W5 - Genetics / Development

Question 1

What proteins does genes make?

Answer 1

• membrane channels
• Na+/K+ pump
• enzymes
• muscle fibres
• etc.

Question 2

protein:

Answer 2

Tiny ‘machines’ that allows cells to work.

Made of ‘simple’ string of amino acids that fold in complex ways

Question 3

Double stranded molecules: Double Helix

Answer 3

Paired bases:

• Adenine x Thymine
• Guanine x Cytosine

Question 4

DNA

Answer 4

• deoxyribonucleic acid
• self replicating molecule
• 3 DNA/RNA bases = an amino acid

Question 5

RNA

Answer 5

• ribonucleic acid
• copy of one strand of the DNA
• 3 RNA/DNA bases = an amino acid

Question 6

Epigenetics

Answer 6

• The study of how behavior and environment can cause changes, affecting how genes work
• Reversible, only change how body reads a DNA

Question 7

When does the CNS (Central Nervous System) start to form

Answer 7

2 weeks old, by 7 weeks the hindbrain, midbrain, forebrain starts to form.

Question 8

Forebrain

Answer 8

• Cerebrum

- Diencephalon

Question 9

Midbrain

Answer 9

• Substantia nigra

- Superior & Inferior colliculi

Question 10

Hindbrain

Answer 10

• Cerebellum
• Pons
• Medulla oblongata

Question 11

Stages of neuronal development

Answer 11

1. Proliferation > 2. Migration > 3.Differentiation > 4.Myelination > 5. Synaptogenesis

Question 12

Stage 1 of neuronal development: Proliferation

Answer 12

cells undergo mitosis, neural tube divide , producing stem cells / neuroblasts.

Question 13

Stage 2 of neuronal development: Migration

Answer 13

cells follow chemical path to final destination

• radial migration
• tangential migration

Question 14

Stage 3 of neuronal development: Differentiation

Answer 14

different genes activated in different types of neurons

• axons first
• dendrites form when close to its destination

Question 15

Stage 4 of neuronal development: Myelinationn

Answer 15

addition of insulating sheath that speeds transmission

Question 16

Stage 5 of neuronal development: Synaptogenesis

Answer 16

formation of synapses and dendritic branches, continues throughout a lifetime.

Question 17

Determinants of Neuronal survival

Answer 17

In the PNS: must form synapse with target cell to receive NGF ( nerve growth factor, a neurotrophin ).

In the CNS: Must be stimulated to release neurotransmitters to the synapse.

Question 18

Apoptosis

Answer 18

programmed cell death when synapse little NGF

Question 19

Chemoaffinity hypothesis - Sperry (1943)

Answer 19

neurons find trager locations guided by chemical gradient

Question 20

Synaptic elimination

Answer 20

if the synapse doesn’t contribute to useful neural circuit, it loses it.