Cell Biology Flashcards

Prokaryotic Cells

• Prokaryotic cells are simple, unicellular organisms without a nucleus or membrane-bound organelles.
• They have a rigid structure called the cell wall that provides support and shape.

Fimbriae

• Fimbriae are surface appendages that allow bacteria to adhere to surfaces.
• They are crucial for the colonization of surfaces and contribute to bacterial virulence.

Capsule Function

• A bacterium's capsule serves a protective role against environmental threats and immune responses.
• Capsules can enhance a bacterium's ability to cause disease.

Nucleoid Region

• The nucleoid region is where the bacterial DNA is located, indicated by letter D in diagrams.
• Unlike eukaryotic cells, bacteria do not possess a true nucleus; their DNA is concentrated in the nucleoid.

DNA Location

• Bacterial DNA is found exclusively in the nucleoid region, as bacteria lack nuclei.

Protein Synthesis

• Ribosomes are the sites of protein synthesis within the bacterial cell.
• They facilitate the assembly of amino acids into polypeptides (proteins).

Cell Wall Structure

• The cell wall is a rigid feature outside the plasma membrane that supports and protects the bacterium.
• It plays a critical role in maintaining cell shape and preventing lysis in hypotonic environments.

Plasma Membrane Function

• The plasma membrane acts as a selective barrier, regulating the entry of nutrients and the exit of waste.
• It maintains homeostasis within the bacterial cell.

Protein Synthesis Overview

• The first step in polypeptide synthesis is the transcription of DNA into messenger RNA, which occurs in the nucleus.
• Transcription involves transferring genetic information from DNA to mRNA.

Mitochondria Presence

• Mitochondria are essential organelles found in all eukaryotic cells, including both plant and animal cells.
• They are involved in energy production through cellular respiration.