Final

Question 1

Morphogen

Answer 1

Molecule that elicits different responses depending upon its concentration

Question 2

Canoncial wnt pathway

Question 3

Double negative gate

Question 4

HOX genes

Answer 4

Genes regulated by the protein products of gap, pair-rule, and segment polarity genes, specifically the characteristic structures of each segment
Mutations can result in the transformation of one segment into another
Important for the placement of limb buds, early kidney, limb bud patterning, imaginal disks

Question 5

Gastrulation

Answer 5

Movement and rearrangement of blastomeres to form the three germ layers that will comprise the embryo - ectoderm, endoderm, mesoderm

Question 6

Cre-lox

Answer 6

0. Cre is an enzyme that recognizes loxp DNA sequences
1. The mouse is genetically engineered to express cre under a specific cell-type promotor
2. A reporter gene is placed downstream of a loxP stop
3. Cre removes stop cassete allowing the reporter to be expressed
   Allows for a KO of a gene in specific tissues

Question 7

CRISPR KO

Answer 7

• guide RNA directs the Cas9 enzyme to genome location
• Cas9 makes a double strand break in the DNA at the location
• The gene is often repaired incorrectly

Question 8

CRISPR Knock In

Answer 8

• guide RNA directs the Cas9 enzyme to genome location
• Cas9 makes a double strand break in the DNA at the location
• Donor DNA with homology arms identical to the target sequence is also introduced
• The cell repairs the damage with the donor DNA template

Question 9

Lineage Tracing

Answer 9

Using Cre-lox for brainbow in mice

Question 10

Molecular Motors

Answer 10

Proteins that convert chemical energy into mechanical work.
Dynein (Bcd) and kinesin (nos) transport the mRNAs in the unfertilized drosophila egg

Question 11

Find it

Answer 11

The correlation of a molecule or structure w/ a function, the molecule has to be present at the right time and place
- Establishes connection
- Fluorescent tracing
- In situ hybridization ( detect the presence and location of specific mRNA at the right time and tissue)

Question 12

Loose it

Answer 12

The loss of function - get rid of the molecule or structure by mutation or inhibitors
- When you lose the molecule do you lose its function?
- Establishes necessity
- CRISPR KO
- Laser Inhibition
- RNAi

Question 13

Move it

Answer 13

If you put the moleculor structure in a new place, do you get the function appearing
- Establishes sufficiency
- Transplantation experiment
- To new location or different organism.

Question 14

Cell potency

Answer 14

A cell’s ability to differentiate into different types of cells

Question 15

Stem Cells

Answer 15

Make more than one cell type, typically a closely related family

Question 16

Progenitor Cells

Answer 16

Can differentiate into multiple cell types, but can only renew a limited number of times

Question 17

Bicoid / Nanos

Answer 17

In the unfertilized drosophila egg, there is anchored bicoid in the anterior and anchored Nos in the posterior that’s deposited by the maternal genes before fertilization.
Upon fertilization, the localized bcd and nos mRNA are translated into protein gradients.
Bcd protein acts as a txn factor and hunchback is also a txn factor that is activated by bcd
Nos protein represses translation of maternal Hb mRNA in the anterior through 3’ UTR
Bcd protein inhibits Cad mRNA through 3’ UTR

Question 18

How to Maintain Gene Expression

Answer 18

Feedback loops
- autocatalytic feedback loop uses wnt and hh to keep segment polarity genes on

Question 19

Maternal Effect Lethal Mutation

Answer 19

A gene whose product is made by the mother, but is required in the embryo for the early development to proceed normally.
- mom makes and pre-packages the RNA into the egg
- Zygote’s phenotype depends on the mother’s genotype

Question 20

Capacitation

Answer 20

A set of physiological changes by which mammalian sperm become capable of fertilizing an egg
- ability to perform acrosome reaction
- ability to bind to an egg

Question 21

Chemotaxis

Answer 21

Cell orientated movement in response to a chemical gradient
- Sperm Activating Peptides (SAPs) in sea urchin
- Progesterone in mammals

Question 22

Competence

Answer 22

A cell’s ability to respond to specific signaling cues and undergo a particular developmental fate.

Question 23

Polyspermy in sea urchins

Answer 23

Multiple sperm trying to fertilize
Fast block is electrical and transient, Bindin proteins on sperm match to egg receptors and an influx of sodium ions block polyspermy
Slow block is permanent and slow - cortical granule reaction
- IP3 opens Ca channel
- CA causes exocytosis of cortical granules
- Fertilization envelope forms

Question 24

Acrosome reaction

Answer 24

Egg polysaccharides in jelly bind to sperm receptors. Ca++ channels open, Na+ influx/ H+ epplux, Phospholipase enzyme releases secondary messenger. Acrosome is released from sperm head to help sperm penetrate the egg jelly layer and zona pellucida

Question 25

Neural Crest Cells

Answer 25

• unique to vertebrates
• Arise from dorsal neural tube and migrate
• Transient
• Give rise to multipotent progenitors

Question 26

Polyspermy in Mammals

Answer 26

Slow block that releases Juno
-
Slow block that disable ZP2
- the cortical granules release enzymes that digest the proteins ZP2 and ZP3, preventing them from binding to sperm
Zinc Spar
- A rush of zinc is released into zona pellucida after binding, this acts as a chemoreppelent to counteract progesterone