03/12 03 Cell Structure and Organization Free Online FlashCards

What are the three statements of cell theory?

Cell theory states that all organisms consist of one or more cells, the cell is life’s basic structural and functional unit, and all cells arise from pre-existing cells.

How is total microscope magnification calculated?

Total magnification equals ocular magnification multiplied by objective magnification. A 10× eyepiece and 40× objective produce 400× total magnification.

How do resolution and magnification differ?

Resolution is the ability to distinguish two nearby structures as separate. Magnification enlarges an image, but magnification without improved resolution produces a larger, blurry image.

What is the nucleoid?

A nucleoid is the region of a prokaryotic cell containing its main chromosome. It is not enclosed by a membrane-bound nucleus.

Why does cell size affect material exchange?

As a cell becomes larger, its volume increases faster than its surface area, so its surface-area-to-volume ratio decreases. This can limit exchange with the environment.

What does the fluid mosaic model describe?

The fluid mosaic model describes the plasma membrane as a dynamic phospholipid bilayer containing a mosaic of proteins, carbohydrates, and other lipids.

What is the main role of the rough ER?

The rough ER synthesizes and begins processing proteins destined for secretion, membranes, or lysosomes. Its surface is covered with ribosomes.

What does the Golgi apparatus do?

The Golgi apparatus modifies, sorts, and packages proteins and lipids received from the endoplasmic reticulum into new vesicles.

What is the function of lysosomes?

Lysosomes are membrane-bound compartments containing hydrolytic enzymes that digest macromolecules, worn-out organelles, and material taken into the cell.

Why are mitochondrial cristae important?

Cristae are folds of the mitochondrial inner membrane. They increase surface area for electron transport and ATP synthesis.

What are grana and stroma in a chloroplast?

Chloroplast thylakoids are flattened membrane sacs often stacked into grana; the surrounding fluid is the stroma. These structures support photosynthesis.

What are three functions of microtubules?

Microtubules organize organelle movement, form the spindle during cell division, and contribute to cilia and flagella. They are composed of tubulin.