Question

newborn babies and hibernating animals contain a large amount of brown adipose (fat) tissue (bat). certain proteins in the bat cells increase the permeability of the inner mitochondrial membrane to protons, disrupting the proton gradient
which of the following best predicts the effect of disrupting the proton gradient in bat?
a the ph of the matrix will increase, allowing the production of more atp per gram of substrate
b the ph of the intermembrane space will decrease, allowing a steeper proton gradient to form
c electron transport and oxidative phosphorylation will be decoupled, generating more heat but less atp
d the number of protons available to pass through atp synthase will increase, resulting in more atp

Explanation:

Step1: Recall BAT function

Brown adipose tissue (BAT) uses uncoupling proteins (UCPs) in mitochondria to disrupt the proton gradient.

Step2: Link gradient disruption to ATP

The proton gradient drives ATP synthesis via ATP synthase. Disrupting it uncouples electron transport (which continues, producing heat) from ATP production (which decreases).

Step3: Evaluate options

Option C matches: decoupling of electron transport/oxidative phosphorylation, more heat, less ATP. Other options are incorrect (e.g., pH changes don’t drive more ATP, proton movement isn’t faster, proton number through ATP synthase doesn’t increase).

Answer:

C. Electron transport and oxidative phosphorylation will be decoupled, generating more heat but less ATP