chemicals of life

What are the main types of cells in the nervous system?

• Neurons (in brain)

• Receptor cells (in sensory organs)

• Ganglion cells (neurons clustered in PNS)

• Glial cells (in brain)

What are the key components of an animal cell?

- Organelles (specialized structures inside cell)

- Nucleus (contains DNA and majority of genes)

- Cytoplasm

- Cell membrane (surrounds everything)

What is a gene and how does gene expression work?

- Gene: length of DNA containing information for constructing a specific protein

- Gene expression has two phases:

1. Transcription (DNA to RNA)

2. Translation (RNA to protein)

What are proteins and their functions?

• Large, complex molecules doing most cell work

• Enzymes that facilitate biochemical reactions

• Messengers for chemical communication (e.g., hormones)

• Structural components (e.g., membrane channels, neurotransmitter receptors)

What is the difference between cytoplasm and extracellular space?

- Cytoplasm: watery solution inside cell (intracellular space)

- Extracellular space: watery solution outside cell

- Separated by double layer of lipids (fats)

What is the role of the neuronal membrane?

- Keeps water in/out of cell (insoluble fat layer)

- Acts as physical barrier for most chemicals

- Contains channel proteins that pump ions

- Maintains different electrical charge (more negative inside, more positive outside)

How do neurons generate electrical signals?

- Neurons are electrically charged

- Generate electrical currents by changing ion imbalances between intra/extracellular space

- Movement of ions through cell membrane generates electrical impulses

What is myelin and its function?

- Fatty substance that insulates axons

- Does not have channels/pores for ions

- Makes signals travel faster

- Acts like insulation tape for neurons

What are the main neurotransmitters?

• Acetylcholine

• Serotonin

• Glutamate

• Dopamine

• GABA

What are the key points about neurons and proteins?

- Brains are mostly made of neurons

- Neurons contain DNA coding for proteins

- Genes are DNA segments encoding specific proteins

- Neurons are specialized for transmitting electrical signals

- Ion imbalances define electrical activity

- Specific proteins enable neurons to send/receive signals