BIO May Exam
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| Proof for Davson-Danielli model? | 1. Chemical analysis of plasma membranes showed that they were made of phospholipid and protein 2. Evidence showed that the membranes of red blood cells had enough phospholipid to make an area twice as large 3. Experiments showed the membrane was creating a barrier to some substances, they thought it could be protein |
| Proof for Singer-Nicholson model? | 1. Freeze etched micrographs showed globular proteins in the middle of the membrane 2. Analysis of membrane protein showed parts of their surface were hydrophobic, so they would have to be within the bilayer 3. Fluorescent antibody tagging showed that membrane proteins tagged with red and green eventually fused after 40 mins, showing the fluidity of membranes |
| Proof for Davson-Danielli model? | 1. Chemical analysis of plasma membranes showed that they were made of phospholipid and protein 2. Evidence showed that the membranes of red blood cells had enough phospholipid to make an area twice as large 3. Experiments showed |
| How does cytokinesis happen in plants and in animals? | In animal cells, a cleavage furrow forms using actin and myosin (contractile proteins) and is pinched off to form the two genetically identical cells. In plant cells, vesicles fuse at the equator to create a new membrane that will ultimately join the preexisting membrane of the daughter cell, and pinch off. |
| What does the cell theory state? | All living things are made of cells, all cells come from pre-existing cells, cells are the smallest unit of life |
| What's the correct order in the unit scale? How do you convert between units? | M, mm, μm, nm, pm. If you want to make a unit smaller, you multiply by 1000, if you want to make it bigger, you divide by 1000 |
| Do the procedures necessary | 2.a) M= I/A : M= 63mm/8μm (conversion) : M= 63mm/0.008mm : M = 7875× b) I = MxA : I= 7875x 5μm : I= 39 375 μm OR 39.375 mm c) A= I/M: A= 23mm/7875 : 0.0029 mm (remember that anytime they ask for the ACTUAL size of a diagram, you have to measure the organism displayed on the diagram with the ruler, to get I) |
| What are some exceptions to the cell theory and why? | Striated muscle fiber: they have multiple nuclei and are very large Aseptate fungi: no divisions (septa) and many nuclei Acetabularia: only one nucleus for a very large organism |
| Why is surface are to volume ratio important? | It impacts the efficacy of the exchange of substances in and out the cell, and it regulates heat loss and use within the cell. Because both heat and substances accumulate in the cell faster than they can be lost across the membrane if the ratio is too small |
| How do you get the SA/V ratio ? | SA: length x width x number of sides V: length x width x length *simplify the results *the greater the ratio the most effective movement in and out of cells |
| Compare and contrast the functions of life in paramecium and chlamydomonas | Nutrition: Paramecium ingests smaller organisms through endocytosis, whereas Paramecium makes its own food through photosynthesis Growth: Paramecium increases in size and dry mass after ingesting organic matter and minerals, whereas chlamydomonas increases in dry mass through the absorption of minerals Excretion: Paramecium excretes CO2 from cell respiration, chlamydomonas excretes oxygen from photosynthesis Response: Paramecium uses cilia to swim away from objects, chlamydomonas uses its eyespot and its flagella to swim towards light Homeostasis: both organisms use contractile vacuoles to expel excess water through their membranes Reproduction: both organisms can reproduce sexually or asexually Metabolism: both have enzymes that catalyze reactions inside their cells |
| What is a tissue? | A group of cells specialized to carry out the same function |
| What is euchromatin and heterochromatin? What is their significance to specialized cells? | Euchromatin are the expressed genes in a cell whereas Heterochromatin are the unexpressed genes in a cell. The expression of some genes and not others leads to the specialization of a cell, because all cells carry the same set of genes |
| Why are stem cells of such high interest to researchers? | Because they produce copious amounts of cells and they're not fully differentiated |
