- C2 ✏︎ Cells -
C2.1 - Chemical Signalling (HL)
LECTURE VIDEO
DESCRIPTION
Your cells are expert gossips using chemicals as DMs. Some signals knock on the door (transmembrane receptors), others slip straight into the DMs (intracellular receptors). But the real drama is in the replies: some say “MORE!” and some say “ENOUGH!”
Crash course in cellular messaging:
- Ligands & Receptors: The chemical DMs (ligands) and the inboxes that receive them—doorbell receptors on the surface vs. VIP passes straight to the cell’s nucleus.
- Positive Feedback: The “OMG TELL ME MORE” reply. Like oxytocin turning contractions up to eleven during childbirth.
- Negative Feedback: The “k thx bye” autopilot. Like insulin shutting down its own production once blood sugar is back to boring.
- Quorum Sensing: How bacteria count their friends before throwing a toxic rave. Once the guest list hits critical mass, they all turn on their party lights at once.
Learn how your cells flirt, argue, and shut down conversations—and how even bacteria know not to party alone.
TIMESTAMPS
STUDY RESOURCES
00:00 – Outline of this video
00:43 – Intro to chemical signalling
05:17 – Types Of Ligands
07:51 – Neurotransmitter [Ligands]
10:39 – Hormones [Ligands]
17:59 – Cytokines & Calcium [Ligands]
20:26 – Types Of Receptors
27:04 – Chemically gated ion channel [Receptor]
28:59 – G-protein coupled receptor [Receptor]
40:29 – Tyrosine kinase [Receptor]
45:23 – Intracellular receptors [Receptor]
47:23 – Negative feedback
52:36 – Positive feedback
54:59 – Quorum sensing
58:36 – Questions & Answers
NOTES – All you need to know in one place!
QUESTIONS – Test your Big Brain!
C2.2 - Neural Signalling (SL/HL)
LECTURE VIDEO
DESCRIPTION
Your brain’s messaging app is the nervous system. The CNS is headquarters, the PNS are the delivery drivers, and your neurons are the dramatic, wire-like employees that either scream an electrical impulse or ghost you with chemical silence.
Get the employee handbook for your body’s fastest chat app:
- CNS vs. PNS: Headquarters (brain & spinal cord) vs. the delivery fleet (nerves to your limbs and organs).
- Neuron Structure: Meet the cell body, the gossip-receiving dendrites, and the long, dramatic axon that shouts the message.
- Impulse Generation & Transmission: How a neuron gets salty (literally) to fire an electrical action potential down its length.
- Synaptic Transmission: How neurons flirt chemically across a tiny gap, using neurotransmitters to slide into the next neuron’s DMs.
- Speed of Impulses: Why some texts are instant (myelinated axons) and some are painfully slow (unmyelinated), and what happens when the Wi-Fi is bad.
Understand how your body sends texts at lightning speed—and why some messages get lost in translation.
TIMESTAMPS
STUDY RESOURCES
00:00 – Outline Of Video
00:39 – Intro To Nervous System
04:05 – CNS V.S PNS
11:04 – Neuron Structure
18:16 – Neuron V.S Nerve
20:57 – Impulse Generation & Transmission
36:00 – Synaptic Transmission (+ Word Summary)
46:37 – Speed Of Impulses
51:29 – Correlation (Case Based Knowledge)
58:25 – Questions & Answers
NOTES – All you need to know in one place!
QUESTIONS – Test your Big Brain!
C2.2 - Neural Signalling (HL)
LECTURE VIDEO
DESCRIPTION
Your neurons aren’t just wires—they’re moody drama students. Some signals are pep talks (EPSPs), some are brutal critiques (IPSPs), and the final decision to fire is based on who shouts loudest. Meanwhile, some axons wear puffy coats to make messages bounce faster.
Backstage at the neuron theater:
- Impulse Propagation: How a neuron throws an electrical tantrum (action potential) that races down its axon.
- EPSPs vs. IPSPs: The excitatory pep rallies vs. the inhibitory “sit down and be quiet” lectures that decide if the neuron fires.
- Saltatory Conduction: How myelinated axons turn a sprint into a series of ridiculous, energy-saving long jumps.
- Chemical Interference: How your morning coffee (exogenous) and your brain’s own happiness juice (endogenous) hijack the same receptors to mess with the show.
Understand the high-school-level drama of how your brain makes decisions, speeds up texts, and gets chemically hacked by everything from espresso to serotonin.
TIMESTAMPS
STUDY RESOURCES
00:00 – Outline Of This Video
01:34 – Nerve Impulse Propogation (Transmission)
19:15 – Summary Page [Nerve Impulse Transmission]
23:49 – IPSP & EPSP
33:06 – Saltatory Conduction
36:56 – Endogenous & Exogenous chemicals
47:15 – Role Of Receptors
54:14 – Questions & Answers
NOTES – All you need to know in one place!
QUESTIONS – Test your Big Brain!
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