Chapter 4: Cells and Microscopy Review

35 practice flashcards in Q&A format covering chapter four notes on cells, microscopy, organelles, endomembrane system, and cell structure.

What are the two main types of microscopes used to study cells?

Light microscopes and electron microscopes.

What are the three main components of the cell theory?

All organisms are made of at least one cell; the cell is the smallest unit of life; cells arise from pre-existing cells.

Do bacteria and archaea have a true nucleus?

No; they lack a membrane-bound nucleus and have a nucleoid region instead.

Where is genetic information stored in bacteria and archaea?

In a nucleoid region containing circular DNA.

What shapes do bacteria and archaea commonly adopt?

Rod-shaped, spiral, and spherical (coccus).

What structure encloses the interior of all cells and separates it from the outside environment?

The plasma membrane (cell membrane).

How does a cell membrane differ from a cell wall?

Membrane is a phospholipid bilayer surrounding the cell; the wall provides rigid support and is not present in all cells.

What are the three main components of the cytoskeleton?

Microfilaments, intermediate filaments, and microtubules.

Which organelle is commonly called the powerhouse of the cell?

Mitochondria.

Which organelle carries out photosynthesis in plants?

Chloroplasts.

What constitutes the endomembrane system?

Nucleus, rough and smooth ER, Golgi apparatus, lysosomes, and associated transport vesicles that process and transport cellular materials.

Where does transcription occur in eukaryotic cells?

In the nucleus.

What is the rough endoplasmic reticulum and its function?

ER with ribosomes on its surface; it synthesizes proteins and packages them into transport vesicles.

What is the smooth endoplasmic reticulum and its function?

ER lacking ribosomes; it synthesizes lipids and helps regulate glucose and calcium storage.

What is the Golgi apparatus responsible for?

Modifying, folding, sorting, and shipping proteins via transport vesicles.

What is the lysosome's main role?

Digestion and breakdown of macromolecules, damaged organelles, and invading bacteria.

What is the vacuole's role in plant cells?

Stores water and helps maintain turgor pressure; in plants, vacuoles can store acids and other substances.

Which organelles contain their own DNA and ribosomes?

Mitochondria and chloroplasts.

What theory explains how mitochondria and chloroplasts became part of eukaryotic cells?

Endosymbiotic theory.

What are thylakoids and where are they located?

Flattened membrane sacs inside chloroplasts where light-dependent reactions occur.

What is the stroma?

The fluid surrounding the thylakoids inside chloroplasts.

What are microfilaments, intermediate filaments, and microtubules?

Three major components of the cytoskeleton: microfilaments, intermediate filaments, microtubules.

What protein makes up microfilaments?

Actin.

What are microtubules used for in cells?

They form tracks for movement of organelles and chromosomes and provide structural support.

What are cilia and flagella, and how do they differ?

Both are motility appendages; cilia are short and numerous, while flagella are longer and fewer in number.

Do all cells have a cell wall?

No; cell walls are present in bacteria, archaea, and plants; animal cells generally lack a cell wall.

What is cellulose's role in plants?

Cellulose forms plant cell walls, providing rigidity.

What does Gram staining distinguish in bacteria?

Gram-positive versus Gram-negative, based on peptidoglycan exposure; Gram-positive absorb purple dye; Gram-negative do not.

How do bacteria and archaea differ in cell wall composition and environmental tolerance?

Bacteria have peptidoglycan in their walls; archaea lack peptidoglycan and often have unique lipids; many archaea are extremophiles.

Which domain includes plants, animals, fungi, and protists?

Eukarya (Eukaryota).

How do eukaryotic cell sizes compare to bacterial/archaeal cells?

Eukaryotic cells are typically 10 to 100 times larger.

What organelle is the site of photosynthesis and what substructures carry out light reactions?

Chloroplasts; thylakoids contain the light-absorbing machinery.

Do mitochondria and chloroplasts have their own DNA and ribosomes?

Yes; both contain their own DNA and ribosomes.

What is a practical description of the endosymbiotic origin of mitochondria and chloroplasts?

They originated as independent prokaryotes that were engulfed by a host cell and became organelles.

What is the relationship between transcription and translation and where do they occur?

Transcription happens in the nucleus to produce mRNA; translation occurs in the cytoplasm at ribosomes to synthesize proteins.