Essential Cell Biology - Flashcards (Ch. 1-2; Organelles; Microscopy; Model Organisms)

A set of question-and-answer flashcards covering core concepts from the notes: macromolecules, central dogma, cell organelles and pathways, endosymbiotic theory, model organisms, genome sizes, microscopy techniques, and related topics.

What are the four major macromolecule classes that build cells?

Nucleic acids, proteins, polysaccharides (carbohydrates), and lipids.

What are the monomers for the four macromolecule classes?

Sugars for carbohydrates; amino acids for proteins; nucleotides for nucleic acids; fatty acids for lipids.

What is the Central Dogma of molecular biology?

DNA → RNA (transcription) → protein (translation).

What is a gene?

The basic functional unit of heredity; DNA that contains instructions to make a protein.

How do prokaryotic and eukaryotic cells differ?

Prokaryotes lack a true nucleus; eukaryotes have a nucleus; both can be unicellular or multicellular.

What characterizes Gram-positive bacteria?

Thick peptidoglycan cell wall, lack outer membrane; targeted by penicillin.

What are organelles?

Membrane-bound structures in eukaryotic cells that perform specific functions.

What is the nucleus and what are its key features?

A double lipid bilayer nuclear envelope with nuclear pores; contains chromatin and nucleolus.

What are ribosomes?

The cell’s protein synthesis machinery; composed of rRNA and proteins; has large and small subunits.

What does the Rough Endoplasmic Reticulum do?

Synthesis and modification of proteins; contains chaperones for proper folding.

What does the Smooth Endoplasmic Reticulum do?

Synthesizes lipids; stores Ca2+ in muscle; detoxifies drugs and toxins.

What is the Golgi apparatus’ function?

Packaging, distribution, and modification of ER products; has cis and trans faces.

What are lysosomes?

Digestive organelles that break down macromolecules, recycle components, and participate in autophagy.

What is the endomembrane system?

Group of membranes that work together via vesicles (ER, Golgi, lysosomes, plasma membrane).

What are mitochondria?

Powerhouse of the cell; produce ATP; have own circular DNA and ribosomes; double membrane with cristae; origin via endosymbiosis.

What is evidence for the endosymbiotic origin of mitochondria and chloroplasts?

Two membranes; DNA similar to bacterial DNA; bacterial-like ribosomes; replicate by binary fission.

What are peroxisomes?

Membrane-bound organelles containing enzymes that oxidize fatty acids and amino acids; produce H2O2.

What are chloroplasts?

Sites of photosynthesis in plants; contain thylakoids and stroma; circular DNA and ribosomes; origin from cyanobacteria.

What is the cytoskeleton?

Network of protein fibers that gives shape, positions organelles, and enables movement.

What is the extracellular matrix (ECM)?

Material outside the plasma membrane that organizes tissues, supports the membrane, and communicates with the cytoskeleton.

What is special about plant cell walls?

Primary and secondary cell walls made of cellulose.

What are model organisms?

Species used for study due to fast reproduction, genetic tractability, ease of imaging, safety, and similarity to target species.

Give an example of a model prokaryote and what it’s used to study.

Escherichia coli; used to study DNA replication, transcription, and translation.

Give an example of a model eukaryote used for basic mechanisms like cell division.

Saccharomyces cerevisiae (budding yeast); used to study basic cellular mechanisms such as cell division.

Name a model plant and its research focus.

Arabidopsis thaliana; used to study genetics, molecular biology, and evolution of flowering plants.

Name a model organism used for development and genetics in insects.

Drosophila melanogaster (fruit fly); used for developmental biology and genetics.

Name a model organism used for development and genome sequencing in nematodes.

Caenorhabditis elegans (C. elegans); first multicellular organism with its genome fully sequenced.

Which model organism is popular for vertebrate development studies?

Zebrafish; used to study vertebrate development.

What is the approximate human genome size and gene count listed in the notes?

About 3.1 x 10^9 bp; ~20,000 protein-coding genes.

What is the approximate genome size of E. coli and its gene count?

About 4.6 x 10^6 bp; ~4,300 protein-coding genes.

What is the genome size of Saccharomyces cerevisiae (yeast) and its gene count?

About 12.5 x 10^6 bp; ~6,600 protein-coding genes.

What is the difference between light and electron microscopy in terms of resolution?

Light microscopy resolves ~0.2 μm; electron microscopy uses shorter wavelengths for much higher resolution.

What are confocal, fluorescence, and super-resolution microscopy used for?

Confocal: optical slicing and 3D reconstruction; Fluorescence: dynamic, color-specific labeling; Super-resolution: exceeds ~200 nm limit to ~20 nm.

What is endocytosis vs exocytosis?

Endocytosis imports materials into the cell in vesicles; exocytosis exports materials via vesicles fusing with the plasma membrane.

What is the nucleolus and its function?

A region within the nucleus where ribosomal RNA (rRNA) is synthesized and ribosomal subunits are assembled.

What are the four major macromolecule classes that build cells?

