Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL 432 > Final Exam Review > Flashcards

Final Exam Review Flashcards

1
Q

Which of the following statements is
INCORRECT?

A

ZPA transplanted to the posterior part of the
limb leads to duplication of digits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The purpose of the Shh-expressing cell
transplantation experiment is to show that

A

Shh is expressed in the right place and at the right time for limb development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The Shh mutant limbs contain only
one digit, which digit is it?

A

1 (thumb)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A piece of foil inserted between IM and LPM
prevents limb induction because it…

A

Stops a secreted inducer from reaching LPM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What do you expect in a mouse
carrying an IM-specific Fgf8 mutation?

A

No limb forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How Does Shh Induce Motor Neurons?

A

Model 1: Shh directly induces motor
neurons at relatively low concentration

Model 2: A secondary signal produced by
the floor plate induces motor neurons
through a relay mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which of the following is INCORRECT?

(A) FP is closer to the source of Shh than MN

(B) It takes more Shh to induce FP than MN

(C) After being induced by Shh, FP produces a secondary
signal that induces MN

(D) MN can be induced by Shh in the absence of FP

A

After being induced by Shh, FP produces a secondary
signal that induces MN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens in Shh target cells?

A
  1. Shh binds its receptor, Ptch1, on the
    surface of the target cell
  2. Smo, another cell surface protein of the
    target cell, is activated
  3. Gli transcription factor is activated and
    enters the nucleus
  4. Gene transcription is activated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Will ectopic expression of Shh induce
an ectopic floor plate in Smo mutant
spinal cord? Why?

A

No, it will not!

Without Smo, the cells do not respond to
Shh, thus ectopic expression of Shh cannot
induce the formation of a floor plate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

A chimera analysis can tell us…

A

(A) Shh forms a simple gradient in the spinal
cord

(B) A moderate concentration of Shh is
important for the formation of motor neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which of the following is the earliest event in the limb development?

A

Fgf8 expression in intermediate mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

A bead pre-soaked in saturated Shh solution
is implanted into the anterior part of a chicken
limb bud for 4 hours before it is removed.
Which extra digit can it induce?

A

Digit 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In the lineage tracing experiment I described
today, why is lacZ expression restricted to
Shh-expressing cells and their descendants?

A

lacZ proteins need to interact with a protein that is only present in Shh-expressing cells and their descendants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In the lineage tracing experiment, I described
today, why does lacZ continue to be expressed
in cells long after Shh expression stops?

A

Cre is very stable and continues to activate lacZ expression after Shh expression is terminated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What regulates transcription?

A
  • Proteins:
    • Transcription factors: Bind DNA
      activators and repressors
    • Transcription cofactors: Do not bind DNA
      co-activators and co-repressors
  • DNA sequences:
    • Enhancer: Bind activators
    • Operator: Bind repressors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Cis-regulatory elements:

A

Have to be on the same chromosome to regulate gene transcription, enhancers and operators (DNA elements)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Trans-regulatory elements:

A

The genes encoding them can be on any chromosome, transcription factors and cofactors
(Proteins, RNAs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which of the following is NOT a cis-
regulatory element for transcription?

(A) Promoter
(B) Enhancer
(C) Operator
(D) Transcription factor

A

Transcription factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which of the following is NOT done to
identify a cis-regulatory element?

(A) Identify a conserved DNA sequence
(B) Drive a reporter with the conserved DNA
sequence
(C) Remove the conserved sequence to see if gene
expression is disrupted
(D) Perform a chemical mutagenesis screen to see if
the development of an animal is disrupted

A

Perform a chemical mutagenesis screen to see if
the development of an animal is disrupted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which of the following is INCORRECT about
ZRS?

A. It is a trans-regulatory element for Shh expression in ZPA.

B. Ssq insertion alters its activity

C. It is conserved between human, mouse, chicken and fish

D. It is in an intron of Lmbr1

A

A.

It is a trans-regulatory element for Shh expression in ZPA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which of the following is NOT
associated with RNAi?

(A) Dicer
(B) Slicer
(C) RISC
(D) DISC

A

DISC

22
Q

What was the most important reason why
the RasGAP shRNA-expressing ES cells
was introduced into a tetraploid embryo
instead of a diploid embryo?

(A) To save time
(B) To save money
(C) Tetraploid embryos are bigger
(D) A chimera may not give birth to a mutant
pup

A

A chimera may not give birth to a mutant pup

23
Q

Which of the following is present in the
Smo morphant, but not mutant fish?

