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Bio Exam 3
Terms in this set (149)
DNA -- RNA--- Protein
how RNA differs from DNA
- Less stable (easily degraded)
- T is replaced with U
- sugar only OH on 2'
- usually only 1 strand
needed for transcription
DNA template for base pairs.
RNA Polymerase functions
cataylzes RNA synthesis
- doesn't require primers and cannot proofread
3 Phases of transcription
copies info from DNA sequence to RNA sequence (same language)
Converts RNA sequence into amino acid (protein) nucleic acid to amino acid different language
Describe initiation of transcription
RNA polymerase arrives and attaches to the DNA sequence. RNA polymerase requires contact with activator proteins in order to release RNA Polymerase. Once initiated, RNA polymerase unzips the DNA and starts to copy 1 strand
Location on gene where RNA polymerase binds
Elongation of transcription
RNA polymerase works its way down the DNA strand unwinding 10 bases at a time while matching the letter code for the mRNA strand. The subunits of RNA strand enter through the enzymes intake hole.
Direction elongation synthesis RNA
5'--3' direction is antiparrallel to DNA template and adds nucleotides to the 3' end.
RNA polymerase reaches the terminator part of DNA
modifications of mRNa before leaving nucleus
G-cap and poly A tail
added to 5' end facilities mRNA binding to the ribosome and protects MRNA from being ingested by ribosomes
Poly A tail
added to 3' end may assist in export from nuclues, important for mRNA stability
modifications of mRNa before leaving the nucleus
RNA splicing removes introns and splices exons together.
non coding proteins, are removed from final mRNA then mRNA can exit into cytoplasm
Sometimes, the separated exons code for different __________________ of the protein.
domains (functional regions)
# of amino acids
a sequence of 3 base pairs, each codon specifies a particular amino acid.
genetic code dictates how codons on translated into ___________
characteristics of genetic code .....
redundunt, nearly universal, without punctuation (no gaps) any codon for one amino acid does not code for any other amino acid.
not all mRNA molecules code for _________
punctuation of coding regions
start codon AUG, end codon (3 difference codons)
Needed for translation
mRNA, tRNA, amino acids, Enzymes, ATP, ribosomes
Process of translation
mRNA carries the nucleotide sequence code for protein to be made
tRNA molecules function
interpret the nucleotide code, transfer amino acids from cytoplasm to ribosome so they can be attached to protein (peptide chain)
tRNA molecule carries_____________ and a __________ complementary to a codon on mRNA
amino acid, anti codon
Stages of translation
intiation, elongation, termination
initiation of translation
ribisome attatches to mRNA at the start codon
ribosome reads mRNA code and tRNA bring the correct amnio acids
terminator tRNA releases ribosome mRNA complex when thee stop codon reaches the A site, protein is completed & released from tRNA and ribosome separates into 2 subunits again
tRNA/ anicodon bonds to the codon on mRNA at the __________. (codon recognition)
the __________ site holds the first amino acid (peptide formation)
P site, where the growing peptide grows from, 1 by 1
Frame shift mutation
too long or too short
substituaion, deletion, or insertion
change in amino acid codon into a stop codon resulting in a terminated protein
substitutaion of 1 amino acid, does not change the protein, (same amino acid)
regulation of gene expression is....
turning on of off genes. (DNA--- mRNA express or not)
every cell in our body has the same ______ but different cells express different ___________ and produce different __________ which define their ________ and activity.
DNA, sections, proteins, indentity,
ex LAc operon. When lactose is plentiful E.COli makes enzymes to ___________ sugar and use it as energy
ex LAc operon. When lactose is NOT plentiful E.Cli does not waste its enegry producing ______________
Ecoli can turn _________ genes coding for lactose utilizing enzymes or ________ deepening on avialibity of lactose
group of genes that are located adjacent to each other in the bacterial chromosome.
Proteins interact with DNA to turn genes on or off in response to _________________ changes
rare exceptions of operons....
only exist in prokaryotes,
characteristics of operons
-they use shared regulatory sequences coordinately regulate gene expression
- are polycystronic (many genetic info) transcribed as a single RNA that includes many genes
genes can be ___________ or _____________ regulation
positive or negative
regulatory proteins bind and activate transcription. (genes are off when activators are absent)
regulatory proteins bind and repress transcription.
(genes are on unless repressors are present)
genes are off in the absence of some signal
genes are on all of the time
Lac operon conatins genes for enzymes involoved in lactose metabolism.
1), _______ adjacent lactose utilization genes
2) a ____________ sequence
3) an ___________ sequence
2) promoter, where RNA polymerase binds to initiate transcription of all three lactose genes
3) operator, where the repressor can bind block RNA polymerase action
In the absence of lactose the repressor _________ the operator
Lactose ____________ the repressor so RNA polymerase can bind the promoter and lactose metabolism genes are transcribed.
________________ do not have operons
Eukaryotes, they use other methods to regulate gene expression
Gene expression can be controlled by _________________
DNA modification. (epigenetics)
epigenetics permanently effects the ____________ of an individual but are not permanent across_____________ because they do not change DNA sequence.
the phenotype, generations,
coiled or condensed DNA. histones modify how tightly DNA is packaged around histones.
