Molecular Genetics Flashcards
Each strand of DNA separately serves as a template for a new complementary strand
semiconservative
The area that is being separated from the parent DNA as it is unwound
replication fork
The new DNA strand that can be continuously synthesized in the 5’ to 3’ direction
leading strand
the strand that is made in okazaki fragments in the 5’ to 3’ direction
lagging strand
a __ ____, a short segment of nucleotides, is laid down by the enzyme ____. Once this is place __ __ can latch onto it and synthesize a new strand of DNA
RNA primer, primase, DNA polymerase
__ ___ unwinds the the DNA strand, forming a ____ shaped replication fork. __ ___ ___ proteins keep the DNA uncoiled until the replication process is complete. ______ will break and rejoin the double helix ahead of the replication fork in order to prevent __ and coiling
DNA helicase, Y, single stranded binding, topoisomerase, knotting
DNA _____ occurs when DNA ___ __ is used for replication. It moves in a __ to ___ direction
elongation, polyermase III, 5’ 3’
Since DNA must be synthesized in the __ to __ direction, the lagging strand is synthesized in segments as the polymerase must wait for the DNA to further ___. These fragments are called ____ fragments. For each individual okazaki fragment an ____ ___ is needed for each.
5’, 3’, unwind, okazaki, RNA primer
In DNA termination, __ __ removes the RNA primer strips and replaces them with DNA. Then __ ___ seals the ___ ____ between the okazaki fragments. ___ ___ and ____ proofread the strands to remove and replace wrong segments
polymerase I, DNA ligase, phosphodiester bonds, polymerase I, III
process by which DNA results in the synthesis of RNA and protein, leading to expressible changes
gene expression
Transcription takes place in the __ in eukaryotes, and in the ___ in prokaryotes
nucleus, cytoplasm
the enzyme that latches on to DNA and makes the complementary RNA strand
RNA polymerase
The ___ or the _____ strand is what acts as a guide for the synthesis of a new RNA strand, while the ___ or ____ strand does nothing
template, anti-sense, coding, sense
Before RNA polymerase starts synthesizing an RNA strand, it bind to the _____ segment of the DNA, which is ____ of the site of RNA synthesis. The parts of the promoter that the RNA polymerase actually bind to are called the ___ element or the TATA box, and the ___ element.
promoter, upstream, -10, -35
In transcription ___, RNA polymerase binds to specific promoter regions indicated by ____ ____, which determine the genes that should be expressed. Once RNA polymerase binds to the DNA it ___ it
initiation, transcription factors, unwinds
During transcription elongation, RNA continues unwind DNA and use the ___ strand as a template to synthesize RNA in the __ to ___ direction
antisense, 5’ 3’
Transcription termination occurs when RNA polymerase encounters the __ ___ which is usually a long sequence of ___ nucleotides, and ____ ___
stop point, adenine, falls off
mRNA ____ is a process by which pre-mRNA is modified before translation into a protein product. It occurs only in _____.
processing, eukaryotes
The 5’ cap is a ____ sequence that is added to the __ end of the mRNA. It provides __ for the mRNA and a point of attachment for ____
5;-G-P-P-P, 5’, ribosomes
The poly-A tail is the addition of ___ nucleotides to the end of an mRNA transcript which provides _____ and prevents it from ____
adenine, stability, degradation
RNA sequences that are translated into a final protein product
exons
RNA sequences that are removed before the RNA is translated
introns
___ and proteins form a ___ complex which helps to remove introns, and __ together exons.
snRNA, spliceosome, splice
process of removing introns and joining together exons
RNA splicing
__ ___ is a term used when the remaining exons can be combined in different ways to create different __ from the same __ ___. It allows a gene to code for multiple ____
alternative splicing, mRNA, RNA transcript, multiple proteins
sit on or near the promoter sequence and help the transcription factors and RNA polymerase to assemble
activator
Prevents transcription factors from assembling and blocks transcription
repressor
The most effective way to prevent gene expression is to __ the promoter region.
