Eukaryotes (Cell Structure- Organelles) Flashcards
cell theory
- All living things are made of cells
- cells represent smallest living thing
- cells come from previously existing cells
plasma membrane
a phospholipid bilayer (with proteins, etc) with genetic material (DNA) in the middle
Prokaryotes
- “Pro-” before the nucleus
- genetic material in the middle without another membrane surrounding the DNA
- *All bacteria are prokaryotes.
Eukaryotes
real nucleus which contains DNA and has as a nuclear envelope or a membrane for the nucleus
*all other living things
electron microscope
needed to look at substructure in cells 2 micrometers .2 micrometers- can see ribosome 2nm- diameter of DNA strand .1 nm - 1 angstrom, diameter of H atom
bacterial cell
2.5 microns long, 10X smaller than eukaryotic
Plasma membrane surrounding some substance in the middle (cytoplasm, cyto- cell)
DNA inside
Nucleoid region
- no membrane around it- where genetic material is found
- prokaryotic cells
Cell wall
- just outside of the plasma membrane
- made of peptidoglycan in bacterial cells
- made of cellulose in plant cells
Nucleus
- Membrane bound structure→ creates a separate chamber where genetic material is stored
- Membrane = nuclear envelope
- 2 membranes (double membrane) that create space called lumen
- ribosomes assembled in nucleus
Organelles
small organs inside cells
3 cifferences in plant cells
Cell wall
Chloroplast
Large central vacuole (animal cells often have small)
Nuclear envelope
- Inner and outer layer of nuclear membrane
- pores- holes in membrane
- complex structure that allows things to move in and out
- ex. DNA gets shipped out and will go through pores
lumen
- also called perinuclear space
- region between the two lipid bilayers of the nuclear envelope
- also in ER (ribosomes only on exterior of lumen)
Nuclear pore complex
Pores are complex structures, not just holes
Regulate what goes in and what comes out
Nucleolus
- within the nucleus
- area where ribosomes are being assembled
- rRNA is made here- used to make the ribosomal structures–> transcription
- Sometimes the nucleolus will go away depending on the stage of the cell
Chromatin
- material in the nucleus that takes up a colored stain
- DNA in the nucleus + associated proteins and some RNA
- two types- Heterochromatin and Euchromatin
Heterochromatin
- Condensed and inactive chromatin around the edges of the nucleus
- Light staining
- ex. liver genes would be “off” in a skin cell, so it would be in the heterochromatin
Euchromatin
- Chromatin that is actively expressing genes
- in the middle of cell- to do work
- dark staining
- ex. liver genes would be “on” in liver cells, so in the euchromatin
Genes
genetic material that is making particular proteins
expressed in the middle of the nucleus
Lysosome
- Lysis- split, Some = body/structure
- membrane bound sac that contains dozens of enzymes that break down macromolecules into monomers that can be recycled
- pH optimum
- Phospholipid bilayer around it
break down food from outside cell, and old organelles from inside cell
pH optimum (lysosome)/proton pump (acid hydrolysis)
- Internal pH ~7.0, when activated, pH lowers to ~5.0
- Membrane has an ion channel (proton pump) that can pump in H+–> pH falls (becomes acidic), and the enzymes become active for digestive
- breaks down macromolecules into monomers by adding water
- Monomers are shipped out by metabolite transporter for use of other things
Secretory pathway- Phagocytosis (lysosome)
- cell eats food from environment
- phagocytosis creates vesicle called an endosome = food vesicle
- vesicle fuses together with a lysosome
- goes into combined chamber of vesicles (2 prime) which is further digested
Digestive enzymes in lysosome break down food particle
Proton pump starts up and turn pH down
primary/secondary lysosome
primary- lysosome is first produced
secondary0 when pH is lowered
smooth endoplasmic reticulum
- No ribosomes here
- make carbohydrates and lipids
- Detoxifies material from outside of cell
rough endoplasmic reticulum
- With ribosomes stuck to the membranes
- making proteins for export
- proteins secreted out of cell to be used in biological membranes
Signal Hypothesis (Gunther Blobel)
- all protein synthesis starts in cytoplasm on free ribosomes
- if the signal is present, it moves to the rough ER, if the signal is not present, it will remain in the cytoplasm
- if chain has nonpolar properties- signal protein (SRP) will pull whole chain to membrane of ER and directs newly synthesizing proteins through pore to complete synthesis
Golgi apparatus
- series of membranes that are stacked closely together
- Site of sorting, packaging, and shipping
- Assembly of compound proteins
- Polypeptide, attach sugars, fat→ called glycolipids, lipoproteins, glycoproteins
- Organizes enzymes for where they should go
- range of signals to tell where golgi to send something
circular transport (golgi), secretory pathway
- Er Lumen comes off in little vesicles, fuses with golgi
- Proteins get sorted→ then some are secreted–> fuse with membrane
CIS side- receiving
TRANS side- sending
BSA
Secretory pathway made on rough ER and goes through golgi- circulates through blood to keep osmotic balance
Mitochondria
- Energy managing organelle, long and thin
- Mito- thread-like
- double membrane- creates intermembrane space
- Inner membrane is folded up = called crista–> creates large surface area
- Makes ATP
Chloroplast
Energy managing organelle in plants
Peroxisome in epithelial cell (glyoxysome in plants)
- organelle membrane bound compartment- has specialized enzymes that deal with reactive oxygen species
- to keep toxic intermediate products produced in biochemical reactions in chamber so they don’t interfere with other things
- Might produce a free oxygen radical
- Highly reactive, enzyme converts it to H2O2 (which is also a little reactive but not as reactive)–> enzyme detoxifies product
epithelial cell (polarized)
- lines a void and creates barrier of tight junctions between lumen on one side and tissues underneath
- polarized cells- functional differences of top and bottom
- Microvilli at top of cell- “finger” like- job of absorbing good nutrients (sugars and amino acids), increases area of cell
- Bottom of cell- job is to secrete materials that are absorbed at the top, ship them out
housekeeping gene
- active genes in all cells that do normal processes
protein syntehsis
- synthesized in cytoplasm
- mRNA looks for signal
- signal present
- SRP takes protein to ER
- ER forms vesicle with protein
- sent to golgi
- packages/ships to new
vacuole
- in animal and plant cells
- space filled with something (food, water)
cytosol
- the aqueous component of the cytoplasm of a cell, within which various organelles and particles are suspended.
