OCR Gateway GCSE Biology B B4 B5 B6 (12th June 2015)

Smashed it! Counted at least 70 marks.
For the other factors to consider question on the second page I put that increasing the temperature would increase the amount of water lost by transpiration.
Got 0.08 for the atria question, and 1.51 for the heart disease 6 marker.

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Yep, atria was definitely 0.08.
I rounded the heart disease index to 1.5, should be okay.
Do you think we were supposed to round up the area of the artery (12.56 to 12.6)? A lot of people did that and got 1.6. Our method is more mathematically accurate though, what do you think?

Reply 101

haes

6

Original post by lasertown

Cross-sectional area of artery while relaxed was given, 11.5.
Area of a circle: pi r(squared) Pi: 3.14

r was given, 2

3.14 x 2 squared = 12.56

(12.56-11.5)/0.7 = 1.51428 . . .

1 d.p. = 1.5

Some people got 1.6, as they rounded up the 12.56 when working out the area. I only round up at the end, it gives a more accurate result. So I don't know which will get the mark. 1.5 is more mathematically correct, however. The mark scheme may allow a range of results, e.g. 1.5-1.6.

How did you get 1.42?

I remember the question giving us the information that pi=3.14.. so i just used what they gave me and got 1.514, rounded it to 1.51. i know that i definitely saw this because i couldn't find pi on my calculator and had to check what number i could use as appropriate! i have no idea if it said you must use 3.14, but i'm certain they accept 1.51

Reply 102

Kienzan

8

I put, among other things, that the antibiotic was neutralising the lactic acid in the yoghurt, spoiling the flavour and texture.

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Reply 103

Mudas

13

Original post by swingrx

I did god awfully in that paper...
What were the points for the last 6 marker on yogurt?

LactoBacillus is used in milk to convert lactose into lactic acid. The antibiotics kill the LactoBacillus so therefore you saw the increase in pH as less lactic acid is produced. To counter this, i said the yogurt maker would have to filter the antibiotics out before production which would be costly. (The lactic acid, therefore, turns the milk into yogurt).

Reply 104

Andy tech

2

Original post by hatexams

0.0.4?????????????

I put 0.04

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Reply 105

haes

6

Original post by Kienzan

Smashed it! Counted at least 70 marks.
For the other factors to consider question on the second page I put that increasing the temperature would increase the amount of water lost by transpiration.
Got 0.08 for the atria question, and 1.51 for the heart disease 6 marker.

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I ALSO SAID THAT!!! it said factors that heat affected other than photosynthesis right??? so i automatically assumed that by factors they meant other processes and talked about transpiration.. i was a bit iffy though afterwards because the six marker became about transpiration.

Reply 106

mark36

7

Original post by swingrx

What were the points for the last 6 marker on yogurt?

I said something along the lines of higher antibiotic concentration producing higher pH levels, therefore "cancelling out" action of Lactobacillus (which produces lactic acid in yoghurt and making the yoghurt have a more acidic taste). As for the problems this would mean the yoghurt tastes less sour and the milk wouldn't clot properly, making the yoghurt less thick. I also put down that increased bacterial antibiotic resistance due to feeding large concentrations of antibiotic weaken the immune system of cows and cause death so less cows would produce milk for yoghurt (i completely guessed that part haha)

(edited 8 years ago)

Reply 107

lasertown

1

Original post by Kienzan

I put, among other things, that the antibiotic was neutralising the lactic acid in the yoghurt, spoiling the flavour and texture.

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How does the antibiotic neutralise the lactic acid? It''s not an alkali?
I wrote that the antibiotic concentration would kill/weaken the bacteria that feed on lactose to produce the lactic acid, pH was higher than it should be, not as much lactic acid produced. Yoghurt makers would create poor quality yoghurt, lose money.
Great 6 marker to be honest. All the 6 markers were fantastic.

Reply 108

JSAN

2

what was the bacteria answer for if she had the average amount of bacteria?

Reply 109

Jack1246

1

For the second 6 marker I got 1.6 for the index im sure that right because a bunch of people got the same

Reply 110

Mudas

13

Original post by lasertown

How does the antibiotic neutralise the lactic acid? It''s not an alkali?
I wrote that the antibiotic concentration would kill/weaken the bacteria that feed on lactose to produce the lactic acid, pH was higher than it should be, not as much lactic acid produced. Yoghurt makers would create poor quality yoghurt, lose money.
Great 6 marker to be honest. All the 6 markers were fantastic.

Yup

Reply 111

lasertown

1

Original post by mark36

I said something along the lines of higher antibiotic concentration producing higher pH levels, therefore "cancelling out" action of Lactobacillus (which produces lactic acid in yoghurt and making the yoghurt have a more acidic taste). As for the problems this would mean the yoghurt tastes less sour and the milk wouldn't clot properly., making the yoghurt less thick I also put down that increased bacterial antibiotic resistance due to feeding large concentrations of antibiotic weaken the immune system of cows and cause death so less cows would produce milk for yoghurt (i completely guessed the last sentence haha)

Lactobacillus is a bacteria, antibiotics kill/weaken bacteria, can't make as much/any lactic acid.
What do you mean by cancelling out?

Reply 112

Jack1246

1

What do you think the grade boundrys will be ?

Reply 113

haes

6

Original post by swingrx

I did god awfully in that paper...
What were the points for the last 6 marker on yogurt?

i can't remember the question fully but i said something like

>as the dose(?)of antibiotic increased, the pH levels increased
>this is because antibiotics will kill the lactobacillus bacteria, preventing them from breaking down lactose sugar into lactic acid
>less lactic acid is produced so the pH becomes higher

and then i also said less milk becomes clotted because milk proteins aren't denatured as much (which idk if it's true) which makes it difficult for the yogurt makers to get the correct consistency, as well as flavours, in the yogurt

Reply 114

Hppy_bug

7

with the pesticides being in the leaves faster did you guys talk about transpiration, photosynthesis and xylem?

Reply 115

lasertown

1

Original post by Suzie17

with the pesticides being in the leaves faster did you guys talk about transpiration, photosynthesis and xylem?

That was a great question.
I talked about transpiration and xylem vessels, yes, where does photosynthesis come into it? Can't remember talking about that.

Reply 116

swingrx

4

Does anyone have access to the paper, or know all the questions?
Im really worried about how i did, and i want to count up my marks.

Reply 117

mark36

7

Original post by lasertown

Lactobacillus is a bacteria, antibiotics kill/weaken bacteria, can't make as much/any lactic acid.
What do you mean by cancelling out?

Guess I lost some points on that one then...:/ Since there's less of them they cause less lactic acid to break down or something like that. our class didn't have a proper teacher for the last modules (he was more of a "permanent cover teacher', if that makes sense) and i had to self-teach myself all of B6...yesterday

I think I might've made some silly mistakes too, but I'm not gonna worry too much about it :tongue:

it's all over now, thank God

(edited 8 years ago)

Reply 118

Hppy_bug

7

Original post by lasertown

That was a great question.
I talked about transpiration and xylem vessels, yes, where does photosynthesis come into it? Can't remember talking about that.

Yeah i was a bit iffy about including photosynthesis :') i said something along the lines of, as there was more light the speed at which photosynthesis took place increased and as a result more water was needed more quickly from the roots? :')

Reply 119

Mudas

13

Anyone wanna make a unofficial mark scheme?

OCR Gateway GCSE Biology B B4 B5 B6 (12th June 2015)

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