Block B Part 2: Gradients, Differentiation, Organisation and Sexual Dimorphism Flashcards
What do cells in isolation undergo?
Differentiation
(Lecture 1, Slide 65)
What happens in differentiation?
Cells become specialised until they reach their terminally differentiated form.
(Lecture 1, Slide 65)
Is differentiation one-way or two-way?
Differentiation is usually a one-way process.
(Lecture 1, Slide 65)
What do stem cells do when transplanted?
They adopt the form appropriate for their new home.
(Lecture 1, Slide 68)
What 2 processes must be occurring during tissue differentiation?
Local cellular interactions that organise tissues
Long-range “morphogen” signals that determine the orientation of the embryo and its specific regions.
(Lecture 1, Slide 72)
What does Long-range “morphogen” signals and local cellular interactions that organise tissues do to a cell?
They cause migration and specific differentiation processes to be irreversibly started.
(Lecture 1, Slide 72)
How do cell types organise themselves locally?
They organise themselves into regional embryo-like structures sorting of cells like-with-like
(Lecture 1, Slide 73)
What is a morphogen?
A secreted molecule that induces cell fate decisions in recipient cells in a concentration gradient-dependant long-range manner.
(Lecture 1, Slide 75)
What 3 things are required for a morphogen to function?
Production from a point source
Long-range distribution
Reception and interpretation by the cell.
(Lecture 1, Slide 75)
What can injection of Wnts or Nodal induce?
A secondary axis
(Lecture 1, Slide 83)
How do cells interpret and act on Morphogen signals?
Morphogen receptors.
(Lecture 1, Slide 90)
What do Homeotic genes regulate?
The development of anatomical structures in various organisms.
(Lecture 1, Slide 91)
What can mutations in the Homeotic genes cause?
They can cause transformation of one area of the body in another area of the body.
(Lecture 1, Slide 91)
What do Hox genes direct?
The body plan.
(Lecture 1, Slide 93)
How are HOX genes arranged on the chromosome?
In a co-linear fashion (having corresponding parts arranged in the same linear order)
(Lecture 1, Slide 93)
How many HOX clusters do humans and higher organisms have?
4
(Lecture 1, Slide 94)
What 3 things occur in the first trimester of pregnancy?
Early cell divisions, establishment of germ layers, beginning of organogenesis
(Lecture 1, Slide 97)
What occurs in the second trimester of pregnancy?
Organogenesis is complete
(Lecture 1, Slide 97)
What occurs in the third trimester of pregnancy?
Fetal growth, organ systems become fully functional.
(Lecture 1, Slide 97)
How do sperms determine the sex of a fetus?
The sperm (spermatozoa) can contain either an X or a Y chromosome, if the fertilising sperm contains an X chromosome then the fetus becomes female and if the sperm contains a Y chromosome the fetus becomes male.
(Lecture 1, Slide 100)
What is the “default” gender in terms of development?
If unspecified the “default” is female
(Lecture 1, Slide 103)
Which gene regulates male characteristics and where is it located?
SRY gene on the Y chromosome
(Lecture 1, Slide 103)
How does the SRY gene regulate male characteristics?
It promotes development of male reproductive anatomy and supresses development of female reproductive anatomy
(Lecture 1, Slide 103)
What drives secondary sexual characteristics?
Hormones.
(Lecture 1, Slide 104)
What is Turner’s Syndrome?
Turner’s syndrome is when a female has only 1 X chromosome; XO.
(Lecture 1, Slide 106)
What 3 things does Turner’s Syndrome result in?
Female patients do not mature sexually, have a short stature and often have other congenital (from birth) abnormalities.
(Lecture 1, Slide 106)
What is Klinefelter’s Syndrome?
Klinefelter’s Syndrome is when a male has 2 X chromosomes and a Y chromosome.
(Lecture 1, Slide 108)
What 4 things does Klinefelter’s Syndrome result in?
It results in the male patient being sterile with small testicles, they may have breast growth, they tend to be tall and may have mild mental impairment.
(Lecture 1, Slide 108)
