Molbio Handout Flashcards
The substrates for RNA synthesis are?
RIBONUCLEOSIDE TRIPHOSPHATES
The ____ controls the binding of the core enzyme to the promoter
Sigma factor
3 stages jn the transcription process:
Initiation, elongation, and termination
Transcription begins at the start site, which is determined by___
Consensus sequences
2 types of terminators in bacterial cells
Rho- independent terminators and rho dependent terminators
True or false
RNA polymerases are capable of proofreading
True
It is often defined as a sequence of DNA nucleotides that is transcribed into a single RNA molecule
GENE
Noncoding sequences that interrupt the coding sequences (exons) of gene, which are common in eukaryotic cells but are rare in bacterial cells
INTRONS
An mRNA molecule has three primary parts:
5’ untranslated region
Protein coding seauence
3 untranslated region
The pre mRNA of a eukaryotic protein encoding gene is extensive processed:
A modified nucleotide and methyl groups
Collectively termed the cap are
Introns that are removed within a structure is called?
Spliceosome
Messenger RNAs may be altered by the addition, deletion, or modification of nucleotides in the coding sequence, a process called ?
RNA EDITING
The amino acids in a protein are linked together by?
Peptide bonds
It is a triplet code
Genetic code
Protein synthesis comprises four steps
The binding of amino acids to the appropriate tRNAs
Initiation
Elongatin
Termination
The binding of an amino acid to a tRNA requires the presence of a specific:
AMINOACYL- tRNA SYNTHASE AND ATP
Each mRNA may be simultaneously translated by several ribosomes, producing a structure called
Polyribosome
The simplest type of substitution is a :
Bass substitution
Are base substitutions in which purines are replaced by purines or pyrimidines are replaced by pyrimidines
Transitions
Are base substitutions in which a purine replaces a pyrimidine or a pyrimidine replaces a purine
Transversions
Are the addition of nucleotides
Insertions
Are the removal of nucleotides
Deletions
This type of mutation alters the coding sequence so that one amino acid substitutes for another
Missense mutation
This type of mutation changes a codon that specifies an amino acid into a termination codon
Nonsense mutation
This type of mutation produces a synonymous codon that specifies the same amino acid as the original sequence
Silent mutation
This type of mutation alters the amino acid sequence but does not change the functioning of the protein
Neutral mutation
This type of mutation reverses the effect of a previous mutation at a different site and may be intragenic or intergenic
Supressor mutation
DNA repair mechanisms
Mismatch repair
Direct repair
Base- excision repair
Nucleotide- excision repair and other repair pathways
Double strand breaks are repaired by:
Homologous recombination and nonnomologous end joining
The strand that gets transcribed is the:
Template strand
Transcribing the template strand requires getting its complementary RNA sequence to produce the transceipt so that the template strand is also known as the
ANTISENSE STRAND
Nontemplate strand is also known as the
Sense strand
The 5’ intronic signal is ?
GU
3’ intonic signal is
AG
Stop codons are
UAA
UAG
UGA
Refers to the multistep process that ultimately results in the production of a functional gene product: either RNA or protein
Gene expression
The first step in gene expression is the:
Use of DNA for the synthesis of RNAs
True or false: Not all genes are regulated
True
The initial step in all gene expression, is controlled by regulatory sequences of DNA, usually embedded in the non coding regions of the genome
Regulation of transcription
These DNA sequences flanking a gene are called
Cis acting
It is the regulatory molecule itself, which can diffuse through the cell from its site of synthesis to its DNA binding site
Trans acting factor
The binding of proteins to DNA is through structural motifs such as:
Zinc finger
Leucine zipper
Helix turn helix
Genes can be either
Constitutive or regulated
It seals the nicks that remain in the sugar phosphate backbones when the tRNA primers are replaced by DNA nucleotides
DNA LIGASE
Is non reciprocal genetic exchange and produces abnormal ratios of gametes
Gene conversion gene conversion
The sample is suspended in an alkaline solution containing NaOH and SDS detergent, causing the denaturation of chromosomal DNA.
Alkaline extraction
