Cells & Microscopes
Which organelle contains most of a cell’s DNA and controls its activities?
The nucleus.
Which parts of a phospholipid are hydrophilic (attracted to water), and which are hydrophobic (repel water)?
The heads are hydrophilic, and the tails are hydrophobic.
Put these in order from simplest to most complex: organ, cell, organ system, tissue.
Cell → tissue → organ → organ system.
What is the name of a plant’s growth response to light?
Phototropism.
What has a neck but no head?
A bottle.
What is the main difference between prokaryotic and eukaryotic cells?
Eukaryotic cells have a nucleus and membrane-bound organelles. Prokaryotic cells do not.
What is the movement of water across a selectively permeable membrane called?
Osmosis.
Which leaf cells control the opening and closing of stomata?
Guard cells.
Which vascular tissue transports water and minerals from the roots, and which transports sugars throughout the plant?
Xylem transports water and minerals. Phloem transports sugars.
What has to be broken before you can use it?
An egg.
What are the three principles of cell theory?
All living things are made of cells; cells are the basic unit of structure and function in living things; all cells come from pre-existing cells.
Glucose moves from high to low concentration through a membrane protein without using cellular energy. What process is occurring?
Facilitated diffusion.
Which leaf tissue contains many chloroplasts and carries out most of the leaf’s photosynthesis?
Palisade tissue.
What is turgor pressure? What does it help control?
Turgor pressure is the pressure that helps guard cells open and close the stomata.
What has cities but no houses, forests but no trees, and rivers but no water?
A map.
A microscope has a 10× eyepiece and a 40× objective lens. What is the total magnification?
400×.
A root cell absorbs minerals even though the mineral concentration is already higher inside the cell than in the soil. What process does it use, and why is energy needed?
Active transport. Energy is needed to move minerals against their concentration gradient.
How does a root hair’s shape help it absorb water and minerals?
Its long, thin shape increases its surface area relative to its volume, providing more membrane area for absorption.
How do cohesion and adhesion help water move upward through xylem?
Cohesion keeps water molecules together, maintaining a continuous column. Adhesion helps water cling to the xylem walls as transpiration pulls it upward.
What disappears as soon as you say its name?
Silence.
How did Pasteur’s swan-neck flask experiment provide evidence for biogenesis?
The broth stayed free of microorganisms when the flask’s curved neck trapped dust and microbes. Microorganisms grew when they could reach the broth, showing that life came from existing life.
An animal cell contains 1% non-penetrating solute and is placed in a solution containing 4% solute. Is the solution hypotonic, hypertonic, or isotonic? What happens to the cell?
Hypertonic. Water moves out of the cell, causing it to shrink.
A cube-shaped cell has sides measuring 2 cm. Calculate its surface area, volume, and surface-area-to-volume ratio.
Surface area = 24 cm²; volume = 8 cm³; SA:V = 3:1.
Write the balanced chemical equation for photosynthesis.
6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂.
Two fathers and two sons go fishing. They catch three fish, and each person takes home one fish. How is this possible?
There are only three people: a grandfather, his son, and his grandson.