Leys Study Guide #3 Flashcards
Cells acquire nucleotides through 2 processes: ____________ and __________
Cells acquire nucleotides through two processes: DE NOVO SYNTHESIS and SALVAGE PATHWAYS
De novo synthesis of purines results in the synthesis of ______ that can be converted to ______ and ___________
De novo synthesis of purines results in the synthesis of INOSINE that can be
converted into ADENOSINE and GUANINE
Atoms in newly synthesized purine are derived from several sources, name these 4 sources
Atoms in newly synthesized purine are derived from….
- Aspartate
- Glutamine
- Glycine
- Methyl Groups supplied by folic acid and carbon dioxide
_______ and _______ regulate de novo synthesis of purines at multiple points in the pathway.
ADP and GDP regulate de novo synthesis of purines at multiple points in the pathway.
(in other words, ADP and GDP => regulator of de novo synthesis.)
________ and _______ can be recycled through the __________ with (HGPRT) hypoxanthine guanine phosphoribosyl transferase.
HYPOXANTHINE and GUANINE can be recycled through the SALVAGE PATHWAY with (HGPRT) hypoxanthine guanine phosphoribosyl transferase.
__________ catalzyes a ____________ type reaction leading to the formation of __________ that can be excreted
XANTHINE OXIDASE catalyzes a HYDROXYLASE type reaction leading to the formation of URIC ACID that can be excreted.
Excess ________ is the cause of gout
Excess URIC ACID is the cause of gout
Gout is most often caused by ______________, but can also be caused by __________.
Gout is most often caused by LOW LEVELS OF SECRETION OF URIC ACID, but can also be caused by EXCESS PRODUCTION
Crystallization of ____________ in the joints leads to a localized ______ response
Crystallization of SODIUM URATE in the joints leads to a localized INFLAMMATORY response.
__________, a purine analog, is used to treat gout
ALLOPURINAL, a purine analog, is used to treat gout
Allopurinol inhibits ____________ preventing the formation of uric acid
Allopuriol inhibits XANTHINE OXIDASE preventing the formation of uric acid
A HGPRT deficiency causes _______ that results in severe retardation, crippling gouty arthritis and self-mutilation
A HGPRT deficiency casues LESCH-NYHAN SYNDROME that results in severe retardation, crippling gouty arthritis and self mutilation
Lesch-Nyhan syndrome occurs in males only because ___________
Lesch-Nyhan occurs in males only because the HGPRT GENE is located on the X CHROMOSOME
The breakdown of ______ can replenish TCA cycle intermediates through the production of _______
The breakdown of PURINES can replenish TCA cycle intermediates through the production of FUMERATE
Atoms in the pyrimidine ring are derived from ______ and ________.
The atoms in a pyrimidine ring are derived from ASPARTATE and CARBAMOYL PHOSPHATE
The ________ in the synthesis of pyrimidines are located of the same protein, ___________
The FIRST 3 ENZYMES in the synthesis of pyrimidines are located on the same protein, CAD PROTEIN
The pyrimidines _____ and _______ can be interconverted
The pyrimidines U and C can be interconverted
dUMP is converted to TMP by _________, an enzyme requiring the transfer of a methyl group from ___________
dUMP is converted to TMP by THYMIDYLATE SYNTHASE, an enzyme requiring the transfer of a methyl group from TETRAHYDROFOLATE.
Inhibitors of tetrahydrofolate production are used as therapeutic agents for _______ and _________
Inhibitors of tetrahydrofolate production are used as therapeutic agents for TREATING CANCER and BACTERIAL INFECTIONS
_________ that inhibit thymidylate synthase are used as anticancer agents
FLURO SUBSTITUTED PYRIMIDINE ANALOGS that inhibit thymidylate synthase are used as anticancer agents
Ribunucleotide reductase converts ______________ to ___________
Ribunucleotide reductase converts RIBONUCLEOTIDES to DEOXYRIBONUCLEOTIDES
Base-pairing in DNA is ____-____ and ____-____. In RNA it’s _____-____ and ____-____.
Base-pairing in DNA is A-T and G-C. In RNA it’s A-U and G-C.
