Cell Theory and Scientists
Who first used the term "cell" after observing cork under a microscope?
Robert Hooke
Which organelle is the site of photosynthesis in plant cells?
Chloroplast
What are the two main types of molecules that make up the cell membrane's bilayer?
Phospholipids and proteins
Is simple diffusion an active or passive transport process?
Passive transport
What is the primary purpose of mitosis in multicellular organisms?
To produce genetically identical somatic (body) cells for growth, tissue repair, and asexual reproduction in some organisms.
Which two scientists are credited with proposing that plants and animals are made of cells?
Matthias Schleiden (plants) and Theodor Schwann (animals)
What organelle is responsible for producing ATP energy in eukaryotic cells?
Mitochondria
What is the role of cholesterol in the cell membrane?
Cholesterol helps stabilize membrane fluidity, preventing it from becoming too rigid or too fluid.
What is osmosis?
The diffusion of water across a semi-permeable/selectively permeable membrane.
During which stage of mitosis do sister chromatids separate and move to opposite poles?
Anaphase
Which scientist stated that "all cells come from pre-existing cells"?
Rudolf Virchow
Which organelle modifies, sorts, and packages proteins for secretion?
Golgi Apparatus/Golgi Bodies
Fluid Mosaic
Define facilitated diffusion and give one example of a molecule that uses it.
Facilitated diffusion is passive transport of molecules across a membrane via transport proteins; example: glucose transport via GLUT transporters or ions through ion channels.
Put these mitosis stages in the correct order: metaphase, anaphase, prophase, telophase.
Prophase, Metaphase, Anaphase, Telophase
Which early scientist observed single-celled organisms (animalcules) and improved microscope lenses?
Antonie van Leeuwenhoek
Name the organelle(s) involved in protein synthesis and briefly state the role of each. (Hint: There's two!)
Ribosomes (make proteins) and rough ER (site where ribosomes are attached and initial protein folding/processing occurs).
What are membrane proteins that help move substances across the membrane without using energy called?
Channel proteins or carrier proteins (facilitated diffusion proteins)
Explain the difference between active transport and passive transport, naming one cellular structure involved in active transport.
Active transport requires energy (ATP) to move substances against their concentration gradient; example: sodium-potassium pump (Na+/K+ ATPase).
Describe two key events that occur during prophase.
Model answer: During prophase, chromatin condenses into visible chromosomes and the nuclear envelope begins to break down; spindle fibers begin to form from centrosomes and move to opposite poles.
Explain how the discoveries of Hooke, Leeuwenhoek, Schleiden, Schwann, and Virchow together support the modern cell theory.
Model answer: Hooke named the cell after observing cell walls in cork; Leeuwenhoek observed living single-celled organisms; Schleiden and Schwann proposed that plants and animals are composed of cells; Virchow stated that cells arise from preexisting cells. Together these observations support the ideas that cells are the basic unit of life and that all cells come from other cells.
Describe the differences between the rough endoplasmic reticulum and smooth endoplasmic reticulum and give one specific function for each.
Model answer: The rough ER has ribosomes on its surface and is involved in synthesizing and folding proteins for export or membrane insertion; the smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.
What is the optimal solution for plants? Animals?
Hypotonic (plants); Isotonic (animals)
A red blood cell is placed in a solution and it swells and bursts. Describe the tonicity of the solution and explain why this happened in terms of water movement.
The solution is hypotonic relative to the red blood cell (lower solute concentration outside), so water moved into the cell by osmosis, causing it to swell and burst (lyse).
Explain how mitosis and cytokinesis together result in two genetically identical daughter cells. Include mention of what happens to the chromosome number.
Model answer: During mitosis, duplicated chromosomes are separated so each set of sister chromatids is pulled to opposite poles; during cytokinesis the cytoplasm divides, forming two daughter cells. Because chromosomes were duplicated during S phase and then evenly divided, each daughter cell has the same chromosome number as the original parent cell and is genetically identical.