| Name benefits and disadvantages of embryonic, umbilical cord, and adult stem cells | Embryonic -Capacity to differentiate into any cell -embryo dies though -more chance for tumor formation and rejection of an adult patient Umbilical Cord -limited amount -less differentiation potential -easily obtained and stored -fully compatible with individual later on in life -umbilical cord is discarded either way Adult -fully compatible with adult's tissue -less chance of a malignant tumor forming -harder to obtain -less capacity to differentiate -adult does not have to die |
| Compare and contrast light and electron microscopes | They both magnify an image, and they both work based on wavelengths of light. However, an electron micrograph uses a beam of electrons (2-12 pm) and a light microscope uses visible light (400-700nm), so the shorter wavelength of the electron microscope gives it a higher resolution. Dead or alive organisms can be seen under a light microscope, but only dead ones in an electron. Light mic: resolution 0.2 micrometers magnification 500x, electron mic: 1 nm, resolution 500,000x |
| What should you include in a diagram of a palisade mesophyll cell? | Vacuole, chloroplasts with grana and double membrane, mitochondria with double membrane, nucleus, cell wall, plasma membrane, LABEL diagram |
| What should you include in a diagram of an E. coli cell? | Nucleoid (genophore), plasmid, plasma membrane, cell wall, slime capsule, pili, flagella, free ribosomes, LABEL diagram |
| What should you include in a diagram of a pancreatic exocrine gland cell? | Nucleus with nucleolus and nuclear pores, rER, lysosomes, ribosomes, secretory granules por abajo, Golgi App nearby, mitochondria (double membrane), plasma membrane, LABEL diagram |
| Where are ribosomes and lysosomes made? | Ribosomes in nucleolus and lysosomes in RER |
| What are some benefits of having membrane-bound organelles? | The enzyme and substrates are more highly concentrated, movement of substances is facilitated within the cell (such as the vesicles that bud off from the rER to the Golgi) and no other enzymes disrupt the process |
| What is the structure of a mitochondrion in a eukaryote? | Inner membrane is called cristae, it has two membranes. It is filled with a fluid called Matrix which contains 70s ribosomes like prokaryotes, and it also has circular DNA like a prokaryote |
| What should you include in a diagram of the phospholipid bilayer? | Phosphate hydrophilic heads, hydrocarbon hydrophobic tails, integral proteins, peripheral proteins, glycoprotein, channel protein, cholesterol |
| What makes the phospholipid bilayer so stable? | The attraction between the hydrophilic head and hydrophobic tails |
| Why is cholesterol important in the bilayer? | It regulates membrane fluidity by reducing it. It makes it less easy for hydrophilic substances such a sodium or hydrogen ions to pass through, and thats important because there has to be a concentration difference across the membrane |
| Some functions of membrane proteins? | Neurotransmitter receptor between pre and postsynaptic cells - acetylcholine receptor Hormone receptor - insulin Channel for facilitated diffusion cell to cell adhesion to form tight junctions between cells in tissues |
| What is the importance of the universality of the genetic code? | Since all 64 codons mean the same for all organisms, it serves as evidence to show that all organisms evolved from the same group of cells |
| Explain the endosymbiotic theory | It is thought that it happened at least two times. The first time, an anaerobic organism took in an aerobic bacterium. The smaller, aerobic cell existed inside a vesicle in the cytoplasm of the larger cell, and reproduced at the same rate. Eventually, the bacterium turned into mitochondria and the larger cell into a heterotrophic eukaryote (animal). Then the second time, a heterotrophic cell took in a photosynthetic bacterium, and eventually the bacterium turned into chloroplasts and the larger cell into an autotrophic plant. Chloroplasts and mitochondria are very alike prokaryotes; both have 70s ribosomes to synthesize their own proteins, they reproduce like cells, they have naked circular DNA, and a double membrane which is what you would expect when a cell is taken in as a vesicle |
| What are the 4 theorized steps for the creation of cells from non-living matter? | 1. Scientists simulated Earth's atmosphere billions of years ago by passing electrical charges through hydrogen, methane and ammonia. Carbon compound and amino acids necessary for life were produced. 2. To turn those carbon compound into polymers, it is thought that energy from deep sea vents was taken. It's where there is hot water gushing out, and where reduced inorganic chemicals such as iron sulphide could be found. 3. To make plasma membranes, a bilayer was formed, where amphipathic carbon compounds assembled vesicles to resemble a plasma membrane 4. RNA instead of DNA might've been used to pass on genetic material, since RNA is self replicating, serves as a catalyst and also stores genetic material |
