Prokaryotic cells

Prokaryotic Cells Flashcards (Knowt Ready)

Front: What is a prokaryote?

Back: A unicellular organism that lacks a true nucleus and membrane-bound organelles; belongs to Bacteria or Archaea.

---

Front: What four structures do ALL prokaryotic cells have?

Back: Plasma membrane, cytoplasm, DNA (nucleoid), and 70S ribosomes.

---

Front: Where is DNA found in prokaryotes?

Back: In the nucleoid, which is not surrounded by a nuclear membrane.

---

Front: Do prokaryotes have membrane-bound organelles?

Back: No.

---

Front: What is found in the cytoplasm?

Back: Water, ribosomes, nucleoid, plasmids, inclusion bodies, proteins, carbohydrates, lipids, and ions.

---

Front: What are plasmids?

Back: Small circular double-stranded DNA molecules that replicate independently.

---

Front: Why are plasmids important?

Back: They often carry genes for antibiotic resistance, toxins, and other advantageous traits.

---

Front: Are plasmids required for bacterial survival?

Back: No, but they improve survival under stressful conditions.

---

Front: What type of ribosomes do prokaryotes have?

Back: 70S ribosomes (50S + 30S).

---

Front: What does the 'S' in 70S stand for?

Back: Svedberg unit.

---

Front: Functions of the plasma membrane?

Back: Selective permeability, transport, metabolic enzymes, separates inside from outside.

---

Front: Composition of the plasma membrane?

Back: Phospholipid bilayer with hydrophilic heads and hydrophobic tails.

---

Front: Difference between passive and active transport?

Back: Passive requires no ATP and moves down the gradient; active requires ATP and moves against the gradient.

---

Front: Define osmosis.

Back: Movement of water across a selectively permeable membrane; water follows salt.

---

Front: Why do salt and sugar preserve food?

Back: They create a hypertonic environment that pulls water out of bacteria.

---

Front: What is the bacterial cell wall made of?

Back: Peptidoglycan composed of NAG and NAM.

---

Front: Functions of the bacterial cell wall?

Back: Maintains shape, protection, prevents osmotic lysis.

---

Front: How does penicillin kill bacteria?

Back: Prevents peptidoglycan cross-linking, weakening the wall and causing lysis.

---

Front: Characteristics of Gram-positive bacteria?

Back: Thick peptidoglycan, teichoic acids, no outer membrane, stain purple.

---

Front: Characteristics of Gram-negative bacteria?

Back: Thin peptidoglycan, outer membrane containing LPS.

---

Front: Which bacteria are generally more antibiotic resistant?

Back: Gram-negative bacteria.

---

Front: What makes acid-fast bacteria unique?

Back: They contain mycolic acid in the cell wall.

---

Front: Function of bacterial flagella?

Back: Motility; made of flagellin.

---

Front: What is chemotaxis?

Back: Movement toward or away from chemical stimuli.

---

Front: Difference between a run and tumble?

Back: Run = straight movement; tumble = reorientation.

---

Front: Function of fimbriae?

Back: Attachment to surfaces.

---

Front: Functions of pili?

Back: Attachment, gliding motility, and DNA transfer during conjugation.

---

Front: What is the glycocalyx?

Back: A capsule or slime layer surrounding some bacteria.

---

Front: Functions of the glycocalyx?

Back: Protection, adhesion, immune evasion, prevents desiccation, food storage.

---

Front: What are inclusion bodies?

Back: Storage granules for glycogen, sulfur, phosphate, or lipids.

---

Front: What are endospores?

Back: Dormant, highly resistant structures formed in harsh conditions.

---

Front: Which genera produce endospores?

Back: Bacillus and Clostridium.

---

Front: How do bacteria reproduce?

Back: Binary fission (asexual reproduction).

---