(A) Short, curly tail
(B) Abnormally-shaped somites
(C) Increased cell death in the head
(D) Decreased p53 expression

A

Increased cell death in the head

24
Q

Why do the Egfl7 morphants and
mutants show different phenotype?

(A) The morpholino induces non-specific cell
death
(B) The mutation in Egfl7 is not a null
(C) The upregulation of Emi proteins in the
mutant compensate for the loss of Egfl7
(D) The morpholino can target genes other than
Egfl7

A

The upregulation of Emi proteins in the
mutant compensate for the loss of Egfl7

25
Q

Why do we clone animals?

A

To demonstrate that all cells have the same
genetic information

To study certain aspects of biology only
cloned animals can provide the answer

To use as a genetic tool for developmental
biology study

26
Q

How do we clone animals?

A

Somatic cell nuclear transplantation
(SCNT)

27
Q

An animal can be cloned through
SCNT because all cells in the animal
have the same…

A

DNA content

28
Q

What is application 1 of animal cloning and how do they work?

A

Application 1: Genetic modification in non-Genetic Animals

Mice and rats are the only species in which fully
functional ES cells have been isolated

Somatic cell culture, gene-targeting or other
mutagenesis manipulations

Once a mutant cell is identified, make a cloned
animal from that cell

Example: Gene-targeted Sheep
- Perform gene-targeting in sheep fibroblasts
- Transfer targeted fibroblast nucleus into an enucleated egg
- A gene targeted lamb is born

29
Q

What is application 2 of animal cloning and how do they work?

A

Cross-Species Cloning

Nuclei from (recently) dead animals can be used for animal cloning

Cross-species SCNT can be performed

Fibroblasts were isolated from a recently dead mouflon.

The nucleus from a fibroblast was transplanted into a sheep oocyte.

A cloned mouflon was born

30
Q

What is application 3 of animal cloning and how do they work?

A

Therapeutic Cloning

31
Q

The production of a gene-targeted
sheep contains all the following steps
EXCEPT…

A

Transfer the blastocysts into a pseudopregnant
sheep

32
Q

Which of the following did NOT happen?

A

Overexpression of Pax7 leads to ectopic Dbx1 expression in the ventral spinal cord

33
Q

Which of the following suggests that Shh
spreads more easily through mPtc1Dloop2-
expressing cells?

A

Pax6 expression is inhibited on the dorsal side of patches of mPtc1Dloop2-expressing cells

Nkx2.2 expression is dorsally expanded on the dorsal side of patches of mPtc1Dloop2-expressing cells

34
Q

Where is AER?

A

at the distal edge

35
Q

Which of the following is NOT true
about Shh?

(A) Shh-expressing cells induce digit duplication
when they are grafted to the anterior edge of
the limb bud

(B) Shh is expressed in the floor plate and
notochord of a mouse embryo

(C) Shh is required for the formation of all digits
except for the thumb/big toe

(D) Shh is expressed in the AER and promotes
the outgrowth of the limb buds

A

D

36
Q

When an FGF4 bead is implanted to the mesoderm in
the interlimb region, an extra limb develops. What
does this tell you?

A

One of the FGF family members must be expressed there

37
Q

Which of the following results in Shh
expression in the anterior part of the limb
bud?

(A) RA beads, no AER
(B) FGF8 beads, no AER
(C) RA beads, with AER
(D) FGF8 beads, with AER

A

C

38
Q

Which of the following is NOT true?

(A) A moderate level of Shh can induce motor neurons in a spinal cord explant

(B)The spinal cord explant experiment addresses whether motor neuron is induced by Shh in vivo

(C) Smo mutant cells fail to become motor neurons in a chimera

(D) The chimera analysis does NOT address whether motor neurons form at a specific Shh concentration

A

B

39
Q

Which of the following was observed when Shh
beads were implanted into the anterior part of
the chicken limb buds?

(A) Beads containing higher concentration of Shh
induce more posterior digits

(B) Beads have to be in the limb buds for at least 16
hours to induce extra digits

(C) It takes longer time to induce the posterior digits
than the anterior ones

(D) All of the above

A

D

40
Q

Which of the following is INCORRECT about cis-regulatory elements for gene expression?