| Proof for Davson-Danielli model? | 1. Chemical analysis of plasma membranes showed that they were made of phospholipid and protein 2. Evidence showed that the membranes of red blood cells had enough phospholipid to make an area twice as large 3. Experiments showed that some substances couldn't pass through the membrane, so proteins were thought to create that barrier |
| New evidence for Singer-Nicholson model? | 1. Freeze etched micrographs showed globular proteins in the center of the bilayer 2. Analysis of membrane proteins showed that parts of them were hydrophobic, and therefore they would have to be within the bilayer 3. Fluorescent antibody tagging of membrane proteins showed how they fused together after 40 mins, showing the fluidity of membranes |
| What are two processes that only happen in the cell during interphase? | Protein synthesis in the cytoplasm and DNA replication in the nucleus |
| How does cytokinesis happen in plants and in animals? | In animal cells, a cleavage furrow forms using actin and myosin (contractile proteins) and is pinched off to form the two genetically identical cells. In plant cells, vesicles fuse at the equator to create form tubular structures. These create a new membrane that will ultimately join the preexisting membrane of the daughter cell, and pinch off. |
| How do tumors form? | Oncogenesis results from several mutations to an oncogene, which is a set of genes involved in controlling the cell cycle |
| How is the cell cycle controlled? | Proteins called kinases bind to enzymes called cyclin dependent kinases, which attach phosphate groups to other proteins in the cell in charge of carrying out tasks specific to their respective phase of the cell cycle. |
| What makes non living organisms different from living organisms? | Natural selection |
| How was vitalism falsified? | When urea was synthesized in 1828 by Wohler using silver isocyanate and sodium chloride it showed that there was no need for a 'vital' factor |
| Why are carbon compounds so stable and used for life? | Because they're stronger than intermolecular forces, given that they can form up to four covalent bonds, making them very stable |
| What are some features of an alpha d glucose molecule? | Tiene 6 esquinitas, carbon en cada una excepto oxygen en la top right one, tiene un down down up down sequence. Y beta d glucose mas bien es up down up down (se usa en plantas to make cellulose). Tiene un CH2OH en el top left corner, y hay un hydrogen attached al otro lado de cada carbon |
| What are some features de un ribose diagram? | Tiene 5 esquinitas, up down down, CH20H en el top left corner, carbon en cada esquina y oxygen en el very top, un hydrogen attached al otro lado del carbon |
| How can a disaccharide be recognized? What kind of bond is between them? What carbon bond is between branched monosaccharides? | By its double ring structure, and they have a glycosidic bond. Theres a 1-6 carbon bond between branched monosaccharides |
| Name 3 disaccharides, how theyre made and their products. Remember they are formed by condensation reactions | Glucose + glucose = maltose + h2o glucose + fructose = sucrose + h2o glucose+ galactose = lactose + h2o |
| Talk about cellulose | The glucose monomers alternate, that's why it looks straight. It's also unbranched. Only hydrogen bonds form here to give high tensile strength for plant cell walls. polymer de beta d glucose |
| Talk about starch | There are two forms of starch. Amylose is unbranched. Amylopectin is branched, and this is why more glucose can be attached or detached from amylopectin. polymer of alpha d glucose |
| Talk about glycogen | It's also a polymer of alpha d glucose, and also branched like amylopectin. Por eso se ven iguales, aunque glycogen is actually moRe branched than amylopectin. It's used for energy storage in animals, whereas starch is used for energy storage in plants. It's insoluble in water so osmosis doesnt occur |
| Whats a key difference between carbs and lipids in terms of elemental ratios? | Lipids contain less oxygen compared to carbon than carbs |
| Describe triglycerides? | Three fatty acid tails linked to one glycerol, ester bonds between fatty acid and glycerol, and three water produced for every tail |
