Module 5 EXAM PRACTICE Flashcards
High concentration of which which protein stimulates the development of anterior structures?
Bicoid
Conserved developmental genes can lead to _______ evolution.
parallel
The correct sequence in which Drosophila body axis genes act is:
egg-polarity genes—>gap genes —>pair-rule genes—->segment polarity genes—>homeotic genes.
Pair-rule genes loss-of-function mutation phenotype
Deletes every other segment
Gap genes loss-of-function mutation phenotype
Delete adjacent segments
Segment-polarity genes loss-of-function mutation phenotype
Affect polarity of segment; part of segment is replaced by mirror image of part of another segment.
Genes that regulate development are conserved. This means that they
have changed very little over the course of evolution.
When the mammalian Pax6 gene is overexpressed in flies,
flylike eyes develop.
The following are NOT characteristics of maternal effect mutations:
When mutant offspring arise they account for 50% of the offspring.
Mutant offspring arise from homozygous mutant fathers crossed to heterozygous mutant mothers.
Wild-type offspring arise from crosses of heterozygous mutant fathers regardless of the genotype of the mother.
Heterozygous mutant fathers crossed to homozygous normal mothers will not produce normal offspring.
The following are characteristics of maternal effect mutations:
Mutant offspring arise from homozygous mutant mothers irrespective of the genotypes of the father
Deletion of the _______ gene in Drosophila converts the 3rd thoracic segment into the second thoracic segment, resulting in a fly with 2 sets of fully formed wings.
Ubx
The expression of a zygotic gene product is based on the ____________________.
genotype of the zygote
TRUE or FALSE?
In Drosophila homeotic genes are present in 2 gene complexes.
True
A self-contained unit that is made up of other units is called a
module
Establishment of the dorsal-ventral axis of the Drosophila embryo:
Involves the nuclear localization of Dorsal protein in the ventral nuclei.
Many of the genes that control development encode _______ that act on proteins in a cascade of events.
transcription factors
Which of the following statements is true?
- The transcription factors and the extracellular signals that govern pattern formation can be thought of as the molecular “black box.”
- Developmental processes in both Drosophila and vertebrates are controlled by similar sets of genes.
- Many regulatory genes are required to bring about the diversity of organisms that we observe.
Developmental processes in both Drosophila and vertebrates are controlled by similar sets of genes.
TRUE or FALSE?
The human Hox genes are similar in sequence to the homeotic genes found in Drosophila, but are not lined up in the the same order.
FALSE
The ability of an organism to modify its development in response to environmental conditions is called
developmental plasticity.
Which of the following is NOT a way plants differ from animals regarding regulatory genes that affect their development?
a) Plants have tremendous developmental plasticity.
b) Plant cells do not have MADS box genes and homeobox genes.
c) Future reproductive cells are not set aside during early plant development.
d) None of the above
e) Plant cells do not move relative to one another.
Plant cells do not have MADS box genes and homeobox genes.
Which scientist performed experiments with eyeless and Pax6?
Rebecca Quiring
The transcription factors that govern pattern formation in multicellular organisms, and the genes that encode them, are components of what biologists call the molecular _______.
tool kit
Ways that plants differ from animals regarding regulatory genes that affect plant development:
Plants have tremendous developmental plasticity.
Future reproductive cells are not set aside during early plant development.
Plant cells do not move relative to one another.
What is true of homeotic transformations in Drosophila?
they can be passed on from generation to generation
The action of genes controlled by _______ determines where and when they will be expressed or suppressed.
genetic switches
Which of the following is NOT a developmental environmental signal?
a) Temperature
b) Light
c) The presence of predators
d) All of the above are developmental environmental signals.
All of the above ARE developmental environmental signals.
List some developmental environmental signals
Temperature
Light
The presence of predators
What are the role and relationship of egg-polarity genes, segmentation genes, pair-rule genes, gap genes, and homeotic genes in Drosophila development?
??
EXTENDED RESPONSE
Egg polarity genes establish the anterior-posterior axis of the embryo using a concentration gradient of maternal mRNAs and proteins.
This gradient activates the gap genes, which divide the embryo into broad bands of head/thorax/abdomen.
Gap gene products activate pair-rule genes, which divide embryo into segments.
