Lecture 5

Question 1

In most embryos, _____ is immediately followed by cell division.

Answer 1

fertilization

Question 2

divides the fertilized egg into a number of smaller cells.

Answer 2

Cleavage

Question 3

What phases consist the cleavage cycle

Answer 3

DNA replication
Mitosis
Cell division

Question 4

is in essence the emergence of organized structures from an initially very simple group of cells.

Answer 4

Development

Question 5

Four main developmental processes

Answer 5

a. pattern formation
b. morphogenesis
c. cell differentiation
d. growth

Question 6

Process by which cellular activity is organized in space and time so that a well-ordered structure develops within the embryo.
It is of fundamental importance in the early embryo and also later in the formation of organs.

Answer 6

Pattern formation

Question 7

What is involved in Pattern formation?

Answer 7

Defining main body axes

Question 8

• Defined as change in form
• Embryos undergo remarkable changes in three-dimensional form

Answer 8

Morphogenesis

Question 9

the cells on the outside of the embryo move inwards and, in animals such as the
sea urchin,

• transforms a hollow spherical blastula into a gastrula with a tube through the middle—the gut

Answer 9

Gastrulation

Question 10

cells become structurally and functionally different from each other, ending up as distinct cell types, such as blood, muscle, or skin cells

Answer 10

Cell differentiation

Question 11

is a gradual process, cells often going through several divisions between the time at which they start differentiating and the time they are fully differentiate

Answer 11

Differentiation

Question 12

Defined as the increase in size

Answer 12

Growth

Question 13

Various ways that brought subsequent growth

Answer 13

• Cell multiplication
• increase in cell size
• deposition of extracellular materials

Question 14

important features of cell surface, adhesive proteins

Answer 14

Cell adhesion molecules

Question 15

WHat does cell adhesion molecules do?

Answer 15

• hold cells together in tisssues
• enable cells to sense the nature of surroundings
• serves as a guide migratory cells (such as neural crest cells in vertebrates)

Question 16

• control development mainly by specifying which proteins are made
• the agents that directly determine cell behavior

Answer 16

Genes

Question 17

• comprises a coding region, and adjacent DNA sequences that act as a control region.

Answer 17

Protein-coding gene

Question 18

a stretch of DNA that contains the instructions for making the protein

Answer 18

Protein-coding gene

Question 19

the region of protein-coding gene that act as a
control region

Answer 19

Adjacent DNA sequence

Question 20

2 components of protein coding gene

Answer 20

• Coding region
• Adjacent DNA sequence

Question 21

2 components of control region

Answer 21

• promoter region
• Regulatory region

Question 22

which general transcription factors and the enzyme RNA polymerase bind to start transcription

Answer 22

Promoter region

Question 23

consisting of one or more modules, at which other transcription
factors bind to switch the gene on or off.

Answer 23

Regulatory region

Question 24

A very common post translational modification is the
- addition of carbohydrate side chains

Answer 24

Glycosylation

Question 25

prevent the expression of a given gene and so prevent its protein from being made

Answer 25

Antisense RNAs

Question 26

Artificial RNA molecules

Answer 26

Morpholinos

Question 27

exploit cells' own metabolic pathway for degrading mRNAS - uses small interfering RNAs (siRNAs)

Answer 27

RNA interference

Question 28

the differences between cells must therefore be generated by differences in gene activity that lead to the synthesis of different proteins

Answer 28

Differential gene expression

Question 29

highly regulated to ensure they are switched on only at the right time and place in development.

Answer 29

Developmental genes

Question 30

How does developmental gene regulates itself?

Answer 30

by having a extensive and complex cis-regulatory regions

Question 31

means that each module can function somewhat independently.

Answer 31

Modular nature of the regulatory region

Question 32

implies a stable change in the internal state of a cell, and an alteration in the pattern of gene activity is assumed to be the initial step, leading to a change in the proteins produced in the cell.

Answer 32

Determination

Question 33

the direct line of descent of a particular cell

Answer 33

Lineage

Question 34

the term that defines as a group of cells merely describes what they will normally develop into

Answer 34

Fate

Question 35

WHen is cell called "specified"?

Answer 35

When the cultures and isolated cell developes according to their normal fates

Question 36

Where the developmental potential of cells is much greater than that indicated by their normal fate they are said to be ______

Answer 36

Capable of regulation

Question 37

Effects restricted to the gene-expressing cell - due to proteins such as transcription factors that act only within the cell that makes them

Answer 37

Cell-autonomous

Question 38

gene expression in one cell that has an effect on other cells - typically due to a gene product such as an intercellular signaling protein

Answer 38

non-cell-autonomous

Question 39

a mosaic of cells with different genetic constitutions; fusing together two very early embryos with different genetic constitutions

Answer 39

Chimera

Question 40

one cell, or tissue, directs the development of another, neighboring, cell or tissue; where a signal from one group of cells influences the development of an adjacent group of cells

Answer 40

Induction

Question 41

Two types of induction

Answer 41

-Permissive -Instructive

Question 42

occur when a cell makes only one kind of response to a signal, and makes it when a given level of signal is reached.

Answer 42

Permissive inductions

Question 43

the cells respond differently to different concentrations of the signal

Answer 43

Instructive induction

Question 44

block induction - by preventing the inducing signal reaching the cell or binding to a cell-surface receptor

Answer 44

Antagonistic signal molecules

Question 45

function by producing extracellular signaling molecules or factors that influence intracellular signaling pathways in neighboring cells to determine their fate.

Answer 45

Organizing regions

Question 46

information on their position along the line with respect to boundaries at either end

Answer 46

Positional information

Question 47

can represent the amount of morphogen that must bind to receptors to activate an intracellular signaling system, or concentrations of transcription factors required to activate particular genes

Answer 47

Threshold concentrations

Question 48

given a group of cells that all have the potential to differentiate in a particular way,

Answer 48

Lateral inhibition