AP bio vacuoles and other structures (plant cells)

food vacuoles, contractile vacuoles, and central vacuole

3 types of vacuoles

food vacuole

formed by __phagocytosis__

* in protists and some animal cells

contractile vacuole

* in protists like amoebas and paramecia
* ^^pump out excess water^^
* squeezes out of cell
* help **regulate salt/solute concentration** in a cell
* stop cell from absorbing too much water and exploding

central vacuole

* ^^__**very large and obvious in plant cells**__^^
* __tonoplast__: membrane that encloses and surrounds the central vacuole in plant cells
* stores water for plant cell, but what else:
* organic molecules such as proteins
* not as food, but used to build things plants need
* ions, such as k+ and cl-
* metabolic byproducts too dangerous for cytosol
* pigments that color the cell (brightly colored petals)
* secondary organelle for this
* poisonous chemicals to discourage others from eating them

plastids

* general name for storage organelles in plants
* includes: chloroplasts, leucoplasts, and chromoplasts
* wouldn’t have more than one active in same part of plant

chloroplasts, leucoplasts, and chromoplasts

3 types of plastids

chloroplasts

* ^^__site of photosynthesis in plant cells and photosynthetic protists__^^
* contain the pigment __**chlorophyll**__ (green)
* __**granum**__: stack of thylakoid

chloro

“green”

chlorophyll

green pigment in chloroplasts

granum

stack of thylakoid

thylakoid

individual disk; membranes are the site for the light reactions

chromoplasts

* ^^__store red, orange and yellow pigments (primarily)__^^
* important in fruit ripening
* (in use AFTER chloroplasts \[?\])

chromo

“color”

leucoplasts

* aka: __**amyloplasts**__
* ^^colorless/white plastids that store starch^^

leuco

“white”

cell wall

* cell walls are found surrounding: plant cells, bacterial cells, fungi, and a few protists
* prokaryotes/bacteria: cell walls are made of ^^peptidoglycan^^
* euk:
* fungi: cell walls made of chitin
* plants: cell walls made of cellulose
* cell walls and membranes __**arent**__ the same; **cell walls** are like brick walls while **membranes** are like chain link fences

plant cells, bacterial cells, fungi, and a few protists

cell walls surround

peptido

“protein”

glycan

“sugar”

peptidoglycan

prokaryote/bacteria cell walls are made of…

chitin

fungi cell walls are made of…

cellulose

plant cell walls are made of…

primary cell wall

* ^^**outermost layer of the cell wall**^^
* ^^__***every cell*** *has this layer*__^^
* __**fexible**__; alows for expansion
* ergo, plant cell dont burst as much

primary cell wall

every cell has…

secondary cell wall

* ^^__**innermost layer**__ **of plant cell wall**^^
* ^^**very rigid/not very flexible**^^
* found in woody stems (cork aswell)
* layer that **remains** when plant cell dies
* what hooke found

middle lamella

* not actually part of cell wall
* ^^__sticky pectin that “sticks”__ __**adjacent**__ __plant cells together__^^

plasmodesmata

* ^^__channels that connect the cytoplasm of__ __**neighboring**__ __plant cells__^^
* allows the passage of water and some solutes

gap junctions, tight junctions, and desmosomes

3 types of junctions ^^**between animal cells**^^

gap junctions

* ^^__cytoplasmic channels that connect one animal cell to another__^^
* allow ions, sugars, and other small molecules to pass through
* similar to __**plasmodesmata**__ between plant cells
* important part of intercalated disks in heart muscle tissue

tight junctions

* ^^**membranes of neighboring cells pressed very tightly against each other**^^
* bound by specific proteins that tie up like **laces**
* __purpose__: to make the space between cells impermeable to fluid

desmosomes

* ^^__**common in the skin**__^^
* attach to __intermediate filaments__ (made of keratin) in the cytoplasm
* act as ^^“reinforcements” to hold the skin cells together and strengthen the skin^^ since it can be subject to mechanical stress

tonoplast

membrane surrounding central vacuole in plant cells