BIOLOGY EXAM 2
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What is a chemical reaction?
Making and breaking of bonds
What is metabolism
The sum totaly of all chemical reactions ina biological cell that are aften organized into metabolic pathways
Whats the difference between catabolic and
anabolic pathways/reactions? Give an example of each.
- Catabolic-Breakdown (complex to simple) hydrolysis
- Anabolic-Build Up (simple to complex) proteins, DNA
Energy is the capacity to cause change, what
is kinetic and potential energy?
- Kinetic-Energy of motion, heat
- Potential- energy of location, stored energy, chemical energy
Energy transform states that energy can be
transfered from one form to another, what are the 2 laws of thermodynamics?
- 1.Conservation of Energy-Energy cannot be created nor destroyed
- 2.energy transformation increases the disorder in the universe (entropy-heat emmission- energy cant be recycled because of heat loss)
What is Free Energy Change or DELTA G?
energy available to do work
What des positive DELTA G mean? negative?
- Positive-not sponaneous-needs input to react
- Negative-spontaneous- can react on its own
Differentiate between Exergonic and Endergonic reactions
- Exergonic-exit, Negative DELTA G, spontaneous-catabolic, anabolic
- Endergonic-enter, Positive DELTA G, not spontaneous-absorb
What is Energy Coupling
Using an exergonix process to drive and endergonic process (i.e.building DNA, breaking down ATP)
What are the componenets of ATP, a ribonucleotide?
adenine, ribose, phosphate groups
What is phosphorylation?
The transfer of a phosphate group to anoterh molecule; generates a reative phsophoylated intermediate; can also change the shape of a molecule
ATP contains 7.3 kcals/mol of energy, what
does ATP drive?
- Transport Work
- Mechanical Work-helps motorize proteins
What are the stages of the ATP Cycle?
- The addition of water releases a phosphate group
- (which is inorganic when released because it doesn't have a carbon) and energy (heat)
What are enzymes
specific catalyst without eing consumed
Define Activiation Energy Barrier (Ea)?
- The intial amount of energy needed to start a chemical reaction; must overcome a reaction to proceed; determines the rate of reaction; the higher the barrier the slower the reaction
How do Enzymes play a role in activation energy
enzymes lower activation energy *DOES NOT affect DELTA G/Free Energy
Describe enzymes in terms of active sites and substrates
- Enzymes are proteins which means they have a
- specific shape-> compatible fit between active site(Region on an exyme where substrate bonds) and substrate (reactant)
What is a polar active site?
A charged substrate=H Bonds
What is induced fit?
The binding of the substrate causes a change in the shape
How is Activation Energy lowered by an enzyme?
- Orient substrates (Creates mold)
- Strain substrate bonds (induced fit)
- Participate in reaction (R Groups)
What factors affect anzyme activity?
- Fucntional partners-enzymes unable to do reactio on own
- Environmental factors-temperature and pH
How does temperature and pH effect enzyme activity?
- Temperature-denaturizes proteins
- pH-changes shape when not in optimal conditions
- (because at physiological state shapes are charged)
How does on regulate enzyme activity?
Through amount (gene expression) or activity
What are inhibitors?Decipher between irrecersible and reversible.
- Inhibitors-chemicals that selectively inhibit the activity of enzymes
- Irreversible-covalent bonds Reversible-weaker bonds
Decipher between ompetitive and non competitive inhibition.
- Competitive-fills in the active site not letting the substrate in
- NonCompetitive- different location from substrate-changes active site shape
What is allosteric regulation?
regulatory inhibition changing where changing the shape of the active site either helps or does (inhibits)
What is feedback inhibition?
control processes to help maintain processes
What is the cell theory?
- All living organisms are made of cells
- Strucual and Functional unit of all living organisms
- All cells come from preexisting cells
What are the shared characteristics between prokaryotic and eukaryotic cells?
- Plasma Membrane (carbs, phospholipids, proteins, steroids)
- Cytosol (semifluid aqueous solution)
- Cytoplasm (includes cytosol but also has organelles and suspended particles)
- DNA (organized into 1 or more chromosomes)
- Ribosomes (peptide bonds)
- Must obtain energy and raw materials (nutrients)
How does metabolism set the limit on the size of cells?
