BIO120 CH10

what is biological tissue

collection of cells that work together to perform a function

what are the four types of tissue

epithelial, connective, nervous, muscle

cell shape is determined by

cytoskeleton

the connection between cells relies upon

cell junctions

what are cell junctions

complexes of proteins in the cell membrane where cells make contact with each other

what is the extracellular matrix

network of proteins and polysaccharides that support cells tissues and organs

what is the structure of skin tissue

epidermis and dermis

what is the epidermis

outer layer, water-resistant, protective barrier

what is the dermis

inner layer, supports epidermis with structure and nutrients, cushions body

how many layers are epithelial cells

>1 layers

what types of cell line the digestive tract and blood vessels

epithelial cells

what are the components of the epidermis

keratinocytes, basal lamina

what is the function of keratinocytes in the epidermis

specialized to protect underlying tissues and organs

what is the function of basal laminate in epidermis 

underlies and supports all epithelial tissues

cytoskeletal elements

microfilaments, microtubules

animal cells have what type of cytoskeletal elements that plant cells don’t have

intermediate filaments

all cytoskeletal elements are made of what?

long chains (polymers) of protein subunits

what are microfilaments (how are they made)

double helix of actin polymers

what are microtubules:

hollow tube formed by tubular dimers

what are intermediate filaments

a strong fiber made of protein subunits

what are all cytoskeletal elements made of

polymers, but differ in size

what type of cytoskeletal structure is the smallest

microfilaments

what do microfilaments do

reinforce the cell membrane and its proteins, help cells maintain their shape

what do intermediate filaments do

provide cells with mechanical strength, attach to cell junctions to provide structural support for cells

what are intermediate filaments made of

polymers of proteins that link to form strong cable-like structures

where do intermediate filaments attach?

they attach to cell junctions

what does anchoring to cell junctions do for cells and tissue

anchoring to cell junctions creates structural continuity between cells and strengthens all epithelial tissue

what type of cytoskeletal element is crucial for cell types subjected to physical stress (like skin)

intermediate filaments

what is made of polymers of protein dimers

microtubules

what contains two tubulin proteins, alpha and beta

dimers

what are dimers made of

two tubules proteins, alpha and betaw

what do dimers do for cells

maintain cell shape and internal structure

where are dimers tethered

to organelles to guide internal arrangement

what is attached to centrosome

microtubules

what is the centrosome

where all the microtubules begin, the center of the cell, heart of the tubules radiating outward

what are the two tubules proteins called in dimers

alpha and beta

cells change rapidly (T or F)

false, cells change slowly

what is added to the cytoskeletal structure at a rate that depends on the amount of tubular and actin that is available

protein subunits

what are continuously growing and shrinking during an organism’s lifespan

microtubules and microfilaments

what does the rate of microtubule and microfilament growth depend on

amount of tubular and actin that is available

what instigates faster assembly on one or both ends of a filament or tubule

high concentration of protein subunits in a cell

which end of a tubule or filament is the rapid assembly side

the plus side

which end of a tubule or filament is the slow assembly side

the minus end

microtubules are capable of rapid _________ and less rapid _________

depolymerization , polymerization

what is dynamic instability

when microtubules are able to grow and shrink constantly

why is dynamic instability good for cells

it allows spindles to find and attach to chromosomes during cell division

what is polymerization

the building up of the microtubuels

what are motor proteins and what do they do

associate with tubules and microfilaments to cause movement

movement of vesicles within the cell requires ____________ and ____________ to associate with motor proteins like Kinesin

microfilaments and microtubules

what things allow muscle cells to contract to facilitate movement

myosin and microfilaments

which direction does kinesis transport cargo toward on a microtubule

toward the plus end

what do microtubules do to help transportation of molecules thru the cell

provide tracts to facilitate transportation

what makes up cilia

microtubules

what are cilia

rod-like structures that extend outside of cells

what is the primary use for cilia

sensory purposes, to receive environment signs that inform cell function and movement

how do chlamydomonas move

motion of two long cilia

how do paramecium move

short cilia that beat in coordinated fashion

why do epithelial cells have cilia in airway

they sweep fluid and Debris and pathogens out of airway

tissues are held together and joined as unit bc of

cell junctions

what do cell junctions do

physically connect cells together and anchor them to extracellular matrix

cell junctions physically connect cells together and anchor them to the __________-

extracellular matrix

what is cell adhesion

cells of the same type stick together bc of surface proteins recognize each other

what is an a cadherin

important type of cell adhesion molecule (can only bind to other cadherins)

what type of protein is a cadherin

calcium dependent adherence protein

how do cadherins bind to other cells

they are transmembrane proteins that bind to other cadherins on the outside of another cell

what are adherens junctions

beltlike structures that allow cadherins to link to other cells

how do cadherins use adherens junctions to link to other cells

They are anchored through the membrane of the cell and grab on to the cadherins poking thru the other cell’s membrane

what are desmosomes

cell junctions that allow cells to attach to other cells

how do cadherins in desmosomes work

cadherins in the desmosomes of one cell bind to cadherins in the desmosome of another cell

how are desmosomes different from adherens junctions

desmosomes are more button like and tightly packed while adherens junctions are more belt-like and more spread out

what are epithelial cells attached to

each other and the extracellular matrix (basal laminate)

how are cells anchored to the basal laminate

with a type of desmosome called Hemidesmosome

what are integrins

a type of hemidesmosome that participates in cell adhesion

what do tight junctions do

prevents the movement of substances thru the spaces between cells

which junctions don’t prevent the movement of materials between cells

adherens junctions and desmosomes

what are tight junctions

band of interconnected strands of membrane proteins

are all junctions involved in cell adhesion

no not all

WHAT are gap junctions (NOT what they do)

complex of membrane proteins called connexins

what do gap junctions do

allow material to pass between cytoplasm of cells and allow communication between cells

what are connexins

membrane proteins in gap junctions

what shape are connexins

ring of proteins

what do connexins connect to

connect to a similar ring of proteins in the adjacent cell

two connexion rings form a channel for molecules to pass thru

how do ions move in the heart

ions pass thru cell junctions that connect to cardiac muscle cells

what allows rapid communication between heart cells

movement between cells 

what is plasmodesmata

passages thru the cell wall of plant cells

do animal cells have plasmodesmata

no only plant cells

what does plasmodesmata do

allow cells to exchange ions and small molecules

what does the extracellular matrix do for organisms

provides the molecular framework that determines structure of organisms

what is the extracellular matrix made of

proteins and polysaccharides at a cells surface

what is the ECM of plants

cell wall

main component of plant cell wall is

polysaccharide cellulose

how many layers are in plant cell walls

3 layers

what are the three layers of plant cell walls

middle lamella, primary cell wall, secondary cell wall

what is the function of middle lamella

allows plant cells to stick together

which cell wall layer is synthesized first

middle lamellawh

what is middle lamella made of

gluelike complex carbs

what’s the primary cell wall made of mostly

cellulose with some molecules like pectinw

which layer of plant cell wall is thin and flexible

primary cell wall

what layer of cells walls is not always constructed in all plant cells

secondary cell wallw