General Biology 1 – Cells and Tissues Review (Flashcards)

A comprehensive set of Q&A flashcards covering cell theory, organelles, plant and animal tissues, cell division, genetics, and cell transport from the lecture notes.

What are the three postulates of the Cell Theory?

1) All living organisms are composed of one or more cells. 2) The cell is the basic unit of structure and function in living organisms. 3) All cells arise from pre-existing cells (Omnis cellula e cellula); there is no spontaneous generation.

Who contributed to the development of the Cell Theory in 1838, 1839, and 1855?

1838: Matthias Schleiden (plants) defined the cell as the basic unit of structure and function; 1839: Theodor Schwann (animals) extended the idea to all living things; 1855: Rudolf Virchow added that cells arise from pre-existing cells.

What key idea did Louis Pasteur provide in 1862 related to the Cell Theory?

He disproved spontaneous generation, supporting Virchow’s idea that cells come from pre-existing cells.

Who coined the term 'cell' and what did they observe?

Robert Hooke; observed cork slices and described the tiny box-like structures as 'cells'.

What was Anton van Leeuwenhoek known for in cell history?

Improved microscope lenses and observed living cells, including bacteria and protozoa.

What is the cell nucleus and what does it contain?

The largest organelle; the control center of the cell; houses DNA on chromosomes; contains the nucleolus where rRNA is synthesized and ribosomal subunits are assembled.

What are ribosomes and what is their function?

Tiny, non-membranous particles made of rRNA and protein; synthesize proteins by translating mRNA.

What is the endoplasmic reticulum (ER) and what are its two types?

A network of membranes; Rough ER (with ribosomes) synthesizes, folds, and transports proteins; Smooth ER (no ribosomes) synthesizes lipids, detoxifies poisons, and stores calcium.

What is the Golgi apparatus and its primary functions?

A stack of flattened sacs that receives proteins/lipids from the ER, modifies/sorts/concentrates, and packages them into vesicles for delivery.

What are lysosomes and their role in the cell?

Small, spherical organelles with hydrolytic enzymes that digest macromolecules and participate in cellular recycling and defense.

What are vacuoles and how do they differ in plant and animal cells?

• Plant cells: one large central vacuole for storage and turgor pressure; + Animal cells: several small vacuoles for storage and transport.

What are mitochondria and why are they important?

Double-m membrane-bound organelles with cristae; contain mitochondrial matrix; site of cellular respiration and ATP production.

What are chloroplasts and where are they found?

Found in plant cells and some algae; contain thylakoids arranged in grana and stroma; perform photosynthesis and contain chlorophyll.

What are peroxisomes and what do they do?

Small, single-membrane-bound organelles with enzymes that break down fatty acids and detoxify substances; produce hydrogen peroxide and convert it to water and oxygen.

What is the cytoskeleton and its main components?

A network of protein filaments: microfilaments (actin), intermediate filaments, and microtubules; provides shape, movement, and organelle transport.

What is the centrosome and what are centrioles?

The main microtubule-organizing center in many animal cells; centrioles are two perpendicularly arranged structures within the centrosome that help organize spindle fibers during cell division.

What is a cell wall and its general composition in plants, fungi, and bacteria?

Rigid outer layer: cellulose in plants, chitin in fungi, and peptidoglycan in bacteria; provides structure, protection, and helps prevent excessive water uptake.

What is the plasma membrane and its key functions?

A selectively permeable phospholipid bilayer with proteins and cholesterol; regulates what enters and leaves the cell, maintains homeostasis, and participates in signaling and cell recognition.

What are the four common components shared by all cells, and how do prokaryotes differ?

All cells have a plasma membrane, cytoplasm, DNA, and ribosomes. Prokaryotes lack a true nucleus and membrane-bound organelles.

What are capsule, pili, and flagella in bacteria?

Capsule: a protective carbohydrate layer for attachment; Pili: hair-like structures for attachment and DNA transfer; Flagella: tail-like structures for movement.

What is cytoplasm and what are its main components?

The jelly-like interior of the cell; includes cytosol (fluid), chromosomes (nucleoid in bacteria), and plasmids; site of metabolism and replication.

What are plastids and what are the main types?

Membrane-bound organelles in plants/algae; types include chloroplasts (photosynthesis), amyloplasts (starch storage), and chromoplasts (carotenoids).

What are the three basic plant tissues and their general roles?

Dermal (protective outer layer), Ground (storage, photosynthesis, filler), and Vascular (xylem and phloem for transport).

Who is known as the Father of Plant Anatomy?

Nehemiah Grew.

What is meristem and its main types?

Regions of undifferentiated plant cells responsible for growth; Apical (height), Intercalary (internode length), Lateral (girth/secondary growth).

What are apical, intercalary, and lateral meristems responsible for?

Apical for increasing height; Intercalary for internode length; Lateral for thickening and secondary growth.

What are the dermal and vascular tissues in plants?