- Lower limits set by basic requirements for life
- upper limit set by ratio Surface Area:Volume Or Plasma Membrane:Cytoplasm
- *The higher the volume, the greater the need to rid waste and get nutrients
Put the following Domains into the catagory of Prokaryotic or Eukaryotic:Bacteria, Eukarya, Archae
- Prokaryotic- Bacteria, Archae
There are common characteristics between Prokaryotes? Specify purposes. *Remember they are not in all
- Cell Wall (maintains shape, physical protection, prevents bursting)
- Capsule(covers cell wall, sticky (polysaccharides or proteins; helps cells stick to surface)
- hair like appendages (fimbriae, pili)
- Lack compartmentalization
- Specialized Membranes (part of plasma membrane i.e. respiratory)
- Genomic Information (less DNA, circular chromosomes, in nucleoid region)
What is Taxis? What are the different kinds?
- Movement to or away from a stimulus
- Positive (to stimulus)
- Negative (away from stimulus)
- *over half of all Pokaryotes intentionally move
What are common characteristics of Eukaryotic Cells?
- larger, true nucleus
- membrane bound organelles
- elaborate cytoskeleton
What differentiates animal cells from plant cells?
- Animal Cells-lysosome, centrosome, no cell wall
- Plant Cells-cell wall, central vacuole, chloroplast
What organelles are used for genetic control (Eukaryotic Cells)?
store and usage of genetic information (nucleus and ribosomes)-DNA replication and gene expression
The nucleus stores DNA, break down DNA to other components.
- DNA->chromosomes->chromatin (DNA+Proteins)
- *Mitotic chromosome in X shape
- *Usual form of chromosome in jumbled mess within nucleus
The Nuclear Envelope encloses the nucleus, what is it made of? Whats its purpose?
- Consists of 4 phospholipid bilayers (double membrane)
- Nuclear Pores-perferations in the envelope, holes line by proteins-regulate entry/exit
What is the nuclear lamina?
Nuclear Laminia-support/structure for the nucleus, lines nuclear side of envelope Nucleolus-rRNA synthesis, ribosomal subunit assembly, can have more than 1 depending upon the cells numbers of proteins made
What is a Ribosome made of?
- *NOT AN ORGANELLE
- Consist of rRNA and proteins
- 2 subunits (1 large, 1 small) and come together via mRNA (protein synthesis)
Decipher between free and bound ribosomes.
- Free Ribosomes-in cytosol, make cytosolic proteins and proteins for non endomembrane system
- Bound Ribosomes-attached to ER or nuclear envelope ("cytostolic face"), makes proteins for secreation, mebranes and endomembrane organelles
*Free becomes bound by attaching to ER
What is the size difference between Ribosomes in prokaryotic and eukaryotic cells
- Prokaryotic Ribosomes-SMALLER 70S
- Eukaryotic Ribosomes0BIGGER 80S
What is the Endomembrane System?
The production, distribution and breakdown of biomolecules; physically continous or connected by vesicles, different in structure and function, ER helps for it (phospholipids)
What is the difference between Smooth ER and Rough ER?
- Smooth- no ribosomes, synthesis of lipids and steroids, calsium storage, detoxification, carb metabolism
- Rough-ribosomes, protein synthesis, glycoprotein synthesis, membrane production
What is the Golgi Apparatus?
cell's receiving and shipping center, Modify and stores prodcuts, makes biomolecules
What is the Golgi Apparatus made of?
- Cisternae-stacked flattened membrous sacs
What is the Cis and Trans of the Golgi Apparatus?
- Cis-receiving end
- Trans-end-away from the ER, packed to another place
What are the products of the Golgi Apparatus?
What do lysosomes do?
- Digestive compartments,used to break down old organelles to usable components (phagocytosis-cell eats, autophagy-self eat)
- *Only in animals
What is the structure of lysosomes?
- Membranous Sac
- Phospholipi Bilayer
- Lumen-hydrolytic enzymes (work at acidic pH *Built in bound ribosomes)
What is the most direct source of phospholipids fround in the lysosome membrane?
What are Vacuoles?
- membrane bound compartments with diverse funtions
- larger vesicle with more specialization
- Metabolic functions-food, contractile (carries water), central (plants)-storage i.e. water, disposal, has pigments, can hold toxins-form of protextion,
What organelle carries out respiration for nearly all eukaryotes?
What are the components of the mitochondria?
