NEET-PG 2015 — Biochemistry

Q: APAF-1 is involved in the activation of which of the following caspases?

Caspase 9. ***Caspase 9*** - **APAF-1** (Apoptotic Protease Activating Factor-1) is a key component of the **apoptosome**, which is formed in response to intrinsic apoptotic signals. - The apoptosome recruits and activates **pro-caspase 9**, leading to its proteolytic cleavage and activation into **caspase 9**. *Caspase 8* - **Caspase 8** is primarily involved in the **extrinsic apoptotic pathway**, activated by cell surface death receptors and DISC (Death-Inducing Signaling Complex) formation. - It is not directly activated by APAF-1, which is specific to the intrinsic pathway. *Caspase 10* - **Caspase 10** is also an initiator caspase often associated with the **extrinsic apoptotic pathway**, similar to caspase 8. - Its activation typically occurs within the DISC and not through the apoptosome complex involving APAF-1. *Caspase 3* - **Caspase 3** is an **effector caspase** that is activated by upstream initiator caspases (like caspase 9 or caspase 8) in both intrinsic and extrinsic apoptotic pathways. - While it's a crucial caspase in apoptosis, it is too far downstream and not directly activated by APAF-1; APAF-1 activates caspase 9, which then activates caspase 3.

Q: Spectroscopy primarily studies the interaction between _____ and matter.

Electromagnetic radiation. ***Electromagnetic radiation*** - **Spectroscopy** is the study of the interaction between **matter** and **electromagnetic radiation**, which includes a range from radio waves to gamma rays. - This interaction provides information about the **structure, composition, and physical properties** of matter. *Alpha particles* - **Alpha particles** are composed of two protons and two neutrons, essentially a helium nucleus. - While they interact with matter, their study is more characteristic of **nuclear physics** and **radioactivity**, not the primary focus of spectroscopy. *Protons* - **Protons** are subatomic particles with a positive charge found in the nucleus of an atom. - Their interaction with matter is studied in various fields, but spectroscopy primarily uses **electromagnetic radiation** to probe atomic and molecular energy levels. *Positrons* - **Positrons** are the antimatter counterparts of electrons, having a positive charge. - Their interaction with matter leads to **annihilation events** producing gamma rays, which is fundamental to techniques like Positron Emission Tomography (**PET**), but not the broad field of spectroscopy.

112 Questions — Page 12 of 12

Q111

APAF-1 is involved in the activation of which of the following caspases?

Q112

Spectroscopy primarily studies the interaction between _____ and matter.