Calvin Cycle and Photosynthesis

These flashcards cover key concepts related to the Calvin cycle, photosynthesis, DNA repair, mutations, and genetic transcription processes.

Calvin Cycle

A series of biochemical reactions that take place in the chloroplasts of photosynthetic organisms, converting carbon dioxide and other compounds into glucose.

ATP

A molecule that carries energy within cells. In the Calvin cycle, ATP is used to convert 3-PGA into G3P.

NADPH

An electron carrier molecule that provides reducing power for the Calvin cycle.

RuBP (Ribulose bisphosphate)

A five-carbon sugar that is carboxylated by RuBisCO in the first step of the Calvin cycle.

RuBisCO

The enzyme that catalyzes the first step of the Calvin cycle, fixing carbon dioxide to RuBP.

Photorespiration

A process where RuBisCO binds with oxygen instead of carbon dioxide, leading to a waste of energy and loss of fixed carbon.

C4 Photosynthesis

A pathway in some plants that spatially segregates the initial carbon fixation from the Calvin cycle to minimize photorespiration.

CAM Photosynthesis

A pathway in some plants that temporally segregates the initial carbon fixation at night from the Calvin cycle during the day.

PGA (3-Phosphoglycerate)

A three-carbon molecule produced in the Calvin cycle during the carbon fixation phase.

G3P (Glyceraldehyde-3-phosphate)

A three-carbon sugar produced in the Calvin cycle; used to form glucose and regenerate RuBP.

Malate

A four-carbon compound produced during the initial carbon fixation step in C4 plants.

NADPH's role in the Calvin cycle

Provides high-energy electrons for the reduction phase of the Calvin cycle.

Glucose

The primary product of photosynthesis used as an energy source by plants and other organisms.

C3 Photosynthesis

A type of photosynthesis that occurs in plants like wheat and rice, where the Calvin cycle directly fixes CO2.

Light-dependent reactions

The first stage of photosynthesis where sunlight is converted to ATP and NADPH, taking place in the thylakoid membranes.

Stomata

Small openings on the surface of leaves that allow for gas exchange, including the intake of CO2 and release of O2.

Cyclic Photophosphorylation

A type of photophosphorylation that produces ATP without NADPH, operating in certain light-dependent reactions.

Krebs Cycle

The metabolic pathway that produces CO2 as a waste product during cellular respiration.

Glucose synthesis

The process of forming glucose from G3P in the Calvin cycle after multiple cycles.

Exons

Coding regions of RNA that are retained in mature mRNA after splicing.

Introns

Non-coding regions of RNA that are removed during the splicing of the mRNA transcript.

Photolyase

An enzyme that repairs thymine dimers in DNA using energy from light.

DNA replication check mechanisms

Processes such as proofreading by DNA polymerase that ensure the integrity of the newly synthesized DNA.

Transcription Factors

Proteins that bind to specific DNA sequences to enhance or inhibit the transcription of genes.

Operons

A cluster of genes transcribed as a single mRNA in prokaryotes, allowing coordinated expression.

Mutation

A change in DNA sequence that can lead to changes in the phenotype of an organism.

Frameshift Mutation

A mutation caused by insertions or deletions that shift the reading frame of the genetic message.

Silent Mutation

A mutation that does not change the resulting amino acid in the protein.

Missense Mutation

A mutation that results in a different amino acid being incorporated into a protein.

Nonsense Mutation

A mutation that creates a premature stop codon in the protein sequence.

Degradation

The breakdown of molecules, often referring to the enzymatic digestion of RNA.

Five Prime Cap

A modification added to the 5' end of eukaryotic mRNA for stability and to assist in ribosome binding.

Poly A Tail

A long sequence of adenine nucleotides added to the 3' end of mRNA molecules for stability and export from the nucleus.