- Inner-cristae-surface area
- *More Inner membranes than outter membranes
- 2 compartments:intermemrane space, mitochondiral matrix-chemical reactions, ribosomes-FREE, and DNA
What prokaryotic characeristics are in mitochondria?
- DNA->Circular Chromosomes
What is the endosymbiotic theory? What organelles does it address?
- Mitochondria and Chloroplast
- believed to be free living bacteria and over time was engulfed by a cell and survived
What is the purpose of chloroplasts?
place for photosynthesis in plant cells
What are cholorplasts made of?
- Chlorophyll-captures light, pigmented
- Thylakoid membrane-made of Chlorophyll that are stacked=grana
- intermembrane space-compartment
- stroma-outside of the thylakoid membrane
- Thylakoid space
What is the purpose of the cytoskeleton?
What is the cytoskeleton made of?
- network of protein fibers extending thoughout the cytoplasm
- Intermediate Filaments (protein fibers)
What are microtubules?
- thick hollow tubes made of tubulin
- 2 centrioles and matrix-by nucleus
- cells ahpe, vesicle/organelle movement-acts as track for motor proteins, cel division (mitosis)
What are differences/similarities between cilia and flagella
- Similar:same diameter, 9+2 pattery (9 microtubule doublet, 2 dingle microtubules; crosslinking proteins, motor proteins
- flagella-longer cilia-shorter
- flagella-1 or 2 cilia-many
- flagella-swim,wavelike cilia-oar
Centrosome are only in BLANK cells
What organelles are part of the Endo Membrane System?
- Golgi Apparatus
- Nuclear Envelope
- *Secrete proteins
- *Plasma Membrane
What organelles are NOT in the EndoMembrane System?
What kind of ribosomes are EMS and nonEMS built on?
- Bound Ribosome-EMS
- Free Ribosomes-nonEMS
What are microfilament's composition and function?
- Composition:thin, solid walls made of action, twisted double chain that are network or linear
- Function: helps determine cell shape (right under membrane), cell division (cytokenisis), muscle cell contraction, cell crawling
Intermediate filaments are the strongest and longest lasting of the cytoskeleton proteins, what functions does it serve?
- support cell shape
- fix organelles in place
- support organelle shape/structure
What are extracellular components and connections?
strong fibers in a matrix whether solid or liquid
What are some characteristics of a Plant's cell wall?
- maintainence of shape (rigid)
What are the structures of plant cell walls?
- thicker than plasma membrane
- cellulose microfibrils embedded in a polysaccharide and protein matrix
- Thin primary wall-furthest away from membrane
- Secondary wall-thicker and stronger, put in place when cell "matures"
- Middle Lamella-adhession to plant cells via sticky carbs (outside of cell wall)
What functions does the ECM of Extracellular Matrix serve?
- regulation of cell behavior
- connects to cells via fibronectina nd integrins
What is the structure of Extracellular Matrix?
glycoprotein (few sugars with more proteins) in a matrix of protyoglycans (more sugar with few proteins) and water
What purpose do Intracellular Junctions serve?
- Allows direct contacct between cells
- cell communication
What is plasmodesmota?
- Cytoplasmic channels linked by plasma membranes between plant cells
- not highly regulated
- adhesion due to middle lamella
what are tight junctions?
- Pressing together of membranes between two neighboring cells
- highly regulated
- forms seal
What are desmosomes?
- Fasten cells together, connects cytoskeleton of neighbor through intermediate fiaments
- does not form barrier
- ex.heart cells dont fall apart when beating
What are gap junctions?
- protein linked channel between adjacent cells (creates pores)
- importnat in sending electric signals
What is keratin?
provides dead skin cells with strength
What do lamins help build?
What is the fuild mosaic model?
phospholipid bilayer embedded with proteins
How are lipids brought together in the phospholipid bilayer?
weak Vander Waal interactions
What kind of movement can the fluid mosaic model posses?
What is fluidity dependent upon for the mosaic model?
- temperature (hotter=more fluid)
- phospholipid tail length and saturation
- cholesterol-only in animal cells- decrease fluidity by restricting it
How do you make an animal cell's membrane more fluid?
- cis unsaturated fatty acid
- short fatty acid chains (because there are fewer interactions between neighbors)
The mosaic in the fluid mosaic model are membrane proteins, what purpose do they serve?
- enzymes (catabolic)
- communication (receptors)
- cell cell recognition
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