Cell Structure and Types of Organisms Lecture Notes

Question-and-answer flashcards covering definitions, examples, microscope magnifications, plasma-membrane details, bacterial cell parts, and differences between plant and animal cells.

What is a multicellular organism?

An organism made up of more than one cell.

Give three examples of multicellular organisms mentioned in the lecture.

Fungus, animals, and plants.

What is a unicellular organism?

An organism made up of only one cell.

Give three examples of unicellular organisms provided in the lecture.

Euglena, Paramecium, and Yeast.

What is the maximum magnification of a compound microscope?

About 2000×.

What is the maximum magnification of an electron microscope?

About 500 000×.

What term describes the detailed structure of a cell observed with an electron microscope?

Ultrastructure.

Which cellular structures can be observed only with an electron microscope?

Extremely small cell structures such as the plasma membrane’s detailed layers and other ultrastructural features.

Describe the basic composition of the plasma membrane.

Two layers of lipid molecules with protein molecules floating within them.

What is the typical thickness of the plasma membrane?

Approximately 75–110 Å (Angstroms).

List four main functions of the plasma membrane.

Maintains cell shape and size, protects internal contents, regulates entry and exit of substances, and maintains homeostasis.

Name three structural components found in a bacterial cell.

Examples include pili, ribosomes, and a cell wall (others: capsule, flagellum, nucleoid, plasmid, plasma membrane, cytoplasm, food granule).

What circular DNA element separate from the nucleoid is found in many bacterial cells?

A plasmid.

Compare the typical size ranges of plant and animal cells.

Plant cells: about 10–100 µm; Animal cells: about 10–30 µm.

Name two organelles present in plant cells but absent in animal cells.

Cell wall and chloroplasts (also acceptable: large central vacuole, plasmodesmata).

Name two structures typically present in animal cells but usually absent in plant cells.

Lysosomes and centrioles.