L1 - Introduction to Developmental Biology

Question 1

What are the implications of development not stopping at birth?

Answer 1

The UK population is ageing faster than its growth

Question 2

How much of the UK welfare budget is spent on pensioners?

Answer 2

55%

Question 3

What are the 3 experimental approaches to developmental biology?

Answer 3

Animal models
Microscopy
Genetics

Question 4

What is the epigenesis theory?

Answer 4

Organisms develop progressively through the generation of new structure and forms

Question 5

Who came up with the epigenesis theory?

Answer 5

Aristotle

345 BC

Question 6

What is the preformationism theory?

Answer 6

Organisms develop from miniature versions of themselves - homunculus

Question 7

Who came up with the preformationism theory?

Answer 7

Nicolaas Hartospeker

1695

Question 8

What is cell theory?

Answer 8

All organisms are composed of one or more cells
The cell is the most basic unit of structure, function, and organization
All cells arise from pre-existing, living cells

Question 9

What led to discovery of the cell?

Answer 9

Microscope technology
Robert Cooke
1665

Question 10

How cells become different from each other - germ plasm determinants theory

Answer 10

Cells may show a subset of the programme available – somatic cells
Cells may show the whole programme – germ cells

Question 11

Who came up with the germ plasm determinants theory?

Answer 11

Friedrich Leopold August Weismann

1880

Question 12

Experimental demonstration of Weismanns theory method

Answer 12

1. Took fertilised frog egg and allowed it to develop to 2 cell stage
2. Burned half
3. Only half developed with cell fate – disrupted cell-cell signalling
   Wilhem Roux
   1888

Question 13

How cells become different from each other - induction theory

Answer 13

1. Took sea urchin egg and allowed it to develop to 2/4 cell stage
2. Separated the cells from each other and allowed them to develop
3. Each of the cells lead to the development of a full embryo

Question 14

Who came up with the induction theory?

Answer 14

Hans Driesch

Question 15

What are the two ways cells communicate with each other via cues?

Answer 15

Intrinsic cues – cell differentiates into another

Extrinsic cues – cell influences/instructs another cell

Question 16

What are some examples of changes in cell behaviour?

Answer 16

Cell division – asymmetric or symmetric
Cell adhesion – condensation or dispersal
Cell shape – epithelial or epithelial to mesenchymal
Cell migration
Cell death

Question 17

What are the four types of cell-cell communication?

Answer 17

Paracrine
Autocrine
Juxtacrine
Endocrine

Question 18

What is paracrine communication?

Answer 18

Shh, Wnt, TGFb, BMP, FGF signalling

Cell secretes ligand that binds to receptor on a neighbouring cell

Question 19

What is autocrine communication?

Answer 19

Shh, Wnt, TGFb, BMP, FGF signalling

Cell secretes ligand that binds to receptor on the same cell

Question 20

What is juxtacrine communication?

Answer 20

Notch signalling

Short distance direct communication

Question 21

Signal reception requires cells to be competent and have…?

Answer 21

Permissive environment, receptor and transduction components

Question 22

What are the two types of signals?

Answer 22

Instructive

Permissive

Question 23

What are instructive signals?

Answer 23

Initiates a new program in the cell

Question 24

What are permissive signals?

Answer 24

Provides a favorable environment for a specific program

Question 25

Signals can act as morphogens

Answer 25

Instruct distinct cell fates according to their concentration

Question 26

What is involved in signal transduction cascade?

Answer 26

Used to transmit information to the nucleus

Cell surface, cytoplasmic and nuclear proteins that relay signals from cell surface to nucleus

Question 27

Signal transduction pathway method

Answer 27

Reception – ligand binds to a cell surface receptor and activates it
Transduction – receptor activation induces the transduction of the signal from membrane to nucleus via a cascade of secondary messenger activation
Response – transcription factor is activated and induces transcription of target genes

Question 28

If gene content is identical in all cells what dictates the different proteins?

Answer 28

Transcription/translation dictate protein content

Question 29

At what different levels do cells operate to control the gene program?

Answer 29

Production of mRNA
Processing/stability of mRNA
Production of proteins
Activity of proteins

Question 30

What are the two ways the genetic programme is controlled at the level of gene transcription?

Answer 30

Differential gene expression

Enhancer mediated control of gene expression – binding of transcription factors

Question 31

What is tissue homeostasis required for?

Answer 31

Essential for normal development, growth and repair

Question 32

How is tissue homeostasis achieved?

Answer 32

Through the control of cell division and cell death via

• Negative feedback loop
• Stem cell mediated repair

Question 33

What does disruption of tissue homeostasis cause?

Answer 33

Causes diseases and contributes to ageing and degeneration

Question 34

Excess of stem cell self-renewal leads to?

Answer 34

Tissue hyperplasia

Tumorigenesis

Question 35

Depletion of stem cells leads to?

Answer 35

Tissue degeneration

Tissue ageing

Question 36

What is produced from ectoderm?

Answer 36

Epidermis
Neurons
Pigment cells

Question 37

What is produced from mesoderm?

Answer 37

Muscle cells
Red blood cells
Tubule cells

Question 38

What is produced from endoderm?

Answer 38

Lung cell

Pancreatic cell