Developmental Biology

Question 1

What is regional specification?

Answer 1

Patterns appear in a previously similar region of cells, creating body axes

Question 2

Which model organisms do we study for experimental embryology?

Answer 2

Frog, chick

Question 3

Which model organisms do we study for developmental biology?

Answer 3

Fish, mouse, worm, fly

Question 4

What is the conservation of body plan?

Answer 4

The idea that embryos of the model organisms are very similar to human embryos

Question 5

What does the PAX6 gene regulate

Answer 5

It controls many of the functions and formation of the eye

Question 6

What does the PAX6 mutation cause?

Answer 6

Heterozygous = small eye, decreased function
Homozygous= no eye, incompatible with life

Question 7

What is a conserved gene sequence?

Answer 7

A sequence that has a very similar nucleotide sequence

Question 8

What are primordial germ cells and when do they first start to develop?

Answer 8

They are the early germ cells, and they develop during gametogenesis

Question 9

What is the cortical reaction?

Answer 9

This is when the fertilised egg forms a fertilisation membrane to prevent more sperm binding

Question 10

What ion is released to prevent any more sperm attaching to human egg cells

Answer 10

Calcium

Question 11

What is holoblastic cleavage patterns? And give an example

Answer 11

Holoblastic occurs when 4 cells divide equally

Humans, mice

Question 12

Describe what happens in Meroblastic cleavage and give an example

Answer 12

4 cells appear at the top of the embryo

Zebra fish, chick

Question 13

What happens with superficial cleavage and give an example

Answer 13

Cells divide equally around the inside of the embryo

Drosophila

Question 14

What is the cell cycle in the early embryo?

Answer 14

1. Rapid synchronous cleavages
2. Only S&M phases, no g phases
   Maternal stores provide building block for DNA synthesis
   Transcription is suppressed

Question 15

What are the two cell embryo segregation methods in embryos and describe them

Answer 15

Segregation of cytoplasmic components- becomes unequally divided during cell cell division
Cell cell signalling- cells talk to each other

Question 16

What is developed in the ectoderm?

Answer 16

Neurons
Glia
Epidermal tissue
Neural crest

Question 17

What is developed in the. Mesoderm?

Answer 17

Muscles
CT
kidney
Heart

Question 18

What is developed in the endoderm

Answer 18

Gut

Yolk

Question 19

What is gastrulation? And what is formed from it?

Answer 19

Gastrulation occurs when the blastula is converted into 3 separate layers known as the gastrula
Formation of the gut

Question 20

What is epiboly?

Answer 20

This is the process by which cells formed at the top of the embryo flow down the side

Question 21

What is convergent extension and what organisms does it effect?

Answer 21

It is a process which causes spherical cells to elongate

Tadpoles are formed this way

Question 22

What forces drive cell tissue rearrangement?

Answer 22

Cell death
Cell proliferation
Cytoskeleton arrangements
Adhesion by change in proteins

Question 23

What do neural crest cells give rise to?

Answer 23

Bone, smooth muscle

Question 24

Why is the drosophila fly a good model organism?

Answer 24

It is small
Quick to breed
Able to see into the embryo
Sequenced genome
Fast embryogenesis

Question 25

What are the advantages of the worm as a model organism?

Answer 25

Small Sequenced genome Hermaphrodite Invariant lineage

Question 26

What is invariant lineage?

Answer 26

Cell division patterns aren the same from organism to organism

Question 27

What are the advantages of the zebra fish as a model organism?

Answer 27

Transparent embryo Fast generation time Vertebrate Haploid development possible

Question 28

How to transplant cells in a zebra fish embryo

Answer 28

Label donor cells by injection of dye Transplant cells to unlabelled host Observe labelled cells at a later date

Question 29

What is a transgenic animal?

Answer 29

An animal carrying a gene that has been incorporated into the genome using recombinant DNA technology

Question 30

What is targeted transgenesis? And in which species does it occur?

Answer 30

It is easy to knock out genes due to pluripotent stem cells Mouse

Question 31

What is fate? ( in relation to cells)

Answer 31

What cells will normally become in development

Question 32

What method is used to create a fate map for c. Elegans

Answer 32

Observation- transparent embryo, few cells, so watch devision

Question 33

What is useful about the application of a marker for tracing fate maps?

Answer 33

It can be easily detected, applied at any stage of embryogenesis, does not leak into neighbouring cells

Question 34

What methods can be used to test for commitment of cells?

Answer 34

Culturing isolation | Transplantation

Question 35

What are morphogens?

Answer 35

A specialist class of signalling molecules released from a certain part of the cell

Question 36

How do morphogens move from cell to cell?

Answer 36

Through diffusion | Through active transport

Question 37

What is bicoid and where is it found?

Answer 37

It is a morphogen which is produced in the drosophila It forms a concentration gradient across the blastoderm It causes the release of hunchback which is at the top of a cascade of genes

Question 38

What is induction?

Answer 38

It is signalling from one cell to another causing a change in the recipient cell

Question 39

What is competence?

Answer 39

The ability of a cell to respond to an induction or signal

Question 40

What factors effect the transcriptional activity of a gene?

Answer 40

External signals Intrinsic factors Accessibility of the chromatin

Question 41

What are somites and what do they develop into?

Answer 41

They are blocks of tissue containing undifferentiated mesodermal progenitor cells They develop into skeletal muscle cells

Question 42

What is MyoD and what is it able to do?

Answer 42

It is a key part of the cascade to produce muscle cells It is sufficient to direct the formation of muscle cells when transferred into non-muscle cells such as fibroblasts

Question 43

What is an amorphic mutation?

Answer 43

Complete loss of function of the protein

Question 44

What is hypermorphic mutation?

Answer 44

An over expression of the gene

Question 45

What is mutagenesis?

Answer 45

Rate of spon

Question 46

What is development?

Answer 46

A change in structure over time and how a single cell develops into a fully formed organism

Question 47

What is caused by the activation of the kit receptor by steel factor

Answer 47

It is important in the development of melanoblasts and stem cells

Question 48

What does the hedgehog pathway relate to in the embryo?

Answer 48

It is required for segmentation in the embryo

Question 49

What is recessive epistasis?

Answer 49

When 2 genes work together and they are both mutated, then one mutation may mask the effect of the other

Question 50

What is lateral inhibition and what is it mediated by?

Answer 50

It is the process by which a group of cells only allow one cell to go on to grow, e.g. Neurons It is mediated by delta notch signalling