___________ can be compared among different species to determine phylogenetic relationships
HOMOLOGOUS REGIONS OF DNA can be compared among different species to determine phylogenetic relationships
Closely related organisms contain similar _________, however they are often arranged differently on the __________ of each species
Closely related organisms contain similar DNA COMPLIMENTS, however they are often arranged differently on the CHROMOSOMES of each species
The living world is made up of 3 divisions, or domains: ______, ________, & _________.
The living world is made up of 3 divisions, or domains: BACTERIA, ARCHEA, and EUKARYOTES
There are 4 main processes for generating change in a genome, name all 4.
There are 4 main processes for generating change in a genome:
- INTRAGENIC MUTATION (single base change), 2. GENE DUPLICATION
- DNA SEGMENT SHUFFLING
- HORIZONTAL TRANSFER (from one cell to another).
___________ are usually clustered into groups of operons that are ________ as a single unit
BACTERIAL GENES are usually clustered into groups of operons that are TRANSCRIBED as a single unit
Eukaryotic genes are often broken up with regions of ________ between regions of ________
Eukaryotic genes are often broken up with regions of NONCODING DNA (INTRONS) between regions of CODING DNA (EXONS)
In comparison of the same gene is several closely related species, the _____ will generally be very similar (conserved), while the _______ will vary in size and content
In a comparison of the same gene in several closely related species, the EXONS will generally be very similar (conserved), while the INTRONS will vary in size and content.
Most of the DNA in higher eukaryotes including humans does not _____ for ______
Most of the DNA in higher eukaryotes including humans does not CODE for PROTEINS
Most of the human genome is made up of repeated sequences, many of which are ______________________
Most of the human genome is made up of repeated sequences. Many of those sequences are MOBILE ELEMENTS THAT CAN MOVE AROUND IN THE GENOME
____________ chromosomes are linear and __________ chromosomes are _________
EUKARYOTIC chromosomes are linear and BACTERIAL chromosomes are circular
In addition to the human genome, the entire genomes of a large number organisms have been completed including _________
In addition to the human genome, the entire genomes of a large number organisms have been completed including SEVERAL BACTERIA THAT ARE FOUND IN THE ORAL CAVITY
It is possible to construct __________ and compare them with other organisms by examining their entire ________ content
It is possible to construct METABOLIC PATHWAYS and compare them with other organisms by examining their entire GENOME content
Genes can be grouped into families bases on ____________________
Genes can be grouped into families bases on SIMILAR SEQUENCES (HOMOLOGOUS) FOUND IN DIFFERENT ORGANISMS
Homologous sequences can be found in genes of the same organism that carry out ________
Homologous sequences can be found in genes of the same organism that carry out DIFFERENT BUT SIMILAR FUNCTIONS
Genes that have similar functions in ___________ can have similar sequences (homology)
Genes that have similar functions in VERY DISTANTLY RELATED ORGANISMS can have similar sequences (homology)
The Phylogenetic relationship of different organisms can be compared by comparing _______________
The phylogenetic relationship of different organisms can be compared by comparing DNA SEQUENCES of SIMILAR GENES in the TWO ORGANISMS
DNA polymerase is a ______________ enzyme
DNA polymerase is a DNA DEPENDENT (uses DNA as a template) DNA SYNTHESIZING enzyme
RNA polymerase is a _____________ enzyme
RNA polymerase is a DNA DEPENDENT RNA SYNTHESIZING enzyme
Reverse transcriptase is a __________________ enzyme
Reverse transcriptase is a RNA DEPENDENT DNA SYNTHESIZING enzyme
Primase is a ___________ polymerase
Primases is a DNA DEPENDENT RNA polymerase
Primase synthesizes a small RNA primer that can be ___________
Primase synthesizes a small RNA primer that can be USED BY DNA POLYMERASE TO ELONGATE THE CHAIN
DNA polymerase minimizes the __________ by using a 3’-5’ ________ activity that is part of the same protein
DNA polymerase minimizes the NUMBER OF MISTAKES by using a 3’ to 5’ EXONUCLEASE activity (proofreading activity) that is part of the same protein
DNA polymerase as well as all other nucleic acid polymerases synthesize DNA in the _______ direction only