Pair-rule genes activate segment polarity genes in each segment, dividing each into anterior and posterior regions and aligned linearly.
Homeotic genes will determine the identity of each segment by determining which adult structure will be formed by the segment.
Flies have _______ eyes, while mammals have _______ eyes.
Flies have compound eyes, while mammals have _______ eyes.
dorsal
nuclear localization
bicoid and nanos
??!
c, anterior–posterior axis
Bicoid (bcd) is a maternal effect gene required for anterior development in fruit flies. Suppose that a egg from a mutant mother is destined to develop into an embryo with two posterior ends. A scientist does an experiment with this embryo.
The scientist injects wild type bicoid mRNA at the location that in a wildtype would have formed the posterior end of a developing embryo. What will be the phenotype of the injected larva? Justify your answer.
Certified Correct:
(i) The injected DNA will have no effect since bicoid is a maternal effect gene. Thus, the insertion of DNA into the embryo will have no effect. The larva will still develop two posterior ends.
(ii) The injected mRNA will cause the larva to develop normally (1 posterior end and 1 anterior end). It will compensate for the lack of functional bicoid mRNA from the mother.
Morphogens control cell fate at ____________ concentrations.
??!!
3 or more
Which of the following statements is false?
a) All of the above are true.
b) Homologous genes encoding similar transcription factors are expressed in similar patterns along the anterior–posterior axes of both mammals and insects.
c) Ubx is a Hox gene.
d) The full-sized wing in Drosophila is normally produced on just the third thoracic segment.
e) Deletions of the Ubx gene convert the 3rd thoracic segment into the 2nd thoracic segment.
The full-sized wing in Drosophila is normally produced on just the 3rd thoracic segment.
The developmental pathway for sex determination in Drosophilia is best exemplified by which of the following statements:
One developmental state is the default, whereas its alternative requires the activation of a series of regulatory gene products.
One developmental state is the default, whereas its alternative requires the activation of a series of regulatory gene products.
Regulation occurs at more than one level from the gene to the active protein.
An on-off decision for a master switch is made early on in development.
All of the above are true.
What are some of the different signals that can initiate programmed cell death (apoptosis)?
??!!!
EXTENDED RESPONSE
Infection by Virus, DNA damage, damage to the mitochodria
Drosophila passes through ______ larval stages and a ____before developing into an adult fly.
??
3, pupa stage
There are ______ Hox gene cluster in mammals
4
Mutations in homeotic genes often cause
structures to appear in the wrong place
_______ is the ability to express different phenotypes under different environmental conditions.
Developmental plasticity
Master regulatory genes are ___________ and ____________ to determine cell fate.
??!!!
“necessary, sufficient”
ontogeny recapitulates phylogeny
j, Ernst Haeckel
In wild-type flowering plants, carpel development is determined by what class of gene products?
C gene products
Which of the following statements is false?
a) The cameralike eyes of mammals are composed of thousands of individual lenses known as ommatidia.
b) eyeless/Pax 6 acts as a molecular switch.
c) Evolutionary developmental biology is often called “evo-devo.”
d) All of the above are true.
e) Eyes evolved many times independently within the animal kingdom.
The cameralike eyes of mammals are composed of thousands of individual lenses known as ommatidia.
The _______ thoracic segment of Drosophila bears small hind wings that function as _______ organs.
third; balance
Insects have _______ legs.
6
The nanos mRNA is localized at the ________ end of the Drosophila egg.
posterior
TRUE or FALSE?
The function of the gene dorsal is required for determining the left/right axis during Drosophila development.
False
What is the role of maternal-effect genes?
Certified Correct:
Genes derived from the maternal genome are actively transcribed to support the zygote and are required for the proper patterning of the embryo.
Mutant phenotypes of maternal-effect reflect the genotype of the mother.
Genetic switches are involved in….
helping various modules develop differently.
Egg-polarity genes regulate __ genes, which in turn modulate the activity of __ genes.
??!!!
“gap, pair-rule”
The bicoid mRNA is localized at the ________ end of the Drosophila egg.
anterior
_______ allows morphological changes to occur without disrupting the entire organism.
Modularity
The expression of a maternal gene product is based on the _____________________________.
??
genotype of the mother
Match the Drosophila developmental stages with the gene families regulating the development of these stages.
