Ap Bio SEM. 1 Final
How do the laws of thermodynamics relate to the biochemical processes that provide energy to living systems?
1st law of thermodynamics: Energy can be transferred and transformed, but NEVER destroyed or created (science, God would not be pleased). Second law is that entropy occurs everytime energy is transformed or transferred. Living organisms take in energy, then use some of it, and release most in heat and waste. During all processes of organisms, energy is never created/destroyed, it is merely converted from unusable to a usable form of energy.
how do cells generate atp in the absence of oxygen
Anaerobic glycolysis
describe anabolic and catabolic reactions
Catabolism refers to chemical reactions that result in the breakdown of more complex organic molecules into simpler substances. Catabolic reactions usually release energy that is used to drive chemical reactions. Anabolism refers to chemical reactions in which simpler substances are combined to form more complex molecules. Anabolic reactions usually require energy. Anabolic reactions build new molecules and/or store energy. The energy of catabolic reactions is used to drive anabolic reactions.
structure and function of cell walls and cell membranes
Cell wall protects the cell (thicker than membrane, present in only plant cell) Cell membrane selects which molecules can enter (present in both plant and animal cell) The function of the cell membrane is the same as that of the skin. It separates the components inside the cell from the outside. The cell membrane provides support to the cytoskeleton of the cell, gives shape to the cell, and helps in the formation of tissues by attaching the matrix found in the extra cellular. It allows the passage of a certain substance; it maintains the potential of the cell, helps in communication with other cells, and act as molecular signals. Protein receptors are present which receives signals from the other cells and the environment. The function of the cell wall is to provide strength and rigidity to the cell. It protects the cell against mechanical forces. The function of the cell wall varies in different cells. In multi-cellular organism, it is responsible for its morphology. It prevents only large molecules from entering the cell and thereby, prevents toxicity to the cell whereas cell membrane prevents entry of smaller molecules. The cell wall also helps in retaining the water of the cell, thus a stable osmotic environment is created in the cell.
How does compartmentalization help organize a cell's functions?
Compartmentalization allows each compartment to perform specific functions without interference from other cell functions. For example, lysosomes can break down cell debris in a compartment without accidentally digesting the cell itself. It also allow enzymes and substrates to reach higher concentrations than if everything was diluted by the entire cytoplasm. For example, the mitochondria accumulates a large electron gradient in order for the electron transport chain to work.
how is the activity of an enzyme regulated
Competitive inhibitor: primarily reversible and the inhibitor binds to the enzyme's active site which keeps substrate from binding with the enzyme. Noncompetitive inhibitor: primarily reversible and binds somewhere other than the active site of the enzyme, resulting in the enzyme's active site changing shape so that the substrate can no longer bind with it. Allosteric inhibitor: enzymes that are allosterically regulated are constructed from two or more subunits, each composed of a polypeptide chain having its own active site. The entire complex changes between two different shapes; an active form and a non active form. The binding of an allosteric inhibitor binds to one of the enzyme's active sites and causes the non active form to stabilize and results in no more substrate binding to any of the active sites. Heat- increased heat can make enzymes work at a faster rate Increase in substrates- rate increases increase in enzymes - rate increases Each enzyme not only has an optimal temperature, but also has an optimal pH level. Most enzymes work best under pHs of 6 to 8. There are some exceptions, like pepsin, in the stomach, which works best at a pH of 2. If an enzyme with the optimal pH of 8 were placed in the stomach, it would denature.
how is the cell cycle regulated
Cyclins
What are the similarities and differences between prokaryotic and Eukaryotic cells?
Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not. SIMILARITIES: 1. They both have DNA as their genetic material. 2. They are both membrane bound. 3. They both have ribosomes . 4. They have similar basic metabolism . 5. They are both amazingly diverse in forms. DIFERENCES: 1. eukaryotes have a nucleus, while prokaryotes do not 2. eukaryotes have membrane-bound organelles, while prokaryotes do not. The organelles of eukaryotes allow them to exhibit much higher levels of intracellular division of labor than is possible in prokaryotic cells. 3. Eukaryotic cells are, on average, ten times the size of prokaryotic cells. 4. The DNA of eukaryotes is much more complex and therefore much more extnsive than the DNA of prokaryotes. 5. Prokaryotes have a cell wall composed of peptidoglycan, a single large polymer of amino acids and sugar . Many types of eukaryotic cells also have cell walls, but none made of peptidoglycan. 6. The DNA of prokaryotes floats freely around the cell; the DNA of eukaryotes is held within its nucleus and associated with histones (proteins) 7. Eukaryotes undergo mitosis; prokaryotes divide by binary fission (simple cell division)
What evidence supports the theory that mitochondria and chloroplasts were once free-living prokaryotes
Evidence for endosymbiosis comes from DNA sequencing and the comparison of bacterial, mitochondrial and chloroplast characteristics. DNA analysis reveals that eukaryotes contain many bacterial genes. Mitochondria and chloroplasts are similar to bacteria in size and divide independently of the eukaryote host cell by a process called binary fission. Bacteria also replicate by binary fission, while eukaryotes multiply by mitosis or meiosis. Mitochondria and chloroplasts inside the eukaryotic cell have single, circular DNA molecules just like bacteria. The inner membrane of bacteria, mitochondria and chloroplasts contains the electron transport chain, which provides chemical energy. Mitochondria and chloroplasts also have a second membrane surrounding their inner membrane, which is thought to have arisen from the host cell membrane indenting and surrounding the early prokaryote to take it up.
