Cell Structure and Function Quiz
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Questions and Answers

Which of the following is a key distinction between prokaryotic and eukaryotic cells?

  • Prokaryotic cells have membrane-bound organelles, while eukaryotic cells do not.
  • Eukaryotic cells possess a true nucleus and membrane-bound organelles, while prokaryotic cells lack these. (correct)
  • Prokaryotic cells contain DNA, while eukaryotic cells do not.
  • Eukaryotic cells lack a plasma membrane, while prokaryotic cells have one.

What is the primary function of the plasma membrane in a cell?

  • To synthesize proteins.
  • To store the cell's genetic material.
  • To produce energy through cellular respiration.
  • To selectively control the movement of substances into and out of the cell. (correct)

Which of the following cell features is exclusive to prokaryotes?

  • A cell membrane.
  • Golgi apparatus.
  • Ribosomes
  • A circular chromosome. (correct)

How does the genetic material of a prokaryotic cell differ from that of a eukaryotic cell?

<p>Prokaryotic DNA is circular and located in the cytoplasm, while eukaryotic DNA is linear and contained within a nucleus. (A)</p> Signup and view all the answers

Which structure is responsible for producing copies of the cell in prokaryotes?

<p>Binary Fission (C)</p> Signup and view all the answers

What is the main structural component of a bacterial cell wall?

<p>Peptidoglycan (A)</p> Signup and view all the answers

Which of the following is a true statement about the reproduction methods of eukaryotic cells?

<p>Eukaryotes can reproduce both asexually through mitosis, and sexually through meiosis and fertilization (B)</p> Signup and view all the answers

What is the function of a flagellum in prokaryotic cells?

<p>To enable movement. (A)</p> Signup and view all the answers

Which of the following is NOT a characteristic of mitochondrial DNA?

<p>It undergoes homologous recombination. (C)</p> Signup and view all the answers

Mitochondrial myopathies are typically characterized by

<p>Neuromuscular disease symptoms. (C)</p> Signup and view all the answers

What is the primary function of lysosomes within a cell?

<p>Degrading macromolecules and cellular waste. (B)</p> Signup and view all the answers

Tay-Sachs disease results from a deficiency in which enzyme?

<p>Hexosaminidase A (B)</p> Signup and view all the answers

What is a common clinical finding in patients with infantile Tay-Sachs disease?

<p>A cherry-red spot on the retina. (B)</p> Signup and view all the answers

Hurler syndrome is caused by a defect in the enzyme:

<p>α-L-iduronidase (B)</p> Signup and view all the answers

What is the primary function of peroxisomes?

<p>Breakdown of very long chain fatty acids and detoxification. (D)</p> Signup and view all the answers

Which of the following is a known function of the endoplasmic reticulum (ER)?

<p>Serving as quality control for proteins and intracellular calcium storage. (C)</p> Signup and view all the answers

Proteins translated on the ER contain a signal sequence that does what?

<p>Directs the ribosome to the ER for translation, and is then cleaved off. (D)</p> Signup and view all the answers

Which of the following is NOT a main function of the Golgi apparatus?

<p>Synthesis of proteins (A)</p> Signup and view all the answers

What is the primary function of peptidoglycan in bacteria?

<p>Maintaining the structural integrity and osmotic balance of the cell. (B)</p> Signup and view all the answers

How do β-lactam antibiotics, such as penicillin, inhibit bacterial growth?

<p>By binding to and inactivating enzymes involved in the synthesis of peptidoglycan. (D)</p> Signup and view all the answers

How do glycopeptide antibiotics, such as vancomycin, interfere with bacterial cell wall synthesis?

<p>They bind to the D-alanine-D-alanine residues in peptidoglycan, preventing cross-linking. (D)</p> Signup and view all the answers

What is the consequence of inhibiting bacterial cell wall formation?

<p>Cell lysis due to the inability to withstand osmotic pressure. (C)</p> Signup and view all the answers

Which component of eukaryotic cells is responsible for generating most of the cellular energy?

<p>Mitochondria (B)</p> Signup and view all the answers

What is the primary function of flippases within the cell membrane?

<p>To mediate the exchange of phospholipids between the inner and outer leaflets of the lipid bilayer. (C)</p> Signup and view all the answers

What is the main purpose of the phospholipid bilayer in the plasma membrane?

<p>To act as a selectively permeable barrier to regulate the passage of molecules. (B)</p> Signup and view all the answers

Why is the plasma membrane described as a fluid structure?