Egg-polarity genes
Establishment of main body axis
Match the Drosophila developmental stages with the gene families regulating the development of these stages.
Homeotic genes
Establishment of identity of each segment
Match the Drosophila developmental stages with the gene families regulating the development of these stages.
Segmentation genes
Determination of the number of body segments
Which of the statements below are true about the pattern of gap gene expression in early Drosophila development?
- It is determined by the activity of the anterior-posterior morphogens BCD and HB-M.
- It contributes to dorsal-ventral patterning of the embryo.
- It determines the pattern of expression of the homeotic genes.
- it can overlap with the expression domain of another gap gene
- It is dependent upon previous expression of the segment polarity genes.
- It determines the pattern of expression of the pair-rule genes.
It is determined by the activity of the anterior-posterior morphogens BCD and HB-M.
It determines the pattern of expression of the homeotic genes.
It can overlapp with the expression domain of another gap gene
It determines the pattern of expression of the pair-rule genes.
Developmental plasticity is…
the ability to express different genotypes under different environmental conditions.
Most regulatory genes have evolved little over a period of millions of years; therefore, they are said to be _______.
conserved
antennapedia complex
h, homeotic gene
Which of the following about Ubx is true?
a) It turns on the genes that promote the function of the veins and other structures of the forewing.
b) It binds to cells of the third thoracic segment in butterflies.
c) None of the above
d) All of the above
e) In Drosophila, it is expressed by cells that form the hindwings.
In Drosophila, it is expressed by cells that form the hindwings.
What are morphogens and what do they do?
??
EXTENDED RESPONSE
Morphogens are master regulators that determine embryo fates at 3 or more concentrations.
They signal certain parts of the cell telling that part of the embryo what it will turn into.
BCD and HB-M are examples
Formation of concentration gradients of diffusible developmental regulatory molecules (morphogens) establishes positional information in developmental fields.
The homeotic, gap, pair-rule, and segment polarity genes ALL control:
the number of segments.
pair-rule genes
i, segmentation gene
The ability of organisms to modify their development (and hence, their phenotype) in response to environmental stimuli is known as developmental _______.
i, segmentation gene
Components of DNA, called _______ control how the molecular toolkit is used.
genetic switches
How do developmental genes constrain evolution?
a) Modifying previously existing structures
b) Maintaining highly conserved genes
c) Creating novel structures
d) Both a and b
e) All of the above
Both a and b:
Modifying previously existing structures
AND
Maintaining highly conserved genes
Which of the following statements about the gene eyeless is true?
a) None of the above
b) It encodes a transcription factor.
c) It is found in Drosophila.
d) All of the above
e) Pax6 is the equivalent gene in mice.
All of the above
To study mammalian segmentation in the mouse, zygotically acting mutations are generated. A recessive mutation is identified. It causes all seven cervical vertebrae to be missing. Given the striking evolutionary conservation of many aspects of development in mice and flies, one way to determine which gene is mutated is to look for a gene affecting an analogous process in Drosophila.
What type of segmentation gene in Drosophila is most analogous to the loss of seven cervical vertebrae produced by the recessive mouse mutation?
Gap gene
TRUE or FALSE?
Segmentation genes determine the identity of individual segments during development.
False
egg-polarity genes
??!!!
c, anterior–posterior axis
TRUE or FALSE?
Many plant cells remain totipotent throughout development.
True
What are Hox genes?
??
EXTENDED RESPONSE
Hox genes are homeotic genes that are expressed in a particular pattern along the Anterior-Posterior axis of many animals, including humans and Drosophila.
Hox genes code for transcription factors that are involved in the production of segment-specific structures.
The arrangement of Hox genes on a fruit fly chromosome correspond with expression of Hox genes in different body segments of a fruit fly embryo.
The maternal-effect Bicoid gene codes for ________________
a DNA-binding transcription factor
Alterations in the spatial expression patterns of regulatory genes can result in
evolutionary change.
TRUE or FALSE?
A morphogen is a protein that can restore totipotency to cells from an adult animal.
False
TRUE or FALSE?
Plant cells can not be cloned from single isolated cells.
