General Biology and Cytology: Introduction to Biology, Cell Theory, and Cell Biology

Comprehensive practice flashcards covering introductory biology, levels of life organization, history of microscopy, classical and modern cell theory, prokaryotic vs. eukaryotic cytology, organelle anatomy, and the cell cycle.

Which scientists independently coined the term "biology," and in which years?

The term was introduced independently by F. Burdach (1800), G. Treviranus (1802), and J.-B. Lamarck (1803).

What are the five fundamental principles underpinning modern biology?

The five fundamental principles are energy, cell theory, evolution, genetics, and homeostasis.

Which integrative field of biology is demonstrated by the development of this aerodynamic vehicle modeled after the tropical boxfish?

Bionics (the engineering integration of biological structures and mechanisms into technical designs).

What are the key differences and challenges associated with in vivo versus in vitro biological experiments?

In vivo studies use whole living organisms and face ethical challenges; in vitro studies use isolated cells, tissues, or organs grown in culture outside the body and face data interpretation challenges.

Which level of biological organization is depicted here, whose elementary unit is the gene and whose elementary phenomenon is covariant reduplication?

The molecular level of organization.

Which level of biological organization is represented here, consisting of individuals of a single species capable of sustaining themselves indefinitely under optimal conditions?

The population-species level of organization.

Which level of biological organization is illustrated here, defined as a community of organisms from various species and kingdoms interacting with abiotic factors?

The biogeocenotic (ecosystem) level of organization.

What are the elementary units and corresponding elementary phenomena for the cellular, organismal, and biospheric levels?

Cellular level: cell (cellular metabolism); Organismal level: individual (ontogenesis); Biospheric level: biosphere (living matter).

How is the biological property of equifinality defined?

The regular attainment of a characteristic final end-state regardless of variations in initial conditions or developmental pathways.

What is "Mowgli syndrome" as demonstrated by the case of Kamala and Amala?

A condition seen in children raised by wild animals where human psychological functions and upright walking fail to develop; Kamala knew only $45$ words after $7$ years in human care and functioned like a $4$-year-old at age $17$.

How did Louis Pasteur's refutation of spontaneous generation revolutionize medicine?

By demonstrating that fermentation and putrefaction are caused by microorganisms, stimulating surgical advances through the implementation of antisepsis and asepsis.

What contribution did Robert Hooke make to cell biology in his 1665 publication Micrographia?

He utilized an improved microscope with a micrometer and illuminator to examine cork, coining the term "cell" (cellula) to describe the box-like pores.

Which early anatomist visualized plant structure as an interlaced weave of fibers comparable to textile fabric in The Anatomy of Plants (1671)?

Nehemiah Grew (who also introduced the terms "tissue" and "comparative anatomy").

What microscopic discoveries were made by Antony van Leeuwenhoek in 1674, 1676, and 1677?

Bacteria and protozoa in 1674, plastids and chromatophores in 1676, and human spermatozoa in 1677.

Who discovered the cell nucleus in plant cells and animal cells, respectively?

Robert Brown discovered the nucleus in plant cells (orchids) in 1831, and Gabriel Valentin discovered it in animal cells (conjunctival epithelium) in 1835.

Identify this German botanist who co-founded cell theory with his 1838 work Contributions to Phytogenesis.

Matthias Schleiden.

Identify this German zoologist who formulated the classical cell theory in 1839 in Microscopic Researches.

Theodor Schwann.

What major postulate and conceptual model did Rudolf Virchow contribute to cell theory in 1858?

The aphorism "Omnis cellula e cellula" (every cell arises from a pre-existing cell) and the concept of an organism as a "cellular state" (Zellenstaat).

What are the core tenets of modern cell theory?

1) All living organisms consist of cells; 2) Cells arise only from pre-existing cells via division; 3) The cell is the structural, developmental, and functional unit of life; 4) Cells of multicellular organisms form an integrated system.

How do prokaryotic and eukaryotic cells differ in size, DNA organization, and compartmentalization?

Prokaryotes are $0.5\text{--}3.0\,\mu\text{m}$ in diameter with circular DNA (nucleoid) and no compartmentalization; eukaryotes are up to $40\,\mu\text{m}$ in diameter with linear chromosomes, a true nucleus, and membrane-bound organelles.

What is the resolving limit of the optical light microscope shown here compared to a transmission electron microscope?

A light microscope resolves objects down to $0.2\,\mu\text{m}$ ($500\times$ human eye), whereas an electron microscope resolves objects down to $0.1\,\text{nm}$ ($500\times$ light microscope).

What is the Singer-Nicolson model of the plasma membrane, and what is its thickness?

The fluid mosaic model consists of an asymmetrical lipid bilayer ($8\text{--}12\,\text{nm}$ thick) with hydrophobic tails facing inward, hydrophilic heads facing outward, and embedded or peripheral proteins.

How do phagocytosis and pinocytosis differ in terms of particle size and mechanism?

Phagocytosis involves the ingestion of large particles ($d > 1\,\mu\text{m}$) engulfed by cellular extensions; pinocytosis involves the uptake of fluid droplets and dissolved solutes ($d < 0.3\,\mu\text{m}$) via membrane invagination.

