TEAS® Science Study Guide
The Cell
The cell is the basic unit of life. Every question in this half connects back to it.
Two cell types
- Prokaryotic — No nucleus, no membrane-bound organelles. Small and simple. Bacteria.
- Eukaryotic — Has a nucleus and membrane-bound organelles. Larger and complex. Plants, animals, fungi, protists.
Key organelles and their jobs
- Nucleus — Contains DNA; directs the cell’s activities. The control center.
- Mitochondria — Produce energy (ATP) through cellular respiration. The "powerhouse."
- Ribosomes — Build proteins.
- Endoplasmic reticulum — Rough ER (studded with ribosomes) makes proteins; smooth ER makes lipids.
- Golgi apparatus — Packages and ships proteins.
- Lysosomes — Break down waste and worn-out parts.
- Cell membrane — Selectively permeable boundary; controls what enters and exits.
Plant cells have three extras
Cell wall (rigid support), chloroplasts (photosynthesis), and a large central vacuole (storage). Animal cells have none of these.
Moving substances across the membrane
- Passive transport — No energy needed. Includes diffusion (particles spread from high to low concentration) and osmosis (diffusion of water).
- Active transport — Requires energy (ATP) to move substances against the concentration gradient.
Terms to know
- Organelle — A specialized structure inside a cell.
- Selectively permeable — Lets some substances through but not others.
- Osmosis — Movement of water across a membrane.
- ATP — The cell’s energy currency.
What the TEAS asks most
- Which organelle produces energy? Mitochondria.
- What do ribosomes make? Proteins.
- What do plant cells have that animal cells don’t? Cell wall, chloroplasts, large vacuole.
- Which transport type requires energy? Active transport.