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BIOL 205 > Exam 3- Developmental Biology > Flashcards

Exam 3- Developmental Biology Flashcards

1
Q

What is a gamete cell?

A

cells that contribute to the next generation (sperm and egg cells) that are haploid

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2
Q

What is a somatic cell?

A

a regular body cell that doesn’t contribute to the next generation and is haploid

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3
Q

What are the 3 functions of germ-line cells?

A
  1. preservation of genetic integrity of germ-line
  2. the generation of genetic diversity
  3. transmission of genetic information to the next generation
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4
Q

True or False
Germline cells differ from somatic cells because they do not divide as frequency as somatic cells in early embryogenesis

A

True

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5
Q

What are gonads?

A

specialized reproductive organs

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6
Q

What are the precursors of germline cells that arise early in development called?

A

primordial germ cells

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7
Q

True or False
In some animals, primordial germ cells are made in a region that is far from where gonads will eventually form, and eventually migrate from the their origin location to form gonads.

A

True
This is so that the germline cells are protected from mutations and inductive effects from the somatic cells

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8
Q

What is germplasm?

A

specialized cytoplasm in the egg that are responsible for specifiying the germ cells

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9
Q

What are pole cells

A

Pole cells are primodial germ cells (germplasm) that become become distinct shortly after fertilization

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10
Q

What were the results of the experiments with the pole cells?

A

germ cell development was restored when donor cytoplasm is injected from the posterior end of the donor cell (not anterior end)

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11
Q

What is required by many oogenesis in many mammals?

A

accessory cells like nurse cells

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12
Q

What is often required in order to specify a germ cell fate?

A

repression of transcription
-in Nematode, pie-1 maintain stem cell property and repressing new transcription of zygotic genes

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13
Q

What are the function of nurse cells in oogenesis?

A

they transport organelles to developing oocytes and die

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14
Q

How are germ cells induced in mammals?

A

they are induced by cell-cell interactions

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15
Q

What is the oskar gene ?

A

the gene that plays a central role in the organization and assembly of pole plasm in drosphilia and is the only gene to have its mRNA localized at the posterior side

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16
Q

What is the importance of P granuales?

A

they are important for specification of germ line cells
-the P granules all migrate to one side before division and when the cell divides, one daughter cell goes on to become a somatic cell, while the other daughter cell has the p granuale, these divisions continue to happen

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17
Q

How are germ cells induced?

A

by cell-cell communication from extra embryonic tissue

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18
Q

What do eggs contain that is crucial to development ?

A

they contain proteins, RNA, and nutrients and also provide determinants for axis development in some species

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19
Q

How do egg yolks differ?

A

they differ in the amount of yolk material

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20
Q

What is a polar body?

A

during meiosis, small cells can be formed that are asymmetric in size

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21
Q

What stage are more oocytes locked into until fertilzation?

A

locked in meiosis 2 until fertilization where they complete meiosis

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22
Q

What is capacitation?

A

the process where sperm are activated in the reproductive tract

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23
Q

How are sperm attracted to the egg?

A

through chemotaxis, sperm swim up a gradient of chemicals released by the egg

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24
Q

True or False
Fertilization triggers the completion of meiosis in the egg in many mammals

A

True.
Most oocytes are locked in meiosis 1 until fertilization happens

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25
Q

What are the three layers of the egg that the sperm cell must get through to fertilize the egg?

A
  1. cumulus cell layer
  2. zona pelicula
  3. plasma membrane
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26
Q

What content are in the sperm cells?

A

nucleus, few hundred mitochondria for energy, a centrosome, and a flagellum
(they have virtually no cytoplasm)

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27
Q

What is true of the sperm of C. elegans and other invertebraes?

A

their sperm more closely resemble tissues cells and move by ameboid movement

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28
Q

What is the cumulus cell layer made of out?

A

hyaluronic acid and somatic follicle cells that form a sticky layer

29
Q

What reaction that sperm cells undergo helps them through the zona pellucida?

A

the acrosomal reaction
-when sperm binds to the zona pellucida, it triggers the acrosomal reaction

30
Q

What is the acrosomal reaction?

A

the release of enzymes in the acrosome that help sperm through the zona pellucida

31
Q

What is the zona pellucida made of?

A

its a layer of fibrous glycoproteins that are secreted by the oocyte

32
Q

What zone pellucida proteins does sperm bind to?