DNA __________ charger and histones are __________ charger. The more _______________ the higher the charger
negatively, positively, histones the more tightly packaged.
X inactivation (epigenetics)
1 chromosome of females is randomaly activated (expressed).
-a blocking factor binds to 1 chromosome prevents it from being transcribed (Barr Body)
- occurs in embryonic development
Barr bodies are four in female but not male cat cells. Therefore...
All calico cats are female. (orange cat fur/black fur)
transcription factors bind to ______________ and initiate transcription by acting as activators. or they bind to __________ ____________
enhancers, mediator proteins
a combination of __________ ___________, ____________ and _____________ expressed in the cell determine the patterns of gene expression.
control elements, activators, repressors
TATA box is
part of the promoter region
transcription initiation complex
specific genes are turned on at specific time often to ....
activation by other genes. (cascade)
RNA splicing can produce alternate RNA splicing and can produce different mRNA from same transcript. Which results in...
production of more than 1 protein from the same gene.
Only a small amount of human genome codes for proteins. much of the rest ...
is transcribed into functioning but non protein coding RNA's
Micro RNA bind to complementary sequences on mRNA molecules to either _____________ or ___________
degrade or block translation.
is a pathway used to regulate gene expression using small RNA that are derived from double stranded DNA that is introduced and results in degradation.
PCR (polymerase chain reaction)
________________ growth throughout cycle
denaturation, annealing, extension,
exponential growth doubling copies each time.
when the temp is increased to separate DNA strand
when temp is decreased to allow primers to base pair to complementary DNA template
polymerase extends primer to form a new DNA strand
mRNA --- DNA by reverse transcriptase
Processes of DLC array
mRNA is isolated, reverse transcriptase makes cdNA from mRNA, cDNA is applied to wells, unbound cDNA is rinsed away, spots without florescent color are unexpressed.
an organism produce by asexual reproduction from a single parent is called a ___________
process of nuclear transplantation
nucleus is removed from an egg cell, a somatic cell from an adult donor is added, the nucleus grows inside the cell, the cell becomes an early embryo (blastocyst)
The blastocyst can implanted in a surrogate mother which is called________________ clone of donor is born
the embryonic stem cells can be removed and grown in culture to be induced to form specialized cells.
total organism, can become any cell (Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent)
certain types of cells (can give rise to all of the cell types that make up the body; embryonic stem cells are considered pluripotent)
differentiated groups, cannot cross (more limited that pluripotent)
DNA technology can provide us with info and resources of...
gene cloning and the production of recombinant proteins
GMO, DNA fingerprinting: forensics and paternity
gene therapy and personalized medicine, genomics
Process of gene cloning and the production of recombinant DNA
plasmid is isolated from bacteria , DNA is isolated from cell, both DNA and plasmid are cut by restriction enzymes, they are combined together and DNA ligase joins the two parts together, makes recombinant DNA
recombinant DNA is placed in ______________, the bacterium reproduces, and they may be use for ____________ ______________ and used directly or the genes ma be inserted into other organisms for __________________
restriction enzymes are used to ________ and _________ DNA. They help make ____________ need for cloning.
cut and paste
(complementary DNA aka cDNA)
Cut and Paste process
restriction enzymes cut the DNA into sticky ends
the DNA fragment from another course is added, two or more base pairs stick together (overlapping)
ligase paste the strands together
GMO can be both __________ or _________ that arise from gene cloning
plants or animals
1 or more genes introduced by artificial genes
transgenic organisms contain
at least 1 gene from another species
Process of GMO
gene with the desired trait is inserted into the plasmid, recombinant plasmid is introduced into a plant cell, the plant cell grows into a plant with the desired trait.
What is gene therapy
aims to help treat a variety of diseases someday by supplying a funcional allele.
- alteration of an afflicted individuals genes
- theoretical attempt to teat disease
gene therapy may be used best to treat___________
disorders traceable to a single defective gene.
Process gene therapy
an RNA cloned gene is inserted into a retrovirus, bone marrow is affected with the virus, the RNA genome of virus that is now DNA is inserted into the cells chromosomes, the engineered cells are injected into the patient.
Darwains 4 theories in origin of species
- the earth is very old, and present day species have evolved from ancestral speices over time
- species change over time
- species that share a common ancestor may have distinct current forms
- natural selection derives changes from ancestral form
5 Decent with modifications
- evolution occurs through the accumulation of adaptions over time
- all organisms are related through descent form a remote common ancestor
- descendants spread into diverse habitats over millions of years and acquire adaptions to their environments.
- the history of life resembles a tree with multiple branches from a common trunk
- species that are closely related share characteristics.
Darwins proposal evolution by natural selection
over production- organisms produced more offspring than can survive to an adult
variation- individuals of a population have many characteristics that differ.
selection- some individuals live longer and reproduce more than others
adaption- traits of the individuals that survive and reproduce will become more common in a population
Darwin + mendels=
evolution that results from heritable changes of 1 or more characteristics of a population from one generation to the next.
points of evolution by natural selection
1. individuals do not evolve.... _______________ evolve
2. evolution is not deliberate, its _______________
ex. birds evolved wings vs. wings evolved in birds
3. Natural selection can diminish only ________________,
heritable traits, acquired characteristics cannot be passed on to offspring
4. Evolution is NOT _________________ and does not lead to perfection
goal directed. favorable traits vary as environments change.
