🧬 Chaoter 4 bio

3 Rules of Cell Theory

1. All organisms are made of cells.
2. Cells are the smallest living things.
3. Cells come from pre-existing cells.

(Mnemonic: 'All Cells Come')

4 Structures Present in ALL Cells

1. DNA
2. Cytoplasm
3. Plasma membrane
4. Ribosomes

(Mnemonic: DCPR = 'Don't Cook Pizza Raw')

Key Characteristics of Prokaryotes

Lack a nucleus (DNA is in a nucleoid) and lack membrane-bound organelles. Examples include Bacteria and Archaea.

Key Characteristics of Eukaryotes

Contain a membrane-bound nucleus and membrane-bound organelles. Examples include Plants, Fungi, Animals, and Protists.

Nucleolus Function

Produces ribosomal subunits (acts as the ribosome factory inside the nucleus).

Chromatin vs. Chromosomes

Chromatin: Loose, unwound DNA material (like tangled string). Chromosomes: Packaged, tightly condensed DNA ready for cell division (like a packed suitcase).

Ribosomes Function

Synthesize proteins by reading RNA. Can be free in the cytoplasm or bound to the rough ER/nuclear envelope.

Components of the Endomembrane System

1. Endoplasmic Reticulum (ER)
2. Golgi apparatus
3. Lysosomes
4. Vacuoles
5. Vesicles

(Mnemonic: 'Every Good Little Vehicle')

Rough ER vs. Smooth ER

Rough ER: Studded with ribosomes; synthesizes proteins. Smooth ER: Lacks ribosomes; synthesizes lipids.

Golgi Apparatus (Cis vs. Trans Face)

Cis Face: Receiving side that takes in transport vesicles from the ER. Trans Face: Shipping side where vesicles depart for their destinations.

Lysosome Function

Acts as the cell's garbage disposal, using digestive enzymes to break down macromolecules, waste, and damaged organelles.

Tonoplast

The membrane surrounding the central vacuole in plant cells.

Mitochondria Function

Powerhouse of the cell; carries out cellular respiration to produce ATP.

Chloroplast Function

Site of photosynthesis in plant cells; contains chlorophyll to absorb sunlight and produce sugars and ATP.

3 Cytoskeleton Fibers (Thickest to Thinnest)

1. Microtubules (thickest)
2. Intermediate filaments (in-between)
3. Microfilaments (thinnest)

Structures Present in Plant Cells but Absent in Animal Cells

1. Chloroplasts
2. Cell wall (made of cellulose)
3. Large central vacuole