Biology 201 Fall 2017 - Exam 2 - Uwe Pott - UWGB
Compare cytokinesis in animal and plant cells
*Animals = constriction takes place and is made up of actin *Plants = cell plate formation and inside-out growth (can't have constriction because of the cell wall)
Describe cell division in prokaryotes and calculate the number of offspring after a certain number of divisions
*Cell division in Prokaryotes: no nuclei, circular DNA and additional small circles of DNA *Formula to calculate cell divisions: Z(n) = Z(0) x 2^n (n = number of divisions)
Differentiate between diploidy and haploidy and explain the two meanings of karyotype
*Diploidy = 2 copies of each gene that comes from the parents *Haploidy = contains only one copy of each chromosome *Karyotype = looking at the set of chromosomes an organism has and also analyzing those chromosomes
Put a monohybrid cross on paper, explain the Rule of Segregation, and define the term testcross; state the characteristic genotypic and pheontypic ratios in the F2 generation
*During gamete formation the alleles of a gene separate and each gamete receives only one of them *Testcross = the way to check an unknown genotype *F2 generation = traits seen in the P generation but not the F1 generation will be seen (combination of P and F1 traits will be seen)
Name the subdivisions of interphase and the key events in each of them and compare the duration of interphase with the duration of mitosis and cytokinesis
*G1 = cell growth before DNA is duplicated *S = DNA is duplicated *G2 = preparation for cell division *Interphase is the longest phase by far, takes up roughly 60%
Define the terms gene, gene locus, allele, homozygous, heterozygous, dominant, and recessive
*Gene = traits of a character determined by heritable factors *Gene locus = the location of a particular gene on a chromosome *Allele = genes that come in alternate versions *Homozygous = identical alleles *Heterozygous = different alleles *Dominant = the trait most likely to show up *Recessive = the trait that will most likely not show up
Name the four steps of respiration and the cellular locations at which they take place
*Glycolysis (cytoplasm) *Formation of Acetyl-CoA (mitochondria) *Krebs Cycle (also takes place in the mitochondria) *Electron Transport Chain (inner membrane of mitochondria) - makes 34 molecules of ATP
Explain incomplete dominance, codominance and pleiotropy, and elaborate on the ABO blood system in humans
*Incomplete dominance = genetic situation in which one allele does not completely dominate another allele, and results in a new phenotype *Codominance = when alleles of a gene pair in a heterozygote are full expressed thereby resulting in offspring with a phenotype that is neither dominant nor recessive *Pleiotropy = the production by a single gene of two or more apparently unrelated effects *you should know about the ABO blood system
Explain the involvement of microtubules and motor proteins in chromosome movement
*Kinetochores shorten *Spindles elongate by action of polar microtubules and astral microtubules *Involves the motor proteins dynein and kinesin
Distinguish between lactic acid fermentation and alcoholic fermentation, and name the final electron acceptor in each of these processes
*Lactic acid fermentation: pyruvate is the final electron acceptor, easiest, lactate acid is accumulating and has to be transported because it's the end product *Alcoholic Fermentation: acetaldehyde is the final electron acceptor
Describe and contrast gamete formation in male and female animals
*Male = "spermatogenesis" end up with four sperm cells, and all can do the same thing *Female = "oogenesis" end up with one egg cell and three polar bodies which can't develop because they don't have any cytoplasm
Distinguish between the two meiotic divisions and explain how interkinesis differs from interphase of the mitotic cell cycle
*Meiosis I = reductional division 2n-> n (number of chromosomes is half) *Meiosis II = mitosis-like equational division n->n *Interkinesis - interphase without DNA replication
Distinguish between nuclear division and cytoplasmic division of a eukaryotic cell
*Nuclear Division = Karyokinesis (in mitosis = simple division in which mother and daughter cells are genetically identical, ie: clones) *Cytoplasmic division = Cytokinesis (when the cytoplasm divides)
Compare the mechanisms and outcomes of meiosis and mitosis
*Outcome of meiosis = four non-identical haploid cells from one diploid cell *Outcome of mitosis = two identical cells
Give an overview of mitosis and describe its phases in detail
*Prophase = centrosome divides and halves move to opposite poles *Metaphase = chromosomes align in the middle and are condensed *Anaphase = sister chromatids separate and chromatids are now considered chromosomes in their own right *Telophase = chromosomes uncoil, nuclear membrane and nucleolus reform and cytokinesis begins (basically this step is prophase in reverse)
Explain the essential aspects of chromosome behavior in prophase I, metaphase I, and anaphase I that make meiosis different from mitosis
*Prophase I = synapsis formation, homologous chromosomes pair up with each other (2 chromosomes of each type meet up) *Metaphase I = Homologous chromosomes align in pairs at the metaphase plate *Anaphase I = homologous chromosomes are separated and move to opposite poles, distribution of non-homologous chromosomes is random
Describe the purpose of cell division and name its ground rules
*Purpose: production of new generations of cells from parental cells *Ground Rules: daughter cells must be provided with hereditary instructions encoded in DNA, and enough metabolic machinery to begin their own operation
Put a dihybrid cross on paper and explain the Rule of Independent Assortment; state the characteristic genotypic and phenotypic ratios in the F2 generation
*Rule of Independent Assortment = used for two different traits, during gamete formation the alleles of one gene segregate independently of alleles of other genes (9:3:3:1 ratio)
Describe the two substrate-level phosphorylations, the three irreversible reactions, and the key regulatory step of glycolysis
*Two substrate-level phosphorylations: direct transfer of phosphate group from energy-rich substrate to ADP *Irreversible reactions: glucose + ATP -> glucose-6-P + ADP, fructose-6-P + ATP -> fructose-1,6-bisP + ADP, PEP + ADP -> pyruvate + ATP *Key regulatory step in glycolysis: fructose-6-P + ATP -> fructose-1,6-bisP + ADP
Describe Drosophila melanogaster as experimental system for inheritance
*Wild type = most abundant phenotype in nature (brick colored eyes) *mutant = any other form of the wild type (white eyes) *recessive mutation = small letters *dominant mutation = big letters *different alleles = have superscripts
Depict the entry point of the Krebs cycle and distinguish the release of the final four glucose carbons in form of CO2 and the regeneration of oxaloacetate
*entry point: acetyl-CoA enters and combines with oxaloacetic acid then forms citric acid. NAD becomes NADH, FAD becomes FADH2 and two ATP molecules are formed. *four glucose carbons: for each acetyl-CoA entering the cycle, 2 CO2 are formed (two acetyl-CoA molecules enter the cycle and each has two carbon atoms) *oxaloacetate is regenerated when malate is combined with NAD+ and the NADH is released
Explain epistasis and gene linkage
*epistasis = two genes control one character *gene linkage = alleles located on the same chromosome
Describe the factors that determine the phenotype of an organism and give an example of environmental contribution
*genotype and environment with random developmental events *ex of environmental event: if mother smokes while pregnant, child will have complications
Describe the use of a proton gradient for ATP formation in chemiosmosis and contrast oxidative phosphorylation and substrate-level phosphorylation
*the proton gradient provides the energy for the membrane-localized ATP synthase to make ATP from ADP and inorganic phosphate (Pi) *subtrate-level phosphorylation - is directly phosphorylating ADP with a phosphate and energy *oxidative phosphorylation - when ATP is generated from the oxidation of NADH and FADH2 and the subsequent transfer of electrons and pumping of protons
Explain the cell-external control of cell proliferation involving growth factors and describe how proto-oncogenes become oncogenes
-growth factors regulate the cell cycle control machinery (no growth factor -> no cell division) -growth factors are the reason why proto-oncogenes become oncogenes
Write down a balanced equation for photosynthesis, and list the input and output of the light-dependent and light-independent reactions
12 H2O + 6 CO2 -> 6 O2 + C6H12O6 + 6H2O or 6 H2O + 6CO2 -> 6 O2 + C6H12O6 Light-dependent: input: sunlight and H2O output: O2, ATP, and NADPH Light-independent: input: CO2 output: C6H12O6
Determine the yield of ATP from respiration and fermentation, and calculate the energy efficiency of respiration
32 ATP in liver, heart, and kidney but 30 in muscle and brain
Distinguish between the absorption and transmission of radiation, and explain how pigments absorb light and why they have color
Absorption of light - incoming energy matches exactly the required energy to lift electrons to a higher energy level Transmission of radiation - incoming energy does not match the required energy to lift the electrons Pigments - carry light catching array of atoms and have electrons which can be excited by visible light
Describe the solutions that have evolved in C4 or CAM plants to overcome the problem of photorespiration
C4 plants: have a high local concentration of CO2 maintained by fixing CO2 twice in different cells then release to cells that go through the Calvin-Benson cycle (spatial separation) CAM plants: these have a C4 pathway, however they do it at night because it's not as hot as the day
Describe the noncyclic flow of electrons from water through photosystems II and I to the final electron acceptor NADP+
In photosystem II, sunlight gives the electrons the energy needed to increase in energy from stable to unstable then the electrons go through the electron transport chain to make ATP and lose enough energy to reach a stable point again. At this point the electrons have made it to photosystem I. More sunlight gives them energy so they become unstable again so they go through the electron transport chain again but this time makes NADPH
Describe in which part of a chloroplast the different reactions take place
Light Reactions happen in the thylakoid membrane Dark Reactions happen in the stroma
Explain the cell-internal control mechanism of the cell cycle involving cyclins and cyclin-dependent kinases
Made up of cyclins (proteins associated with the cell cycle) and cyclin-dependent kinases (CDKs) - this is an enzyme and they use ATP to put phosphate groups on proteins
Explain Mendel's experimental system