<p>Because the phospholipids molecules can move laterally within the same monolayer. (B)</p> Signup and view all the answers

What component of the cell membrane makes it more rigid and less permeable?

<p>Cholesterol (B)</p> Signup and view all the answers

What is a key characteristic of transmembrane proteins?

<p>They span both layers of the plasma membrane, being exposed to both the extracellular and intracellular sides. (C)</p> Signup and view all the answers

What are glycolipids primarily involved in?

<p>Cell recognition and signaling. (B)</p> Signup and view all the answers

What structural feature of mitochondria is responsible for increasing its surface area?

<p>The cristae, which forms in-foldings in the inner membrane (B)</p> Signup and view all the answers

What is the significance of the difference in ion concentrations between the inside and outside of a cell?

<p>It sets up an electrochemical gradient. (C)</p> Signup and view all the answers

What is a unique characteristic of mitochondrial inheritance?

<p>Mitochondria are exclusively inherited from the mother. (A)</p> Signup and view all the answers

What is the shape of mitochondrial DNA (mtDNA)?

<p>Circular (plasmid) (D)</p> Signup and view all the answers

Flashcards

Cell

The fundamental unit of life, responsible for all living processes.

Prokaryotes

Single-celled organisms lacking a true nucleus and membrane-bound organelles.

Eukaryotes

More complex organisms with a true nucleus and membrane-bound organelles.

Plasma membrane

A phospholipid bilayer that regulates the passage of substances into and out of the cell.

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Nucleus

The control center of eukaryotic cells, containing the cell's DNA.

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Mitochondria

Organelles responsible for energy production in eukaryotic cells.

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Golgi apparatus

Organelles involved in the processing and packaging of proteins.

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Binary fission

Asexual reproduction in prokaryotes, where a cell divides into two identical daughter cells.

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Lysosomes

A small, membrane-bound organelle containing digestive enzymes (hydrolases) responsible for breaking down various macromolecules. Often referred to as the 'stomach of the cell'.

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Lysosomal Storage Diseases (LSDs)

A group of genetic disorders caused by the malfunction of lysosomes, resulting in the accumulation of undigested substances within the cell.

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Tay-Sachs Disease

An LSD caused by a deficiency in the enzyme hexosaminidase A, leading to the accumulation of ganglioside in neurons, resulting in neuronal cell death and severe neurological deterioration.

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Peroxisomes

A small, membrane-bound vesicle that provides a contained environment for oxidative reactions within the cell. Contains enzymes like catalase and is involved in the breakdown of very long chain fatty acids.

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Peroxisomal biogenesis disorders

Genetic disorders caused by defects in the formation or function of peroxisomes, leading to accumulation and/or deficiencies in specific molecules.

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Endoplasmic Reticulum (ER)

A continuous membrane-bound system of interconnected sacs and tubes that is involved in protein synthesis, folding, and transport. Also serves as a calcium store.

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Unfolded Protein Response (UPR)

A cellular mechanism triggered by the accumulation of unfolded proteins in the ER, leading to a response aimed at restoring protein folding and quality control.

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I-cell disease

A rare genetic disorder caused by a deficiency in an enzyme required for the proper glycosylation of proteins, leading to the accumulation of misfolded proteins in the lysosomes.

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Mitochondrial Myopathy

Mitochondria are organelles responsible for cellular respiration and ATP production. Mutations in their DNA can lead to a range of diseases termed mitochondrial myopathies.

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Peptidoglycan

A mesh-like layer in bacterial cell walls, composed of carbohydrate backbones cross-linked by peptide bridges.

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Cell Wall Inhibitors

A class of antibiotics that inhibit the formation of the bacterial cell wall, leading to cell lysis and death.

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β-lactam Antibiotics

A group of antibiotics, such as Penicillin, that inhibit the synthesis of peptidoglycan in bacteria by binding to and inactivating enzymes involved in its formation.

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Glycopeptide Antibiotics

A class of antibiotics, such as Vancomycin, that bind to the D-alanine-D-alanine residues in peptidoglycan, preventing its cross-linking and assembly.

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Cell Lysis

The process of a cell bursting due to an inability to withstand osmotic pressure.

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Phospholipid

A type of lipid that forms the basis of the plasma membrane, composed of a hydrophilic head and two hydrophobic tails.

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Selective Permeability

The characteristic of the plasma membrane that allows certain substances to pass through while blocking others.

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Membrane Proteins

Proteins embedded within the plasma membrane, acting as channels, carriers, receptors, or enzymes.

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Cholesterol

A type of lipid that makes up a significant portion of the plasma membrane, contributing to its fluidity and rigidity.

