Answer: Option C. -> Oxidation of the respiratory substrate consumed more oxygen than the CO2 released
:
C
Ratio of the volume of carbon dioxide liberated to the volume of oxygen absorbed during respiration is called respiratory quotient (RQ). When the amount of oxygen used and amount of carbon dioxide evolved are equal then the: Quantity of $C{O}_2$ liberated =Quantity of $O_2$ used
and
RQ value = Quantity of $C{O}_2$ liberated/ Quantity of $O_2$ used = 1
When more $O_2$ is consumed than $C{O}_2$ liberated then the RQ value is less than 1
When less $O_2$ is consumed than the $C{O}_2$ liberated then the RQ value is more than 1
$\begin{array}{cc}Substrate& RQ\\ Carbohydrates& One\\ FatsandProteins& Lessthanone\\ Organicacids& Morethanone\\ Succulents& Zero\end{array}$

Answer: Option B. -> A.- 3. B.- 4. C.- 1. D.- 2
:
B
$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{Oxaloacetate}& \text{4C-compound}\\ \text{Phosphoglyceraldehyde}& \text{3 C-compound}\\ \text{Isocitrate}& \text{6 C-compound}\\ \alpha -\text{ketoglutarate}& \text{4C-compound}\end{array}$

Answer: Option A. -> ATP in small stepwise units
:
A
Glycolysis, Krebs’ cycle and electron transport system are meant for ATP synthesis in different steps, ATP is the energy currency of the cell.

Answer: Option A. -> ATP in small stepwise units
:
D
Endergonic reaction is one that absorbs energy. All the reactions given here give out energy and are exergonic reactions.

Answer: Option D. -> Succinate dehydrogenase
:
D
Succinate dehydrogenase enzyme is present on inner membrane of mitochondria and is a part of the complex II in the ETC. It catalyses the oxidation of succinate to fumarate in the Kreb's cycle and channels the FADH2 produced during this reaction into the ETC.

Answer: Option A. -> Anaerobic respiration
:
A
Cyanide is a deadly poison of respiration and inhibit the activity of cytochrome –coxidase complex (which contains cytochromeaand cytochromea₃) of the electron transport chain inaerobic respiration. Thus, no proton gradient will be established and no ATP will be formed. As the reoxidationof NADH and FADH₂ceases, due to the blockageof the ETC, the availability of hydrogen acceptors like NAD⁺and FADfor Kreb’s cycle and glycolysis pathways also ceases. Thus stopping respiration. In anaerobic respiration the electron acceptors NAD+ and FADH2 can be regenerated anaerobically and therefore anaerobic respiration is a cyanide resistant pathway.

Answer: Option A. -> All living cells
:
A
Glycolysis is a series of reactions that takes place in the cytoplasm of all prokaryotes and eukaryotes. The role of glycolysis is to produce energy (both directly and by supplying substrate for the citric acid cycle and oxidative phosphorylation) and to produce intermediates for biosynthetic pathway.

Answer: Option C. -> A proton gradient forms across the inner membrane
:
C
As per chemiosmotic hypothesis ATP synthetase becomes active in ATP formation only where there is a protein gradient having a higher concentration of H+ or protons on the inner side as composed to the outer side

Answer: Option A. -> Oxidation of pyruvic acid
:
A
In aerobic respiration the first CO2 is liberated during oxidation of pyruvate. Here pyruvate a 3C compound is broken down to acetate, a 2C compound and linked to CoA to form acetyl CoA. The Carbon lost from pyruvate is released as CO2. And the acetyl CoA formed is funnelled into the Kreb's cycle.

Answer: Option B. -> Neither O2 is used, nor CO2 is liberated
:
B
In lactic acid fermentation neither $O_2$ is used nor$C{O}_2$ is liberated as it is anaerobic respiration.