delete
siRNA or ____ RNA, is loaded with a sequences that matches an existing mRNA sequence the body wants to ___. It will bind to it, and ___ it into small ineffective pieces that cannot be translated
small-interfering, silence, chop
miRNA or ____ RNA, also has a matching sequence to the mRNA needing to be silenced, but acts as a physical ___ that prevents translation
micro, block
the process of creating proteins by using the genetic information from mRNA
translation
The genetic code is __ or ___, but it does not contain any ____. This allows possible mistakes in the ____ process to possibly be coded for by the same amino acid
redundant, degenerate, ambiguity, transcription
The stop codons that do not code for an amino acid
UAA, UAG, AGA
The start codon is always ___ and results in a ____ amino acid
AUG, methionine
The 3 letter codon that is read at a time
reading frame
A clover shaped molecule responsible for transporting nucleotide triplets called anticodons and their associated amino acid; each is designated to carry a specific amino acid
tRNA
Ribosomes function in the binding of a ___ __ with its associated mRNA codon. It has ___ binding sites for tRNA and an additional site for the ____ molecule being translated
tRNA anticodon, 3, mRNA
Ribosomes that are free floating directly in the cytosol
free ribosome
ribosomes that are bound to the cytosolic side of the rough ER surface
bound ribosomes
___ ribosomes are bigger than ___ ribosomes. However, in both, translation takes place in the ___, across ___
eukaryote, prokaryote, cytosol, ribosomes
The attachment of an amino acid to its corresponding tRNA molecule
tRNA charging
The ribosome contains the mRNA binding site, the ___ site, where the tRNA will detach after it has contributed to translation, the ___ site, that carries the tRNA molecule that is bound to the elongating peptide chain, and the ___ site, the site where the second tRNA binds to delivery the next amino acid in the sequence
exit, peptidyl, aminoacyl
In translation initiation the ____ subunit of the ribosome attaches to the mRNA. Then the tRNA ___ that is complementary to the __ sequence will attach.Then the ___ subunit of the ribosome assembles. This occurs at the ___ site of the ribosome
small, anticodon, start, large, P
During translation elongation, the tRNA bringing the next amino acid binds to the __ site, and a ___ bond is formed between the amino acid chain in the ___ site and the new amino acid in the A site is formed. The ribosome then moves in the __ to __ direction, causes the tRNAs to shift down, and the one in the __ site leaves, while the one in the P site stays, and the __ site is open again
A, peptide, P, 5’ 3’, E, A
Termination occurs when a __ __ enters the A site, and proteins called ___ ___ attach to the stop codon in the A site. The tRNA and __ ___ detach. The release factors than unbind from the mRNA and the __ ___ disassemble
stop codon, release factors, polypeptide chain, ribosomal subunits
Extra segments at the ends of chromosomes that prevent the genome from being shortened during cell replication
telomeres
Chromosomes become shorter with each DNA replication because the ___ ___ removed at the ends of the DNA cannot be filled in by __ ___
RNA primer, DNA polymerase
Telomeres are ___ that attach to the end of the DNA template and adds a short ___ sequence of DNA
enzymes, repeating
First telomeres carry the ___ template and bind to the ___ DNA ___ at the end of the strand. Then, the RNA template is used to synthesize the new strand, and telomerase ____ to continue the process. Then, a ___ can be added and polymerase can fill in the rest of the strand
RNA, 3’. overhang, shifts, primer
The limit on cell replication imposed by the shortening of telomeres with each division
hayflick limit
the hayflick limit is a concept used to explain __ __ and states that the number of possible cell divisions is dependent on the __ of the telomeres. ___ cells will hit their hayflick limit sooner than ___ cells
cellular aging, length, older, younger
Mutations that occur in a single nucleotide base
point mutation
A point mutation in which a single base is exchanged with another
substitution
A point mutation in which a base is added
insertion
A point mutation where a base is deleted
deletion
