Lecture #10: Development

Question 1

What does N mean?

Answer 1

number of chromosomes in a species

Question 2

How many chromosomes do humans have?

Answer 2

46 total, 23 from mom and 23 from dad

Question 3

N for fruit flies?

Answer 3

N = 4

Question 4

N for humans?

Answer 4

N = 23

Question 5

Egg

Answer 5

1N (Haploid)

Question 6

Sperm

Answer 6

1N (Haploid)

Question 7

What does Egg + Sperm create?

Answer 7

Zygote

Question 8

Zygote

Answer 8

2N (Diploid)
- 2 sets of chromosomes

Question 9

Path of development from zygote to adult

Answer 9

Zygote (2N, Dipole) -> Blastole -> Gastrula -> Neural tube -> Juvenile -> adult (mostly 2N)

Question 10

Parts of sperm?

Answer 10

Flagellum, Haploid nucleus, Acrosor, Mitochondria

Question 11

Acrosomal reaction

Answer 11

• Enzymes in Acrosor allow sperm to contact the egg cell membrane
• Reaction between sperm proteins and egg membrane protein for membranes to fuse
  
  • if sperm is from another species, reaction will NOT occur
• sperm nucleus is introduced into egg

Question 12

Blocks to polyspermy?

Answer 12

1. Fast-block - Na+ ion enters egg, wave of electrical potential prevents 2nd sperm from entering
2. Slow-block - Cortical grandules dumped between cell membranes and vitelline membrane

Question 13

Steps in Fertilization

Answer 13

1. combine set of chromosomes from egg with sperm
2. Block polyspermy
3. initiates cell division in egg

Question 14

Deuterostomes

Answer 14

vertebrates
- Anus forms before mouth forms

Question 15

Echinoderms

Answer 15

sea star + sea urchin

Question 16

Protestones

Answer 16

most invertebrates
- mouth forms before anus

Question 17

Stem cell

Answer 17

a cell that can be used to regenerate new cells

Question 18

Embryonic stem cells

Answer 18

totipotent

Question 19

Totipotent

Answer 19

cell that can become any structure in body or extra-embryonic structures

Question 20

Pluripotent

Answer 20

cells that can become any structure in body

Question 21

Multipotent

Answer 21

a cell that can become a number of different structures

Question 22

Adult stem cells

Answer 22

multipotent

Question 23

Egg developement

Answer 23

Ferilized egg -> clevege decisions -> 4-cell -> 8-cell -> Blastula -> Gastrula -> Mid/late Gastrula

Question 24

Blastula

Answer 24

ball of cells

Question 25

Gastrula

Answer 25

has a blastopore (hole)
- blastopore eventualy becomes anus

Question 26

Mid/late gastrula

Answer 26

• Ectoderm
• Mesoderm
• Endodertm

Question 27

Ectoderm

Answer 27

Becomes skin + nervous system

Question 28

Mesoderm

Answer 28

• Multipotent stem cells -> Myeloid stem cells -> Red blood cells + macrophage
• Lymphoid stem cell -> T cell and B cells (in immune systems)
• becomes blood, bone, muscle cells, etc

Question 29

Endoderm

Answer 29

Becomes most of digestive systems

Question 30

Induction

Answer 30

One group of embryonic cells influencing the fate of another group of cells, usually by tactile (touch) or chemical communication between cells

Question 31

Neural tube

Answer 31

embryonic structure that forms the brain and spinal cord (produced by folding of ectoderm)

Question 32

Notochord

Answer 32

A rod of cartilage that supports the body in all embryos and some adult vertebrates

Question 33

At what stage of development do we see the formation of the archenteron?

Answer 33

Gastrule