| Describe phospholipid in the context of lipids | Two fatty acid tails linked to one glycerol. Instead of the third fatty acid tail there is a phosphate group (hydrocarbon tails y phosphate head!! :D) |
| How do you recognize steroids y give four examples? | They have a four ring structure. testosterone, progesterone, estrogen, cholesterol |
| Whats the effect of a trans fat not being bent? | They have a higher melting and boiling point, and that why theyre solid fat at room temperature, whereas cis fatty acids are oils |
| What makes a fatty acid unsaturated or saturated? What do they look like? | There's usually 14-20 carbons joined by single covalent bonds, with hydrogen attached to every single carbon. there's a methyl group on one end and a carboxyl group on the other end. they're saturated when theyre joined by a DOUBLE covalent bond, and you can have your trans saturated version with hydrogen atoms on opposite sides of the covalent carbon bond, or the cis version, where the hydrogen atoms are on the same side |
| Where is glycogen and fat stored? What carbon compound do they represent? | Glycogen is in the liver (carbs), and fat in adipose tissue (lipids) |
| Three reasons why lipids act as more effective storages of energy | 1. No water is associated with lipids, whereas theres 2g of water associated to a gram of carbs 2. lipids add half as much to body mass as carbs would to store the same amount of energy 3. there is more energy released per gram of lipid in cell respiration than per gram of carb |
| Examples of anabolism? | Protein synthesis in ribosome, polymerization of starch, glycogen or cellulose, photosynthesis |
| Examples of catabolism? | Breaking down food in the mouth with enzymes, cell respiration, decomposers breaking down carbon compounds |
| What's the structure of an amino acid? | An amine group (NH2), un carbon in the middle, un hydrogen attached to carbon, un carboxyl al otro lado, y el R group attached al carbon que es el que varía |
| Where is the peptide bond? | Es la rayita entre el C-N entre el carboxyl y amine group de dos AA |
| Como se hace para saber cuantos AA sequences pueden haber en un polypeptide? And are polypeptides branched? | THEYRE NOT branched, and you just do 20^power of how many amino acids there are en ese polypeptide |
| Why is the proteome different from the genome? | Because you need different proteins for different cell activities and it can change throughout an individual's lifetime |
| Name the six proteins esas and their functions | 1. rubisco: fixes co2 to the atmosphere 2. rhodopsin: makes retina cells photoreceptive 3. insulin: reduced glucose levels in blood 4. immunoglobulin: acts as an antibody 5. spider silk: structural protein to catch prey and suspend spider 6. collagen: structural protein that prevents tearing of skin |
| What are some benefits of immobilized enzymes? how can you immobilize them? | They can be reused, theyre not contaminated by other enzymes, and the enzyme concentration is higher. you can immobilize them by entrapping them in a gel/membrane, attaching them to a surface like glass |
| What are some benefits of lactose-free milk? | Good for lactose intolerants, galactose and glucose are sweeter than LACTOSE, so less added sugar is needed, and glucose and galactose are fermented faster by bacteria too so production is sped up |
| Acuérdese de este ejemplo de limiting factors, pero for now, cual es el impact de all three limiting factors in photolysis. what is photolysis? | Photolysis is the splitting of water molecules to get high energy electrons to turn co2 into glucose. low light intensity doesnt allow for fast enough production of ATP to convert co2 into glucose w high energy electrons, low co2 concentration leaves a lower collision rate between rubisco and co2, and low or too high temperature also impact activity in rubisco |
| What is photosynthesis, formula? | The production of carbon compounds using light energy. co2+water --> glucose + OXYGEN |
| Difference between an absorption and actions spectrum? | An absorption spectrum shows the amount of wavelength that a particular pigment absorbs, whereas an action spectrum shows how a certain wavelength impacts the rate of photosynthesis, how much of that wavelength is used |
| Define cell respiration | Controlled release of energy from organic compounds to produce ATP |