5. the environment does selecting via a ___________ process through which certain traits are favored within a population. Species do not evolve because of ____________. An _______________ in one context might be handicap in another context.
natural selection is more of an __________ ____________ than a creative mechanism
naturals selection is contingent on _____________ and ___________ favoring those characteristics in a population that fit the current local environment
time and place
selective breeding is ___________ ____________. designed to modify _______________ in domesticated species. Made possible by ___________ ______________
_____________ choose parents in natural selection
_____________ choose in artificial selection
5 Evidence of evolution
Fossils show ____________ ________________. the oldest known fossils _. _ billions years ago were ______________. Oldest eukaryotes were ___________ years ago.
3.5 , prokaryotes
biogeography shoes ________________ _____________ of species and ___________ similarities
comparative anatomy deals with __________ ___________. Simullartities that result from common ancestry.
homologous have ______________ functions, but are structurally ______________ due to ancestry
different , similar
analogous have _______________ functions but are structurally _______________.
same , different
comparative embryology compares the _____________________________ among different organisms reveals ____________ not visible in adult organisms
early stages of development, homologies
ex of comparative embryology are _____________ ____________ which are remnants of features that served important functions in a organisms ancestor
molecular biology compares _________ and ________ _________ . All life shares common DNA that code for __________ found in living cells. Humans and __________ shares ______________ genes that have been inherited from vary distant common ancestors.
DNA and amino acids.
3 major points of microevolution
natural selection, genetic drift, gene flow,
natural selection- if individuals differ in their ____________ and __________ success, natural selection with alter ___________ ______________
survival and reproductive
natural selection can alter variation in 3 ways
stabilizing, directional, disruptive
favors intermediate phenotypes, acting against extreme phenotypes
acts against individuals of one of the phenotype extremes
favors individuals at both of the extreme phenotypes.
elimination of unfavorable genotypes. In ______________ organisms recessive alleles are usually not subject to __________ ____________ in heterozygotes.
balancing selection maintains ___________ ___________ of two ro more ______________ in a population.
_______________ have greater reproductive success than homozygotes
Frequency-dependent selection is a type of ___________ ____________ that maintains two different phenotypes in a population.
Genetic Drift is a change in ______ _______ of a population due to _________. A small population, chance events may lead to loss of __________ ________
gene pool, chance
bottleneck leads to a loss of genetic diversity when....
a population is greatly reduced by a chance event
part of genetic drift
original population--bottleneck effect-- surviving population
founder effect leads to a loss of genetic diversity when ....
a few individuals colonize a new habitat.
part of genetic drift
genetic flow is the movement of individuals between _______________ mechanism for an increase the _________ of a population
an individual's ___________________ is the contribution it makes to the ______ ______ of the next generation relative to the contribution of other individuals.
the fittest individuals are those that produce
the largest number of viable, fertile offspring and pass on the most genes to the next generation
sexual selection: sexual dimorphism where __________ and _________ show different appearances
males and females
intrasexual selection: _______________
intersexual selection: ______________
competition for mates (males)
between sexes or mate choose (usually females)
3 major points of macroevolution
continental drift- movements in ___________ to cause plates to move
theory of plate tectonics, the earths crust is divided into ____________ , irregularly shaped _____________ that essential float on the underlying ________________ . Once known as ________
giant, plates, mantle
There have been _____ mass extinctions and we are in the middle of the _______ where large numbers of __________ are lost over _______ % of earths species went extinct
Adaptive radiations have _______________ the diversity of life. Evolutionary change that occurs when.... (often following extinction event) or when.....
Large changes, warm to cold, sea to land
many species evolve from a common ancestor that colonizes a new area
or... when a few individuals are isolated from a larger population.
Slight changes in the relative growth of different body parts can change __________________________
the adult form drastically
Complex structures may evolve by increments from simpler versions with the ________ ________ functions- but it is critical that
same basic functions
any step in the evolution of a new feature must:
• bring a selective advantage to the organism possessing it and
• increase the organism's fitness.
More complex structures arrive from gradual adaptation of existing structures to new functions known a ________________
Exaptations: evolve in one context but become useful for another function
- Ex. Feathers may have first been used for insula<on, now for flight.
- Ex. Penguin flippers first for flight, then for swimming
Hardy Weinburg states frequencies of __________ and _____________ will remain constant over time in the absence of other ____________ __________
alleles and genotypes
Hardy Weinburg equilibrium must satisfy 7 conditions...
2. large population
3. no gene flow between populations
4. generations an not overlapping
5. no mutations
6. random mating
7. no natural selection
Hardy Weinburg equations
p^2 x 2pq x q^2 = 1
frequency of dominant alleles
frequency of recessive alleles
frequency of dominant homozygous individuals
frequency of recessive homozygous individuals
frequency of heterozygous individuals
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