If pyruvate-2-14C (pyruvate with the middle carbon atom radioactively labeled) is provided to actively respiring mitochondria, most of the radioactivity will be incorporated into citrate. Trace the route whereby radioactively labeled carbon atoms are incorporated into citrate, and indicate where in the citrate molecule the label will first appear.

The middle carbon atom of pyruvate in the TCA cycle becomes the carboxyl carbon of acetate and hence the newly added (upper) carboxyl group in citrate

Explanation:

Before entering the TCA cycle, pyruvate is converted into Acetyl-CoA by  oxidative decarboxylation of pyruvate. 1st two carbons of glucose to be fully oxidized. This reaction is catalyzed by Pyruvate dehydrogenase.

The middle carbon atom of the pyruvate in the TCA cycle becomes the carboxyl carbon of the acetate as the carboxyl group is removed from the pyruvate , releasing CO2. NAD is reduced to NADH. Acetyl group is transferred to coenzyme-A , resulting in acetyl coA

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !