Lecture 32. Multicellular Organisms 1

Question 1

What determines the four essential processes of development?

Answer 1

Selective gene expression

Question 2

What are the four essential processes of development?

Answer 2

Cell proliferation, cell specialisation, interaction of cells with surrounding environment, cell movement and migration

Question 3

What are the shared sequence of events in all animals?

Answer 3

Egg – Cleavage – Gastrulation – Germ layers

Question 4

What do conserved genes between species show?

Answer 4

Common ancestry

Question 5

What proteins are important for multicellular development?

Answer 5

Cell adhesion and signalling transmembrane
proteins

Question 6

What are two types of anchoring junctions that connect with the intracellular cytoskeleton?

Answer 6

Cell-cell and cell-matrix

Question 7

Adherens junctions

Answer 7

Actin filaments via cadherin proteins

Question 8

Desmosome junctions

Answer 8

Intermediate filaments via cadherin proteins

Question 9

Actin-linked cell matrix adhesion

Answer 9

Actin filaments via integrin proteins

Question 10

Hemidesmosomes

Answer 10

Intermediate filaments via integrin proteins

Question 11

Transcription factors

Answer 11

DNA regulatory proteins

Question 12

Enhancers

Answer 12

Non-coding regulatory DNA

Question 13

What leads to variation in body plan/shape/structure?

Answer 13

Transcription factors and enhancers

Question 14

How were pivotal genes and protein products identified?

Answer 14

Natural or induced mutations of normal phenotype

Question 15

The first developmental genes were first identified as?

Answer 15

Spontaneous mutations which produce an abnormal phenotype

Question 16

How was cell lineage and cell-cell interactions deciphered?

Answer 16

Experimental embryology

Question 17

What is the embryo divided up into?

Answer 17

A small number of broad regions

Question 18

What will the broad regions in the embryo become?

Answer 18

The future germ layers (mesoderm, ectoderm and endoderm)

Question 19

What is ‘fate’?

Answer 19

What a cell will normally develop into

Question 20

What are the two stages of commitment?

Answer 20

Specification and determination

Question 21

What is ‘specification’?

Answer 21

A cell is specified when it can be cultured in a neutral environment and differentiate according to it’s fate

Question 22

What is ‘determination’?

Answer 22

It can differentiate according to its fate even if in a different environment. (Fully determined- no matter what)

Question 23

Induction

Answer 23

Where a signal from one group of cells influences the developmental fate of another

Question 24

Inductive interaction

Answer 24

Determines pattern formation i.e. what drives cells with the same potential to follow a different path of development

Question 25

What is the main influence on a cell’s behaviour?

Answer 25

Its environmental signals which can determine gene expression

Question 26

Inductive signals

Answer 26

Cell-cell, short or long range = Morphogens

Question 27

What can also determine cell fate?

Answer 27

Asymmetrical cell division

Question 28

What are HOX genes?

Answer 28

Homeotic selector genes

Question 29

What do HOX genes do?

Answer 29

Important in the regulation of animal body plan