A

ZP2 and ZP3

33
Q

What is the importance of the izumo protein?

A

it is the only cell-surface protein expressed on the sperm that has been shown to be essential for sperm-egg fusion

34
Q

What is the ligand for the izumo protein?

A

Juno
-a folate receptor on the egg plasma membrane

35
Q

What happens if a egg cell lack juno or a male sperm cell lack izumo?

A

they are both infertile

36
Q

What membrane in sea urchins is similar to the zona pellucida in mammal oocytes?

A

vitelline membrane

37
Q

What is the block to polyspermy?

A

the mechanism by which egg cells ensure that only 1 sperm cell fertilizes the egg

38
Q

What happens during the fast block to polyspermy in sea urchin?

A

it happens in 1-3 seconds and happens when one sperm fuses with the egg. the egg plasma membrane depolarizes via Sodium ions
**if depolarization doesn’t happen, then polyspermy can happen

39
Q

What forms around the egg as the egg repolarizes after the fast block to polyspermy?

A

the fertilization membrane forms around the egg which is a impenetrable membrane

40
Q

What ion triggers the slow block to polyspermy?

A

triggered by a wave of Ca2+ release due to sperm entry

41
Q

What does the slow block to polyspermy triggered by calcium lead to?

A

it leades to the cortical granules releasing their contents to the outside of plasma membrane via exocytosis

42
Q

What happens to the vitelline membrane of urchins when the cortical granuales release contents?

A

causes the vitelline membrane to life from plasma membrane and the cortical granule contents use molecules from the vitelline membrane to make a hardened “fertilization membrane”

43
Q

What enzyme does the calcium wave activate?

A

calmodulin-dependent kinase II

44
Q

What does calmodulin-dependent kinase II do?

A

it indirectly results in the degradation of the cyclin component of MPF which deactivates if Cdk1 kinase allowing egg to complete meiosis

45
Q

what is a blastula ?

A

a multicellular hollow sphere of cells

46
Q

What is the blastderm?

A

the outside layer of cells in the bastula

47
Q

What is the blastderm?

A

the outside layer of cells in the blastula

48
Q

What is blastocel?

A

the hollow part of the blastula

49
Q

What is radial cleavage?

A

a symmetrical form of cleavage that divides cells in half at each round of division

50
Q

True or False
Some animals have asymmetric cell divisions that can give rise to cells of unequal size?

A

True.
C. Elegans are examples of this

51
Q

What determines the cleavage plane of cell divisions?

A

the locations of centrosome

52
Q

What is the hollow ball of cell in mammals called ?

A

blastocyst

53
Q

What is the ICM the blastocyst?

A

embryo

54
Q

What is the trophectoderm?

A

extra embryonic tissue

55
Q

Where does the first epithelial layer come from?

A

it comes from the outside layer of the blastocyst

56
Q

What happens when cells undergo compaction?

A

the blastomere flatten against each other and maximize cell-cell contact developing an apico-basal polarity

57
Q

What is true of E-cadherin based junctions during compaction?

A

they become enriched and are markers that compaction is taking place

58
Q

What ion is E-cadherin dependent on ?

A

Ca2+

59
Q

What type of interaction is E-cadherin molecules?

A

homophilic interactions

60
Q

How do cadherin molecules link two cells together?

A

adherins junction via actin; actin filiments in each cell link to linker protein that the cadherins bind to

61
Q

If cells have no E-cahedrin what will happen?

A

they will not be able to compact because compaction requires the cell adhesion protein E-cahedrin

62
Q

What happens to the epithelial cells as they are formed?

A

epithelial layer cells become polarized into the apical-basal polarity making the ends of the cells different

63
Q

What end of the epithelial cells are adheren junctions formed at?

A

apical end

64
Q

What holds the epithelial cells together in the blastocyst?

A

E-cadherins containing adherens junctions

65
Q

What are tight junctions used for?

A

seals neighboring cells to make sure things don’t get released from the cell

66
Q

What do adherins junction do?

A

connect to actin

67
Q

What are desmosomes used for?

A

strength in response to shear stress

68
Q

How do cells link the molecules in the extra cellular matrix?

A

they use integrins to link the proteins

69
Q

What two molecules seal the right junctions?

A

claudin and occulin

BIOL 205 (2 decks)

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