compare and contrast endergonic and exergonic reactions
Exergonic reactions: spontaneous, -∆G, release energy; endergonic reactions: not spontaneous, +∆G consume energy
what is one way genetic information can be altered?
Genetic information can be altered in many ways such as an error in mitosis or meiosis; however, mostof these alterations occur because of mutations. One type of mutation is point mutations, which arechemical changes in just one base pair of a gene. If a point mutation occurs in a gamete or in a cellthat gives rise to gametes, it may be transmitted to offspring and to a succession of future generations.If the mutation has an adverse effect on the phenotype of a human or other animal, the mutantcondition is referred to as a genetic disorder, or hereditary disease. Some different types of pointmutations are base-pair substitutions and insertions and deletions. Mutations can also be caused bymutagens which interact with DNA to cause mutations.
how are organic molecules broken down by catabolic pathways
Hydrolytic enzymes attack the bonds holding subunits together. As the molecules are digested, other enzymes can remove side groups of units to prepare the molecules for synthesis of new molecules or complete oxidation through cellular respiration.
How amphipatic nature of phosopholipids influences the structure and permeability of membranes
It is the shape and amphipathic nature of the lipid molecules that cause them to form bilayers spontaneously in aqueous environments.
Which organelle would be responsible for breaking down complex lipids
Lysosome
How do organelles function together in cellular processes?
Lysosomes fuse with vacuoles and secrete enzymes that result in digestion of waste particles inside the vacuole. The vacuole membrane protects the rest of the cell from the enzymes. Ribosomes in the endoplasmic reticulum build proteins, which are then modified and transported by the Golgi apparatus.
Describe the functions of the various organelles
Organelles such as the cell wall and membrane work with the rest of the cell by not letting in/out certain particles, and providing structural integrity. The nucleus works with the nucleolus by creating to make ribosomes, which are then transported to the rough endoplasmic reticulum. Proteins are then made. Proteins travel through channels in the endoplasmic reticulum and go to the golgi body. The golgi body packs and makes them ready to be transported to the border of the cell. The nucleus is the organelle that functions as the command center. The nucleus contains the genetic code material, in the form of DNA, that coordinates the growth and function of the rest of the cell.An organelle that works very closely with the nucleus is the ribosome. The ribosome---through the molecule messenger RNA---obtains the codes from the DNA in the nucleus for building cellular proteins.A fairly large and extensive organelle is the endoplasmic reticulum. The endoplasmic reticulum is a complex series of folded membranes. It is connected to the membrane that surrounds the nucleus and extends out into the cell's cytoplasm. In doing so, it establishes a chemical communication pathway between the nucleus and the cytoplasm. One of its critical functions is to transport proteins within the cell. An organelle that is somewhat similar to the endoplasmic reticulum is the Golgi apparatus. It functions in a similar way except that it specializes in preparing materials, like proteins, for transport through the cell membrane to the exterior of the cell.
Which organelle would be involved in the detoxification process?
Peroxisome//Smooth E.R
how does photosynthesis convert light energy into chemical energy
Photosynthesis transfers electrons from water to energy-poor CO2 molecules, forming energy-rich sugar molecules. This electron transfer is an example of an oxidation-reduction process: the water is oxidized (loses electrons) and the CO2 is reduced (gains electrons). Photosynthesis uses light energy to drive the electrons from water to their more energetic states in the sugar products, thus converting solar energy into chemical energy.
describe the features of a carrier protein
Proteins that change shape to allow a substance to pass through the plasma membrane a membrane protein that transports substances across a cell membrane; the protein changes shape (conformational change) to move the substance; passive and active transport
How are the structures of the various sub-cellular organelles related to their functions?