(A) They can only regulate the expression of genes on
the same chromosome

(B) They have to be right next to the promoters of the
genes they regulate

(C) They usually associate with proteins that regulate
transcription of the gene

(D) Their sequences are usually conserved during
evolution

A

B is false because

A is true because it is cis meaning same in this case -if it was trans it could regulate other chromosomes

C is true because

D is true because

41
Q

Which of the following is NOT true about
miRNAs?

(A) They are short double-stranded RNAs
(B) They mainly interfere with protein translation
(C) DICER is important in the processing of miRNAs
(D) miRNAs mainly target virus RNAs for
degradation

A

D

42
Q

Which of the following is NOT part of a
transgene expressing shRNA?

(A)A RNA polymerase II-based promoter

(B)A 7-base spacer between the sense and antisense
sequence

(C) Multiple Ts at the end of the transcript

(D) A palindromic sequence matching the target gene

A

A

43
Q

The Morpholino knockdown of Egfl7, but not a
mutation in Egfl7 gene in the genome, disrupts
blood vessel network because…

(A)The morpholino knockdown causes non-specific effect
(B) The mutation in Egfl7 is a hypomorph

(C) The increase in emi proteins compensate for the loss of
Egfl7 in mutants, but not in morphants

(D) The increase in emi proteins compensate for the loss of
Egfl7 in morphants, but not in mutants

A

C

44
Q

An siRNA against lacZ results in which of the
following in zebrafish

(A) The reduction of the expression of a lacZ transgene
(B) The reduction of the expression of many
developmentally important genes
(C) Defects in the heads and tails
(D) All of the above

A

D

45
Q

Which of the following about animal cloning
is INCORRECT?

(A)A cloned animal is exactly the same as the nucleus
donor
(B)Animal cloning works because the same genetic
information exists in the chromosomes of all cells in an
animal
(C) During cloning, proteins in the cytoplasm of the oocyte
help to erase the chromosomal modifications on the
donor nucleus
(D) The cloning efficiency correlates inversely with the age
of the nucleus donor

A

A

46
Q

Which of the following is INCORRECT?

(A) The purpose of therapeutic cloning is to derive ES cells
from cloned embryos
(B) After ES cells are derived from cloned embryos, they
can be transplanted back into the patient directly
(C) Therapeutic cloning is expected to minimize
immunorejection of transplanted cells
(D) Caffeine is critical for the success of therapeutic cloning

A

B

47
Q

Which of the following about Yamanaka
Factors is NOT true?

(A)They can convert skin cells into stem cells
(B)They can cause tumor
(C)They are hydrophobic proteins that can easily cross the
cell membrane
(D) Their stem cell inducing effect can be mimicked by
small chemicals

A

C

48
Q

Inducing pluripotent stem cells with
chemical compounds…

(A) Is less expensive than the original Yamanaka
method
(B) Is faster than the protein-based induction
method
(C) May disrupt endogenous genes
(D) May turn the cells into tumor cells

A

A

49
Q

Essay 1: Based on the temporal gradient
theory, what kind of phenotype do you expect
to see in mouse limb development if Shh is
mutated at E11.5?

A

According to this theory, the
posterior digits require longer exposure to Shh
than anterior digits. Therefore, if Shh is
mutated at E11.5, the fifth digit may not form.
Digits 3 and 4 should be normal as they no
longer express Shh at this stage.

50
Q

Essay 2: Name two methods to ensure the
phenotype you observed in siRNA or
morpholino knockdown animals are NOT due
to off-target effects.

A

method 1: If you can rescue the phenotype by
re-introducing the target gene, the phenotype is likely
specific.

method 2: If you do not see the same
phenotype when you introduce a scrambled siRNA or
morpholino, the phenotype in the knockdown animal
is likely specific.

Additional methods you can mention: perform
the knockdown in p53 mutants, perform the
knockdown in a KO animal, etc

51
Q

Essay 3: Describe how you can generate a
mutant farm animal for which ES cells do not
exist and it is still too expensive to take the
CRISPR/Cas9 approach and screen hundreds
of animals.

A

You can take the approach described in the
lecture. First, you culture skin fibroblasts from
an adult animal, and generate mutant cells
through gene-targeting or CRISPR/Cas9. Then
you produce a cloned animal by transplanting
the mutant nucleus into an enucleated oocyte.
A pseudo-pregnant female will be needed for
the oocyte to develop to term.

BIOL 432 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions