M1. review and basic concept

Question 1

How does a single cell divide and change to form a multicellular organism?

Answer 1

• cell division
• cells become different
• form organized structures such as tissues and organs
• coordination of cell communication, gene expression, cell fate, cell migration, cell proliferation, cell and tissue shape changes

Question 2

genes control _____ and _____ by controlling the __________

Answer 2

cell properties, behaviour, protein expression

Question 3

gene expression

Answer 3

transcription, nuclear processing, nuclear-cytoplasmic transport, mRNA translation, protein modification and protein stability

Question 4

Control regions of Genetic loci

Answer 4

• enhancers and promoters are acted on by transcription factors (TF) to activate or repress transcription
• TF binding sites within enhancers dictate levels and spatial/temporal control of expression of that gene

Question 5

Differential gene activity is regulated at ____ levels.

Answer 5

several

Question 6

what does differential gene activity control?

Answer 6

development

• determines where and when proteins are synthesized
• transcription factors, signalling proteins, cytoskeletal proteins, cell cycle proteins and enzymes
• full complement of protein determines cell identity and behaviour
• gene expression is dynamic
• past and current patterns of expression define a cell’s fate

Question 7

Genes expression responds to different combinations of ?

Answer 7

inputs

-a gene can have many different control regions

Question 8

a combination of inputs control final ______ pattern.

Answer 8

expression

• cellular signalling
• transcription factor levels
• developmental history -can determine if areas of the genome are in a open or closed configuration (heterochromatin vs. euchromatin)

Question 9

how is gene expression regulated?

Answer 9

control regions

Question 10

genetic equivalence

Answer 10

somatic cells contain identical genetic information

Question 11

differential gene expression

Answer 11

differences in cells are generated by differences in gene activity

Question 12

positive and negative feedback regulatory loops

Answer 12

genes are usual part of complex interdependent gene networks

Question 13

cell communication

Answer 13

• exchange/transmission of signals
• can involves many cells or immediate neighbours
• induction
• competence
• intercellular communication
• permissive signalling
• instructive signalling
• antagonist signalling

Question 14

exchange/transmission of signals

Answer 14

1. secreted diffusible molecules
2. surface molecule receptor
3. gap junction

Question 15

indcution

Answer 15

process by which signals from one (group) of cell(s) influences the development of another

Question 16

competence

Answer 16

the state of being able to respond to inductive signals

Question 17

intercellular communication

Answer 17

allows cells to communicate

Question 18

permissive signalling

Answer 18

cells make only one kind of response to a signal when a required level of a signal is reached

Question 19

instructive signalling

Answer 19

cells respond differently to different levels of a signal (tells them what response to make depending on the signal)

Question 20

antagonist signalling

Answer 20

inhibition of a signal

Question 21

intracellular signalling

Answer 21

1) alter gene expression in the nucleus and / or 2) activate or change activity of intracellular molecules through a relay type response (ie. signal transduction)

Question 22

when a signal (ie a ligand) is transmitted from the membrane (transmembrane receptor) to the cell’s interior (cytoplasm and or nucleus)

Answer 22

intracellular signalling

Question 23

Fibroblast growth factor (FGF) pathway

Answer 23

• a diffusible ligand (extracellular signalling molecule) activates a membrane bound receptor (FGF) receptor)
• protein kinases (intracellular signalling proteins) initiate a relay of protein phosphorylations [P] called a “signalling cascade”
• phosphorylation of a transcription factor changes it into an active form

Question 24

The Wnt and transforming growth factor (TGF)-beta pathways

Answer 24

• a diffusible ligand (Wnt or TGF-beta) activates a membrane bound receptor
• the activity of a signalling complex associated with a transcription factor (TF) activates or inactivates TF
• TF can enter nucleus and activate or repress trancription

Question 25

notch signalling pathway

Answer 25

- requires direct cell-cell contact - membrane bound ligand (Delta) binds membrane bound receptor (Notch) of adjacent cell - ligand binding induced proteolytic cleavage of notch to create a co-activator - co-activator (cleaved notch) translocates into the nucleus and controls transcription factor activity