when no changes occur to the desired amino acid because of the degeneracy of the genetic code
silent mutations
When a substitution causes a change in an amino acid that was originally coded
missense mutation
When a substitution mutation causes a codon that codes for an amino acid to change into a stop codon
nonsense mutation
Point mutation that leads to the alteration of the reading frame
frameshift mutation
DNA is ___ charged and ___ bonded to the ___ charged histones
negatively, ionically, positively
The DNA histone complex
nucleosome
chromatin that is loosely packed; allows for RNA polymerase to transcribe
euchromatin
Chromatin that is tightly packed; prevents RNA polymerase from transcribing
heterochromatin
The complete set of DNA
genome
the study of genomes
genomics
the entire set of expressed mRNA
transcriptome
the entire set of expressed proteins
proteome
application of computer science to analyze biological data
bioinformatics
a global attempt to sequence the human genome
human genome project
splitting the DNA and using fluorescent nucleotides to synthesize new strands that allow to determine the order of the genetic sequence
sanger sequencing
Cloning and splicing DNA into fragments and using software to order them
whole genome shotgun sequencing
sequencing the DNA of entire communities of species
metagenomics
metagenomics is helpful in the sequencing of a ___ or a ___ ___, and allows us to determine ___ __, __ __ and __ ___
microorganism, microbial population, genome size, gene number, gene density
The total number of nucleotides an organism has
genome size
____ genome size are usually bigger than ___, but bigger does not mean a more ___ organism
eukaryotes, prokaryotes, complex
the amount of genes or nucleotides that code for a ___ is called the __ __. __ have more gene sequences than the ____. This not related to ___ ___
protein, gene number, eukaryotes, prokaryotes, gene size
The ratio of the number of genes to the total number of nucleotides is called ____ ____. Prokaryotes are ___ than eukaryotes
gene density, denser
serve as a binding site for regulatory proteins and control the expression of genes
regulatory genes
gene sequences that don’t code for anything
non coding
DNA sequences that are repeated throughout the genome e.g. telomeres
repetitive
stretches of DNA that can move from one region of the genome to another; in both prokaryotes and eukaryotes
transposable elements
transposons are seen in ___ genome sizes. They move their DNA by either ___ their DNA out of the existing location before being ___, or by ____ and then ___ their DNA into place
larger, cutting, relocated, copied, inserted
Retro-transposons are seen in ____ genomes. They _____ _____ the DNA onto an ___ intermediate and then ___ it back to DNA to insert it into the target area
smaller, reverse, transcribe, RNA, transpose
Transposition can interrupt the gene sequence it inserted itself into, and cause both a __ or __ effect
positive, negative
multiple copies of identical genes that are grouped close to each other to produce rapid copies of a gene product
identical mutligene
multiple copies of related families of genes
nonidentical multigene
Closely related organisms can be compared using small __ ___. Distantly related species can be compared by observing __ ___ ___, or identical genes. Organisms in the same species can be compared by using __ and ____
genetic differences. highly conserved regions, SNPs, CNVs
SNPs are __ _ ___, or a single _ __ difference in the genome. This contributes to __ ___
single nucleotide polymorphism, base pair, individual diversity
CNVs are __ __ __, or regions where one or more ___ __ is present. This arises from _ ____ ___ or ___
copy number variants, gene copies, irregular genome duplications, deletions
the study of the developmental changes in different organisms
evolutionary developmental biology
ensure that the anatomical structures of the organism develop correctly and right order
homeotic gene
DNA sequence found in homeotic genes that encodes for homeodomain proteins; highly conserved
homeobox
Transcription factors that control the expression of many developmental genes
homeodomain proteins
A specific homeotic gene that ensure body position and correct anatomical sequence
hox gene
the majority of the human genome is made of ___ __ __
non coding genes
