Study Guide: Photosynthesis and Cell Cycle (General Biology, Chapter 12)

Photosynthesis and Cell Cycle: Key Study Topics

Overview

This study guide covers essential concepts from Chapter 12, focusing on photosynthesis and the cell cycle. It is designed to help students prepare for exams by outlining major terms, processes, and comparisons relevant to General Biology.

Key Terms and Definitions

• Cell division: The process by which a cell splits into two daughter cells.

• Genome: The complete set of genetic material in an organism.

• Chromosome: A structure composed of DNA and proteins that carries genetic information.

• Chromatin: The complex of DNA and proteins that forms chromosomes within the nucleus.

• Gametes: Reproductive cells (sperm and egg) that carry half the genetic information of an organism.

• Somatic cells: All body cells except gametes.

• Mitotic phase: The phase of the cell cycle during which cell division occurs.

• Interphase: The phase of the cell cycle when the cell grows and DNA is replicated.

Cell Cycle and Its Phases

The cell cycle consists of a series of stages that prepare a cell for division and ensure accurate genetic transmission.

• Phases of the cell cycle:

  • G1 phase: Cell growth and preparation for DNA replication.

  • S phase: DNA synthesis and replication.

  • G2 phase: Further growth and preparation for mitosis.

  • M phase (Mitosis): Division of the nucleus and cytoplasm.

• Mitotic spindle: Structure made of microtubules that separates chromosomes during mitosis.

• Cytokinesis: Division of the cytoplasm, resulting in two separate cells.

Chromosome Structure and Function

• Sister chromatids: Identical copies of a chromosome connected by a centromere.

• Centromere: Region where sister chromatids are joined.

• Kinetochore: Protein structure on chromatids where spindle fibers attach during cell division.

Mechanisms of Chromosome Movement

• Chromosomes move during mitosis due to the action of spindle fibers and motor proteins.

• Microtubules attach to kinetochores and pull chromatids apart during anaphase.

Regulation of the Cell Cycle

• Checkpoints: Control points where the cell cycle can be halted until certain conditions are met (e.g., DNA integrity, proper chromosome attachment).

• Cyclins and cyclin-dependent kinases (CDKs): Proteins that regulate progression through the cell cycle.

Comparison: Mitosis vs. Meiosis

Feature	Mitosis	Meiosis
Number of divisions	One	Two
Number of daughter cells	Two	Four
Genetic composition	Identical to parent	Genetically unique
Role	Growth, repair	Sexual reproduction

Photosynthesis: Overview

Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose.

• Light reactions: Occur in the thylakoid membranes; convert solar energy to chemical energy (ATP and NADPH).

• Calvin cycle: Occurs in the stroma; uses ATP and NADPH to fix carbon dioxide and produce glucose.

Key Equations

• Photosynthesis overall equation:

$6CO_2 + 6H_2O + light \rightarrow C_6H_{12}O_6 + 6O_2$

• Cell cycle regulation (CDK activity):

$\text{CDK Activity} = \text{Cyclin concentration} \times \text{CDK concentration}$

Experimental Techniques and Applications

• Use of fluorescent labeling to track chromosome movement.

• Microscopy to observe cell division stages.

• Genetic analysis to study mutations affecting the cell cycle.

Additional info:

• Some topics inferred from the study guide include the importance of checkpoints, the role of cyclins/CDKs, and the comparison between mitosis and meiosis.

• Students should be familiar with diagrams of the cell cycle and mitosis, as well as experimental evidence supporting cell cycle regulation.