recombination between mobile DNA elements dispersed throughout ancestral genomes may have generated gene duplications and other DNA rearrangements during evolution.
genomes of all eukaryotes
The ________ studied from yeast to humans contain retrotransposons.
germ line
Similar to other mobile elements, most SINEs have accumulated mutations from the time of their insertion in the ________ of an ancient ancestor of modern humans.
H1
The five major types of histone proteins- termed ________, H2A, H2B, H3, and H4- are rich in positively charged basic amino acids, which interact with the negatively charged phosphate groups in DNA.
cytogenetic work
Almost all ________ (i.e., studies of chromosome morphology) has been done with condensed metaphase chromosomes obtained from dividing cells- either somatic cells in mitosis or dividing gametes during meiosis.
multiple copies
Like mitochondria, chloroplasts contain ________ of the organellar DNA and ribosomes.
SARs
Generally, ________ are found between transcription units.
Early microscopic observations
________ on the number and size of chromosomes and their staining patterns led to the discovery of many important general characteristics of chromosome structure.
Genetic studies
________ in yeast indicate that specific histone acetylases are required for the full activation of transcription of a number of genes.
protein synthesis
In most eukaryotes, all the tRNAs used for ________ in mitochondria are encoded by mtDNAs.
Genes
________ are located primarily within chromatin loops, which are attached at their bases to a chromosome scaffold.
Alu
________ elements exhibit considerable sequence homology with and may have evolved from 7SL RNA, a component of the signal- recognition particle.
Invertebrates
________ and ________, the genes encoding rRNAs and some other noncoding RNAs such as some of the snRNAs involved in RNA splicing occur as tandemly repeated arrays.
acid sequence
In molecular terms, a gene commonly is defined as the entire** nucleic ________** that is necessary for the synthesis of a functional gene product** (polypeptide or RNA**)
Translation initiation
________ can begin at any of these multiple internal sites, producing multiple proteins.
YACs
To construct ________, TEL sequences from yeast cells or from the protozoan Tetrahymena are combined with yeast CEN and ARS sequences.
enzyme
The ________ is a protein and RNA complex called telomere terminal transferase, or telomerase.
cluster of genes
The ________ that form a bacterial operon comprises a single transcription unit, which is transcribed from a particular promoter into a single primary transcript.
ORF1
________ and ORF2 proteins are from a LINE RNA.
H2A
The amino acid sequences of four histones (________, H2B, H3, and H4) are remarkably similar among distantly related species.
DNA transposition
________ by the cut- and- paste mechanism can result in an increase in the copy number of a transposon when it occurs during S phase.
G bands
________ are produced when metaphase chromosomes are subjected briefly to mild heat or proteolysis and then stained with Giemsa reagent, a permanent DNA dye.
mammalian cells
In ________, heterochromatin appears as darkly staining regions of the nucleus, often associated with the nuclear envelope.
yeast genome
The ________ contains many ≈100- bp sequences, called autonomously replicating sequences (ARSs), that act as replication origins.
salt concentration
When chromatin is extracted from nuclei and examined in the electron microscope, its appearance depends on the ________ to which it is exposed.
telomere repeat
The ________ sequence in humans and other vertebrates is TTAGGG.
Eukaryotic chromosomes
________ are apparent when we consider that all known DNA polymerases elongate DNA chains at the 3 end, and all require an RNA or DNA primer.
ARS
If circular plasmids containing a(n) ________ and CEN sequence are cut once with a restriction enzyme, the resulting linear plasmids do not produce LEU colonies unless they contain special telomeric (TEL) sequences ligated to their ends.
isotonic buffers
When the DNA from eukaryotic nuclei is isolated in ________ (i.e., buffers with the same salt concentration found in cells, ≈0.15 M KCl), it is associated with an equal mass of protein as chromatin.
DNA sequences
Most genes are transcribed into mRNAs, which encode proteins, clearly, some ________ are transcribed into RNAs that do not encode proteins (e.g., tRNAs and rRNAs)
specific DNA sequences
The highly reproducible banding pattern seen in Drosophila salivary gland chromosomes provides an extremely powerful method for locating ________ along the lengths of the chromosomes in this species.
larval salivary glands of Drosophila
The ________ species and other dipteran insects contain enlarged interphase chromosomes that are visible in the light microscope.
Eukaryotic DNA Transposon
________: McClintocks original discovery of mobile elements came from the observation of certain spontaneous mutations in maize that affect the production of any of the several enzymes required to make anthocyanin, a purple pigment in maize kernels.
Replication of DNA
________ begins from sites that are scattered throughout eukaryotic chromosomes.
RNA transcripts of mtDNA
All ________ and their translation products remain in the mitochondrion, and all mtDNA- encoded proteins are synthesized on mitochondrial ribosomes.
mtDNA
The ________ is located in the interior of the mitochondrion, the region known as the matrix.
Certain dyes
________ selectively stain some regions of metaphase chromosomes more intensely than other regions, producing characteristic banding patterns that are specific for individual chromosomes.
LTR retrotransposons
Since LINEs do not contain LTRs, their mechanism of transposition through an RNA intermediate differs from that of ________.
DNA
In cells, newly replicated ________ is assembled into nucleosomes shortly after the replication fork passes.
flexible amino
Each of the histone proteins making up the nucleosome core contains a(n) ________ terminus of 11- 37 residues extending from the fixed structure of the nucleosome; these termini are called histone tails.
Interphase chromatin
________ and metaphase chromosomes also contain small amounts of a complex set of other proteins.
