Exam #1 (CH9-10) Flashcards
Prokaryotes: what is a nucleotide needed for?
DNA Storage
Prokaryotes: what is supercoiled DNA?
Bonus DNA
Prokaryotes: what is the purpose of the plasma membrane?
Separates life from non-life
Prokaryotes: what is the purpose of ribosomes?
Manufacture proteins + RNA
Prokaryotes: what is the purpose of the cell wall?
Be a “exo-skeleton”, a fibrous layer surrounding cell, meant to maintain:
- structure
- function
- osmotic pressure
Prokaryotes: what is the purpose of plasmids?
Contain functional genes, may not need them but can be useful (antibiotic resistance)
Prokaryotes: what is the purpose of flagella?
“whips” that allow for swimming
Eukaryotes: what is the purpose of the nucleus?
DNA is highly organized, condensed
- nucleolus is where ribosomal RNA is manufactured
- nuclear shape is held by protein filaments (scaffolding)
- info storage = inside nucleus
- info use = outside nucleus
- nuclear envelope is continuous with ER
Eukaryotes: what is the purpose of the endoplasmic reticulum (Rough ER)?
Protein synthesis (more SA = more ribosomes)
- proteins are inserted into lumen at ER
- proteins shipped to areas of cell via vesicles
Eukaryotes: what is the purpose of the endoplasmic reticulum (Smooth ER)?
Lipid metabolism (hormones)
- synthesizes/breaks down lipids
- builds membranes (phospholipids)
- stores Ca2+
Eukaryotes: what is the purpose of the Golgi Apparatus?
modifies proteins
- stacked, flattened membrane sacs
- cis-side faces nucleus
- cis-side receives vesicles from rough ER*
- trans-side faces plasma membrane
- proteins processed inside Golgi lumen
Eukaryotes: what are free ribosomes?
proteins made in cytosol
not organelle - not enclosed in membrane
Eukaryotes: what is the function of a lysosome? Vacuole?
Lysosome - recycle other organelles/waste
Vacuole - commonly store water/ions plants and fungi only
What are the differences between eukaryotes and prokaryotes?
- Eukaryotes are compartmentalized (organelles + nucleus)
- Eukaryotes isolate incompatible chemical reactions (greater efficiency of chemical reactions)
- Eukaryotes are much larger (smaller SA:Volume ratio)
-Prokaryotes obtain nutrients more efficiently (greater SA:Volume ratio)
Eukaryotes: what is the purpose of the mitochondria? Chloroplast?
Mitochondria - cellular respiration (double membraned, semi-autonomous)
Chloroplast - photosynthesis (triple membraned)
Both specialize in energy conversion and have their own genome/ribosomes
Eukaryotes: what is the purpose of the cytoskeleton? Cell wall?
Cytoskeleton - network of protein fibers that provide:
- structural stability
- shape
- organization
- vesicle pathways
- moving cell through environment
Cell wall - rigid structure for support/protection
- large carbohydrates
- plants = cellulose
- fungi = chitin
* located outside of plasma membrane*`
Nuclear transport is regulated by ______.
Nuclear pores
- selective and use specific “tags” for entry
What was the purpose of the nucleoplasmin experiment?
Tested existence of “tag” on physical part of protein
- start with nucleoplasmin protein
- cleave tails from cores
- label tails and cores
- inject tails and cores into cells
- locate fragments (tails = nucleus, cores = cytoplasm still)
*Specific tag tells cell to take the nucleoplasmin to nucleus
What was the purpose of the pulse-chase experiment?
Test the idea that proteins move together in an organized fashion over time
- add a pulse of radioactive tracer
- after the pulse, “chase” with non-labeled molecules
- follow the radioactive proteins over time
Rough ER - secretory vesicles - secretory ducts
What is the general movement of a protein entering the endoplasmic reticulum?
- first 20 amino acids attract and bind to signal recognition particle (SRP)
- SRP also binds to endoplasmic reticulum
- ribosome puts amino acid chain through an ER pore
* proteins destined for Golgi are glycosated (+carb = glycoprotein)
What is the general movement of a protein moving to the Golgi Apparatus?
- vesicle buds off ER and moves to cis-side of Golgi
2. fuses to cis-side and dumps protein inside
What is the general movement of a protein moving to the final destination?
- modified by a transmembrane protein*
1. facing inward = recognizes protein
2. facing outward = recognizes protein on membrane of destination - uses receptors (protein) spanning membrane inside and outside Golgi*
Packaged vesicle!
What are three structures involved in the cytoskeleton and what are their functions?
- Actin - twisted pair of strands, define cell’s shape, move organelles around cells, smallest of the three types
- Intermediate Filaments - structure of nucleus, anchors nucleus in cell, NOT involved in movement, provide resistance to pressure/abrasions (keratin)
- Microtubules - hollow tubes, grow/shrink rapidly, tracks for vesicle transport (motor proteins), moves chromosomes during mitosis, largest of elements, uses ATP to carry vesicles and create movement along microtubules
What are fiber composites?
cross-linked network of long fibers embedded in rigid surrounding material
(Tensile strength vs compression)
The primary cell wall (extracellular material) consists of:
- fiber (cellulose)
- surrounding material (pectin = gelatinous polysaccharide)
- cellulose and pectins
- limit water that can enter a cell (turgor pressure)
The secondary cell wall (extracellular material) consists of:
- mature plant cells
- composition depends on function
- stem cells = lignin
- leaf cells = wood
The extracellular matrix (ECM) consists of:
- collagen and gelatinous polysaccharides as fiber composites
- cells attach to ECM via transmembrane proteins (integrins)
- loss of connection to ECM can lead to metastasis in cancer cells
- ECM is more flexible than cellulose or lignin
- breakdown of ECM can be reversed by enzyme pyolyl hydroxylase
catalyzes procollagen - collagen - absorbic acid is a cofactor for prolyl hydroylase
