Cell Basics Flashcards
Eukaryotes (8)
- Protists, Fungi, Plants, Animals
- Cell wall present in fungi and plants
- Nucleus
- Multiple linear chromosomes
- ribosomal subunits 40S and 60S
- Membrane-bound organelles
- mitosis/meiosis
- Steroids in plasma membrane (for rigidity)
Prokaryotes (8)
- Bacteria, archaea
- Cell wall present
- no nucleus, nucleoid
- Predominately circular DNA (plasmids)
- Ribosomal subunits 30S and 50S
- no membrane-bound organelles
- No mito - ETC on cell membrane
- no steroids in membranes (rely on protein network and cell wall for rigidity)
- binary fission
Endosymbiotic theory
the theory that Eukaryotic cells evolved through symbiosis of prokaryotes (similarities between mitochondria, chloroplasts and prokaryotic cells)
similarities between mitochondria, chloroplasts and prokaryotic cells (3)
- multiply through binary fission
- contain circular DNA
transport - proteins called porins
Order Nucleus, mitochondria, ribosome, and chloroplasts from largest to smallest DIAMETER (µm)
Nucleus - Chloroplasts > Mitochondria > ribosome
Order Nucleus, mitochondria, ribosome, and chloroplasts from largest to smallest DENSITY (µm
ribosome - chloroplasts > Nucleus > mitochondria
What are the differences between archaea and bacteria?
Archeae:
- More genetically similar to eukaryotes than bacteria
- some can survive very high temperature
- Membrane lipids have more ether bonds (more resistant than ester bonds)
Bacteria:
- membrane lipids have ester bonds
- some are pathogenic but others have a mutualistic symbiotic relationships (gut bacteria)
- cell walls contain peptidoglycans
- have flagella and fimbriae
What are shared traits between Archaea and bacteria?
- Similar shape
- Same ribosomal density
- binary fission
- singular circular chromosome
- phospholipids
- most have cell walls
- found in animals, soil, oceans
Cell organelles underwen a differential centrifugation process in a sucrose solution. the speed of the centrifugation increased. At the end, where would the ribosomes appear in relation to the mitochondria?
the ribosomes would be further from the surface than the mitochondria
(in centrifugation, the smaller and denser molecules are pushed downward)
- if one or the other, an equation is needed
is ribosome an organelle?
No
from what is driven our undertanding of the plasma membrane?
the Fluid mosaic model
Why is the phospholipid bilayer amphipathic?
hydrophobic tails on the inside and hydrophilic heads on the outside allows the membrane to be both hydrophobic and hydrophilic qualities
What is the structure of a phospholipid?
a glycerol backbone (organic) + 1 Phosphate group (inorganic) and 2 FA chains
types of proteins in membrane
- peripheral (tend to move around a lot)
- integral (completely embedded - more stuck, or transmembrane)
What are some peripheral proteins on the membrane?
Surface proteins and some glycoproteins
What are some integral proteins on the membrane?
Completely embedded (tend to move less) and transmembrane
What are examples of transmembrane proteins ?
- some glyproteins
- transport proteins (channels)
- membrane receptors
What is the role of glycoproteins on the membrane?
Carbs and protein that form H bonds to reinforce the cell’s structure, and membrane receptors
Types of membrane receptors?
- Ligand-gated ion channel receptors
- Enzyme-coupled receptors
- G-protein coupled receptors
The Lipid raft theory
dense regions of the plasma membrane heavy in Cholesterol and serve as protein signaling platforms (can move across the membrane and can be broken down into smaller rafts)
Why is the lipid raft theory controversial?
because it can only be observed indirectly using fluorescent microscopy
What are the types of passive transport?
- Simple diffusion
- Facilitated diffusion
- Osmosis
- Filtration
What are the types of active transport?
- Primary
- secondary
- Exocytosis
- Endocytosis
What are the types of endocytosis?
- Pinocytosis (cell-drinking)
- Receptor-mediated
- phagocytosis
What is passive transport?
Molecules move in and out of the cell according to concentration gradient –> Kinetic Energy, no ATP needed
What is simple diffusion?
Molecule simply passing from one side of the membrane to the other
What is facilitated diffusion?
a transport protein helps the molecule go from one side of the membrane to the other - Important for:
polar hydrophilic molecule beacuse hard to go across the lipid layer.
and large molecules (glucose)
Carrier protein
a type of transport protein where the moleucle binds to the protein and is specific enough, taken in, and released on the other side.
Channels
simple transport proteins where no binding required and less specific
Osmosis
simple transport involving a solvent - usually water - across the permeable membrane, depending on the concentration of the molecules, through aquaporins - not guated, structural only.
Are aquaporins the only way for water to get across the membrane?
no can also simply difuse across but when needed in large quantities, will go through aquaporins.
Osmolarity
Used to describe solute concentration
C= n/V –> Solute concentration / volume solvent
(blood osmolarity: 290 mOSm/L)
Osmolality
Used to describe solute concentration
Solute concentration per mass solvent.
if too high, body wil secrete anti-diuretic hormone (to remove excess water/volume)
Tonicity
Used to describe solute concentration
Measure of osmotic pressure gradient between two solutions
Only influenced by solutes that can’t cross the membrane.
Isotonicity
the solute concentration is the same inside and outside of the cell
Hypertonicity
the solute concentration is greater outside of the cell, water follows out and causes cell to shrivel = crenation
Hypotonicity
The solute concentration is higher inside of the cell, water follows and causes cell to swell/lyse
Filtration
water and small molecules are forced through a selective permeable membrane due to hydrostatic pressure (heartbeat, kidney, liver…)
What is active transport?
it is the movement of molecules against the concentration gradient, using ATP
Primary active transport
makes direct use of ATP to push molecules against their concentration gradient.
Secondary active transport
uses indirect forms of ATP to push molecules and is gradient.
(powers other mechanisms and as a consequence, pushes molecules in and out)
Na-K pump
uses ATP to move 3 Na+ out and 2 K+ in, ATP is converted to ADP and the energy of the cleavage is used to drive the pump