DNA polymerase as well as all other nucleic acid polymerases synthesize DNA in the 5’ TO 3’ direction only
During replication, each new nucleotide is added to the ________________
During replication, each new nucleotide is added to the 3’ CARBON ON THE LAST NUCLEOTIDE of the NEW DNA CHAIN
The ___________ is connected to the sugar at the 1’ carbon, and the adjacent nucleotides in a DNA chain are attached at ____________
The BASE COMPONENT OF EACH NUCLEOTIDE is connected to the sugan at the 1’ carbon, and adjacent nucleotied in a DNA chain are attached at THE 5’ and 3’ CARBONS
The _____ carbon differs between RNA and DNA
The 2’ carbon differs between RNA and DNA
DNA polymerase is an __________ enzyme; it cannot ___________
DNA polymerase is an ELONGATING enzyme; it cannot INITIATE SYNTHESIS
Because DNA polymerase is only an elongating enzyme, a ______ is required for elongation of a ___________ using the DNA polymerase
A PRIMER is required from the elongation of a NEW STRAND using the DNA polymerase
Bacterial chromosomes contain only one _____ of _________
Bacterial chromosomes contain only one ORIGIN of REPLICATION
In bacteria, DNA synthesis proceeds in ____ direction away from the origin until the _____________
In bacteria, DNA synthesis proceeds in BOTH directions away from the origin until the TWO REPLICATION FORKS MEET AT A SPECIFIC SEQUENCE ON THE OTHER SIDE OF THE CHROMOSOME
In bacteria, new rounds of DNA replication can begin ____________
In bacteria, new rounds of DNA replication can begin BEFORE THE PREVIOUS ROUND IS COMPLETED
Eukaryotic chromosomes contain many ________ that may change during the development of the organism
Eukaryotic chromosomes contain many ORIGINS OF REPLICATION that may change during the development of the organism
In eukaryotes, each entire chromosome is replicated __________, and new rounds of replication do not start until _________
In Eukaryotes, each entire chromosome is replicated ONLY ONCE EACH CELL DIVISION and new rounds of replication do NOT start until AFTER THE CELL DIVIDES.
Eukaryotic chromosomes are ________ in organization, and special structures called ________ are placed on each end
Eukaryotic organisms are LINEAR in organization, and special structures called TELOMERES are placed on each end.
Telomeres are constructed with the enzyme __________ that uses a _______ template to synthesize a ___________ at the ends of chromosomes
Telomeres are constructed with the enzyme TELOMERASE that uses an RNA template to synthesize a SHORT REPEATED DNA SEQUENCE at the ends of chromosomes
Because the polymerase in eukaryotes must synthesize new DNA in a ________ direction, the two polymerase molecules must move __________
Because the polymerase in eukaryotes must synthesize DNA in a 5’-3’ direction, the two polymerase molecules must move AWAY FROM EACH OTHER
The enzyme _________ unwinds the 2 DNA strands _______ polymerization of the new strands
The enzyme HELICASE unwinds the 2 DNA strands BEFORE polymerization of the new strands
______________ keep the 2 complementary strands from reforming a double helix
SINGLE-STRANDED BINDING PROTEINS keep the two complementary strands from reforming a double helix
The polymerase on the leading strand move toward the __________ and the polymerase on the lagging strand move away from it
The polymerase on the leading strand moves toward the REPLICATION FORK and the polymerase on the lagging strand moves away from it.
The lagging strand is synthesized in _______ fragments
The lagging strand is synthesized in SHORT (OKIZAKI) fragments
Primase initiates synthesis of each Okazaki fragment by __________
Primase initiates synthesis of each Okazaki fragment by MAKING A SHORT RNA PRIMER
The leading strand is synthesized by the _____________
The leading strand is synthesized by the CONTINUOUS MOVEMENT OF THE DNA POLYMERASE ALONG THE TEMPLATE
__________ signals that the DNA is unreplicated and is ready to be used as a template for the next round of synthesis
METHYLATION OF THE DNA signals that the DNA us unreplicated and is ready to be used as a template for the next round of synthesis
New or modified genes can be generated by one or a combination of 4 events, name these events.
New or modified genes can be generated by one or a combination of 4 events:
1) point mutations in the coding region that change the amino acid composition of the protein. 2) duplication of the entire gene.
