AD2

Question 1

What are 2 things nuclear DNA does?

Answer 1

1) It replicates itself

2) It makes protein by transcription of RNA

Question 2

What 3 things is development controlled by?

Answer 2

1) The cytoplasm
2) Genes
3) The external environment

Question 3

What is the job of the homeotic genes?

Answer 3

They specify the properties of each segment

Question 4

What are 4 body segmentation genes and their jobs?

Answer 4

1) Gap genes- organise areas along anterior-posterior axis
2) Pair rule genes- divide the embryo into units of 2 segments each
3) Segment polantry genes- determine segment boundaries
4) Homeotic genes- expressed along the length of the body and determine what the segments will become

Question 5

What is apoptosis?

Answer 5

Programmed cell death caused by the activation of ‘death’ genes

Question 6

What is genomic imprinting?

Answer 6

When some development genes are active only if they come from a sperm or only if they come from an egg

Question 7

When is a signal considered to be a morphogen?

Answer 7

1) It directly affects the target cells

2) Different concentrations cause different effects

Question 8

What controls the posituoral information so cells know where they are in the body?

Answer 8

Given by the concentration gradient of a morphogen

Question 9

What is induction?

Answer 9

A factor secreted by some cells to induce other cells to differentiate

Question 10

What is cytoplasmic segregation?

Answer 10

• Where dividing cells receive unequal amounts of material that were distributed unevenly in the zygote
• These differences course differentiation of cells

Question 11

What 2 processes are chemical signals involved in cell differentiation?

Answer 11

1) Cytoplasmic segregation

2) Induction

Question 12

What is the job of the cytoplasm and cytoplasmic factors?

Answer 12

Cytoplasm= fate of the nucleus

Cytoplasmic factors= in the gray crescent necessary for development

Question 13

What does differentiation result from and what is it influenced by?

Answer 13

• Results from differential gene expression

- It is influenced by the cytoplasm and the extracellular environment

Question 14

What is genomic activation? and what is the timing?

Answer 14

• The transition from maternal control to embryo control

- The timing varies in every species

Question 15

What does lack of iodine cause in adults and babies?

Answer 15

Adults= Giotre
Babies= Cretinism