micro ch 7.1 (exam 3)
Terms
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- many of the molecules involved in genetic information flow are
- macromolecules
- functional unit of genetic information
- gene
- a gene specifies...
- sequence of amino acids in a protein
- in all cells, genes are composed of...
- DNA
- DNA specifies the sequence of a protein only with the help of an intermediate macromolecule, which is ___
- RNA
- DNA, RNA, and protein all contain biological information and are often called....
- informational macromolecules
- the duplication of DNA, produces two double helices
- replication
- synthesis of RNA using DNA template, generally goes to mRNA, unused portion of DNA will go to tRNA and rRNA
- transcription
- the synthesis of protein using the genetic information in messenger RNA as a template
- translation
- it takes three bases on the mRNA to encode a single amino acid; this triplet of bases is a...
- codon
- the genetic code of codons is translated into protein by means of the protein synthesizing system. this system consiss of...
- ribosomes, tRNA, various enzymes
- the transfer of sequence information is unidirectional, it travels from ___ to ____
- nucleic acid to protein
- process by which RNA is used for RNA synthesis
- RNA replication
- the use of sequence information in RNA to specify a sequence in DNA
- reverse transcription
- in eukaryotes, protein-encoding genes are split into two or more coding regions - ____, and noncoding regions separating coding regions - ____
- exons, introns
- both intron and exon regions are transcribed into the
- primary transcript/pre-mRNA
- mature mRNA differs from pre-mRNA in that
- intron regions are removed
- three processes involved in genetic information flow
- replication, transcription, translation
- the four different nucleic acid bases of DNA
- adenine, guanine, cytosine, thymine
- genetic information for all cellular processes is stored in DNA in the ____ of bases along the polynucleotide chain
- sequence
- the backbone of DNA is formed by alternating units of _____ and the sugar _____
- phosphate, deoxyribose
- connected to each sugar in DNA is one of the nucleic acid ___
- bases
- the phosphate connecting two sugars spans from the ____ carbon of one sugar to the ____ carbon of the adjacent sugar
- 3', 5'
- at one end of the DNA molecule, the sugar has a phosphate on the ___ hydroxyl, whereas at the other end, the sugar has a free hydroxyl at the ___ position
- 5', 3'
- DNA exists as two polynucleotide strands whose base sequences are___ in all cellular organism chromosomes
- complementary
- The two strands in the double stranded DNA molecule are arranged in ________ fashion
-
antiparallel
5'3' vs. 3'5' - the two strands in DNA are wrapped around each other forming a
- double helix
- proteins that interact specifically with DNA engage predominantly with the ____, where there is a considerable amount of free space
- major groove
- the size of a DNA molecule can be expressed in terms of its ___; each nucleotide has a molecular weight of about ___
- molecular weight, 330
- another means of expressing size of DNA molecules; measured in kilobase/kilobase pairs
-
number of 1000s of bases/base pairs per molecule
number of millions - megabases/megabase pairs - a base pair takes up ____ nanometers in length along the helix; each turn of the helix contains ___ base pairs
- 0.34 nm, 10 base pairs
- replication is ____; the resulting DNA each contain one parental and one new strand
- semiconservative
- precursor of each new nucleotide in the chain is a nucleoside ______, from which the two terminal phophates are removed and the internal phosphate is attached covalently to deoxyribose of the growing chain
- 5'triphosphate
- DNA replication always proceeds from the ____ end to the ____ end
- 5' end , 3'-hydroxyl end
- the _____ of the incoming nucleotide is attached to the ____ of the previously added nucleotide in replication of DNA
- 5' phosphate, 3' hydroxyl
- enzymes that catalyze addition of the nucleotides; none are known to begin a new chain however
- DNA polymerases
- DNA polymerases synthesize new DNA in the ____ direction
- 5' > 3'
- the site at which DNA polmerase can attach the first nucleotide; in most cases, this is a short stretch of RNA
- primer
- enzyme which polymerizes RNA; synthesizes a short stretch of RNA which acts a s a primer
- primase
- At the growing end of an RNA primer is ____ to which DNA polymerase can add the first deoxyribonucleotide
- 3' OH group
- the RNA primer begins a new chain, however the continued extension of the molecule occurs as ___
- DNA