Organelles + Cell Structure

unlike prokaryotic cells, eukaryotic cells have many

organelles surrounding their own membrane

organelles have specialized jobs because they contain

unique sets of molecules + proteins (including enzymes)

nucleus

largest organelle + house DNA

prominent features of nucleus

• chromatin

• nucleolus

• nuclear membrane

chromatin

• fibers of DNA carry hereditary info

• includes DNA plus all attached proteins

• DNA = covered in proteins to help organize it + control what genes are being used to make proteins

• DNA is usually spread out + spaghetti-like, but it condenses into a chromosome structure in cell division

nucleolus

contains the genes that code for ribosomes

nuclear membrane

outer covering of the nucleus + is made up 2 bilayers of phospholipids

• has nuclear pores which allow the transport of proteins, mRNA, ribosomes, and other molecules in + out of nucleus as needed

Cytoskeleton

outside of nucleus in the cytoplasm is a dense web of fibers made up of proteins

functions of cytoskeleton:

• support of cell shape

• transport of materials inside the cell

• cell movement

3 main types of fibers

• Microtubules- transport of materials

• Intermediate filaments- support cell shape

• Microfilaments- movement of cells

histones

wrap around DNA to move them closer + farther and also pack it in and condense

microtubules

• thick hollow tubes

• tracks to which molecules + organelles within cell may attach and move along

• often radiate out from middle of cell

• in specific cell, can also be used for motion within cilia + flagella

• key player in cell division

intermediate filaments

• durable, rope like systems of overlapping protiens

• strength

microfilaments

• long, solid, rod-like

• cell contraction + cell division

• helps with full cell movement

mitochondria

power house of the cell; has the job of turning chemical energy (food) into cellular energy (ATP)

what does the mitochondria preform

cell respiration, requires a lot of energy, 80% of what we breathe

where is the mitochondria most abundant

liver cells, then skeletal muscle cell

mitochondria is a result of what

endosymbiosis

mitochondria was originally a eukaryotic cell, why

It has its own DNA (mtDNA) and can replicate itself independently from the rest of the cells; same as your mother’s

people have how many mitochondria

varying, depends on how much energy they use

lysosomes

Garbage disposal: has a low-pH interior with many destructive enzymes that allow it to break down cell waste

• H+ pump ensures pH stays low

• Final destination for captured bacteria

the endomembrane system

• where proteins are built + get to locations

what does the end-membrane consist of

ER and Golgi; site of photosynthesis for proteins and lipids as well as packaging + shipping to the appropriate parts of the cell

types of ER

smooth + rough

rough ER

• Site of protein synthesis + folding; presence of ribosomes on the surface

• Ribosomes insert proteins (polypeptides) into the rough ER while they are building them

• Once inside, the proteins are added + sent to golgi in vesicles

smooth ER

site of lipid synthesis (including phospholipids + lipid hormones)

• liver cells have extensive smooth ER, which preforms a role in removing toxins from out blood

what is synthesizes by ER and what is it passed to

proteins + lipids; synthesized in the ER and passed to golgi via vesicles

what does the golgi do with the protiens and lipids

Further modifies the proteins + lipids and sends them to the correct location with vesicles

cell wall functions

• provides cell with structural strength

• gives the cell increased water resistance

• provides some protection from insects + other snimals that might eat plants

function of plasmodesmada

allow water + other molecules to pass between adjacent cells

vacuole functions

• store nutrients

• retains + degrades waste products

• accumulate poisonous material

• contains pigments (enabling plants to attract bird or insect pollinators)

• provides physical support

vacuole - store nutrients:

vacuole stores hundreds of dissolved substances

vacuole - waste management

retains waste products + degrades them with digestive enzymes, like lysosomes

vacuole - predator deterrence

poisonous, nasty-tasting materials that accumulate inside the vacuoles of some plants + acts as a deterrent to animals that eat them

vacuole - sexual reproduction

contain pigments that give some flowers color + attract pollinators - birds and insects that help the plants reproduce by transferring protein

vacuole - physical support

high concentration of dissolved substances in the vacuole can cause water to rush into cells via osmosis

• The increased fluid pressure inside vacuole can cause cell to enlarge + push against cell wall

chloroplats function

• site of photosynthesis + conversion of light energy into chemical energy

photosynthesis

Light is collected for photosynthesis on the membranes of thylakoids

• EQ: 6CO2 + 6H20 —> light —> C6H12O6 + 6O2