They are directly related to their functions. The mitochondrial cristae have a higher surface area to facilitate cellular respiration. The phospholipid bilayer of a cell membrane allows nutrients and fat soluble vitamins across the cell membrane. Cilia and flagella function as propellers for locomotion. The rigid cell wall of plants provides structure. In each of the above cases, structure influences function. Cells have evolved over time to efficiently carry out their respective functions.
how does mitosis allow for the even distribution of genetic information to new cells
Well, it replicates every chromosome and makes sure that the daughter cell gets a geneticaly ifentical copy. Theres 5 phases in which the cell divides Interphase, prophase, metaphase, anaphase and telephase. You should also include these in your essay and what occurs on each one which allows an even distribution of genetic info.
how does the cell cycle assure genetic continuity
When the cells divide, they must replicate every chromosome so the new cells have all the genetic material of the old cell. If a chromosome is missing, then the cell with the mutation would not be able to survive. The genetic material is copied during the phase right before prophase, in the S (synthesis phase) of interphase, where the chromosomes are duplicated once. Mitosis then occurs, and it can be divided into 5 phases- prophase, prometaphase, metaphase, anaphase, and telophase. The genetic material is wound, and the copies are split up between the two new cells which are formed. Each new cell gets an exact duplicate of the genetic material.
how does chemiosmosis function in bioenergetics
chemiosmosis: chemical flow of ions ex: flow of H+ ions across the membrane Chemiosmosis is critical in ATP production in eukaryote cells as well as most prokaryote cells.
how does the specificity of an enzyme depend on its structure
each enzyme has exactly one substrate that it induce its structure to fit to yield a real product *They have a tertiary structure with a HIGHLY specific ACTIVE site. The active site will only fit a SPECIFIC substrate. (If it wasn't it woudl start breaking down things it wasn't supposed to) It's described as a "induced-fit model": when the substrate enters the active site it alters slightly to better fit the substrate.
how is genetic information organized in the eukaryotic chromosome
genetic information is organized in a nucleus, within chromosomes. In chromosomes there is a long strand of DNA, which is comprised of a double helix figure of nucleotides.
what is considered to be the most primitive of the metabolic pathways
glycolysis
Describe the molecular architecture of membranes
he fluid mosaic model concept was introduced by Singer and Nicholson. The name arose because they believed there was a phospholipid bilayer where membrane proteins were able to move, rather than be static. The membrane mainly consists of lipids with hydrophobic tails and hydrophilic heads. Within this layer, there are many different proteins. These include integral membrane proteins, which are partially inserted and peripheral proteins which attach to the surface. There also is cholesterol imbedded and carbohydrates on the outer portion, used as markers. The membrane is selectively permeable, as it allows some small molecules to pass through, but keeps others out unless there are certain types of transport proteins which go through the membrane.
where is most of the free energy after glycolysis
in the pyruvate in NADH and FADH2 that are carrying energy-rich electrons
What are the similarities and differences between prokaryotic and eukaryotic genomes?
that they are both made of DNA. In eukaryotes the genomic DNA is stored in a separate cellular compartment called the nucleus and is linear. In prokaryotes, it is circular.
How do the structure of nucleic acids relate to their functions of information storage and protein synthesis?
the bases of the DNA molecule are grouped in threes called codons. These codons are complementary with a amino acid carrying tRNA the order of the codons determines the order of the amino acids which determines protein function.
What is the evolutionary relationship between prokaryotic and eukaryotic cells?
the eukaryotic cell developed from a larger prokaryotic cell engulfing a smaller prokaryotic cell without digesting it. The smaller prokaryotic cell or bacteria lived on in the larger prokaryote, providing it with extra energy, while the larger cell protected the small bacteria, allowing it to survive. Engulfed aerobic bacteria eventually developed into mitochondria, while photosynthetic bacteria became the chloroplasts of eukaryotic cells.
how do enzymes regulate the rate of chemical reactions?
they lower the activation energy required to start the reaction and due to feedback inhibition, they stop when their product overaccumulates Feedback inhibition is when the end product of a metabolic pathway acts as an inhibitor of an enzyme which is acting in that pathway. The original substrate is changed so much, that when it binds to a different active site of the enzyme a second time, the original active site can no longer bind to the original substrate.
what are the similarities between protein synthesis in prokaryotes and eukaryotes
transcription (DNA to mRNA) and translation can happen at the same time in bacteria but not in eukaryotes
How does this organization contribute to both continuity of and variability in the genetic information?
vital genetic information is contained at the ends of the chromosome, where crossing over is likely to occur, increasing genetic variability. also during synapsis of the chromosomes, crossing over can occur