| Compare and contrast aerobic and anaerobic cell respiration | An: no oxygen needed, lower yield of ATP (2), uses glucose ONLY as a substrate, makes CO2 and ethanol in yeast and lactic acid in humans Aer: oxygen needed, higher yield of ATP (38), uses glucose or fat as a substrate (de donde lo saca), makes co2 in humans but also water |
| Why cant anaerobic respiration go on too long? But what are some benefits of it? | Because the h+ ions it releases would make the blood's pH too low soon enough. however, it maximizes muscle contractions and supplies ATP at a faster rate |
| How is DNA structured, osea how are the different parts of a nucleotide bonded between themselves, and how is one base bonded to another one? What's the difference between RNA and DNA? | The bond between the phosphate group, pentose sugar, and nucleotide base is covalent. The phosphate group of a nucleotide bonds with the pentose sugar of the next through covalent bonds too. However there is a hydrogen bond between the nucleotide bases; 2 between adenosine and thymine and 3 between cytosine and guanine. Also note that there are two strands of DNA and they're antiparallel. RNA is single stranded and has ribose instead of deoxyribose as nucleic acid |
| Explain DNA replication | 1. DNA helicase unwinds the two strands 2. Primase adds RNA primers to mark where the copying of the base sequence will start 3. DNA polymerase va haciendo covalent bonds between nucleotides, adding them in the leading strand 5' to 3' direction. Luego it adds the nucleotides in the lagging strand poco a poco 4. exonuclease takes primers away 5. DNA polymerase fills gap again 6. ligase seals fragments between DNA to make two continuous strands |
| Explain Transcription | Its purpose is to make a RNA copy of the DNA to send to the ribosomes to synthesize ribosomes. RNA polymerase separates the DNA strands to use one as a template (antisense). It adds nucleotides to the RNA strand that will match the DNA. RNA strand is released and DNA recoils. |
| Explain translation | MRNA binds to ribosome. Meanwhile, there's a tRNA molecule around with an amino acid that corresponds to its series of anticodons. In 2's the tRNA molecules attach to the mRNA codons in order to release their amino acid and gradually create an amino acid chain, until a stop codon in the mRNA appears. |
| Why is water polar? | Water's polarity occurs when there's an unequal sharing of electrons. The hydrogen atoms are more attracted to the electrons than water in the covalent bond that joins them, so hydrogen is slightly polar and water slightly negative, |
| How do four different substances travel in blood according to their polarity? | 1. NaCl travels as Na+ and Cl+ ions just fine 2. oxygen isn't polar so it has to bind to hemoglobin to travel in blood 3. cholesterol is insoluble so it has to travel in lipoprotein, which is coated in phospholipid and proteins 4. glucose y amino acids too |
| List the properties of water according to dipolarity and hydrogen bonding | Dipolarity Adhesion: due to dipolarity, water adheres to other polar hydrophilic substances, such as water and cellulose in cell walls. Water draws more water from the xylem to keep the plant's walls moist and ready for gas exchange Solvent: many substances are polar and so can dissolve easily in water. Very important for metabolic processes Hydrogen bonding Cohesion: water molecules cohere to each other and draw water from the xylem of a tree to the top without breaking Thermal qualities: due to hydrogen bonding, water has a high latent heat of vaporization which makes it a great coolant, and also a high specific heat capacity which makes it a stable environment for most habitats around the world, and its high boiling point makes it liquid and therefore suitable to act as a habitat |
| How does sickle cell anemia form? what are its effects? | It forms upon a base substitution where instead of glutamic acid, valine is made as an amino acid. The red blood cells life span decreases and theyre less effective at carrying oxygen |
| What are some benefits of diploid cells? | More likely to avoid a recessive allele disease, and it adds hybrid vigor |
| Compare chromosomes in eukaryotes and prokaryotes | Eukaryotes: two or more types of chromosome, associated to histone proteins, they have no plasmid, and it is linear DNA Prokaryotes: only one type of chromosome, naked DNA, plasmid often present, and it is circular DNA |
| Discuss the idea that the more complex an organism the more chromosomes it has | It doesn't hold up when you compare a plant with an animal (plant in theory shouldnt have more), or also when you compare two animals of the 'same' complexity but they have an unequal amount of chromosomes. However it does make sense that the worm, arguably the least complex of all, has the smallest amount of chromosomes |
