Bio 4: Chapter 5

contains and protects DNA
Site of DNA replication/transcription
Partial ribosome assembly

2 lipid bilayers
interior of ER is connected to the space b/w the 2 membranes

region of nucleus that functions as ribosome factory

site of rRNA transcription by RNA pol I

Produce ATP via Kreb's cycle and oxidative phosphorylation

only inherited from mother

inner membrane folded into cristae to increase surface area, e- transport, and ATP synthesis.

contains pyruvate dehydrogenase and enzymes of the Kreb's cycle

smooth, contains large pores that allow free passage of small molecules

site of synthesis/modification of secreted, membrane-bound, and organelle proteins. 1 membrane. All proteins transported via vesicles.
also forms Disulfide bonds

Signal Sequence--> amino acid sequence on N-terminus recognized by signal recognition particle that binds to ribosome. Removed after translation in ER
Ex: Antibodies
Neurotransmitters
Peptide hormones

Signal Sequence
Transmembrane Domains--> hydrophobic amino acid residues that pass through lipid bilayer membranes (integral proteins)
Ex:
Receptors
channels

Signal Sequence
Targeting signal-->sends protein to lysosome
ex: Acid Hydrolases

Signal Sequence
Targeting signal-->sends protein to ER
ex: protein modification enzymes

Signal sequence
targeting signal-> sends protein to ER
ex: lipid synthesis enzymes

Signal sequence
targeting signal--> sends protein to Golgi
ex: protein modification enzymes

No signals!
ex: Glycolysis enzymes

made in cytoplasm
localization signal--> sends protein to nucleus
ex: Histones, DNA/RNA pol

made in cytoplasm
localization signal--> sends protein to mitochondria
ex: PDC/Krebs cycle enzymes

made in cytoplasm
localization signal--> sends protein to peroxisome
ex: catalase enzyme

Detoxification and Glycogen breakdown in liver
Steroid synthesis in gonads

1) modification of proteins made in RER
2) sorting and sending proteins to their correct destinations
3) synthesizes certain macromolecules
some synthesis

Golgi stacks nearest to rough ER.
Vesicles from rER fuse with cis stack

golgi stacks farthest from rER

Proteins leave trans face in vesicles

continuous/unregulated transport of proteins from golgi to the cell surface

when secretory proteins are stored in secretory vesicles and only released in response to a signal from the extracellular environment.
ex: pancreatic cells and b-cells

contain acid hydrolases used for degradation of biomolecules through hydrolysis
pH around 5 while cell pH is 7.4. if lysosome ruptures, it will be diluted ain cell and not harmful.

self-eating
degradation of cell organelles that are damaged or no longer functioning

degradation of large particulate matter engulfed by the cell. particle is stored in phagocytic vesicle that fuses with lysosome and is then degraded
ex:
macrophages in immune system engulf bacteria and viruses

lysosomal digestion of unneeded secretory products

protects the rest of the cell from damage by peroxides

catalase enzyme converts:
H2O2-->H2O+O2

phospholipids-->most abundant
glycolipids
cholesterol

bind extracellular signaling molecules (hormones) and relay these signals into cell

embedded in the membrane and held there by hydrophobic interactions

insertion of these proteins occurs in the secretory pathway of the rER as the protein is translated and threaded across the ER membrane.

stuck to integral membrane proteins and held by H-bonding and electrostatic interactions

lipids and proteins are free to diffuse laterally, but don't flip-flip

so the membrane has polarity

solute diffuses DOWN [gradient]
from [high] to [low]

solvent diffuses instead of solute
water moves from [high] to [low]

[solute] is the same in and out

[solute] inside >[solute]outside

cell bursts

[solute]inside < [solute]outside

cell shrivels

movement of solute down [gradient]
No energy required
ex: osmosis

diffusion of solute through membrane w/o help from protein
ex:
steroid hormones free to move back and forth across membrane by simple diffusion b/c they're hydrophobic
O2, CO2, lipids

movement of solute across membrane down gradient w/ help from channel or carrier proteins
transports: small hydrophilic molecules (very specific!)
ex: glucose into red blood cells
ions: Na+, Cl-, K+, etc.

carrier that transports 1 molecule across membrane at a time

carry 2 substances across membrane in same direction

carries 2 substances across membrane in opposite directions

non-specific holes

movement of molecules against gradient
from low to high

2 types

transport of a molecule coupled to ATP hydrolysis

not couple directly to ATP hydrolysis!
1st, ATP creates gradient.
then, Potential energy in gradient is used to drive transport of molecule across the membrane

transmembrane protein in plasma membrane of cell
ATP is hydrolyzed to pump 3Na+ out and 2K+ into cell (against both gradients)

1. maintains osmotic balance
2. establishes electrical gradient/ resting membrane potential
3. sets up Na+ gradient for 2ndary active transport

K+ leaks back out through these channels to keep osmotic pressure in balance

transport material oustice of cell using a vesicle that fuses to plasma membrane and expells contents into extracellular space.
ex: hormones and digestive enzymes

endosome (vesicle) forms to take in material from extracellular environment
3types

cell eating-->nonspecific
not an invagination

cell drinking-->nonspecific
takes in small molecules and extracellular fluid via invagination

very specific
clathrin coated pits and receptors bind to a specific molecule outside the cell.
ex: uptake of cholesterol from the lipoproteins in blood

lock and key interaction between receptor (lock) and ligand (key)

ligand= hormone or neuro-transmitter

3 types

open ion channel upon binding a particular neurotransmitter.
ex: L-gated Na+ channel on muscle cells at neuromuscular junction
neurotransmitter acetylcholine binds to receptor, which undergoes conformational change and becomes an open Na+ channel. The massive influx of Na+ down [gradient] depolarizes muscle cell and causes it to contract.

enzyme activity is initiated by ligand binding at extracellular surface of cell membrane
ex:
insulin receptor is a tyrosine kinase

transmits signal into cell w/ help from 2nd messenger
ex: cyclic AMP (cAMP)
used for energy mobilization through breakdown of fat and glycogen

hollow rod composed of Alpha-tubulin and B-tubulin
LARGE
uses:
mitotic spindles
transport
cilia/flagella

rod shaped
disassembled and reassembled as needed
made of actin protein (globular)
SMALL and concentrated in the cytoplasm
uses:
cell contraction
pseudopodia
pinch cell in 2 in cytokinesis

made of many proteins
medium sized
more permanent
uses:
provide cell structure and resist mechanical stress

general adhesive junctions. hold skin together tightly, but don't form a complete seal

seal lumens/ separates environments and blocks the flow of molecules across the entire cell layer
ex: blood brain barrier

cell to cell communication
form port-like connections b/w adjacent cells allowing the cytoplasms of two cells to mix. ex: cardiac muscle cells

cell actively replicates its genome

Gap phases separate S and M phases

G1+S+G2 phases
cell is metabolizing and synthesizing materials

more specialized cells are stuck in this phase (G0)

Mitosis--> partitioning of cellular components into two halves

Cytokinesis--> physical process of cell division

1) DNA condenses
2) centriols migrate to poles of cell and form mitotic spindles
3) nuclear membrane degrades

Chromosomes align across cell center

1) Sister chromatids are pulled apart
2) cytokinesis begins

1) Nuclear membrane reforms/reverse prophase
2) Cytokinesis completes

Left w/ 2 identicle daughter cells