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Y2S2 - Differentiation > Diff11 - 41 > Flashcards

Diff11 - 41 Flashcards

1
Q

What are the three kinds of growth?

A

Hyperplasia, hypertrophy, accretion

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2
Q

Outline cell proliferation

A

Gap 1 - cell enlarges; Synthesis - DNA replication; G2 - end of interphase; Mitotic - cell actually divides

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3
Q

What controls the mechanics of cell proliferation?

A

Cyclins > cyclin dependent kinases > trigger proteins

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4
Q

Describe the status of fully differentiated cells

A

G0

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5
Q

Outline cell division in early drosophila

A

Syncytium - single cell, multiple nuclei; rapid synchronous cell cycles with only S and M phases; at 14th cycle, G2 is introduced, and cellularisation occurs; each cell acquires its own cell division rate - mitotic domains

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6
Q

What controls cell division in mitotic domains?

A

String - protein

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7
Q

Outline string expression

A

Maternal during 1st 13 divisions, zygotic after 13th

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8
Q

What delays certain mitotic domain mitosis?

A

Tribble - inhibitor of string

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9
Q

Characterise limb size

A

Intrinsic sizing - absolute dimensions, not number of cells

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10
Q

What determines the size of a structure?

A

No just rate of growth, but also duration

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11
Q

What determines the size of drosophila?

A

Size of larva - determined by insulin signaling which affects duration and rate of larval growth

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12
Q

What important mammalian factors determine growth patterns?

A

IGF1/2

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13
Q

What does IGF stand for?

A

Insulin-like growth factors

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14
Q

What controls post-embryonic mammalian growth?

A

Growth hormone

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15
Q

What mediates GH effects?

A

IGFs

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16
Q

Where is GH made?

A

Pituitary gland

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17
Q

What induce GH release?

A

GH releasing hormone

18
Q

What inhibits GH release?

A

Somatostatin from the hypothalamus

19
Q

How does GH feedback work?

A

GH promotes somatostatin and inhibits GHRH; GH promotes IGF1/2; GH promotes GHRH

20
Q

What is an oncogene?

A

Activated proto oncogene - genes that if mutated lead to a loss of growth control

21
Q

What is a suppressor gene?

A

Genes that normally inhibit growth - a loss of which leads to a loss of growth control

22
Q

What are teratomas?

A

Similar to embryonic cells and can give rise to tissues from all three germ layers

23
Q

What is another term for molting?

A

Ecdysis

24
Q

What are intermolt stages called?

A

Instars

25
Q

How many instars do drosophila undergo before pupation?

A

3

26
Q

What is molting activated by?

A

Activation of stretch receptors, followed by release of protothoracicotropic hormone from the corpus alatum, which leads to the release of ecdyson from the protothoracic gland

27
Q

Outline the influence of ecdyson

A

Cuticle separates from epidermis, freed epidermal cells proliferate, fluid barrier is secreted, new cuticle is secreted

28
Q

What can influence metamorphosis?

A

Nutrition, temperature and light

29
Q

What do external cues for metamorphosis affect internally?

A

Affect the relative levels of juvenile hormone and ecdysone

30
Q

What is the role of juvenile hormone?

A

Prevention of metamorphosis

31
Q

What is the role of ecdysone?

A

Promotion of metamorphosis

32
Q

What two chemicals balance metamorphosis in frogs?

A

Prolactin (-) and thyroxine (+)

33
Q

What is interesting about thyroxine?

A

Positively feeds back; has different effects on different limbs (generation of limbs, degeneration of tail)

34
Q

What is senescence?

A

Age dependent decline in vital physiological functions

35
Q

Give an example of wear and tear senescence

A

Feeding muscles in c.elegans

36
Q

Give an example of genetically programmed senescence

A

Drosophila

37
Q

What is the disposable soma theory?

A

Natural selection tunies life history of the organism so that sufficient resources are invested in maintaining the repair mechanisms that prevent aging at least until that organism has reproduced and cared for its young

38
Q

What factors are thought to contribute to control of aging?

A

DNA damage and oxygen radicals, genetic mutations, binge eating

39
Q

How does the c.elegans extend its life?

A

IGF signalling inhibits FOXO, which regulates increased resistance to stressors such as antimicrobial genes

40
Q

How does binge eating affect life span?

A

Reduction in caloric intake can extend life span - possibly due to reduced reactive oxygen generation, possibly downregulation of IGF

41
Q

What are sirtuins?

A

Protein deacetylases and are thought to be the target of resveratrol - compound from red wine!

Y2S2 - Differentiation (15 decks)

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