Ch. 6 Bio

Vocabulary flashcards covering key terms from the lecture on cell theory, organelles, microscopy, and cellular structures, including comparisons between prokaryotic and eukaryotic cells, and specific plant and animal cell components.

Cell Theory

The fundamental concept that all organisms are made out of cells, the simplest collection of matter that can be alive is a cell, and cells are near the middle of the biological size range.

Size Ranges in biology 

11 orders of magnitude up to a billion fold in cell sizes and structures, ranging from atoms to entire ecosystems.

Light microscopy

light goes through the sample to magnify and visualize structures.

Electron microscopy 

Puts an electron beam through the cell to achieve higher magnifications and resolutions than light microscopy (transmission puts a beam through and scanning focuses on electrons on the surface of specimen providing 3D images)

Cell Fractionation

Takes cells apart and separates the major organelles from one another using centrifugation techniques to isolate cellular components based on their size and density.  

Prokaryotic Cells have: 

No nucleus, smaller than eukaryotic, and lacks membrane-bound organelles.

• unicellular organisms, such as bacteria.

Eukaryote Cells have:

Nucleus with DNA and a membrane, membrane-bound organelles, larger than prokaryotic cells, internal membrane (endomembrane system)

What do both prokaryotes and eukaryotes have in common?

Plasma membrane, semifluid substance (cytosol), chromosomes (carry genes), and ribosomes (make proteins)

Unique things within a plant cell: 

• chloroplasts

• cell walls (made of cellulose)

• central vacuole (air or water filled)

Nucleus

contains most of the cells genes (DNA)

Nuclear envelope

encloses nucleus

Nuclear lamina

maintains the shape of the nucleus comprised of protein

nuclear pores

regulate the entry and exit of molecules

What is the nuclear membrane made of?

a lipid bilayer

Chromatin

The material that makes up chromosomes consists of DNA and proteins.

chromosomes

the structures that carry genetic information, made of chromatin.

nucleolus

Located in nucleus & is site of ribosomes RNA (rRNA) synthesis

Ribosomes

Particles made of ribosomal RNA and protein that carry out protein synthesis; they can be free in the cytosol or bound to the endoplasmic reticulum.

Free ribosomes 

Float in cytosol making soluble protein

Bound Ribosomes 

bound at the rough endoplasmic reticulum 

Endoplasmic Reticulum (ER)

• More than half of the total membrane in a eukaryotic cell

• continuous with the nuclear envelope

• has interconnected sacs and tubules

• functions as a membrane factory and has smooth and rough regions

• 2 distinct regions: smooth & rough ER

Smooth ER

• lacks ribosomes

• synthesis of lipids

• metabolism of carbohydrates

• detoxification of drugs and poisons

• storage of calcium ions.

Rough ER

• studded with bound ribosomes

• involved in the synthesis and secretion of glycoproteins

• distribution of transport vesicles

• a membrane factory for the cell.

Transport vesicles

Membrane-bound sacs that transport proteins and lipids between organelles and to the cell surface.

Glycoproteins

Proteins that have carbohydrates covalently bonded to them, often secreted by bound ribosomes on the Rough ER.

Golgi Apparatus

An organelle consisting of flattened membranous sacs called cisternae, involved in modifying products of the ER, manufacturing certain macromolecules, and sorting and packaging materials into transport vesicles.

Cisternae

The flattened membrane sacs that make up the Golgi Apparatus.

Cis vs trans side of Golgi Apparatus

• cis side is the receiving end where materials arrive from the ER

• trans side is the shipping end where modified materials are sent to their destinations.

Lysosomes

Membranous sacs of hydrolytic enzymes that can digest macromolecules; they work best in the acidic environment inside the lysosome, acting like the 'stomach' of the cell.

Which organelle is like the stomach of the cell?

Lysosomes

Food vacuoles are formed by what?

Phagocytosis, used to engulf food particles or other materials for digestion by fusing with a lysosome.

Autophagy

lysosomes digesting old organellesand recycling their components.

Contractile Vacuoles

pump excess water out of the cell, maintaining water balance.

Central Vacuoles

Large vacuoles found in many mature plant cells that hold organic compounds, water, and inorganic ions, and can cause the cell to essentially be lighter by increasing volume without increasing weight.

Membrane bound organelles:

Mitochondria, chloroplasts, peroxisomes, and the nucleus 

Plasma Membrane

The selective barrier that encloses the cytoplasm of all cells, prokaryotic and eukaryotic.

Cytosol

The semifluid, jellylike substance that fills the cytoplasm, an internal component of all cells.

