BIO CHAPT 4

What is the cell theory?

1) All living organisms are made of one or more cells,

2) All life’s chemical reactions occur in cells,

3) All cells come from pre-existing cells,

4) Cells contain hereditary information (DNA).

What are the main differences between prokaryotic and eukaryotic cells?

• Prokaryotes: Single-celled, circular DNA (in nucleoid), no nucleus or organelles, age ~3.5 bya.
  
  

• Eukaryotes: Single or multicellular, linear DNA, nucleus & membrane-bound organelles, age ~1.5 bya.
  
  

What structures are unique to prokaryotic cells?

Capsule (protection/adhesion), pili (DNA transfer), and flagella (movement).

What theory explains the origin of mitochondria and chloroplasts?

Endosymbiosis: ancient eukaryotes engulfed aerobic and photosynthetic prokaryotes, which became mitochondria and chloroplasts.

What is the function of the nucleus?

Stores DNA, controls cell activities, directs protein synthesis.

What is the function of ribosomes?

Make proteins by linking amino acids.

What is the function of the endoplasmic reticulum (ER)?

• Rough ER: Protein synthesis (ribosomes attached).
  
  

Smooth ER: Lipid synthesis, detoxification.

What is the function of the Golgi apparatus?

Modifies, sorts, and ships proteins and lipids.

What is the function of mitochondria?

Cellular respiration – produces ATP (energy).

What is the function of chloroplasts? (Plant only)

Photosynthesis – converts solar energy into chemical energy (glucose).

What is the function of the lysosome? (Animal only)

 Breaks down waste, macromolecules, and old organelles.

What is the function of the vacuole? (Large in plants)

: Stores water, nutrients, waste; provides structural support in plants.

What is the function of the cell wall? (Plant, fungi, some protists)

 Provides structure, protection, and prevents over-expansion.

What is the function of the plasma membrane?

Selectively controls what enters and exits the cell; communication.