Unit 2 – Bioenergetics + Cell Signaling

Where does glycolysis take place? What are the beginning and ending products?

Takes place in the cytoplasm, starts with glucose, ends with pyruvate, ATP and NADH

Where does the TCA cycle occur? What adds carbon to the cycle? What are the outputs and where do they go?

Takes place in the mitochondrial matrix

Acetyl-CoA adds carbon

Output are CO₂, NADH, FADH₂ , and ATP

Where does the electron transport chain occur? What is the ultimate purpose of these steps? What are the inputs and outputs?

Takes place in inner mitochondrial membrane

Purpose is to create a pool of H+ ions for a proton gradient to power ATP synthesis

Inputs NADH, FADH_2, O₂

Outputs H₂O, H+ gradient, ATP

What powers ATP synthase? What does this enzyme make? What is the output used for?

Powered by the flow of H+ ions down its gradient

Enzyme makes ATP

Output used for cellular work, muscle contraction, active transport etc.

Where do the light reactions occur in plant cells? What are inputs/outputs?

Occur in the thylakoid membrane of the chloroplast

Inputs are light, H₂O, ADP, NADP+

Outputs are O₂, ATP, NADPH

Where does the Calvin cycle occur in plant cells? What are inputs/outputs?

Occurs in the stroma of chloroplasts

Inputs are CO₂, ATP, and NADPH

Outputs are sugar, NADP+, and ADP

In mitochondria and chloroplasts, where is [H+] the highest?

Mitochondria- intermembrane space

Chloroplasts-thylakoid lumen

How are the processes that occur in mitochondria and chloroplasts linked biochemically?

ATP/NADPH are made in chloroplasts during light reactions, glucose made by photosynthesis feeds into mitochondria for ATP production. Simply, chloroplasts convert solar to chemical energy and mitochondria converts it to usable ATP

Indicate where signal reception, transduction, and response occur for a polar signaling molecule.

Reception occurs in on membrane receptors in extra cellular fluid

Transduction occurs in cytoplasmic signaling cascades in the cytoplasm

Response occurs in the cytoplasm

What is happening generally at signal reception, transduction, and response?

Reception- signal binds to receptor, changes shape/activity

Transduction- relay molecules amplify and pass signal along

Response- cell changes behavior

How do phosphate groups facilitate the “on/off” modes of different molecules used in signaling pathways (include both kinases and GCPRs in your description)?

Kinases- add phosphate group to protein, activating/deactivating protein

Phosphatases- remove phosphate group

GPCR-binds to ligand, activate G proteins to turn enzyme on/off by phosphorylation cascades

Phosphorylation- phosphate group added, acts as switch