Cell Development-Growth, Differention And Adaptation

Question 1

What is development and stages

Answer 1

-systematic sequence of gene directed steps during an organisms life cycle

1 growth
2 differentiation
3 morphogenesis / pattern formation

Question 2

What is cell growth and how does it occurs

Answer 2

-increase in cell size and number
-occurs through
1 mitotic divisions
2 cleavage ( rapid mitotic divisions of zygote )
3 synthesis of more structural components through metabolism

Question 3

Limitations of growth

Answer 3

1 stress on DNA ( telomeres shorten )
2 decrease in surface are to volume ratio with increase in size
3 contact inhibition - if cell is overcrowded no room for division or growth

Question 4

What is potency

Answer 4

-different number of possible fates a cell can acquire

Question 5

Stem cells and functions

Answer 5

-unspecialized cells capable of infinite mitotic divisions ( due to telomerase reconstituting telomeres )capable of self-renew and from which differentiated cells arise

• organ maintenance and repair
• therapeutic effect ie reparing worn out body parts.

Question 6

Allometric growth

Answer 6

-diff growth rates of diff body parts

Question 7

Asymmetric division of stem cells

Answer 7

• one daughter will become a stem cell ( self renew )

- the other becomes committed and is a progenitor

Question 8

Types of stem cells and description

Answer 8

1 Embryonic stem cells

• totipotent : can become any cell
• pluripotent : can become most but not all cells ( any of the 3 germ layers )

2 Adult stem cells

• multipotent : most but not all
• ogliopotent : most but not all
• Bipotent and unipotent : 1 or 2 cell types

3 Induce pluripotent stem cell :
-This is when somatic cells have genes introduced into them and then the cell becomes a stem cell it is reprogrammed

Question 9

Use of adult stem cells

Answer 9

-renewal of worn out tissue

Question 10

Cell determination and types

Answer 10

-committing of a cell down a specific differentiation path

1 cell-to-cell interactions
2 inheritance of cytoplasmic determinants

Question 11

Adaptation and types and causes

Answer 11

-conformational changes taken by a cell to respond to a stimuli

1 auto trophy
2 hypertrophy
3 hyperplasia
4 metaplasia

1 reduced workload, nutrient deficiency
2 increased workload , hormone stimulation
3 compensation for damage, hormonal dysfunction
4 current tissue unable to withstand stimuli

Question 12

What is pattern formation

Answer 12

• aka morphogenesis
• the way an organism develops from a single cluster of cells into a complex system
• taking shape of an organism

Question 13

What is cell lineage

Answer 13

-cell types arising from a stem cell or progenitor

Question 14

Types of Tissue in terms of regeneration capability

Answer 14

• labile
• stable
• permanent

Question 15

What is regeneration

Answer 15

-the replacement of dead or infected tissue with an exact type through mitotic divisions of stem cells

Question 16

What is cell fete

Answer 16

-

Question 17

How are cells commited

Answer 17

-turning on and off of specific genes through transcription factors

Question 18

How do stem cell renew themselves

Answer 18

• obligate asymmetric replication
• stochastic differentiation: One stem cell divides into two daughter cells which both differentiate and another stem cells recognize this and divide by mitosis into two other stem cells to make up the cell population

Question 19

How do stem cells stay undifferentiated and what triggers them to be differentiated

Answer 19

They have genes which code proteins to stop transcription factors from causing differentiation

signals in the environment stimulate the stem cells to differentiate example Mitogens in bone marrow

Question 20

Use of embryonic and somatic cells

Answer 20

• build the body tissue and organs

- renewal of worn out tissue

Question 21

How does cell to cell interacts occur ( how are the signals sent )

Answer 21

Direct contact of surface proteins

signals diffuse from one cell to another

signals a pass to gap junctions

Question 22

Describe asymmetric segregation of cytoplasmic determinants

Answer 22

The Zygote has transcription factors in the cytoplasma (along with the precursors mRNA )

which it inherits from the parent

these transcription factors turn off and on specific genes thus differentiating cells

as the zygote divides, the region with the determinants will get those specific transition factors and go on to differentiate