atlantapie
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Here are 2 MCQ questions from the past paper that i don't understand. Can someone explain them for me please?

Q1/ Which statement about respiration is not correct?
A All living cells respire
B Heat is always produced
C Plants respire in the light and in the dark
D Plants take in carbon dioxide and gives out oxygen

⬆️The answer is D, i don't know what's wrong with this statement

Q2/ Which process does not involve an increase in dry mass?
A a bacterium getting larger before it divides
B a fetus developing inside the uterus
C a green shoot growing towards light
D a seed germinating under the ground

⬆️The answer is D, and I don't know the reason too

Thx!!!!
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Star Light
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Q1 - Plants convert carbon dioxide to oxygen in photosynthesis only, so if there is sunlight, the overall effect will be that the plant takes in carbon dioxide and gives out oxygen. However, in the dark, the plant will only be respiring, so it will take in oxygen and give out carbon dioxide.

In summary, D is only correct when the plant photosynthesises more than it respires.

Q2 - Germinating seeds use the stored sugars in the endosperm(I think) of the seed for their initial growth, so they don't take in more minerals, so their dry mass stays the same, just their shape changes.

Hope that helps
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Hype en Ecosse
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(Original post by atlantapie)
Here are 2 MCQ questions from the past paper that i don't understand. Can someone explain them for me please?

Q1/ Which statement about respiration is not correct?
A All living cells respire
B Heat is always produced
C Plants respire in the light and in the dark
D Plants take in carbon dioxide and gives out oxygen

⬆️The answer is D, i don't know what's wrong with this statement
D is wrong because that's talking about photosynthesis! Respiration takes in oxygen and pumps out CO2.

Q2/ Which process does not involve an increase in dry mass?
A a bacterium getting larger before it divides
B a fetus developing inside the uterus
C a green shoot growing towards light
D a seed germinating under the ground

⬆️The answer is D, and I don't know the reason too

Thx!!!!
Any increase in dry mass means you intake molecules from the environment, then add them to your building blocks. Bacteria absorb it all through diffusion; phagocytosis and active transport. Foetuses grow from the nutrients provided by the foeto-maternal circulation; plants get it from the soil and the air when they grow. Seed germination doesn't take in any molecules (except oxygen, which isn't a "building block", so doesn't add to your dry mass!) since it's already made with all its resources inside it to use. It doesn't start incorporating resources from the soil and the air until it's already a seedling!

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atlantapie
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  • (Original post by Star Light)
    Q1 - Plants convert carbon dioxide to oxygen in photosynthesis only, so if there is sunlight, the overall effect will be that the plant takes in carbon dioxide and gives out oxygen. However, in the dark, the plant will only be respiring, so it will take in oxygen and give out carbon dioxide.
(Original post by Star Light)

In summary, D is only correct when the plant photosynthesises more than it respires.

Q2 - Germinating seeds use the stored sugars in the endosperm(I think) of the seed for their initial growth, so they don't take in more minerals, so their dry mass stays the same, just their shape changes.

Hope that helps
Understood, Thanks a lot!
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TammyIce
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Q1. was rather sneaky

*The question asked about respiration.
*The statement says that CO2 would be taken in, and O2 released, but this only true for photosynthesis. plants respire the same as animal cells, taking in O2 and releasing CO2

Q2. Because when a seed germinates, it uses up the stored nutrients inside it. Because it is being used up, the seed will initially have a lower mass (and then the dry mass will increase again)

Hope that helps
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atlantapie
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(Original post by Hype en Ecosse)
D is wrong because that's talking about photosynthesis! Respiration takes in oxygen and pumps out CO2.



Any increase in dry mass means you intake molecules from the environment, then add them to your building blocks. Bacteria absorb it all through diffusion; phagocytosis and active transport. Foetuses grow from the nutrients provided by the foeto-maternal circulation; plants get it from the soil and the air when they grow. Seed germination doesn't take in any molecules (except oxygen, which isn't a "building block", so doesn't add to your dry mass!) since it's already made with all its resources inside it to use. It doesn't start incorporating resources from the soil and the air until it's already a seedling!

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Oh i c, Thank you!
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atlantapie
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(Original post by TammyIce)
Q1. was rather sneaky

*The question asked about respiration.
*The statement says that CO2 would be taken in, and O2 released, but this only true for photosynthesis. plants respire the same as animal cells, taking in O2 and releasing CO2

Q2. Because when a seed germinates, it uses up the stored nutrients inside it. Because it is being used up, the seed will initially have a lower mass (and then the dry mass will increase again)

Hope that helps
Haha I didn't read the question carefully, thank you for ur answer!
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optic123
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What board are these question from ?
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