| Define the size of the genome | The amount of DNA molecules present in ONE chromosome of a species |
| What is autoradiography and how did John Cairns use it? | Autoradiography shows where radioactive atoms decay, and it can be used to show the position and length of DNA. John Cairns cultivated E. coli in radioactive thymine. He placed them on a membrane digested their cell walls so their DNA would spill into the membrane. He coated the membrane with photographic film and left it for two months. He was then able to see where its DNA was and he noticed it was circular |
| When and where does crossing over happen? | It happens in prophase I at the chiasma, which is where the non-sister chromatids exchange genetic information. |
| What factors promote genetic variation? | Meiosis, fusion of gametes in sexual reproduction, and mutation |
| How does a trisomy occur, for example? | It happens due to non-disjunction, when chromosomes are or aren't pulled away so you have more, or less than you should. it could cause Down Syndrome or Klinefelter's |
| How do you retrieve cells for inspection in a karyogram? | Through amniocentesis, or CVS sampling (placental tissue) |
| List some ways to know if a disease is autosomal, sex-linked, recessive or dominant | To see if it's sex-linked check the distribution pattern. If it is, it's dominant when it's passed down from father to daughter and recessive when it's from mother to son. If it's autosomal, it's recessive if the trait skipped generations, or if there are affected children with unaffected parents (means theyre carriers) |
| How is TAQ DNA polymerase prepared for PCR? | It's heated up to separate the DNA strands, then cooled down again so primers can bind next to the sequence to be copied, and then heated up again so taq polymerase can replicate the strands and make two copies from them |
| How is DNA profiling possible? what is STR | You replicate a sample of SRT through PCR and then visualize the pattern of that individual's DNA using gel electrophoresis. STRs are short repeated sequences of bases in a person's chromosome |
| How was Dolly made? | Somatic nuclear cell transfer. They took the nucleus out of an unfertilized egg and fused it with an udder cell of another sheep, then placed it in a surrogate mother. Dolly was identical to the sheep that gave the udder cell |
| Describe the procedure to make a recombinant plasmid | You extract mRNA de un pancreatic exocrine cell. Using reverse transcriptase you make a DNA copy of it, and sticky ends (G nucleotides) are added. Plasmid is cut open with restriction endonuclease and sticky C nucleotide ends are added to it. The DNA of both pancreatic cell and plasmid fuse through complementary base pairing. Ligase then seals the nicks in the recombinant plasmid and the latter is absorbed by the E. coli cell. E. coli is cultured in a fermenter and finally it starts producing human insulin which is then extracted |
| List pros and cons of Bt maize | Economic: (pro) higher crop yield (con) not all farmers would have access to the new technology and big companies would take over Ecological: (pro) less land used for livestock, could be used for wildlife conservation (con) toxins could kill non-pest insects by falling on nearby plants Human: (pro) less pesticide used, better for human health (con) some could be allergic to Bt maize |
| Features of 5 main vertebrate classes | Birds: feathers growing from skin, parabronchial tubes in lungs Bony ray-finned fish: scales, gills Reptiles: dry scaly skin, extensive folding in lungs Amphibians: moist permeable skin, internal folds in lungs Mammals: hair grows from skin, alveolus in lungs |
| Features of 5 main vertebrate classes | Birds: feathers growing from skin, parabronchial tubes in lungs Bony ray-finned fish: scales, gills Reptiles: dry scaly skin, extensive folding in lungs Amphibians: moist permeable skin, internal folds in lungs Mammals: hair grows from skin, alveolus in lungs |
| Give a food chain | Passionflower, heliconias butterfly, tegu lizard, jaguar |
| Features of 5 main vertebrate classes | Birds: feathers growing from skin, parabronchial tubes in lungs Bony ray-finned fish: scales, gills Reptiles: dry scaly skin, extensive folding in lungs Amphibians: moist permeable skin, internal folds in lungs Mammals: hair grows from skin, alveolus in lungs |