Ocr Biology Higher, B1,B2,B3 exam 19th may

WOW!!
I've had countless people explain this to me and i didnt get it. Now from one reply it all makes sense!
You.Are.Amazing.

Please continue, this is making sense.

Omg can someone help me i'm stuck on B3

What topic? This is why I said we should organise a Skype call so we can revise and work on weaknesses


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Aha, that's good to know - *says an aspiring teacher*

These neurones however have a certain way of transmitting impulses from one neurone to the next. Obviously, they don't just jump, they have to have a certain way of transmitting these impulses. Well, between these neurones, there is a gap, called a synapse. When an impulse is travelling along a neurone, it causes a neurotransmitter substance to be released and diffuse across the synapse, and it binds to the receptor molecules of the next neurone.

Wait, wait wait - receptor molecules? These are parts of the neurone where the neurotransmitter substance can attach to (bind to). Once it does this, the impulse can continue

Sometimes, people can drink alcohol or take sleeping tablets. These are depressants, but how do they work? Well, these depressants bind to the receptor molecules, hence meaning that less neurotransmitter substance can diffuse across the synapse (as it won't have anything to attach to).

Stimulants have the opposite affect: they cause more neurotransmitter substance to diffuse across the synapse, which means that the impulse travels faster. This is why your reaction time is faster.

Does that help?


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Meiosis and mitosis and like haploid and diploid cells And ikr does anyone have oovoo?

hi can you please go over all of B2 and 3 please? like the heart and mitosis, meiosis, cloning

I can't type all of that , but if you Skype me, I'll explain it


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can we Skype? like voice call

Yes, add me and we can Skype at like 8:45?


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ok what is your Skype?

kingaaran


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Your nervous system is made up of two parts: the Central Nervous System and the Peripheral Nervous System. The first is your brain and your spinal cord and the latter refers to the part of the nervous system that takes impulses to and fro the CNS.

There are different types of nerve cells (neurones) that you need to know about:

Sensory neurones - the clue is in the name: sensory. They are the neurones that detect a smell, taste, touch or whatever and take it to the CNS.

Motor Neurones - these are neurones that carry what the brain or spinal cord tells the cell to do back to the cell, if that makes sense.

So, in general, when you think about something, this is what will happen:

Stimulus (urge to close the door) --> sensory neurone --> CNS --> motor neurone --> effector (hand muscles, by closing the door)

Sometimes, you might not think about an action, like touching a hot pan. This is called a reflex. Since you don't think about it, it won't go to your brain, but it does go to your spinal cord, so that the impulse can attach to a motor neurone going back to tell the cell what to do. This is what would happen:

Stimulus (hot pan) --> sensory neurone --> relay neurone --> motor neurone --> effector (hand muscles, by moving your hand away)

You're probably wondering where the 'relay neurone' came from, right? This is a neurone which connects the sensory neurone and the motor neurone in the spinal cord, so that the impulse doesn't have to go to the brain, and you don't have to think about it.

Let me know if you get that, then I'll continue


Posted from TSR Mobile

WOW!!
I've had countless people explain this to me and i didnt get it. Now from one reply it all makes sense!
You.Are.Amazing.

Please continue, this is making sense.

Aha, that's good to know - *says an aspiring teacher*

These neurones however have a certain way of transmitting impulses from one neurone to the next. Obviously, they don't just jump, they have to have a certain way of transmitting these impulses. Well, between these neurones, there is a gap, called a synapse. When an impulse is travelling along a neurone, it causes a neurotransmitter substance to be released and diffuse across the synapse, and it binds to the receptor molecules of the next neurone.

Wait, wait wait - receptor molecules? These are parts of the neurone where the neurotransmitter substance can attach to (bind to). Once it does this, the impulse can continue

Sometimes, people can drink alcohol or take sleeping tablets. These are depressants, but how do they work? Well, these depressants bind to the receptor molecules, hence meaning that less neurotransmitter substance can diffuse across the synapse (as it won't have anything to attach to).

Stimulants have the opposite affect: they cause more neurotransmitter substance to diffuse across the synapse, which means that the impulse travels faster. This is why your reaction time is faster.

Does that help?


Posted from TSR Mobile

The exam was so easy!!! Apart from a few things that weren't in my revision guide it went well! How did u do?