Nucleic acids, proteins, polysaccharides (carbohydrates), and lipids.

What are the monomers for the four macromolecule classes?

Sugars for carbohydrates; amino acids for proteins; nucleotides for nucleic acids; fatty acids for lipids.

What is the Central Dogma of molecular biology?

DNA → RNA (transcription) → protein (translation).

What is a gene?

The basic functional unit of heredity; DNA that contains instructions to make a protein.

How do prokaryotic and eukaryotic cells differ?

Prokaryotes lack a true nucleus; eukaryotes have a nucleus; both can be unicellular or multicellular.

What characterizes Gram-positive bacteria?

Thick peptidoglycan cell wall, lack outer membrane; targeted by penicillin.

What are organelles?

Membrane-bound structures in eukaryotic cells that perform specific functions.

What is the nucleus and what are its key features?

A double lipid bilayer nuclear envelope with nuclear pores; contains chromatin and nucleolus.

What are ribosomes?

The cell’s protein synthesis machinery; composed of rRNA and proteins; has large and small subunits.

What does the Rough Endoplasmic Reticulum do?

Synthesis and modification of proteins; contains chaperones for proper folding.

What does the Smooth Endoplasmic Reticulum do?

Synthesizes lipids; stores Ca2+ in muscle; detoxifies drugs and toxins.

What is the Golgi apparatus’ function?

Packaging, distribution, and modification of ER products; has cis and trans faces.

What are lysosomes?

Digestive organelles that break down macromolecules, recycle components, and participate in autophagy.

What is the endomembrane system?

Group of membranes that work together via vesicles (ER, Golgi, lysosomes, plasma membrane).

What are mitochondria?

Powerhouse of the cell; produce ATP; have own circular DNA and ribosomes; double membrane with cristae; origin via endosymbiosis.

What is evidence for the endosymbiotic origin of mitochondria and chloroplasts?

Two membranes; DNA similar to bacterial DNA; bacterial-like ribosomes; replicate by binary fission.

What are peroxisomes?

Membrane-bound organelles containing enzymes that oxidize fatty acids and amino acids; produce H2O2.

What are chloroplasts?

Sites of photosynthesis in plants; contain thylakoids and stroma; circular DNA and ribosomes; origin from cyanobacteria.

What is the cytoskeleton?

Network of protein fibers that gives shape, positions organelles, and enables movement.

What is the extracellular matrix (ECM)?

Material outside the plasma membrane that organizes tissues, supports the membrane, and communicates with the cytoskeleton.

What is special about plant cell walls?

Primary and secondary cell walls made of cellulose.

What are model organisms?

Species used for study due to fast reproduction, genetic tractability, ease of imaging, safety, and similarity to target species.

Give an example of a model prokaryote and what it’s used to study.

Escherichia coli; used to study DNA replication, transcription, and translation.

Give an example of a model eukaryote used for basic mechanisms like cell division.

Saccharomyces cerevisiae (budding yeast); used to study basic cellular mechanisms such as cell division.

Name a model plant and its research focus.

Arabidopsis thaliana; used to study genetics, molecular biology, and evolution of flowering plants.

Name a model organism used for development and genetics in insects.

Drosophila melanogaster (fruit fly); used for developmental biology and genetics.

Name a model organism used for development and genome sequencing in nematodes.

Caenorhabditis elegans (C. elegans); first multicellular organism with its genome fully sequenced.

Which model organism is popular for vertebrate development studies?

Zebrafish; used to study vertebrate development.

What is the approximate human genome size and gene count listed in the notes?

About 3.1 \times 10^9 bp; \sim20,000 protein-coding genes.

What is the approximate genome size of E. coli and its gene count?

About 4.6 \times 10^6 bp; \sim4,300 protein-coding genes.

What is the genome size of Saccharomyces cerevisiae (yeast) and its gene count?

About 12.5 \times 10^6 bp; \sim6,600 protein-coding genes.

What is the difference between light and electron microscopy in terms of resolution?

Light microscopy resolves \sim0.2 \mum; electron microscopy uses shorter wavelengths for much higher resolution.

What are confocal, fluorescence, and super-resolution microscopy used for?

Confocal: optical slicing and 3D reconstruction; Fluorescence: dynamic, color-specific labeling; Super-resolution: exceeds \sim200 nm limit to \sim20 nm.

What is endocytosis vs exocytosis?

Endocytosis imports materials into the cell in vesicles; exocytosis exports materials via vesicles fusing with the plasma membrane.

What is the nucleolus and its function?

A region within the nucleus where ribosomal RNA (rRNA) is synthesized and ribosomal subunits are assembled.

What is the fluid mosaic model?

A model describing the plasma membrane as a mosaic of protein molecules embedded in a fluid bilayer of phospholipids.

What are the three main types of cytoskeletal filaments?

Microfilaments (actin filaments), intermediate filaments, and microtubules.

What is the primary role of ATP in cells?

ATP (adenosine triphosphate) is the main energy currency of the cell, providing energy for most