embryology

Question 1

stages of development

Answer 1

egg&sperm –> fertilization –> cleavage –> gastrulation –> organogenesis –> metamorphosis

Question 2

cleavage

Answer 2

division of zygote into smaller cells every 12-24 hours

Question 3

morula

Answer 3

solid ball of cells

Question 4

blastula

Answer 4

hollow ball of cells

Question 5

gastrulation

Answer 5

• the movement of cells to create germ layers
• starts at dorsal lip
• results in gastrula

Question 6

3 germ layers

Answer 6

ectoderm, mesoderm, endoderm

Question 7

ectoderm

Answer 7

skin, nervous system, teeth, lens

Question 8

mesoderm

Answer 8

blood, skeletal, muscular, circulatory, and lymphatic system

Question 9

endoderm

Answer 9

linings of respiratory, excretory, reproductive, and digestive system

Question 10

deuterosomes

Answer 10

anus first

Question 11

protostomes

Answer 11

mouth first

Question 12

differentiation

Answer 12

• all cells have the same genes
• due to the expression or silencing of genes for specific proteins, determined by location of cells, and signaled by the environment
• signals are the same for many organisms

Question 13

noggin and chordin

Answer 13

induce mesoderm to change to muscle and notochord (spine)

Question 14

retinoic acid

Answer 14

regulates limb development and regeneration

Question 15

homeotic selector genes

Answer 15

• genes whose expression affects the overall body plan / sequences
• bithorax/antennapedia are due to mutations in drosophila

Question 16

lineage map

Answer 16

• tracing the cells during development and creating a map

- allows us to know what cells will become what structures

Question 17

organogenesis

Answer 17

• organ formation begins

- apoptosis and gene activation/silencing are very important

Question 18

apoptosis

Answer 18

hollows out blood vessels, creates fingers and toes, necessary for proper brain development and more

Question 19

complete metamorphosis

Answer 19

egg
larva
pupa
adult
butterfly, mosquito, beetles, frogs

Question 20

aging

Answer 20

• depends on genes and environment

- as we age our cells are less likely to divide and more likely to die

Question 21

embryonic stem cell retrieval

Answer 21

~100 cells total

blastocyst