BIOL 1090 FINAL Flashcards
What do cells require?
Differentiation, information, chemistry, compartments.
What are the characteristics of prokaryotes?
No nuclei, no organelles, no DNA, can’t synthesize RNA, can’t divide, limited repair abilities.
Why is RBC dying off beneficial?
Allows to accommodate max hemoglobin carrying capacity.
What is the method by which RBC eject their nucleus?
Enucleation.
What is differentiation?
The process by which cells become specialized.
What experiment tested the chemical origin of life?
Miller-Urey (1952).
What is abiogenesis?
Chemical origin of life establishes physical boundary.
Who discovered cells?
Robert Hooke in 1665.
What are the elements of cell theory?
- All cells come from other cells
- Cells are the basic unit of life
- All living things are made of cells
What are the properties of cells?
Highly complex and organized, controlled by genetic program, can reproduce, make and use energy, carry out chemical reactions, engage in mechanical activities, respond to stimuli, self-regulate, evolve.
What is the genetic material of prokaryotes found in?
Nucleoid.
How is genetic material in eukaryotes organized?
Into chromosomes.
What are the additional structures found in plant cells?
Cell walls, vacuoles, chloroplasts, plasmodesmata.
What structures are found in animal cells?
Lysosomes and microvilli.
What type of organism is a slime mold?
Single celled, sexual reproduction, multinucleated.
What are viruses unable to do?
Can’t reproduce outside of living cells.
What is a viron?
An inanimate particle outside of a cell.
What is a capsid?
Protein capsule of a virus.
How are viruses categorized?
Based on type of genome and method of replication.
What is the Baltimore classification?
A system that categorizes viruses based on their genome and replication method.
What is an example of a retrovirus?
HIV.
What virus affects the liver?
Hepatitis B (Hep B).
What virus causes hemorrhagic fever?
Ebola.
What type of illnesses does Adenovirus cause?
Respiratory illness, eye infections.
How many viruses have been described?
5000.
What is CRISPR-Cas?
An immune-like system that plays a role in anti-viral defense.
What is lytic viral replication?
Production of virus ruptures and kills the cell.
What is non-lytic viral replication?
Viral DNA inserted, cells can survive but have impaired function.
What is a monopartite genome?
The entire genome is contained in a single nucleic acid segment.
What is a multipartite genome?
Genome occupies several nucleic acid segments.
How many types of rabies are known?
7.
How is Zika virus transmitted?
Mosquitoes, bodily fluids, sexual contact.
What is microcephaly?
Abnormally small head.
What are the effects of microcephaly?
Motor and speech delays, intellectual disability, seizures, balance problems.
When does neurogenesis occur?
Week 10-25.
When does gliogenesis occur?
Week 25-40.
How do RNA vaccines work?
Trick the body into producing antigen.
How does replicase work in RNA vaccines?
Makes lots of copies of the RNA template.
What are the functions of biological membranes?
Define cell boundary, define compartments, control movement in/out, allow response to stimuli, enable interactions, provide scaffolding.
What is the plasma membrane?
A trilaminar membrane.
How thick is the plasma membrane?
6nm.
What is the lipid bilayer made of?
Phospholipids.
What are micelles?
Structures with 1 head and 1 tail.
What are liposomes?
Structures with 2 heads and 2 tails.
What are sphingolipids important for?
Signal transduction and cell recognition.
Where does the synthesis of phospholipids occur?
At the interface of cytosol and outer ER membrane.
What is the process of phospholipid synthesis?
FA activated by CoA, inserted into cytosolic leaflet, phosphate removed by phosphatase, choline linked to P via choline phosphotransferase.
What do flippase and floppase do?
Transfer phospholipids to other leaflet.
What are proteins embedded in the phospholipid bilayer?
They perform various functions.
What are myelin sheaths?
Layers of PM wrapped around neuron’s axon, increasing speed of electrical impulses.
What is the IMM?
Very high concentration of protein needed for ETC and ATP synthesis.
What are the three classes of membrane proteins?
Integral, peripheral, lipid-anchored.
What is the function of integral proteins?
Transport nutrients and ions, communication, attachment.
What is the symmetry of leaflets in the plasma membrane?
Asymmetrical.
How does increased temperature affect the lipid bilayer?
Increases fluidity, known as liquid crystal.
How does decreased temperature affect the lipid bilayer?
Decreases fluidity, known as crystalline gel.
What is the effect of unsaturated lipids on fluidity?
Increase fluidity.
What is the effect of saturated lipids on fluidity?
Decrease fluidity.
What does a balanced membrane allow for?
Mechanical support and flexibility, membrane assembly and modification, dynamic interactions.
What is the function of cholesterol in membranes?
Modulates membrane fluidity.
What is a bidirectional regulator of membrane fluidity?
Cholesterol.
What is the transmembrane protein domain?
