ch. 4 oct 16 a tour of the cell

mitochondria

carries out cellular respiration in all eukaryotic cells

what kind of membrane does the mitochondria have

double membrane, each phospholipid bilayer with embedded proteins

cristae

mitochondria inner membrane, highly folded

• increases surface area to maximize ATP production

intermembrane space

region in between outer and inner membranes of mitochondria

mitochondrial matrix

• region inside inner membrane

• contains mitochondrial DNA ribosomes and enzymes

chloroplast function

photosynthesis: converts solar energy to chemical energy

what kind of membrane do plant cells have

double membrane separated by a thin intermembrane space

stroma

thick fluid inside inner membrane

• contains chloroplast, DNA, ribosomes, and enzymes

thylakoids (plant cells)

network of interconnected membranous sacs

granum

stack of thylakoids, resembles stack of poker chips

thylakoid space

space inside a thylakoid

chlorophyll

embedded in the thylakoid membranes to trap solar energy

endosymbiont theory

mitochondria and chloroplasts were once small prokaryotes that began living inside larger cells

similar characteristics between mitochondria and chloroplasts

closely resemble prokaryotic cells →

• single circular DNA molecule

• ribosomes similar

• reproduce inside the cells in a similar way

endosymbiont theory process (mitochondria)

• photosynthetic prokaryotes filled our atmosphere with oxygen

• large cell engulfed a small cell that could use oxygen to make large amts of energy

• host cell and the endosymbiont emerged → eukaryotic cell with mitochondria

benefit to host cell (endosymbiont theory)

high levels of ATP production

benefit to the small, non-host cell (endosymbiont theory)

protection, large supply of nutrients

endosymbiont theory (photosynthetic eukaryotes)

• early eukaryotic cells engulfed a small photosynthetic prokaryote

• provides the host with nutrients and energy

• eukaryotic cell that contains chloroplasts

cytoskeleton

networks of protein fibres extending throughout the cells

what can the cytoskeleton interact with

motor proteins

• swimming and crawling motility of cells

• internal movement of cellular structures

microtubules →

• what are they

• where do they grow out of in animal cells

• straight hollow tubes composed of globular proteins → tubulins

• centrosome

microtubule functions

• supports and shapes the cell

• track where organelles can move with the help of motor proteins

• guides the movement of chromosomes when cells divide

• main component of flagella and cilia

intermediate filaments →

• where is it found

• what is it composed of

• in most animal cells

• fibrous proteins that supercoil into cables

intermediate filaments function

reinforce cell shape and anchor some organelles that should not move

what is the outer layer of your skin made of

made of dead cells packed full of intermediate filaments

microfilaments →

• what is it and what is it composed of

network inside cell membrane that supports cell shape. rods composed of globular actin protein

what cells are microfilaments important in

animal cells (because they don’t have a cell wall)

how do microfilaments make a cell move

• actin filaments and myosin motor proteins interact

• cells contract (crawling movement in amoeboid)

cilia

short, numerous appendages protruding from cell and move together in a sweeping motion

cilia functions

• propel single celled organisms

• line our trachea to sweep mucous out of lungs

• antennae for signal reception (non-motile)

flagella

long tail-like appendage on cell (one~few per cell)

flagella function

propels cell using whip-like motion

where is flagella commonly found

animal sperm cells, motile prokaryotic cells

extracellular matrix functions

• holds cells together in tissues

• protects and supports the plasma membrane

• relays signals that affect gene expression

• directs movement of embryonic cells

structure of extracellular matrix

glycoproteins

• most abundant: collagen

• collagen fibres are embedded in a network of small glycoproteins and polysaccharides

matrix is bound to the plasma membrane by proteins called

integrins

tight junctions

Plasma

membranes of adjacent cells are

knit tightly together

anchoring junctions

Intermediate filaments fasten cells together into strong sheets

• susceptible to stretching and mechanical stress

gap junctions

channels or pores that allow flow of small molecules from cell to cell

cell wall →

• where is it found in

• what does it provide

• what is it made up of

• found in plant cells

• skeletal support

• cellulose fibres

plasmodesma

channels in cell wall to transport nutrients