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62 Cards in this Set
- Front
- Back
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Why would an organism lose its mitochondria?
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Mitochondria are used only for aerobic respiration so it might actually be more efficient for some organisms to use anaerobic respiration
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What are the universal principles of living cells (8)?
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1. Genetic info is stored in DNA (sometimes RNA) and passed onto daughter cells
2.DNA sequences specify both primary and teriary structures of RNAs and proteins 3. Macromolecular structures assemble (spontaneously) from subunits 4. Membranes grow by expansion of preexisting membranes 5. Zip codes and receptors target molecules to cellular locations 6. cellular components move by diffusion, pumps, or molecular motors 7. Receptors and signaling mechanisms allow cells to adapt to environmental conditions and external stimuli 8. Molecular feedback mechanisms control most processes |
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What are the two types of models that represent polypeptides?
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ribbon and space filling
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What do nucleotide sequences in DNA code for?
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The linear sequences & #D structures of RNAS and proteins
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How does DNA go to protein?
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gene--> transciption-->translation by ribosomes into polypeptide chains of amino acids--> folding into protein
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What is responsible for almot all metabolic functions in present day cells? Was this always the case?
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Proteins carry out almost all metabolic function, but this was not always true
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What are functional proteins comprised of?
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numerous identical subunits (like bricks)
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What makes up cell membranes?
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Lipids along with proteins and sometimes added carbohydrates
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Where do cellular compoent assemble from?
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macromolecules
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How do membranes grow?
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by expansion of preexisting membranes
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What are the two scenarios for the origin of eukaryotes? Which is favored?
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Fusion theory (Where a bacteria and an archaea fused cells and merged genomes)
Engulfment (Archaea engulfed bacterium and transferred most genes to host). This is favored. |
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All forms of life had a common ancestor. What are the features passed on from that ancestor?
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genetic code with DNA, membranes and pumps, carriers and channels, metabolism
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What has lost mitochondria?
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Entamoeba and giardia
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When ddid plants, animals and fungi emerge on tge phylogenic tree?
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800 million years ago
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What happened 2.1 billions years ago?
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protoeukaryote with nucleus and cytoskeleton
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What is a first order reaction?
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one reactant
rate=k(A) units=s-1 caused by a conformational change or dissociation |
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What is pseudo first order?
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1. A+B(slow--)>C(fast)-->B+P
(basically as soon as C is produced B is back so A is the only thing that is affected) 2. One reactantis in vast excess so it appears not to be involved |
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What is the diffusion constant?
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the diffusion constant has units of m2s-1 and it is a measure of fast a molecule moves in solution by diffusion, rates determined by the temp, size and shapes of the molecule and the viscosity
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Most reaction in the body are near_______ so a small change will do to cause shifts
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equilibrium
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What is equal at equilibrium?
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the rates in the two directions (not rate constants)
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What are second order reactions?
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Two reactants M-1S-1
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What is important to remember about the order of a raction?
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the order of a reaction is the power to which the concentration of a reactant must be raid in orde rt obtain a linear relationship between v and A
v=a^n 2. N does not need to be a whole interger 3. most reactions in bio are 1st, pseudo 1st, or 2nd order reactions 4. order must be determined from experiments |
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What is K equal to?
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K1/K-1
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What is a reversible binding reaction coupled to a conformational change
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bind together whcih causes a conformational change the pulls the linked reactions to the right
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What is ^G?
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chnage in disorder, must be less than 0 for a reaction to occur
=^H-T^S =-RTln(K) |
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Which is weaker covalent or hydrogen bonds?
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hydrogen bonds
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What types of bonds are important for macromolecular structure?
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hydrogen bond, electrostatic bond, electrostatic bond with chelated metal,
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What is the hydrophobic effect?
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on outside of cell is covered water, water is excluded from complementary hydrophobic surfaces which increas ^s
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Where did eukaryotes inherit genes from?
