ASVAB Practice

Cell Biology

The cell is the basic structural and functional unit of all living things.

Components in both animal and plant cells: - Cell membrane: Phospholipid bilayer controlling what enters/exits. Selectively permeable. - Nucleus: Contains DNA; controls all cell activities. - Mitochondria: "Powerhouse" — site of aerobic respiration; produces ATP. - Ribosomes: Synthesize proteins. Found on rough ER or floating in cytoplasm. - Endoplasmic reticulum (ER): Transport network. Rough ER makes proteins; smooth ER makes lipids. - Golgi apparatus: Processes and packages proteins for export or internal use. - Lysosomes: Contain digestive enzymes that break down waste and foreign material.

Found only in plant cells: - Cell wall: Rigid cellulose layer providing structural support. (Animal cells do NOT have this.) - Chloroplasts: Site of photosynthesis; contain the green pigment chlorophyll. - Large central vacuole: Provides turgor pressure (keeps the plant firm).

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