Mitochondria

Double-membrane bound organelles that are the sites of cellular respiration, the metabolic process that generates ATP; often called the 'powerhouse of the cell'; has own ribosomes & DNA 

Cristae

Foldings of the inner mitochondrial membrane that increase surface area for ATP production.

Mitochondrial matrix

interior of the inner membrane of mitochondria, containing free ribosomes, enzymes for the citric acid cycle, and mitochondrial DNA,

Chloroplasts

Double-membrane bound organelles found in plant cells and algae that are the sites of photosynthesis, converting light energy to chemical energy; has own ribosomes & DNA

Chlorophyll

A green pigment found in chloroplasts that is essential for photosynthesis, as it absorbs light energy.

Thylakoids

flat membranous sacs (green coin looking things)

Granum

stack of thylakoids in chloroplasts, involved in photosynthesis.

Stroma

the fluid-filled space in chloroplasts surrounding the thylakoids, where the Calvin cycle occurs.

Endosymbiont Theory

The widely accepted theory that mitochondria and chloroplasts originated as prokaryotic cells engulfed by a host cell, later evolving into a single organism.

Peroxisomes

Oxidative organelles with a single membrane that produce hydrogen peroxide as a byproduct of various metabolic reactions and then convert it to water.

• catalyze reactions (redox reactions)

• least understood orgin

Cell Wall (Plant)

A rigid extracellular structure that protects the plant cell, maintains its shape, prevents excessive uptake of water, and provides structural strength; primarily made of cellulose fibers.

• animals dont have

Extracellular Matrix (ECM)

• The “cell wall” within animal cells

• made of glycoproteins (protein covalently bound to a carbohydrate) (like collagen, proteoglycans, and fibronectin)

• functions: support, adhesion, movement, and regulation.

• ECM proteins bind to receptor proteins (integrin)

Integrins

ECM proteins that bind to receptor proteins in the plasma membrane, facilitating adhesion and communication between cells and the extracellular matrix.

Cytoskeleton

A network of protein fibers extending throughout the cytoplasm of eukaryotic cells; it provides mechanical support, maintains cell shape, and is involved in cell motility and transport of organelles.

Microtubules

Hollow rods about 25 nm in diameter, made of tubulin dimers; they maintain cell shape (compression-resisting), function in cell motility (cilia and flagella), chromosome movements during cell division, and organelle transport.

Microfilaments (Actin Filaments)

Thinest fibers made of actin; function in muscle contraction and cell movement, providing structural support and aiding in the maintenance of cell shape.

Intermediate Filaments

Fibers with diameters in the middle range are made of various proteins (e.g., keratin); they bear tension, maintain cell shape, and anchor the nucleus and other organelles.

Actin

A protein that forms microfilaments of the cytoskeleton, essential for cell movement, muscle contraction, and maintaining cell shape.

• forms microfilaments

Myosin

A motor protein that, in conjunction with actin, is responsible for muscle contraction, amoeboid movement, and cytoplasmic streaming.

• forms thicker filaents 

Pseudopodia

cellular extensions; how actin and myosin drive amoeboid movement

cytoplasmic streaming

circular flow of cytoplasm within cells & is actin & myosin driven that helps distribute nutrients and organelles.

Centrosome

In animal cells, microtubules grow out of the cell near the nucleus ('microtubule-organizing center') responsible for producing microtubules.

Centrioles

• each with/ 9 sets of triplet microtubules arranged in a ring

• located in pairs within the centrosome of animal cells; involved in cell division.

Cilia and Flagella

• controlled by microtubule

• containing extensions that project from some cells,

• enabling cell locomotion or movement of fluid over the cell surface

• cilia: short and numerous, move fluid along surface of cell

• flagella: long and usually few, move the entire cell itself (sperm)

Dynein

A motor protein responsible for the bending movements of cilia and flagella by 'walking' along microtubules using ATP.

basal body

• cylindrical structure

• anchors cilia and flagella to the cell

• structurally similar to a centriole

• organizes microtubules extending into cilia & flagella

• coordinates movement where microtubules grow and attach

3 extracellular structures:

Cell walls, extracellular matrix, and intracellular junctions

Intracellular junctions

Specific sets of proteins hold things together with different functions

Plasmodesmata

type of intercellular junction within plants only and transport material between cells from pores

Tight Junctions

• A type of intercellular junction

• in animal cells

• holds cells together

• forms a watertight seal between cells, preventing the leakage of extracellular fluid.

Desmosomes

A type of intercellular junction in animal cells that functions as a 'rivet,' fastening cells together into strong sheets.

Gap Junctions

• A type of intercellular junction in animal cells

• transport material between cells

  • water, ions, small molecules, sometimes, rarely macromolecules

• help cells communicate & coordinate