biology help

Original post by lol9812

Body mass index (BMI) helps to show if a person has a healthy body mass for
their height.
BMI is calculated using the equation:
BMI = body mass in kg
(height in m)2
A woman has a BMI of 27 and a body mass of 68.1 kg
Calculate the woman’s height in metres.
Hi how would you rearrange this formula? Sorry if it seems stupid im fasting so my brain is all over the place

Height = sq root of (body mass / BMI)

So squareroot of (68.1 / 27)

Reply 2

OP

Original post by qwert7890

Height = sq root of (body mass / BMI)

So squareroot of (68.1 / 27)

OMG I NEED YOUR HELP on some of my biology test questions that im struggling with its on a graph so i cant upload it but can i message you on anything to show you? please it would mean a lot

Reply 3

OP

PLEASE ANYONE i need help on these questions particulary 5.4 and 5.4 @qwert7890

(edited 3 years ago)

Reply 4

Original post by lol9812

PLEASE ANYONE i need help on these questions particulary 5.4 and 5.4 @qwert7890

Hi!

Yes I’ll be more than happy to help :smile:

do you need help with all of them or just 5.4?

Before I tell my answer, what value have you written down for 5.3?

Reply 5

OP

Original post by qwert7890

Hi!

Yes I’ll be more than happy to help :smile:

do you need help with all of them or just 5.4?

Before I tell my answer, what value have you written down for 5.3?

Hi im struggling with all of them :frown:

for 5.3 i put 20000 because light intensity isnt a limiting factor anymore but i dont know if thats correct? Thankyou so much for your help !

Reply 6

Original post by lol9812

Hi im struggling with all of them :frown:

for 5.3 i put 20000 because light intensity isnt a limiting factor anymore but i dont know if thats correct? Thankyou so much for your help !

Ok let’s start with 5.2

What do you know about limiting factors?

Reply 7

OP

Original post by qwert7890

Ok let’s start with 5.2

What do you know about limiting factors?

Is it when the rate of photosynthesis isnt happening as quickly as it could due to the amount of light intesnity it is exposed to?

Reply 8

Original post by lol9812

Is it when the rate of photosynthesis isnt happening as quickly as it could due to the amount of light intesnity it is exposed to?

Yes.
But not only light intensity, there are multiple things that could limit the photosynthesis reaction ; carbon dioxide, temperature, concentration.

So for 5.2 , at X since the reaction hasn’t reached its peak yet this means that light intensity is the limiting factor. This is your answer.

Reply 9

OP

Original post by qwert7890

Yes.
But not only light intensity, there are multiple things that could limit the photosynthesis reaction ; carbon dioxide, temperature, concentration.

So for 5.2 , at X since the reaction hasn’t reached its peak yet this means that light intensity is the limiting factor. This is your answer.

Thankyou, I got this correct however it is mainly 5.4 and 5.5 that i am struggling with, could you please help ?

Reply 10

Original post by lol9812

Thankyou, I got this correct however it is mainly 5.4 and 5.5 that i am struggling with, could you please help ?

5.3 is 20k you are right.

For 5.4, there could be a couple of reasons (I'm not so sure myself, I'm speculating):

- Another factor could be limiting at 20,000 lux (for example Temperature or Carbon Dioxide concentration), so in theory the rate of photosynthesis could even go higher at say for example, 30 degrees Celsius or 0.5% in CO2.

- It might not make the farmer the maximum profit because it might be very costly to maintain a light intensity at 20,000 lux.

Reply 11

OP

Original post by qwert7890

5.3 is 20k you are right.

For 5.4, there could be a couple of reasons (I'm not so sure myself, I'm speculating):

- Another factor could be limiting at 20,000 lux (for example Temperature or Carbon Dioxide concentration), so in theory the rate of photosynthesis could even go higher at say for example, 30 degrees Celsius or 0.5% in CO2.

- It might not make the farmer the maximum profit because it might be very costly to maintain a light intensity at 20,000 lux.

Thanks so much! for 5.5 would you say that the rate of photosynthesis was happening really slowly because of the little amount of light intensity, carbon dioxide and temprature that it was exposed to ?

Reply 12

Original post by lol9812

Thankyou, I got this correct however it is mainly 5.4 and 5.5 that i am struggling with, could you please help ?

In 5.5, at 0 lux, I assume photosynthesis cannot take place, so rate of photosynthesis is zero. However the plant still respires (as any living organism), and this would mean that oxygen is consumed, not produced.

Hence the oxygen production becomes negative.

Reply 13

Original post by lol9812

Thanks so much! for 5.5 would you say that the rate of photosynthesis was happening really slowly because of the little amount of light intensity, carbon dioxide and temprature that it was exposed to ?

Photosynthesis isn't happening really slowly, it's not happening at all.

In general during the day, respiration and photosynthesis occur all the time. However, the rate of photosynthesis is always greater than the rate of respiration.

Here, the rate of photosynthesis is zero. Hence the rate of respiration is greater than the rate of photosynthesis, and thus there is an oxygen deficit in "production".

Reply 14

OP

Original post by qwert7890

Photosynthesis isn't happening really slowly, it's not happening at all.

In general during the day, respiration and photosynthesis occur all the time. However, the rate of photosynthesis is always greater than the rate of respiration.

Here, the rate of photosynthesis is zero. Hence the rate of respiration is greater than the rate of photosynthesis, and thus there is an oxygen deficit in "production".

Oh okay, but the question said they were investigating the rate of photosynthesis in tomato plants- it was also during winter which may link back to question 5.4 as the farmer would have to pay for the temprature exposure aswell. This may sound stupid but do tomatos respire?

Reply 15

Original post by lol9812

Oh okay, but the question said they were investigating the rate of photosynthesis in tomato plants- it was also during winter which may link back to question 5.4 as the farmer would have to pay for the temprature exposure aswell. This may sound stupid but do tomatos respire?

hmm yes perhaps temperature exposure as a cost could also be a factor.

And yes, tomatoes are a part of a plant and a plant is a living organism. Fruits are made of living cells and all cells need to respire in order to survive.

Reply 16

OP