Cell Structure, Function, and Transport Across Membranes

Comprehensive vocabulary flashcards covering cell discovery, microscopy, cell theory, organelle structure and function, prokaryotic versus eukaryotic differences, specialized cells, tissue types, and mechanisms of membrane transport.

Passive Transport

→movement of molecules across a membrane
→requires NO energy

→HIGH concentration to low concentration

E.g. osmosis, diffusion, facilitated diffusion

Active Transport

→ movement of substances across membrane

→ AGAINST concentration gradient (low to HIGH)

→ requires energy (ATP)

→ utilizes transport proteins like pumps

Simple Diffusion

→ passive movement of molecules across membrane without helper protein

→ HIGH conc. → low conc. until equilibrium!

Facilitated Diffusion

→passive transport of molecules across membrane with HELPER PROTEIN

Osmosis

→ net movement of WATER molecules

→ SEMI-PERMEABLE MEMBRANE

→ HIGH TO LOW WATER POTENTIAL

Hypertonic Solution

→ High concentration of solutes in cell

→ Water moves OUT of cell

→ Cell shrinks

→ plant cell: pla-PLA-PLASMOLYSIS

Hypotonic Solution

→ Low concentration of solution in cell

→ Water moves IN

→ Cell SWELLS

→ Plant-T-TURGID

Isotonic Solution

→ equal concentration levels

→ cell stays the same

→ plant flaccid

Plasmolysis

→ Plant cell in hyperpertonic

→ Water exits cell

→ Cytoplasm & membrane pu-pull away from cell wall

Turgidity

→ plant cell swollen with water

→ vacuole push firmly against cell wall

Robert Hooke

The scientist who in 1665 observed a thin slice of cork (dead plant cells) using an early microscope and coined the term 'little boxes' (cells).

Anton van Leeuwenhoek

The scientist who was the first person to observe living cells under a microscope in 1675.

Magnification

Refers to a microscope's power to increase an object's apparent size.

Resolution

Refers to a microscope's power to show detail clearly.

The Cell Theory

The foundational theory stating that: 1. All living things are composed of one or more cells; 2. Cells are organisms' basic units of structure and function; 3. Cells come only from existing cells.

Matthias Schleiden

Scientist who concluded in 1838 that all plants are composed of cells.

Theodor Schwann

Scientist who concluded in 1839 that all animals are composed of cells.

Rudolph Virchow

Scientist who determined in 1855 that cells come only from other cells.

Cell Membrane

A selectively permeable boundary composed of a phospholipid bilayer with embedded proteins (channels, markers, and receptors) and cholesterol that maintains cellular integrity and controls substance movement.

Nucleus

A sphere-shaped organelle containing the nucleolus that functions as the storage center for the cell's DNA and manages cell functions.

Mitochondria

Organelles featuring an outer membrane and an inner membrane folded into cristae that convert energy stored in food into usable energy through cellular respiration.

Cristae

The inner membrane folds within a mitochondrion that provide the structural location for cellular respiration.

Chloroplasts

Plant organelles consisting of stacked sacs called thylakoids containing chlorophyll surrounded by a double membrane, which carry out photosynthesis to convert light energy into glucose.

Ribosomes

Cellular structures consisting of two subunits made of protein and RNA that function as the location of protein synthesis.

Vacuoles

Membrane-surrounded sacs of fluid used for the temporary storage of wastes, nutrients, and water, which are especially large and central in plant cells.

Prokaryotic Cell

A small cell ($<1\text{ to }5\,\mu\text{m}$) lacking membrane-bound organelles or a membrane-bound nucleus, containing a single circular chromosome, plasmids, and a cell wall that contains peptidoglycan.

Eukaryotic Cell

A large cell ($10\text{--}100\,\mu\text{m}$) containing a clearly defined membrane-bound nucleus, multiple linear chromosomes, and membrane-bound organelles.

Cell Specialism

The principle that multicellular organisms contain diverse cell types with specialized shapes and features designed to carry out specific functions.

Erythrocyte

A specialized red blood cell packed with hemoglobin molecules whose biconcave (double-dished) shape facilitates rapid, maximal oxygen absorption.

Adipocyte

A bulky adipose (fat) cell crammed with lipid droplets that stores energy reserves in case dietary intake cannot meet body requirements.

Transmission Electron Microscope (TEM)

A microscope that directs an electron beam through an ultra-thin specimen focused by electromagnetic lenses onto a viewing screen to examine internal cellular details.

Scanning Electron Microscope (SEM)

A microscope that scans the surface of a specimen with an electron beam to provide high-detail, three-dimensional views of surface architecture.

Shoot System

The plant organ system comprising all structures located above ground, including stems, leaves, buds, flowers, and fruits.

Root System

The plant organ system comprising underground structures and aerial roots, functioning in anchorage, absorption, storage, and conduction.