AP bio vacuoles and other structures (plant cells)

food vacuoles, contractile vacuoles, and central vacuole

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