False
PLANTS CAN BE CLONED
Which of the following statements is true?
a) Adults are made up of modules.
b) Many developmental genes exert their effects on only a single module.
c) Embryos are made up of modules.
d) All of above
e) None of the above
All of above
TRUE or FALSE?
Homeotic genes in mammals are dissimilar to those in Drosophila
False
_______ is a shift in the relative timing of two different developmental processes that can result in new morphology.
Heterochrony
Which of the following is true of homeotic transformations in Drosophila?
they can be passed on from generation to generation
they are not amenable to genetic analysis
they are caused by genes that are not conserved across species
they are always caused by more than one mutation in these genes
none of the above
they can be passed on from generation to generation
When the mammalian Pax6 gene is overexpressed in flies,
flylike eyes develop.
_______ allows morphological changes to occur without disrupting the entire organism.
Modularity
Which of the following statements is false?
a) The cameralike eyes of mammals are composed of thousands of individual lenses known as ommatidia.
b) All of the above are true.
c) Eyes evolved many times independently within the animal kingdom.
d) Evolutionary developmental biology is often called “evo-devo.”
e) eyeless/Pax 6 acts as a molecular switch.
The cameralike eyes of mammals are composed of thousands of individual lenses known as ommatidia.
What are homeotic genes and what do they do?
??
EXTENDED RESPONSE
Homeotic genes code for transcription factors that control the development of segment-specific body parts.
This class of genes controls the developmental identity of segments along the anterior-posterior axis.
Homeotic genes are regulatory genes that work after the body axes have been established.
Homeotic genes identify particular body segments in an individual, eventually leading to the formation of segment-specific body structures in the correct locations on the body.
_______ is the ability to express different phenotypes under different environmental conditions.
Developmental plasticity
Components of DNA, called _______ control how the molecular toolkit is used.
genetic switches
Master regulatory genes are ___________ and ____________ to determine cell fate.
necessary and sufficent
Genes that regulate development are conserved. This means that they
have changed very little over the course of evolution.
Many of the genes that control development encode _______ that act on proteins in a cascade of events.
transcription factors
Bicoid (bcd) is a maternal effect gene required for anterior development in fruit flies. Suppose that a egg from a mutant mother is destined to develop into an embryo with two posterior ends. A scientist does an experiment with this embryo.
The scientist injects wild type bicoid mRNA at the location that in a wildtype would have formed the posterior end of a developing embryo. What will be the phenotype of the injected larva? Justify your answer.
Certified Correct:
(i) The injected DNA will have no effect since bicoid is a maternal effect gene. Thus, the insertion of DNA into the embryo will have no effect. The larva will still develop two posterior ends.
(ii) The injected mRNA will cause the larva to develop normally (1 posterior end and 1 anterior end). It will compensate for the lack of functional bicoid mRNA from the mother.
pair-rule genes
i. segmentation gene
The developmental pathway for sex determination in Drosophilia is best exemplified by which of the following statements:
One developmental state is the default, whereas its alternative requires the activation of a series of regulatory gene products.
One developmental state is the default, whereas its alternative requires the activation of a series of regulatory gene products.
Regulation occurs at more than one level from the gene to the active protein.
An on-off decision for a master switch is made early on in development.
All of the above are true.
All of the above are true.
Mutations in homeotic genes often cause
structures to appear in the wrong place
Morphogens control cell fate at ____________________ concentrations.
??
3 or more concentrations.
i. segmentation gene
i. pair-rule gene
antennapedia complex
h. homeotic gene
j. ontogeny recapitulates phylogeny
j. Ernst Haeckel
dorsal
b. nuclear localization
egg polarity
c. anterior–posterior axis
bicoid and nanos
c. anterior–posterior axis
In Drosophila homeotic genes are present in two gene complexes
true
A morphogen is a protein that CANNOT restore totipotency to cells from an adult animal.
….
if maternal-effect:
-and mother is heteroz. wild type/mutant, then progeny will all be wild type…NO MATTER WHAT THE FATHER GENOTYPE IS
-and if mother is homozygous mutant, then progeny will all be mutant …NO MATTER WHAT THE FATHER GENOTYPE IS
if zygotic:
just treat like normal monohybrid cross.
m/+ is wildtype and mm is mutant right?
+ is wildtype and m is mutant. in this scenario m is recessive and + is dominant so yes, what you said is correct
