PAPHY LAB - WS1: Cellular Level of Organization

Cellular Level of Organization

1. Anatomy of the Cell

2. Membrane Transport

3. Cell Division

Nucleus

• It is the control center

• Contains DNA

Plasma Membrane

• Selectively permeable

• Protects the cell

Cytoplasm

It contains organelles for metabolism.

Ribosomes

Organelle responsible for protein synthesis

Smooth Endoplasmic Reticulum (ER)

Organelle responsible for lipid synthesis and detoxification

Rough Endoplasmic Reticulum (ER)

Organelle responsible for protein synthesis (with ribosomes attached).

Golgi Apparatus

Organelle that modifies, sorts, and packages proteins

Lysosomes

Organelle responsible for the digestion of waste materials

Peroxisomes

Organelle responsible for detoxification

Proteasomes

Organelle that degrades unneeded proteins

Mitochondria

• Organelle responsible for ATP production

• Powerhouse of the cell

Microtubules

Organelle that maintains cell shape and assists in transport

Cilia and Flagella

Organelle responsible for movement of substances/cell itself

Passive Transport

Transport that does not require ATP

Simple Diffusion

Movement of molecules from high to low concentration

Facilitated Diffusion

Transport via carrier proteins

Osmosis

Diffusion of water through a selectively permeable membrane

Active Transport

Transport that requires ATP

Primary Active Transport

Uses ATP directly (e.g. Na+ / K+ pump)

Secondary Active Transport

Uses energy from ion gradients

Vesicular Transport

• Endocytosis (into the cell)

• Exocytosis (out of the cell)

Endocytosis

• Into the cell

  • Phagocytosis

  • Pinocytosis

Exocytosis

• Out of the cell

  • Secretion of substances

Mitosis

Division of somatic cells (produces identical daughter cells)

Stages of Mitosis

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

Prophase

This is the stage where:

• Chromatin condenses into visible chromosomes.

• The nuclear envelope begins to break down, and the mitotic spindle starts forming from centrioles.

Metaphase

This is the stage where:

• Chromosomes align in the center of the cell (metaphase plate).

• Spindle fibers attach to the centromeres of the chromosomes.

Anaphase

This is the stage where:

• Sister chromatids are pulled apart to opposite poles of the cell by the spindle fibers. This ensures that each daughter cell receives identical genetic material.

Telophase

This is the stage where:

• Chromosomes decondense back into chromatin, the nuclear envelope re-forms around each set of chromosomes, and the spindle fibers break down.

Cytokinesis

• Division of cytoplasm

• Forms two identical daughter cells

Meiosis

Division of reproductive cells (gametes)