OCR Gateway Biology B4B5B6 - 10/06/13

Question and answer guys? if anyone's up for it :P


Explain how the elbow joint acting as a pivot is an advantage (in terms of arm movement)?

What's an alternative to using pesticides? Name and advantage and disadvantage of it.

Biological Control:
No chemicals, less pollution
Might not eat pest, or eat the useful species

Let me finish B4 properly now! 2 more pages :')

How are plant adaptations also a disadvantage?

Broad leaves for more sunlight - Increased rate of transpiration.

Any others?

Loads more

Mention stomata?

Oh, having stomata for gas exchange means water can evaporate out at an increased rate.

I guess you could say leaves being thin for more light reaching chloroplasts also means it heats up more easily and more water will evaporate.

What are the rest?

I guess that's it actually so not loads more

Haha it's fine.

Alright, how do detritivores help decomposers? Give an example of a detritivore.

Eg earthworm

They break waste down into smaller particles, increasing surface area for decomposers to act on. Speeds up decay.

Explain the cardiac cycle.

1) The two atria fill up with blood. Atria-ventricular and semilunar valves are closed.

2) Atria-ventricular valves open and the atria contract, forcing blood into the two ventricles. The semilunar valves are still closed.

3) Semilunar valves open, the ventricles contract forcing the blood up to the lungs through the pulmonary artery and through to the rest of the body through the aorta.

Explain how electric impulses play a part in the cardiac cycle.

Sino-Atrial Nodes cause atria to contract. This current also causes the Atrio-ventricular nodes to create an impulse, making the ventricles contract.
This means the atria will always contract before ventricles

How can infertility be treated?

That isn't part of the syllabus. We have to know how an arm moves but not why it's an advantage.

I didn't mean like why the fact our arm moves is an advantage! I meant why the pivot system is an advantage for our muscles!

It was an practice work book with slightly different wording, you could of said:

Muscles are attached close to the elbow joint so only have to contract a very short distance, however the hand is able to move a long distance because it's attached to the forearm which acts as a lever,

so the way the muscles are attached close to the elbow joint means hand can move a larger distance for a given force.

We don't need to know that for OCR Gateway

It's in my book - Lonsdale

We don't need to know that for OCR Gateway

This is what it says in the specification but it doesn't specify how much detail we need to know it to...



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I see your name in basically all the threads I look at.. we must be taking identical exams or something