Peptide sequence, hydrophobic, spans across the PM.
What is the most common protein structure element crossing the biological membrane?
Alpha helix.
What are tetraspanins?
A superfamily of membrane proteins found in all multicellular eukaryotes.
What is the function of tetraspanins?
Cell adhesion, motility, and proliferation.
What is simple diffusion?
Nonmediated transport for small, uncharged molecules.
What is diffusion through a channel?
Nonmediated transport for small, charged molecules.
What is facilitated diffusion?
Mediated, passive transport.
What is active transport?
Mediated, active transport.
What is gated ion channels?
Transport that can be turned on/off in response to signals.
What is action potential?
Passage of electric signal down a nerve.
What is a ligand-gated channel?
Responds to binding of a molecule on its surface, causing a conformational change.
What is tetrodotoxin?
Discovered in pufferfish, Na+ channel blocker, causes death by respiratory failure.
What is curare?
Found in plants, occupies the same position on receptor as Ach, causing muscles not to move.
What is a symporter?
Moving from lower to higher concentration, must rely on the chemical gradient of another molecule.
What happens to a cell in a hypertonic solution?
Cell shrivels.
What happens to a cell in a hypotonic solution?
Cell bursts.
What does signal transduction allow cells to do?
Grow, divide, survive, move, differentiate, regulate metabolic activity.
What is a ligand?
A small molecule that binds to a receptor, changing its conformation.
What are the three stages of signal transduction?
Binding of ligand to receptor, signal transduction, cellular response.
What diseases are caused by defects in signal transduction?
Cancer, diabetes, brain disorders.
What is glycogenolysis?
The process of converting glycogen to glucose, often stimulated by epinephrine.
What is glycogenin?
An enzyme that acts as a primer to polymerize glucose molecules in a state of low blood sugar.
What is an example of a community of cells?
Skin.
What are the functions of the extracellular matrix?
Cell adherence, communication, cell shape, filter.
What are plant cell walls composed of?
Cellulose, hemicellulose, pectin, and proteins.
What is the function of the cell wall?
To protect and support the cell.
What is symbiosis?
Living together.
What is aerobic respiration?
Converting energy in food to ATP in the presence of oxygen.
What is photosynthesis?
Converting carbon dioxide to oxygen and carbohydrates.
What is the double membrane organelle?
Mitochondria.
What are the characteristics of the outer mitochondrial membrane (OMM)?
Contains many enzymes and large porins.
What are cristae?
Double layer folds in the inner mitochondrial membrane (IMM).
What is the IMM rich in?
Cardiolipin.
What is the matrix of mitochondria?
High protein content, gel consistency, many ribosomes.
What are the four compartments of mitochondria?
OMM, IMM, intermembrane space, matrix.
What is substrate-level phosphorylation?
The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.
What is oxidative phosphorylation?
The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.
What happens during oxidation?
Lose electrons.
What happens during reduction?
Gain electrons.
Where do light-dependent reactions occur?
In the thylakoid membrane.
Where do light-independent reactions occur?
In the stroma.
What is apoptosis?
Programmed cell death.
What characterizes apoptosis?
Shrinkage of cell, blebbing, fragmentation of DNA, loss of attachment to other cells, engulfment by phagocytosis.
What is the intrinsic pathway of apoptosis?
Causes change in mitochondria to leak Cytochrome C, committing the cell to apoptosis.
What happens with too little apoptosis?
Cancer.
What happens with too much apoptosis?
Alzheimer’s, Huntington’s, Parkinson’s.
What is GFP (green fluorescent protein)?
Used in live imaging by ‘tagging’ a protein with a fluorescent molecule.
What is vesicular transport?
Transport of large particles and macromolecules across plasma membranes.
What are the types of vesicle trafficking?
Movement of vesicle, tethering to target compartment, docking to target compartment, fusion of vesicle and target membrane.
What are membrane-bound organelles found in the cell?
ER, vesicles, Golgi complex, lysosomes, vacuoles.
Where is mucin secreted?
Rough ER.
What is the function of the rough ER?
Synthesis of many proteins and glycosylation of proteins.
What is the function of the smooth ER?
Primary site of lipid synthesis and detoxification.
Why is Ca2+ excluded from cytosol?
Does not bind water well, it will precipitate phosphates and make proteins insoluble.
How do ribosomes synthesize polypeptides from mRNA?
Initiation factor recruits MET, scans mRNA from AUG codon.
Where does RER and protein translation begin?
On free ribosome.
What are the two options for translation completion?
By free ribosomes or ER bound ribosomes.
For translation completed on free ribosomes, what proteins are produced?
Cystolic proteins, peripheral membrane proteins, proteins targeted to nucleus, mitochondria, peroxisomes, and chloroplasts.
For translation completed on ER bound ribosomes, what proteins are produced?
