Exam 1 + 2 Material Flashcards
Flippase
Maintains ASYMMETRY between leaflets of the plasma membrane (charges
Scramblase
Maintains SYMMETRY between leaflets of ER membrane
Protein modifications to regulate chromatin structure
- Methylation of lysine (neutral)
- Acetylation of lysine (+)
- Phosphorylation of serine (-)
Functions of Golgi Apparatus
- Central sorting center for proteins
- Attachment of O-linked carbohydrates to proteins
- Modification of N-linked glycosylation on proteins
Functions of ER
- Attachment of N-linked carbohydrates to proteins
- Calcium storage
- Lipid synthesis
Molecules with charge in a solution
- Phosphatidylserine
- Amino acids
Molecules with NO charge in a solution
Sugars (monosaccharides)
Where is phosphatidylserine found
Inner leaflet
Where is phosphatidylcholine found
Both leaflets
Differences between eukaryotes and prokaryotes
- Eukaryotes: linear cells, nucleus, internal membrane, telomeres, multiple origins of replications, introns
- Prokaryotes: circular cells, no nucleus, no internal membrane, no telomers, one origin of replication, no introns
Sterols
Contains a rigid structure that stiffens phospholipids
Types of sterols
- Animal: cholesterol
- Fungi: ergosterol
- Plants: phytosterol
Plant cell wall components
- Cellulose provides tensile strength
- Tensin provides resistance to compression
- Lignin provides waterproofing
- Turgor pressure allows water to move inside the cell to build up internal pressure and prevent them from wilting against gravity
Nuclear lamina
- Provide structural support
- Site for chromosome attachment during interphase
- Mutations can cause diseases such as Progeria
Nuclear intermembrane space
Continuous with ER lumenal space (not mitochondrial)
Nuclear pores
Allows small molecules to diffuse freely into the nucleus but large molecules require active transport
Nucleolus
Site of ribosome assembly
Resolution vs. Magnification
- Resolution is the ability to distinguish 2 objects that are close to each other
- Magnification is the ability to make an object appear larger/smaller but it will still be blurry
Hydrophobic force
- Effect of entropy as a result of hydrogen bonding of the polar head groups being attracted to water
- The hydrogen bonds increase entropy
Endosymbiont theory organelles
- Mitochondria
- Chloroplasts
Mitochondria endosymbiont theory
- Has 2 membranes
- Contains ribosomes
- Has circular mDNA
- This shows it was a prokaryotic cell that was engulfed by a eukaryotic cell
Heterochromatin features
- Highly condensed
- Can silence genes
Structures in heterochromatin
Centromeres and telomeres
Euchromatin features
Less condensed than heterochromatin
Structures in euchromatin
- Accessible to RNA transcription machinery
- Ex. RNA polymerase
Ribosome function
Protein synthesis
What are two sugars linked by
Oxygen
Electron microscopy
- Higher resolution compared to light microscopy
- Cells must be fixed (Cannot see living cells)
- Cannot see color
Light microscopy
- Can visualize living cells
- Can see different colors
- Limited resolution
Scanned electron microscopy
Can only see the EXTERNAL surface of a cell
Transmission electron microscopy
Can only see the INTERNAL surface of a cell
Fluorescence microscopy
- Absorb light at one wavelength
- Emit light at a longer wavelength
- Can visualize small cells
Confocal microscopy
- Uses scanning laser and pinhole apertures to limit detection in a focal plane
- Useful for obtaining 3D imaging
Resolution ranking
- DIC
- Green
- Red
Fluid Mosaic Model
- NOT continuous with the nucleus
- Fluid because molecules move freely past each other via lateral diffusion
- Mosaic because it contains discrete units that contain microdomains such as lipid rafts
- Phospholipids maintain lateral movements due to high levels of cholesterol
- Lipids can diffuse freely within a microdomain but are limited with neighboring microdomains
Lipid rafts
- Consists of lipids, proteins, and other molecules that act as discrete units
- Help with cell signaling and protein movement
Biomolecules that are polymers
- Carbs
- Proteins
- Nucleic acids
Carbohydrate monomers and functions
- Monomer: monosaccharide
- Store energy
- Provide structural support for a membrane
Protein monomers and functions
- Monomer: Amino acids
- Use their R-groups to interact with their environment
- Maintain cell communication
- Perform most cellular function
Nucleic Acid monomers and functions
- Monomer: Nucleotides
- Short-term energy storage
- Carry genetic information
Lipids
- Composed of fatty acids linked to glycerol
- Energy storage
- Assemble into membranes
Central Dogma
DNA > RNA > Proteins
Spontaneous Reactions
- Increase entropy in a system by releasing energy
- Useable energy decreases in these reactions
- Spontaneous reactions are favored
Second law of Thermodynamics and Cells
- Cells want to increase order to survive, so they need to expend energy to reduce entropy
- The second law states that processes are driven to increase entropy, which applies to closed systems
- Although cells are in open systems, they do NOT violate this law cells release heat into the universe which increases entropy
N-linked glycosylation
- Attaches oligosaccharide to NH2 groups on asparagine
- Can attach to multiple at the same time
O-linked glycosylation
- Attaches oligosaccharide to an OH group on serin and threonine
- Can only attach one at a time
