Week 2 Flashcards
Define the sedimentation coefficient
A measure of how rapidly a particle sediments when subjected to centrifugal force
- Larger/ denser particles tend to sediments faster this have a higher S value.
Precise def: ratio of particle’s sedimentation terminal velocity to the acceleration that is applied to it
How is the sediment coefficient used in cell biology.
To identify where particles have originated from.
Cytoplasm - Function
To hold the internal contents of cytosol, organelles and sub cellular structures
Cytosol
semi fluid material
Plasma Membrane (PM) - Structure
Thick layer of about 4-8 nm (40-80 A) of lipids and proteins
PM - Function
Behaves as a boundary between cell and external environment
- Defines the cell
- Regulates movement in/out
- Mediates communication w/ external environment via protein receptors
Extracellular Matrix (ECM) - Structure
Fibrous network made of various proteins and/ or polysaccharides
ECM is linked to cell via PM components like integrin (inter membrane proteins)
What is the difference between ECM between species
It varies
Animals made of the fibrous protein - collagen
Plants made of polysaccharide - cellulose
ECM - function
- Provide support and structure by:
- Cell walls of plants (cellulose) or fungi (chitin)
- Bone Matrix
- Protection against osmotic pressure changes - Adhesion/ anchorage to surrounding medium (ex: tissue formation)
Nucleus - structure
Large organelle ~ 5- 6 micrometers in diameter and 10% of cell volume
Nucleus - function
Stores DNA = Control Center
Nuclear Envelope (NE) -Structure
surrounds the nucleus/ has a double membrane
NE - Function
Holds DNA in one part of the cell
Nuclear Lamina - Structure
Network of intermediate filaments ( components of the cytoskeleton)
Lamina lies just beneath the inner later of the NE
Nuclear Lamina - Function
Scaffolding by holding the cell up to support the nuclear structure
- Thought to also play a role in chromatin organization
Nuclear Pores - Structure
Regulated openings throughout the NE
Nuclear Pores - Function
Openings are controlled by NPC
Nuclear Pore Complex - Purpose
Behaves sort of like a basket by catching what doesn’t belong
- Controls movement of substances in/out the nucleus
Nucleolus - Structure
Region within the Nucleus
Cluster Region of ribosomal RNA genes surrounded by specific RNA’s and proteins
- Site of ribosomal subunit
Endomembrane System includes (7 organelles)
NE ER Golgi Lysosomes Vacuoles PM Transport vesicles
Endomembrane system is
a comprise system of membranes + internal spaces
Components can be directly connected to each other pr connected via transport vesicles
Rough ER - Structure
Large, Flattened Sheets
Ribosomes are temporally bound to cytosolic side
directly outside of the nucleus
Rough ER - Function
Produces proteins and glycoproteins
Products are distributed throughout EM system via transport vesicles included secreted products
Smooth ER - Structure
lacking in ribosomes right next to the RER
Golgi apparatus - structure
system of flattened sacs
Golgi - function
receives many of the transport vesicles produced in the ER
Modifies the ER products
Manufacture of polysaccharides - sorts and packages molecules for transport to final destinations
Lysosomes - structure
membranous sauce of hydrolytic enzymes
lysosomes - function
Intracellular DIGESTION
Phagocytosis
Conducted by the lysosome
: Ingestion of large particles (.0.5 micrometer diameter)
Autophagy
process of organelle degradation that takes place inside the cell - used to remove old/ damaged cell structures.
Cis Golgi Network
close to the ER
Trans (TGN)
Other side
Are ribosomes organelles
no they are sub cellular component
Structure of ribosomes
RNP - Ribonucleo protein complex
Complex of RNA molecules + proteins
Sizes of ribosomes vary btwn prokaryotes and eukaryotes
Ribosome equation for prokaryotes
50S+ 30S= 70S
Ribosome equation for eukaryotes
60S+ 40S= 80S
Make up of Bacterial Cell walls
Peptidoglycan
Make up of Archaea cell walls
proteinaceous walls
peptidoglycan like called Pseudomurein
What is the lumen of an organelle?
A luminous term referring to the channel within a tube such as a blood vessel or to the cavity within a hollow organ such as the intestine.
the internal volume enclosed by the membranes of a particular organelle;
Peptide
any compound composed of amino acids with the chemical structure of an amide between a carboxyl group of one amino acid and an amino group of another amino acid.
Explain why antibiotics can be used to treat bacterial infections w/o affecting human cells
Certain antibiotics work by inhibiting the CW biosynthesis - meaning compromising the integrity of the CW
–> By making bacteria susceptible to osmotic pressures –> while weakening CW’S so they will become lysed.
Explain what prokaryotic protein synthesis inhibitors do?
certain antibiotics work by inhibiting ribosome activity
Purpose of the Gram Stain
technique used to ID bacteria based on CW characteristics
used as a preliminary diagnostic tool
EX: Used to establish presence/ absence of bacteria
Method of Gram Stain
Cells are stained w/ purple dye –> Rinse w/ alcohol –> Stain again w/ counter stain (usually red dye)
Gram Positive bacteria
Have thick cell walls with larger amounts of peptidoglycan
Results of staining Gram positive staining
CW traps purple dye in cytoplasm –> Positive Purple
EX: Streptococcus
Gram Negative Bacteria
CW is located btwn PM and outer membrane
CW is thinner w/ less peptidoglycan
Results of Gram negative bacteria staining
Cell appears to be pink/ red after counter stain EX: Chlamydia
Gram variable
some stain can have mixed variables EX: leprosy
Initiation of Translation
Scanning until start codon is found causing the subunit ribosomes to attract
Elongation of Translation
Chain of peptides begin to grow
Termination of Translation
Release factor moves into the A site and the unit disassembles and the chain breaks off
