Neurotransmitters and Neuromodulators

Neural Communication

• Glutamate is an excitatory neurotransmitter in the central nervous system, but not the only one.
• Glutamate release increases the likelihood of the post-synaptic neuron firing, not the pre-synaptic neuron.
• As more glutamate is released, the synaptic connection is strengthened.

Neuromodulators

• Neuromodulators influence the activity of other neurotransmitters.
• Dopamine and serotonin are examples of neuromodulators.
• Neuromodulators exert their influence over a longer time period than neurotransmitters.
• Neuromodulators do not release their chemical message into a single synapse, instead, they diffuse into the surrounding tissue.

Cell Biology

Cell Structure

• The plasma membrane is semi-permeable, separating the cell from its environment and regulating what enters and leaves the cell.
• Cytoplasm is a jelly-like substance inside the cell membrane where metabolic reactions occur, providing a medium for chemical reactions.
• The nucleus is the control center of the cell, storing DNA and regulating gene expression.
• Mitochondria generate energy for the cell through cellular respiration, producing ATP.
• The endoplasmic reticulum (ER) is a network of membranous tubules and cisternae involved in protein synthesis and transport.
• Ribosomes are small organelles found throughout the cytoplasm where protein synthesis occurs.
• Lysosomes are membrane-bound sacs containing digestive enzymes that break down and recycle cellular waste.

Cell Functions

• Metabolism is the conversion of energy and nutrients into cellular components and waste products, maintaining cellular homeostasis.
• Cell division is the process by which a cell becomes two daughter cells, involving mitosis and cytokinesis.
• Mitosis is the division of the nucleus in somatic cells, while meiosis is the division of the nucleus in reproductive cells.
• Cell signaling is communication between cells through signaling molecules, regulating cellular behavior.
• Cell transport is the movement of molecules into and out of the cell, involving passive and active transport mechanisms.

Cell Cycle

• Interphase is the period of cell growth and preparation for cell division, involving G1 and G2 phases.
• Mitosis is the division of the nucleus, separating duplicated chromosomes.
• Cytokinesis is the division of the cytoplasm, separating the cell into two daughter cells.
• G1 and G2 checkpoints regulate the cell cycle, ensuring proper DNA replication and cell growth.

Cell Types

• Prokaryotic cells lack a true nucleus, characteristic of bacteria.
• Eukaryotic cells have a true nucleus, characteristic of plants, animals, and fungi.
• Stem cells can differentiate into various cell types, possessing pluripotency.
• Specialized cells have unique structures and functions, such as nerve cells and muscle cells.