3) Mixing of segments of one gene with segments of another gene – segment shuffling.
4) Acquisition of new activities by transfer of genes between two organisms – horizontal gene transfer.
Many genes belong to gene families that share homologous regions. These regions usually _____________________
Many genes belong to gene families that share homologous regions. These regions usually CODE FOR PROTEINS THAT CARRY OUT SIMILAR FUNCTIONS
Breaks in the DNA (especially double-stranded breaks) facilitate ______________
Breaks in the DNA (especially double-stranded breaks) facilitate the INITIATION OF RECOMBINATION
A defect in ______, that affects joining together of adjacent segments of DNA on a chromosome, can cause abnormal amounts of recombination
A defect in DNA LIGASE, that affects joining together of adjacent segments of DNA on a chromosome, can cause abnormal amounts of recombination
Define recombination
Recombination is the reciprocal exchange of genetic information
Recombination can result from 4 “things”….what are they?
Recombination can result from…
- Reciprocal exchange during cell division
- DNA damage (eg X-ray damage)
- Introduction of foreign DNA
- Programmed recombination during the development or maturation of a cell type (eg antibody producing genes during B-cell maturation)
Define gene conversion
Gene conversion is the non-reciprocal exchange of genetic information
Recombination between direct repeated sequences on the same chromosome causes the loss of _______________
Recombination between direct repeated sequences on the same chromosome causes the loss of DNA THAT WAS BETWEEN THE TWO REPEATED SEGMENTS
Circular DNA can be inserted in a chromosome by recombination between a region of ________ and an _______________
Circular DNA can be inserted in a chromosome by recombination between a REGION ON A CIRCULAR MOLECULE and an HOMOLOGOUS REION ON THE CHROMOSOME
X-rays and other agents that cause breaks in DNA induce ______
X-rays and other agents that cause breaks in DNA induce RECOMBINATION
T/F: Transposable elements are found only in eukaryotes
FALSE!! Transposable elements are found in all species from bacteria to human
Transposable elements move from one location in the _______ to another location within that _____
Transposable elements move from one location in the DNA to another location within that CELL.
_______ can cause changes in the DNA at the site of insertion.
TRANSPOSABLE ELEMENTS can cause changes in the DNA at the site of insertion
There are two major types of transposable elements, one type that contains inverted repeated sequences at the ends and causes ___________ and a second type that is structurally similar to a retrovirus and transposes through _________.
There are two major types of transposable elements, one type that contains inverted repeated sequences at the ends and causes A SHORT REGION OF THE GENOME TO BE DUPLICATED AT THE SITE OF INSERTION and a second type that is structurally similar to a retrovirus and transposes through AN RNA INTERMEDIATE.
Unequal crossing over is recombination that resulted from imprecise pairing of _________.
Unequal crossing over is recombination that resulted from imprecise pairing of TANDEMLY REPEATED SEQUENCES
There are 2 general types of mutations, name them.
There are two types of mutations:
- DNA rearrangements
- Base substitutions.
T/F: There are many mechanisms in each cell for repairing DNA
TRUE!
Damage to a nucleotide (eg deamination) can either be _______ or lead to a ________.
Damage to a nucleotide (eg deamination) can either be REPAIRED or lead to a PERMANENT MUTATION
Mutations can be cause be either errors _________ or by injury to the DNA from _____ or ______
Mutations can be caused by either errors DURING REPLICATION or by injury to the DNA from CHEMICALS or RADIATION.
A small fraction of every genome (about 3% in humans) is made up of ____________ or large regions that are present in ______ copy.
A small fraction of every genome (about 3% in humans) is made up of SEGMENTAL DUPLICATIONS or large regions that are present in MORE THAN ONE copy.
The duplicated DNA is generated by a process called _________
The duplicated DNA is generated by a process called GENE AMPLIFICATION
Gene amplification can result in _______, transformation into ______, or other changes in the cell phenotype.
Gene amplification can result in RESISTANCE TO DRUGS, transformation into CANCEROUS CELLS, or other changes in the cell phenotype.
Several human diseases are due to defects in _______ enzymes
Several human diseases are due to defects in DNA REPAIR enzymes