Secreted proteins, integral membrane proteins, soluble proteins associated with the lumen of the endomembrane system.
What directs synthesis to the ER?
Signal sequence located in the amino terminus, containing hydrophobic AA.
What is the function of SRP?
Binds to signal sequence, stops translation process, targets the whole translation complex to ER.
What happens once the SRP is released?
Ribosome binds to translocon and protein synthesis resumes.
What is cotranslational protein import?
The process where proteins are imported into the ER during translation.
What is the TOM complex equivalent to?
SRO complex.
What options do proteins targeted to the lumen have?
Be retained in the ER lumen or transported from ER to Golgi for further modification.
What is a microbody?
Peroxisome.
What is the function of peroxisomes?
Catabolizes long chain FA, reduces reactive oxygen species, biosynthesis of plasmalogens.
What is the function of catalase?
Breaks down hydrogen peroxide into water and oxygen.
What syndrome is associated with brain development defects?
Zellweger syndrome.
How is Zellweger syndrome inherited?
Autosomal recessive.
What mutation causes cystic fibrosis?
Mutation in CFTR.
What does CFTR stand for?
Cystic fibrosis transmembrane conductance regulator.
What mutation accounts for 2/3 of CF cases worldwide?
Deletion of 3 nucleotides, resulting in loss of AA phenylalanine.
What do CFTR modulators do?
Allow soluble proteins to enter the endomembrane system.
Where are proteins targeted to mitochondria and chloroplasts synthesized?
Completely in the cytoplasm.
In what direction does material move from the ER to Golgi to PM?
Proximal to distal.
What is the order of material movement through the Golgi?
CGN to MG to TGN.
What is the structure of the Golgi complex?
Smooth, flat, cisternae; ~8 stacked, curved; shows polarity, biochemically unique, membrane supported by protein skeleton.
What is the function of the Golgi?
Sorting station: determines whether proteins continue to Golgi or are shipped back.
What does the CGN do?
Sorts proteins into different types of vesicles.
What is the processing plant of the cell?
Golgi.
What are the two functions of coat proteins?
Help for vesicle formation & help select cargo that will go in vesicle.
What does COP stand for?
Coat protein complex.
In what direction do COPI and COPII move?
COPI moves in retrograde direction, COPII moves in anterograde direction.
What are COPI and COPII?
Protein complexes that assemble on the cytosolic surface at the site where budding occurs.
What is an example of a regulated secretory pathway?
Insulin and neurotransmitter secretion.
What is an example of a constitutive secretory pathway?
Mucin secretion.
What are lysosomes?
Digestive organelles with low internal pH and enzymes.
What is the lysosome membrane composed of?
Glycosylated proteins, acting as a protective lining next to the acidic lumen.
Where do AP/Clathrin-coated vesicles move from?
From TGN to other vesicles (lysosomes, endosomes, plant vacuoles).
How are macromolecules delivered to lysosomes?
Via vesicles.
What is autophagy?
Normal disassembly of unnecessary/dysfunctional cellular components.
What is an autophagic vesicle called?
Autophagosome.
What forms when a lysosome fuses with an ER-derived autophagic vesicle?
Autolysosome.
What is the process of decomposition of intracellular components via lysosomes?
Autophagy.
What is autophagy dysfunction associated with?
Neurodegenerative diseases, tumorigenesis, etc.
What do hydrolytic enzymes inside lysosomes do?
Degrade and kill pathogens.
What is a plant vacuole?
Fluid-filled, membrane-bound, can take up to 90% of cell’s volume.
What is the function of plant vacuoles?
Regulate pH, sequestration of toxic ions, cell turgor regulation, storage of AA, sugars, and carbon dioxide.
What is the tonoplast?
The vacuolar membrane, containing active transport systems that allow ion and molecule transport.
What is turgor pressure?
Gives rigidity and stretches the cell wall during growth.
What are the functions of the cytoskeleton?
Structural support, spatial organization within the cell, intracellular transport, contractility, and motility.
What are the three components of the cytoskeleton?
Microfilaments, microtubules, intermediate filaments.
What is the largest cytoskeletal element?
Microtubules.
What are the two proteins in microtubules?
Alpha and beta.
What are the two major types of microtubules?
Axonemal MT and cytoplasmic MT.
What are the properties of axonemal microtubules?
Highly organized, stable, involved in cell movement.
What are the properties of cytoplasmic microtubules?
Loosely organized, dynamic, located in cytosol.
What is the structure of microtubules?
Heterodimers form protofilaments, 13 form a hollow cylinder.
What is the fast-growing end of microtubules?
+ end.
What is the slow-growing end of microtubules?
- end.
What is structural polarity important for?
MT growth and direction of movement of material along MT.
What is dynamic instability?
Rapid turnover of most MTs; shrinkage occurs rapidly at the + end.