Identify this organelle system and distinguish the functional roles of its rough and smooth sections.

The endoplasmic reticulum (ER); rough ER bears ribosomes ($21\text{--}25\,\text{nm}$) for protein synthesis, while smooth ER lacks ribosomes and synthesizes lipids and carbohydrates, detoxifies toxins, and stores calcium.

What are the primary functions of the Golgi complex discovered by Camillo Golgi in 1898?

Protein packaging, addition of sulfate and carbohydrate groups, vesicle formation ($30\text{--}60\,\text{nm}$), synthesis of lipids and carbohydrates, lysosome formation, and plant cell wall synthesis.

What is the lifespan of mitochondria in rat liver cells, and what are examples of mitochondrial pathologies?

Lifespan is $20$ days; pathologies include Leber's hereditary optic neuropathy, Pearson syndrome, Parkinson's disease, and atherosclerosis.

Identify the organelle shown in this diagram and name its primary internal structural compartments.

Chloroplast ($4\text{--}6\,\mu\text{m}$); components include the outer and inner envelope membranes, stroma, thylakoids grouped into grana, and connecting lamellae.

What enzymes are housed in lysosomes, and what genetic disease is caused by their functional deficiency?

They contain over $40$ acid hydrolases active at low $\text{pH}$; enzyme deficiency can cause Hurler syndrome (mucopolysaccharidosis type I).

What is the primary function of peroxisomes, and what hereditary pathology is caused by their dysfunction?

Oxidation of substrates with the formation and degradation of hydrogen peroxide using catalase; dysfunction leads to Zellweger syndrome (cerebrohepatorenal syndrome).

Identify this non-membrane organelle measuring $15\text{--}35\,\text{nm}$ that consists of a large subunit and a small subunit.

A ribosome (Palade granule), composed of $\frac{1}{3}$ protein and $\frac{2}{3}$ rRNA, responsible for protein synthesis.

What is the structural organization of the centrosome (cell center) discovered by E. van Beneden in 1876?

It consists of a pair of mutually perpendicular cylindrical centrioles, each composed of $27$ microtubules organized into $9$ triplets ($9 \times 3$).

What cytoskeletal structural elements are shown assembling from monomers into dimers and tetramers with a diameter of $10\,\text{nm}$?

Intermediate filaments.

What category of cellular inclusion is shown in this plant tissue preparation?

Trophic inclusions (specifically, starch grains serving as carbohydrate energy reserves).

Based on this comparative diagram, what are three distinguishing structural features found in plant cells but absent in animal cells?

A rigid cellulose cell wall, plastids (chloroplasts), and large vacuoles containing cell sap.

Identify this central organelle and its principal structural components visible in the cross-section.

The cell nucleus; components include the double-membrane nuclear envelope with nuclear pores ($40\text{--}100\,\text{nm}$), karyoplasm (nuclear matrix), nucleolus, and chromatin.

What is a mixotroph, and which organism serves as a classic example?

An organism capable of combining autotrophic and heterotrophic nutrition; Euglena viridis is autotrophic in light and heterotrophic in the dark.

What three interconnected intracellular flows maintain the cell as an open system, as represented in this model?

The flow of information (nucleus, mRNA, translation apparatus), flow of energy (cellular respiration, photosynthesis, ATP), and flow of matter (metabolic pathways and the Krebs cycle).

How does the efficiency of energy conversion in chloroplasts and mitochondria compare to that of a steam engine?

Chloroplasts achieve $25\%$ efficiency and mitochondria achieve $45\text{--}60\%$, markedly exceeding the $8\%$ efficiency of a steam engine.

What is amitosis, and where does it typically occur?

Direct nuclear and cell division without mitotic spindle formation or chromosome condensation; it occurs in ciliates, growing potato tuber cells, human cartilage, cornea, regenerating tissues, and malignant tumors.

What are the stages of the mitotic cell cycle shown here, and what proportion of interphase does each occupy?

$G_1$ presynthetic period ($30\text{--}40\%$), $S$ synthetic period ($30\text{--}50\%$), $G_2$ postsynthetic period ($10\text{--}20\%$), and $M$ mitosis ($10\%$); $G_0$ is the resting phase.

What are the four phases of mitosis, and what percentage of total mitotic time does each phase occupy?

Prophase ($60\%$), metaphase ($5\%$), anaphase ($5\%$), and telophase ($30\%$).

What occurs during mitotic anaphase, and at what velocity do the chromosomes move to opposite poles?

Centromeres divide, sister chromatids detach to become individual daughter chromosomes, and spindle fibers pull them toward opposite poles at $0.2\text{--}5\,\mu\text{m/min}$.

What is the biological and evolutionary significance of mitosis?

It guarantees identical chromosome distribution ($2n$) across cell generations, facilitates multicellular growth (expanding from $1$ to $6 \times 10^{13}$ cells in humans), drives tissue renewal (replacing $\approx 10^{11}$ cells daily), and provides the mechanism for asexual reproduction.