Embryology - Biology 104, Spring 2006 - Albert Harris and Corey Johnson   Review Questions for First Exam The following are some questions to think about in preparation for Monday's exam. They are not exhaustive of all of the topics but represent the depth and breadth of the exam. The exam will consist of about 30 short answer questions. There may be a short essay at the end. What processes do cells undergo during embryogenesis to produce structure? What are five specific examples of differentiated cell types in humans? What makes a hepatocyte different from a muscle cell, for example (on a molecular level)? Hint: they all have the same number of genes, but... About how many differentiated cell types are there in the human body? Hint: about 250. About how many different genes do we have? Do cells differentiate wherever they happen to end up? How important is cell motility to embryogenesis? Hint: very. What are some ways in which cells change the shapes of tissues? What are the names of the embryo as it proliferates forming different arrangements (zygote, morula, blastula, etc)? What are the processes that lead to different configurations? What makes an amniote an amniote and an anamniote an anamniote? Can you say that again? What is a chordate? A vertebrate? A major difference in the early embryology of the sea urchin, amphibean, bird, and mammal is said to be due to differing amounts of what maternally derived substance? What terms describe the amount? Which animal is macrolecithal? Be able to draw or describe the blastula and gastrula stages of the sea urchin, amphibian, bird, and mammal What two important kinds of cellular rearrangement/movements occur at the vegetal pole of sea urchin embryos after the blastula stage of development? What is the defining property of the vegetal pole of an embryo? Give an example of where you see epiboly, ingression, involution, invagination, etc. What is the purpose of gastrulation? What is produced, and what is their significance? What are some organs or later embryonic structures that develop from each of the 3? What is neurulation? Where does gastrulation begin in frog embryos as compared with sea urchin embryos? What is the blastopore? Blastocoel? Archenteron? What's a blastoderm? What epiblast becomes which layers? Does the avain or mammalian hypoblast contribute to the embryo? What happens at the primitive streak and Henson's node? What's an inner cell mass? What does it become? Is mouse development typical of mammalian development? What cells ingress (undergo ingression) in sea urchin development? What are they= types of mesoderm sandwiched between ectoderm and endoderm? What are some types of symmetry? How would you define symmetry? What kinds of symmetry are found in various organisms? Starfish, human, worm, a sea urchin zygote, a chicken zygote? Somites have which two kinds of symmetry? Hint: one kind is bilateral (reflection) Curie's principle states that the symmetry of a what correlates to the symmetry of its what? Can you explain what this means? How does the symmetry of the pressure inside a soap bubble correlate to the shape of the bubble? What if the tension in the soap film were unequally distributed? Cleavage of the zygote results in the reduction or gain of symmetry? What does the direction of cleavage have to do with the resulting symmetry? Can a balloon have different pressures in different parts? Pressure is a scalar, vector, what? What are examples of scalars and vectors? Something that has a magnitude in multiple directions is called a what? Hint: tension is an example of one. What does all this have to do with embryos? What is Preformationism? Epigenesis? Those who believed the sperm held the contents of the next generation were called? Acceptance of Cell Theory put an end to what? Why? Who were two early comparative embryologists? What was the difference between their ideas? Does the human have a stage comparable to the adult fish? Who said we do? Explain the biogenic law? Explain what Roux and Driesch did. Why did they come to different conclusions? What mechanism of development did Roux identify with? What developmental mechanism had Driesch discovered? What was the name that Driesch gave to the unnatural substance that directed embryogenesis? What is meant by Competence, Specification, Determination, and Differentiation? What physical manipulations can be done to examine the above? How might you test the competence of surface ectoderm to form neural ectoderm? What kind of development is generally characterized by C. elegans? The Mouse? What are some ideas that explain the apparent differences between these 2 modes of development? Describe the process by which Dictyostelium becomes multicellular. In terms of cell movements, contrast gastrulation in animal embryos with "fruiting" in Dictyostelium slugs. What are the properties of Dictyostelium that make it useful as a developmental system? In other words, what cellular processes does it have in common with embryogenesis? If you separate the first two cells, or even the first 4 cells, of a sea urchin embryo, each can form a whole, normally-proportioned pluteus: what equivalent experiment can you do with Dictyostelium slugs? What does this demonstrate? What are 2 pieces of experimental the evidence that Dictyostelium amoebae use chemotaxis? If you had several chemicals that you suspected of being chemotactic attractants for cells of a given species, how would you test them? Kenneth Raper, the guy who discovered Dictyostelium, got his undergraduate degree from where? Hint: not Duke

 

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