L10: Cell Compartments

What do prokaryotes have instead of a nucleus

nucleoid region

where does transcription take place in prokaryotes

cytoplasm

where does transcription take place in eukaryotes

nucleus

where does translation take place in prokaryotes

cytoplasm

where does translation take place in eukaryotes

cytoplasm

prokaryotic cell membrane additions

hopanoids

eukaryotic cell membrane additions

sterols (cholesterol)

are prokaryotes or eukaryotes larger

eukaryotes

do prokaryotes or eukaryotes have a higher ratio of surface area to volume

prokaryotes

are prokaryotes internally organized

no, there are no organelles (some contain plasmids)

are eukaryotes internally organized

yes, they contain organelles

typical features of an animal cell

nucleus, endoplasmic reticulum, lysosomes, mitochondria, golgi apparatus, plasma membrane, cytoskeleton

additional features of a plant cell

cell wall, vacuoles, chloroplasts

• do not have lysosomes

system of interconnected organelles

endomembrane system

how do organelles communicate with other organelles

through the endomembrane system

• physically connected by membrane bridges

• use vesicles to transport substances between them

makes compartments within cell

endomembrane system

where specific functions take place within the spaces defined by the membranes

compartments

exocytosis

vesicles bud off from the endomembrane system and fuse with the plasma membrane to deliver contents

endocytosis

materials from outside cell are brought into cell using vesicles

defines the boundary of the nucleus

nuclear envelope

what does the nuclear envelope consist of

two membranes: inner and outer

nuclear pore proteins

holes in nuclear membrane created by proteins

• allows molecules to move into and out of nucleus

  • essential for nucleus to communicate with rest of cell

network of interconnected tubules & flattened sacs that are continuous with the outer membrane of nuclear envelope

endoplasmic reticulum

inner space of ER

lumen

rough ER

contains ribosomes & site of protein synthesis

free ribosomes

produced in cytosol

bound ribosomes

produced in rough ER

smooth ER

makes lipids (fatty acids and phospholipids); no ribosomes

receives vesicles from ER

golgi apparatus

what are the functions of the golgi apparatus

• modify proteins and lipids produced in ER

• sort proteins and lipids as they move to final destination

  • synthesize cell’s carbs

cisternae

series of flattened membrane sac surrounded by small vesicles found in the golgi

vesicles

transport proteins from ER to the Golgi

enzymes within the Golgi ____ proteins and lipids as they pass through

chemically modify

golgi-derived vesicles that degrade macromolecules

lyosomes

macromolecules needing to be degraded are packaged by the ____ into ____ that fuse with ____

golgi apparatus, vesicles, lysosomes

enzymes inside lysosomes are

• made in RER

• sorted in golgi

• packaged into lysosomes

what contains protein pumps and what are their purpose

lysosomes; keep internal pH around 5 to prevent protein and organelle degradation

t/f lysosome content does not need to be kept separate from the rest of cell

false

what are not parts of the endomembrane system

mitochondria and chloroplasts

what are the properties of mitochondria & chloroplasts

• harness energy for cell

• contain their own genomes

• can grow & multiply independently

mitochondria

harness energy and convert it into ATP

structure of mitochondria

rod-shaped with an outer membrane and complex inner membrane

chloroplasts

capture sun’s energy to synthesize simple sugars via photosynthesis

structure of chloroplasts

surrounded by double membrane with additional internal membrane called thylakoid (membrane containing light collecting molecules such as chlorophyll)

how are free proteins directed to their proper cellular compartments

via signal sequences

no signal peptides

protein go to cytosol

animo-terminal signal

protein goes to chloroplasts or mitochondria

internal signal

protein goes to nucleus

where do proteins produced by ribosomes in the RER end up

• lumen of ER

• embedded in ER membrane

• secreted out of cell

where does the protein go if it is destined to be embedded into the membrane

inserted into membrane as it is synthesized