MLB 111 Cells and Cell structure

What are the three main principles of Cell Theory?

1. Cells are the fundamental units of life. 2. All living organisms are composed of cells. 3. All cells come from preexisting cells.

Why are most cells small?

As volume increases, surface area increases at a slower rate; thus, larger cells need more resources and produce more waste than they can handle.

What role does the cell membrane play regarding substances?

The cell membrane acts as a selectively permeable barrier, regulating the transport of substances in and out of the cell.

What is the definition of cytoplasm?

Cytoplasm is everything inside the cell, except for the nucleus.

What are organelles?

Membrane-enclosed compartments in eukaryotic cells that separate molecules and biochemical reactions from the rest of the cell.

How do prokaryotic cells differ from eukaryotic cells in size?

Prokaryotic cells range from 1–10 μm in diameter, while eukaryotic cells range from 10–100 μm.

What structure encloses the nucleoid in prokaryotic cells?

The cell membrane encloses the nucleoid, which is the region where the DNA is located.

What is the function of ribosomes in prokaryotic cells?

Ribosomes are complexes of RNA and proteins in the cytoplasm that serve as the sites of protein synthesis.

What is the primary role of lysosomes in a cell?

Lysosomes are compartments for the breakdown of food, other cells, or foreign objects using digestive enzymes.

What are the main components and functions of the endomembrane system?

The endomembrane system includes the cell membrane, nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles; it is involved in transport and communication within the cell.

What is the function of microfilaments in the cytoskeleton?

Microfilaments help the cell or parts of the cell move, determine and stabilize cell shape, and are involved in localized changes in cell shape.

What is the function of motor proteins associated with microtubules?

Motor proteins like kinesins and dyneins move materials along microtubules, enabling transport within the cell.

What is the role of the plant cell wall?

The plant cell wall provides support, acts as a barrier to infection, and contributes to plant form as cells expand.

Define plasmodesmata.

Plasmodesmata are cell membrane-lined channels between adjacent plant cells that connect their cytoplasms.

What is the function of peroxysomes?

Peroxysomes accumulate and break down toxic peroxide byproducts safely within the cell.

What distinguishes chloroplasts from mitochondria?

Chloroplasts are sites of photosynthesis and contain chlorophyll, while mitochondria are involved in ATP production through cellular respiration.