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Flashcards in Developmental Biology Deck (135)
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1

What cells are egg and sperm cells derived from?

Germ cells

2

What are the major characteristics of a sperm cell?

- Flagella
- Acrosomal vesicle
- Many mitochondria

3

What are the major characteristics of a egg cell?

- Large
- Contain large amounts of RNA and proteins for zygote
- Arranged asymmetrically

4

What happens in fertilisation?

1. Sperm binds to the pellucida zone
2. Acrosomal reaction - allows penetration through the bona pellucida
3. Fusion of egg and sperm membranes releasing nucleus

5

What are the blocks to polyspermy?

- Depolarisation of membrane
- Cortical reaction

6

What is the cortical reaction?

- Vesicles containing cortical granules bind with plasma membrane
- Froms fertilisation membrane
- The vesicles remaining cause the hyaline layer

7

What happens during egg activation?

- Sperm triggers the release of Ca2+ which act on proteins that initiate cleavage
- Pronuclei fuse and cleavage is initiated
- Oscillations of Ca2+ continue for hours

8

What occurs during cleavage?

- Rapid and can occur in diffeerent patterns
- There is no growth - no S and M phase
- Transcription is suppressed
- Cleavage continues an forms a blastocoel - fluid filled cavity

9

How do cells become different?

- Cell-cell signalling
- segregation of cytoplasmic componants before division

10

What are the three germ layers?

Ectoderm
Mesoderm
Endoderm

11

What does ectoderm develop into?

- Neurones
- Glia
- Neural crest
- Epidermis

12

What does mesoderm develop into?

- Muscle
- Cartilage
- Bone
- Kidney
- Heart
- Blood

13

What does the endoderm develop into?

- Gut and associated organs
- Yolk cells

14

What is a blastula?

Single layer of cells surrounded by a hollow ball

15

What happens during gastrulation?

- Mesoderm moves inside the cavity and endoderm takes its place
- Endoderm cells buckle and move inside the cavity and fuse with the top layer of cells forming a hollow tube - this will become the gut

16

What is the difference between epithelium and mesenchyme?

Epithelium - have polarity - microfilm at the top and secrete at the bottom
Mesenchyme - cells exist in a matrix and are more random

17

What is neurulation?

Further rearrangements in cell and tissue to form the neural tube

18

Give an example cells the migrate after gastrulation?

Neural crest cells
Germ cells

19

When are body plans developed?

After gastrulation and neurulation
Form anteroprosterior (A/P) and dorsoventral (D/V) axes

20

What are the advantages of using drosophila as a model organism?

- Small organism
- Short generation time
- Large batches of embryos
- Sequemced genome
- detailed genetic map

21

What are the disadvantages of using drosophila as a model organism?

- Small embryo

22

What are the techniques available when using drosophila as a model organism?

- Mutagenesis
- Transgenesis
- Clonal analysis

23

How many days after fertilisation is an adult drosophila?

9 days

24

What are the advantages of using worms (C.elegans) as a model organism?

- Small organism
- Invariant lineage
- Short generation
time
- Sequenced
genome
- Hermaphrodite

25

What are the techniques available when using worms (c. elegans) as a model organism?

- Mutagenesis
- Cell ablation
- RNAi

26

What are the disadvantages of using worms (C. elegans) as a model organism?

Small embryo

27

How many hours after fertilisation is a worm fully developed?

50 hours

28

What are the advantages of using a zebrafish as a model organism?

- Small vertebrate
- Large batches of embryos
- Transparent embryo
- Haploid development possible

29

What are the disadvantages of using a zebrafish as a model organism?

Large genome

30

What are the techniques available when using zebrafish as a model organism?

- Mutagenesis
- cell transplantations
- Injections
- Transgenesis