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both archaea and bacteria
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How do eukaryotes differ from bacteria and archaea?
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have compartmentalized cytoplasm with membrane bound organelles including a nucleus
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What does the nuclear envelope do?
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separates the wo major compartments:nuceloplasm and cytoplasm
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What is the endoplasmic reitculum?
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the site of protein and phospholipid synthesis
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What is the golgi apparatus?
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An organelle that adds sugars to memebrane proteins, lysosomal proteins, and secretory proteins
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What are lysosomes
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compartment for digestive enzymes
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peroxisomes?
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containers for enzymes involved in oxidative reactions
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What are mitochondria?
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structures that convert energy stored in chemical bonds of nutrients into ATP
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What are cilia/ flagella?
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Used for motility and sensing the environment
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What do membranes do?
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provide a barrier that allows each type of organelle to maintain ionic and enzymatic interior environment
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How do macromolecular structures assemble from subunits
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The protein, nucleic acid and lipid molecules contain the info that is required to assemble the more complex structure, diffusion usually bringds the molecules together during these asssembly processes, exclusion of water from their complementary surfaces and bonds provide the energy to hold together, sometimes chaperones help out
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How do mitochondria and the er form?
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onyl by growth and division of preexisting organelles that are inherited from the mom
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How is material provided for the golgi apparatus and how does this affect the plasma membrane?
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through a series of budding and fusion events membranes from the er provide material for the golgi apparatus hich in turn provides lipids and proteins for lysosomes and the plasma membrane
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How are proteins and nucleic acids brought to their proper cellular component?
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Specific recognition signals are incorporated into their structure and receptors recognize these signals anf guide each molecule to its compartment
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What do most proteins destined for the nucleus have?
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A short amino acid sequence that bind to receptors to help with their passage
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What do motor proteins do?
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move organelles and other cargo along microtubules and actin filaments
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How do cells adapt to the environment?
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stimulation of receptors activates diverse signal transducing mechanisms that amplify the stimulus and also generate a wide range of cellular responses
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What is the nucleolus?
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assembles ribosomes from more than 50 different proteins and 3 RNA molecules
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What is the nuclear envelope?
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a double membrane that separates the nucleus from the cytoplasm
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What are protein kinases?
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enzymes that phosphates to the side chains of proteins, changes in the stability of proteins allow specific ones to escape from negative regulation and trigger a chain of events leading to replication
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What is the ER
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a continuous system of flattened membrane sacks and tubules that is specialized for protein processing and lipid biosynthesis
motor proteins move along microtubules to pull the ER membranes into a brnaching network spread throughout the cytoplasm |
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What happens between the ER and golgi?
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continuous bidirectional traffic mvoes small vesicles between the ER and golgi carrying soluble proteins in their lumens in addition to membrane lipids and proteins
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What is the golgi appartus?
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processes sugar side chains of secreted and membrane glycoproteins and sorts the proteins for transport to other parts of the cell, membrane vesicle come from the ER and fuse with the golgi
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What are lysosomes?
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contain degrative enzymes
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What is the plasma membrane?
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impermeable to ions and most water soluble molecules
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What is apoptosis?
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cellular suicide
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What is Kinesin?
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moves vesicles and rna protein particles out along the microtubule network
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What is dynein?
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moves cargo to the center of the cell
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What is RNA world?
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life began with slef replicating RNA plymers sheltered inside lipid vesicles, likable because it provides way to store info in a type of molecule that can also have catalytic activity
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What are cyanobacteria?
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use an enzyme to split water into oxygen, electrons, and protons,
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Mitochondria have how many mebranes?
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2
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What links amino acids?
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peptide bonds
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what is the hydrophobic effect?
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increase in disorder of water that results when hydrophobic regions of macromolecules are bureied
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The RAS GTPase
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serves as part of a biochemical pathway linking growth factor receptors in the plasma membrane of animal cells to regulation of the cell cycle
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