Cell and Tissue Form - Biol 130 Module 10

Flashcards for Biol 130 Module 10 on Cell and Tissue Form, covering key vocabulary and concepts related to cell structure and function.

Extracellular Matrix (ECM)

A network of proteins and polysaccharides outside the cell that provides structural and biochemical support to surrounding cells.

Cadherins

Transmembrane glycoproteins responsible for cell-cell adhesion in various types of cell junctions.

Integrins

Transmembrane proteins that facilitate cell-ECM adhesion and play a role in signaling pathways.

Dynamic Instability

The rapid switching between growth and shrinkage phases of microtubules and microfilaments.

tissues

where multicellular organism of cells come together to form them

organs

are formed when two or more tissues combine and function together

stem cells

undifferentiated cell - specialized cell (ex. WBCs, RBCs)

somatic cells

nonreproductive cells in a multicellular organism

germ cells

reproductive cells that produce gametes (sperm or eggs)

shape of cells and organs

reflects their function

cytoskeleton

determinded and maintained by structural protein networks in the cytoplasm formed rom long chains of protein subunits joined together

cellular junctions

structures that connect cells, allowing communication and adhesion between them

epidermis

outer layer that serves as a water-resistant and protective barrierof the skin, consisting of multiple layers of cells that play a key role in barrier function.

dermis

layer beneath the epidermis that supports the epidermis and supplies it with nutrientsand contains connective tissue, blood vessels, and hair follicles.

epithelial tissue

covers the outside of the body and lines many internal structures of the body

melanocytes

cells in the epidermis that produce melanin, the pigment responsible for skin color and protection against UV radiation.

basal lamina

a specialized extracellular matrix below the bottom layer of the epidermis that supports epithelial cells

keratinocytes

the primary cells of the epidermis that produce keratin, a protein that helps protect the skin and underlying tissues.

basal lamina and keratinocytes

the bottom layerof keratinocytes is attached tothe basal lamina → CELL JUNCTION BETWEEN

connective tissue

provides structure and support

main cell type of dermis

fibroblasts, a connective tissue (lots of ECM - fibroblasts produces it)

protein fibers of cytoskeleton

provides internalsupport for cells (like bones to body)

2 cytoskeletal elements in all eukaryotes

microtubules and microfilaments

animals have the 2 and…

intermediate filaments

microtubules

hollow tube like structures made of polymers of protein dimers

dimer monomer(subunit)

made up of 2 tubulin proteins - alpha tubulin and beta tubulin that combine to form microtubules.

function of microtubules

they form the centrosome which helps maintain the cell shape (withstand compression) ad guids arrangement of organelles in a cell

microfilaments

thin fibers that are arranged in a double helix of actin monomers (they are polymers of acin monomers). They are short and extensively branched just beneath the cell membrane and present in various locations in the cytoplasm

microvilli

small, finger-like projections on the surface of epithelial cells that increase surface area for absorption and secretion. They have bundles of microfilaments within each microvillus (actin)

band of long filaments

what microfilaments form in epithelial cells to support structure and is connected to a cell junction that connects neighbouring cells

other microfilament functions

transport of materials inside cells, shorening of muscle cells during contraction, separation of daughter cells at the end of animal cell divison

PLUS END

end where polymers (microfilaments and microtubules) grow faster

MINUS END

end where polymers grow slower

minus end of microtubules in animal cells

positioned at the organizing center of the centrosome

plus end of microtubules in animal cell

located away from the centrosome and outward towards cell membrane

depolymerization

rapid shrinkage in microtubules (due to the removal of tubulin dimers, particularly from the plus end)

polymerization

slower growth in microtubules (due to the addition of tubulin dimers, particularly at the plus end)

dynamic instability

the phenomenon where microtubules rapidly switch between phases of growth and shrinkage, allowing for rapid reorganization and exploration of cell

microtubule catastrophe

the result of dramatic shrinkage

motor proteins

small accessory proteins that move along microtubules or actin filaments, transporting cellular cargo and facilitating movement within cells.

kinesin

a type of motor protein that moves the cargo toward the plus end of microtubules (powered by ATP)

dynein

a type of motor protein that moves cargo toward the minus end of microtubules (powered by ATP)

flagella

hair-like structure that assist in movement of cells (MICROTUBULES + dynein)

cilia

short hair-like structure that assist in movement of substances surroundiing cells (MICROTUBULES + dynein)

intermediate filaments

a strong fiber composed of intermediate filament protein subunits - form strong cable-like polymers of proteins

function of intermediate filaments

provide mechanical strength to the cell

types of intermediate filaments

more than 100 types, made of different proteins depending on cell type

keratins

a type of intermediate filament found in epithelial cells, providing structural integrity and protection.

vimentius

a type of intermediate filament found in connective tissue cells (FIBROBLASTS), providing support and stability.

neurofilaments

a type of intermediate filament found in neurons, playing a crucial role in maintaining neuronal shape and stability.

lamins

a type of intermediate filament found in nucleus

cell junctions

specialized structures that connect one cell to another or to the basal lamina

what is cell polarity

spatial diffeerences in shape, structure, and function within a cell (apical vs basal sides in epithelial cells)

apical surface

the surface of an epithelial cell that is facing outside body or lumbar

basal

the surface of an epithelial cell that is attached to basal lamina (part of ECM)

cadherins

integral transmembrane glycoproteins involved in cel-cel attachment

integrins

integral transmembrane glycoproteins that attach cells to ECM

cytoplasmic domain of integrins

it interacts with cytoskeleton, maintaining tissue integrity under stress

Adherens Junctions

a belt-like junctional complex of cadherins around the cell circumference near the apical side of epithelial cells (cel-cel, microfilaments)

extracellular domain of cadherin molecule (how they bind)imp

binds to extracellular domain of cadherin of the same typeon an adjacent cell

cytoplasmic part of cadherin

linked to the internal cytoskeleton

importance of cadherins

provide structural continuity between cells, increasing tissue and organ strength

use of cadherin in adherin junction

links adjacent cells and connects to actin microfilaments, helping cells stick together and coordinate shape changes

demosome

a strong button-like cell-cell anchoring junction that holds cell membrane of adjacent cells together where cadherins strengthen the connection between the cells

desmosome linking

adjacent cells together via cadherins and intermediate filaments of the cytoskeletontt o provide mechanical stability and resistance to stress.

Hemidesmosomes

a cell-ECM anchoring junction that uses integrins to attach epithelial cells to the basal lamina (extracellular domains), connecting intermediate filaments (cytoplasmic domain) for stability under stress

Tight junctions

a barrier junction that seals the extracellular space between the adjacent epithelial cells, preventing substances from passing between cells and forcing transport to occur through the cells

Gap Junctions

cell-cell communication made of connexin proteins that allow direct passage of ions and small molecules between adjacent cells.

Plasmodesmata

allows communication between plant cells (transfer RNA molecules and proteins) between adjacent cells despite the rigid cell walls (signals to one another) through cell membrane

extracellular matrix

the layer of material secreted beyond the region of the cell mebrane in extracellular area that is formed by insoluble meshwork ofproteins and polysaccharides

plant ECM

the cell wall is a type of ECM composed of 3 layers: the middle lamella (carbs), primay cell wall (thin and flexible), secondary cell wall (rigid —> cellulose and lignin)

animal ECM

the connective tissue of animals (ECM), mixture of proteins and polysaccharides

collagen

most abudant protein in animal ECM (1/4 protein in body with more than 20 types of collagen) - provides support

basal lamina

specialized layer of extracellular matrix that is present beneath all epithlial tissues (provides structural foundation of epithlial tissues)