Dermal: epidermis; Vascular: xylem and phloem responsible for transport.

What are trichomes, root hairs, and mesophyll cells?

Trichomes are epidermal outgrowths; root hairs increase surface area for absorption; mesophyll cells (palisade and spongy) perform photosynthesis in leaves.

What is the difference between xylem and phloem in terms of transport direction?

Xylem transports water/minerals upward; Phloem transports sugars (food) throughout the plant, in multiple directions.

What are the four basic animal tissues?

Epithelial, Connective, Muscular, and Nervous tissues.

How is epithelial tissue classified by layers and by cell shape?

Layers: simple (one layer), stratified (multiple layers), and pseudostratified (appears multi-layered but is one layer). Shapes: squamous (flat), cuboidal (cube-shaped), columnar (tall column-shaped).

What are the main connective tissue types and their general functions?

Bone (osseous tissue) supports and protects; Cartilage (flexible support); Dense fibrous tissue (t tendons/ligaments; connectivity and support); Blood (fluid connective tissue for transport, immunity, clotting).

What are the major muscular tissues and their control?

Skeletal (voluntary, striated, multinucleated), Smooth (involuntary, non-striated, uninucleated), Cardiac (involuntary, striated, with intercalated discs).

What are neurons and glial cells?

Neurons are the functional units that transmit electrical/chemical signals; Glial cells (neuroglia) provide support and protection (e.g., astrocytes, microglia, oligodendrocytes).

What are cell modifications like microvilli, cilia, and flagella?

Microvilli increase surface area for absorption; cilia move substances along surfaces; flagella provide propulsion (e.g., sperm tail).

What are the main types of cell junctions?

Tight junctions (block leakage), Adherens junctions/Desmosomes (mechanical connection), Gap junctions (channels for small molecules/ions).

What are red blood cells (RBCs) characterized by and their energy source?

Biconcave shape to maximize gas diffusion; lack a nucleus and mitochondria; rely on glycolysis (anaerobic) for energy; optimized for oxygen transport.

What is the egg cell, and why is it notable?

Egg cell is the largest cell in the human body and its role is to participate in sexual reproduction.

What is mitosis and what cells divide by it?

A process of nuclear division producing two genetically identical diploid daughter cells; occurs in somatic (non-germ) cells.

What are the phases of mitosis and brief descriptions?

Interphase (G1, S, G2; cell growth and DNA replication) → Prophase (chromosomes condense) → Prometaphase (nuclear envelope breaks) → Metaphase (chromosomes align at the equator) → Anaphase (sister chromatids separate) → Telophase (nuclear envelope reforms) → Cytokinesis (cytoplasm divides, forming two cells).

What is meiosis and what is its purpose?

A two-division process in germ cells producing four haploid, genetically diverse daughter cells for sexual reproduction.

What are the phases of Meiosis I and II?

Meiosis I: Prophase I (crossing over, tetrads form), Metaphase I (homologs align at the equator), Anaphase I (homologs separate), Telophase I/Cytokinesis I (two haploid cells). Meiosis II: Prophase II, Metaphase II, Anaphase II (sister chromatids separate), Telophase II/Cytokinesis II (four haploid gametes).

What are the key differences between mitosis and meiosis?

Mitosis: somatic cells, one division, diploid to diploid, identical daughter cells, no crossing over. Meiosis: germ cells, two divisions, diploid to haploid, non-identical daughters, crossing over occurs.

What are chromosomal mutations and examples of common disorders?

Mutations involving chromosomes or large segments; deletions, duplications, inversions, translocations; aneuploidy (monosomy, trisomy) leading to disorders such as Down syndrome (trisomy 21), Patau (trisomy 13), Edward’s (trisomy 18), Turner syndrome (monosomy X), Angelman syndrome (deletion of part of chromosome 15).

What is osmosis and how does it relate to diffusion?

Osmosis is the diffusion of water across a selectively permeable membrane from high water concentration to low water concentration, driven by solute differences.

What is a concentration gradient and its relevance to transport?

A difference in the concentration of a substance between two regions; substances tend to move down their gradient (high to low) during passive transport.

What is the difference between isotonic, hypotonic, and hypertonic solutions?

Isotonic: equal solute concentration inside and outside; no net water movement. Hypotonic: lower solute outside; water enters the cell (plants: turgor; animals may swell). Hypertonic: higher solute outside; water leaves the cell (plants wilt; cells may plasmolyze in animals).

What is turgor pressure and its significance in plants?

The pressure exerted by the vacuole against the cell wall; maintains rigid structure and support in plants; increased in hypotonic solutions.

What is Facilitated Diffusion and its characteristics?

Passive transport down a concentration gradient that uses transport or channel proteins; specific for certain molecules (e.g., glucose); stops at equilibrium.

What are Endocytosis and Exocytosis?

Endocytosis: process of taking in substances via vesicle formation; Exocytosis: release of substances from the cell via vesicles fusing with the plasma membrane.