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Transmembrane Protein

A type of protein that spans both layers of the plasma membrane, with portions exposed to both the extracellular and intracellular environments.

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Fluidity of Membrane Proteins

The ability of membrane proteins to move laterally within the plasma membrane, contributing to its dynamic nature.

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Membrane-enclosed Organelles

Membrane-enclosed structures within eukaryotic cells that perform specific functions.

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Study Notes

Cell Structure and Function

  • Cells are the fundamental units of life, categorized as prokaryotic (lacking membrane-bound organelles) and eukaryotic (possessing them).
  • The plasma membrane, a phospholipid bilayer, regulates substance passage into and out of the cell.
  • Specialized organelles (e.g., nucleus, mitochondria, Golgi) perform specific functions within eukaryotic cells. Dysfunction can cause genetic diseases.

Prokaryotic Cells

  • Prokaryotes are single-celled organisms lacking a true nucleus and membrane-bound organelles.
  • Genetic material is a single circular chromosome in the cytoplasm.
  • Examples include bacteria and archaea.
  • Reproduce asexually via binary fission.
  • Possess a cell wall composed of peptidoglycan.
  • Cell walls are essential for bacterial structural integrity and osmotic balance.
  • Some antibiotics (e.g., Penicillin, Vancomycin) inhibit bacterial cell wall formation by interfering with peptidoglycan synthesis, leading to cell lysis and death.

Eukaryotic Cells

  • Eukaryotes are complex organisms with a nucleus and membrane-bound organelles.
  • Genetic material is enclosed within the nucleus.
  • Examples include plants, animals, fungi, and protists.
  • Reproduce both asexually (mitosis) and sexually (meiosis, fertilization).

Components of a Bacterial Cell

  • Flagellum: For movement.
  • No membrane-bound organelles
  • No nucleus: DNA is in the cytoplasm.
  • Nucleoid: Region containing the bacterial chromosome.
  • Cell membrane: Encased by a cell wall.

Cell Components and Their Role

Plasma Membrane

  • Separates the cell's interior from its environment.
  • Composed of a phospholipid bilayer.
  • Controls what enters and leaves the cell.
  • Contains proteins, enzymes, and receptors.
  • Phospholipids are amphipathic, having both hydrophobic and hydrophilic regions.
  • The phospholipid bilayer is asymmetrical, with different lipid composition on each side.
  • Forms a fluid structure allowing for lateral diffusion of lipids and proteins.
  • Lipids play a role in signaling pathways.
  • Cholesterol makes the membrane less permeable and more rigid.
  • Proteins are embedded in various ways (transmembrane, peripheral), performing diverse functions.
  • Ion concentrations inside and outside the cell create electrochemical gradients.
  • The plasma membrane is selectively permeable.

Organelles in Eukaryotic Cells

  • Nucleus

  • Contains the genetic material (DNA).

  • Surrounded by a nuclear envelope.

  • Damage to the nuclear envelope can lead to diseases like Progeria.

  • Mitochondria

  • The "powerhouse" of the cell.

  • Generate ATP (energy).

  • Have an inner and outer membrane.

  • Contain their own DNA (mtDNA).

  • Mitochondrial dysfunction can lead to mitochondrial myopathies. These diseases result from mutations in mtDNA or nuclear DNA, with varying symptoms.

  • Lysosomes

  • Contain digestive enzymes for breaking down waste and cellular debris ("stomach of the cell").

  • Lysosomal storage diseases result from deficiencies in enzymes that break down specific substances.

    • Examples: Tay-Sachs (Hex A deficiency) and Hurler syndrome (α-L-iduronidase deficiency).

  • Peroxisomes

  • Break down very long chain fatty acids and other substances.

  • Contain catalase for detoxification.

  • Defects can cause peroxisomal biogenesis disorders.

  • Endoplasmic Reticulum

  • A network of interconnected membranes.

  • Involved in protein synthesis, processing, and transport.

  • Provides intracellular calcium storage.

  • The UPR (unfolded protein response) controls quality control for secretory proteins.

  • Golgi Apparatus

  • Modifies, sorts, and packages proteins for secretion.

  • Creates secretory vesicles.

  • Has a polarity.

  • Dysfunction can lead to diseases like I-cell disease

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Description

Test your knowledge on cell structure and function, focusing on the differences between prokaryotic and eukaryotic cells. Learn about the roles of various organelles and the importance of the plasma membrane. This quiz also covers prokaryotic cell characteristics and antibiotic mechanisms of action.

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