What is the central site of microtubule assembly?
Microtubule-organizing center (MTOC).
What do MAPs do?
Modulate assembly, mediate interactions with other cellular structures.
What are the classes of MAPs?
Non-motor MAP and motor MAP.
What is the function of non-motor MAPs?
Control MT organization in cytosol.
What does defective Tau protein lead to?
Alzheimer’s.
What is the function of motor MAPs?
Moves material along MT using ATP, generates sliding force.
What are the two types of motor MAPs?
Kinesin and dynein.
What direction is kinesin directed?
+ end directed, dynamic.
What direction is dynein directed?
- end directed, stable.
What is the force generating step?
ATP binds to leading head, causing a conformation change, and the trailing head swings.
What are the two most important MTOCs?
Basal bodies (cilia and flagella) and centrosome (spindle formation).
Where are intermediate filaments found?
Only in multicellular animal cells.
What is the function of intermediate filaments?
Support and strength.
How do intermediate filaments compare to microtubules and microfilaments?
They are more stable.
What are microfilaments (MF) functions?
Cell shape, cell movement, vesicle transport, muscle contraction, cytokinesis.
What is microfilament polymer made of?
Actin.
What is the structure of microfilaments?
A double helix of actin monomers.
What are the properties of microfilaments?
Polar, have + (assembles quickly) and - (assembles slowly) ends.
What are early nucleation of G-actin polymerization?
Slow.
How can microfilaments be arranged?
Loosely or tightly.
What organizes the structure of microfilaments?
Actin-binding proteins.
What does profilin do?
Enhances growth of filaments.
What does cofilin do?
Disassembles actin filaments.
What does capping protein do?
Blocks exchange of subunit at + end.
What is myosin?
A superfamily of motor proteins associated with microfilaments.
What are the two groups of myosin?
Conventional and unconventional.
What is the function of conventional myosin?
Muscle contraction.
What is the function of unconventional myosin?
Generate force, contribute to motility in non-muscle cells.
What is the function of the nucleus?
Storage, replication, repair, expression of genetic material, ribosome biosynthesis.
What are the six levels of genetic material organization?
DNA duplex, nucleosome fiber, chromatin fiber, coiled chromatin fiber, coiled coil, condensed chromatid.
What can damage DNA?
UV, chemical exposure, cellular metabolism, replication errors, ionizing radiation.
What is the function of RNA polymerase?
Reads DNA sequence and produces complementary antiparallel strand of RNA.
Where do ribosomes translate mRNA?
In the cytosol.
What are introns and exons?
Introns are excised, exons are spliced.
What does mRNA receive before leaving the nucleus?
5’ cap and poly A tail.
What are the 6 levels of genetic material organization?
DNA duplex, nucleosome fiber, chromatin fiber, coiled chromatin fiber, coiled coil, condensed chromatid.
What can damage DNA?
UV, chemical exposure, cellular metabolism, replication errors, ionization radiation.
What is the function of RNA polymerase?
Read DNA sequence and produce complementary antiparallel strand of RNA.
Where do ribosomes translate mRNA?
Cytosol.
What modifications does mRNA receive before leaving the nucleus?
5’ cap, poly A tail.
What are the 3 parts of the nuclear envelope?
Nuclear membrane, nuclear pores, nuclear lamina.
What are the 3 parts of nuclear content?
Chromatin, nucleoplasm, nucleolus.
What binds ribosomes and is continuous with the RER?
Outer nuclear membrane (ONM).
What connects integral proteins to the nuclear lamina?
Inner nuclear membrane (INM).
What is the importance of the nuclear envelope?
Separates content from cytoplasm, separates transcription/translation processes, selective barrier.
What is the nuclear lamina?
A thin meshwork of filamentous proteins.
How is the lamina bound to the inner membrane of the nuclear envelope?
By integral membrane proteins.
What provides structural support for the nuclear envelope?
Nuclear lamina.
What is the gateway between cytoplasm and nucleus?
Nuclear pore.
Where are nuclear pores found?
Where inner and outer membrane fuse.
What are nucleoporins?
Octagonal, supramolecular, 15-30x size of ribosome.
What is passive diffusion?
40kDA or less, rapid, 100mol/min/pore.
What is regulated movement?
Larger molecules, slower, 6mol/min/pore.
What is required for the regulated movement of proteins into the nucleus?
Nuclear localization signal (NLS).
What is importin?
Transport receptor that binds to the NLS of the cargo and interacts with the nuclear pore.
Why is nuclear import/export important?
For nucleotides for transcription, structural & DNA packaging proteins, proteins for DNA replication, repair, transcription, proteins for RNA processing/export, proteins for ribosome synthesis/export.
What is the largest structure inside the nucleus?
Nucleolus.
What is the primary function of the nucleolus?
Biosynthesis of ribosomes.
