Specifying Identity

Question 1

single celled zygote becomes multicellular by

Answer 1

mitosis

Question 2

_____

Developing cells acquire different ____ depending on their relative _____ within the embryo

Answer 2

Patterning

Identities
spatial positions

Question 3

ensures that tissues and organs develop in the correct place and orientation

Answer 3

pattern formation

Question 4

what happens before pattern formation

Answer 4

cells become committed to develop into a certain part of the organism’s body

Question 5

four process of development

______ sets the fate of the cell
______ a process during which a cell ceases to divide and develops specialized structure elements and distinct functional properties
______ is the organization and spatial distribution of differentiated cells
______ is an increase in body size by cell division

Answer 5

commitment
differentiation
morphogenesis
growth

Question 6

some differentiated cell types and their major products

Type of cell: Differentiated cell product
________ - keratin
________ - Hemoglobin
________ - Neurotransmitter

Answer 6

Keratinocyte (epidermal cell)
Erythrocyte (rbc)
Neurons

Question 7

engagement or involvement that restricts freedom of action according to oxford english dictionary

Answer 7

commitment

Question 8

The process of commitment can be divided into two stages

1._____

The fate of a cell or tissue is said to be _____ when it is capable of ____ when placed into a neutral environment

At this stage, commitment is ____ and __________

2._____

A cell is said to be _____ when it is capable of _____ when placed into another region of cells different to it

At this stage, commitment is ____

Answer 8

1. Specification

Specified
Differentiating autonomously

Labile and reversible

2. Determination

Determined
Differentiating autonomously

Irreversible

Question 9

During embryogenesis an undifferentiated cell matures through specific stages that cumulatively commit to a specific fate

(3)

Answer 9

1. specification
2. determination
3. differentiation

Question 10

modes of specification (general ways by which the commitment of cell can take place)

Answer 10

1. Autonomous specification
2. Conditional specification
3. Syncytial specification

Question 11

Modes of Specification:

________

• Very early on, it “knows” what it is without interacting with other cells
• Here, the blastomeres of the early embryo are apportioned a set of critical ____ within the egg cytoplasm.
• ______ are maternal substances in the egg that influence early development. This also leads to different gene expression.

Answer 11

Autonomous Specification

• Determination factors
• Cytoplasmic/Morphogenetic determinants

Question 12

True or false, in autonomous specification, substances are distributed evenly in the unfertilized egg:

Answer 12

FALSE. it is distributed unevenly

Question 13

Modes of Specification (Autonomous specification):

_____
cell that turns into the flagellated part of the snail patella

Answer 13

Trochoblast

Question 14

Modes of Specification (Autonomous specification):

Characteristic of most _____

____ produce the same lineages in each embryo of thee species

Produces ____/____ development, cells cannot change fate if blastomere is lost

Answer 14

Invertebrates

Invariant cleavages

Mosaic/Determinative

Question 15

Modes of Specification (Autonomous specification):

The association of _____ with autonomous specification was confirmed by _____

_____ provided biochemical confirmation of cytoplasmic segragation of tissue determinants in early tunicate embryos

Answer 15

Conklin’s fate map
Cell-removal experiments

J.R. Whittaker

Question 16

Modes of Specification (Autonomous specification):

_____
muscle-specific transcription factors that give rise to muscle cells

Answer 16

Macho

Question 17

Modes of Specification :

_____
The process where cells achieve their respective fates by interacting with other cells

Two ways cells can communicate. One is ________ signaling, where cells send signals to nearby cells through the space around them. The other is ________ signaling, where the message is passed directly from one cell to another where they touch each other.

Answer 17

Conditional Specification

Paracrine
Juxtacrine

Question 18

Modes of Specification (Conditional specification):

Factors that determine fate (3)

Answer 18

Cell-to-cell contacts

Secreted signals

Physical properties of local environment (mechanical stress)

Question 19

Modes of Specification :

_____

A cytoplasm that contains many nuclei is called a ____. Specification of cells within it is this type of specification.

Usually occurs in insects, involves the action of ____. They influence nuclei in ____ manner.

The insect egg cytoplasm is not uniform

Answer 19

Syncytial Specification
Syncytium

Morphogen gradients
Concentration-dependent

Question 20

Transcription factors acting as Morphogens involved in the Syncytial Specification of Drosophila Embryo:

The _____ (front) produces the ____ morphogen that is highest in concentration there

The _____ (back) produces the _____ and (_____) moprhogen that is highest in concentration there

They’re both transcription factors so different ratios activate different sets of genes

Answer 20

Anterior
Bicoid

Posterior
Caudal (and Nanos)

Question 21

Parts produced in the morphogen gradients (4

_____ high bicoid low caudal and nanos

_____ less bicoid small amount caudal and nanos

_____ little or no bicoid but plenty of caudal

_____ low bicoid high caudal and nanos

Answer 21

Head
Thorax
Abdomen
Tail