Mendel analyzed: *characters with discrete, non-overlapping traits *crosses between true-breeding plants *distribution of traits over several generations
List the number of reduction equivalents (NADH and FADH2) and the number of high energy phosphates (GTP) formed during the Krebs cycle
NADH- 4 FADH2- 1 GTP- 1 bonus: CO2- 3
Explain the linkage between aerobic respiration and photosynthesis
Photosynthesis releases oxygen and aerobic respiration uses that energy. Aerobic respiration releases carbon dioxide and water which is required for photosynthesis
Explain the possible fates of the absorbed energy and what happens with it in the antenna complexes of photosystem I and II
Pigment molecules absorb energy, electrons transfer to electron transport system gets excited, transfers or donates
Explain carbon fixation and sugar formation in the Calvin-Benson cycle, and describe the function of the key enzyme ribulose bisphophate carboxylase (Rubisco)
Rubisco is the enzyme that puts CO2 into RuBP with 12 NADPH and 18 ATP to make 1 molecule of glucose
Calculate the number of genetically different gametes for an organism with any number of chromosome pairs, based on random distribution of non-homologous chromosomes
Z = 2^n "Z" is the number of possible combinations "n" is the number of chromosome pairs
In chemiosmosis, what is the direct source of energy that is used to convert ADP + Pi to ATP? a) energy from movement of protons through ATP synthase b) energy from transferring a high-energy phosphate group from a substrate to ADP (substrate-level phosphorylation) c) energy released as electrons flow through the electron transport system d) no external source of energy is required, because the formation of ATP from ADP and phosphate is exergonic e) energy released from ATP synthase pumping hydrogen ions against their concentration gradient out of the mitochondrial matrix
a) energy from movement of protons through ATP synthase
Independent assortment of the alleles of two genes a) is based on the random distribution of non-homologous chromosomes in meiosis b) is valid only for the garden pea c) is pure speculation d) gives an explanation for the structural changes of chromosomes e) requires the genes to be located on the same chromosome
a) is based on the random distribution of non-homologous chromosomes in meiosis
If two plants that are true breeding for different versions of a particular character (one dominant, the other recessive; e.g. red and white flowers of the character flower color) are crossed, the phenotype of the offspring a) is uniform and identical to one parent b) shows both parental phenotypes c) is uniform and intermediate between the phenotypes of the parents d) cannot be predicted by Mendelian genetics e) varies from experiment to experiment
a) is uniform and identical to one parent
The carbon source for organisms that perform photosynthesis is a) carbon monoxide (CO) b) carbon dioxide (CO2) c) hydrocarbons d) methane e) glucose
b) carbon dioxide (CO2)
Which of the following cells of a rabbit has a different number of chromosomes than the other cells listed? a) nerve cell b) egg cell c) muscle cell d) skin cell e) liver cell
b) egg cell
Which of the following events does NOT occur in prophase of mitosis but does occur in prophase I of meiosis? a) disintegration of the nuclear envelope b) pairing of homologous chromosomes c) spindle formation d) condensation of chromosomes e) none of the above
b) pairing of homologous chromosomes
The carbon dioxide acceptor in the Calvin-Benson cycle is a) 3-phosphoglycerate b) ribulose bisphosphate c) fructose bisphosphate d) oxaloacetate e) phosphoenol pyruvate
b) ribulose bisphosphate
As a pea plant grows, its root cells divide by mitosis. If the diploid chromosome number of the plant is fourteen, how many chromosomes will each newly formed root cell have? a) 28 b) 7 c) 14 d) 21 e) none of these
c) 14
A couple who are both carriers of (heterozygous for) the gene for cystic fibrosis, a recessive disease in people have two children who have cystic fibrosis. What is the probability that their next child will have cystic fibrosis? a) 50% b) 100% c) 25% d) 0% e) 75%
c) 25%
How many differentiated sperm cells can each primary spermatocyte in the testes of a mammal produce? a) 6 b) 2 c) 4 d) 1 e) 8
c) 4
Each time a molecule of glucose is completely oxidized via aerobic respiration, how many oxygen (O2) molecules are required? a) 2 b) 1 c) 6 d) 12 e) 30
c) 6
If a woman with blood type AB has a child from a man with blood type O, the child's blood type could be a) AB or O b) AB only c) A or B, but not AB or O d) B only e) A only
c) A or B, but not AB or O
The light-independent reactions of photosynthesis supply the light-independent reactions with a) light b) CO2 and water c) ATP and NADPH d) O2 and water e) ADP and NADH
c) ATP and NADPH
Which of the following molecules that transfer electrons to the mitochondrial electron transport chain are produced in the Krebs cycle? a) NAD+ and FAD b) NADH and GTP c) FADH2 and NADH d) ATP and CO2 e) CO2 and FAD
c) FADH2 and NADH
Mitosis does NOT occur in a) insects b) fungi c) bacteria d) plants e) humans
c) bacteria
Photorespiration a) is the name of aerobic respiration in plants b) is the breathing process of a photographer c) causes a lower efficiency of carbon fixation in plants d) a and c, but not b e) none of the above
c) causes a lower efficiency of carbon fixation in plants
Which of the following statements about epistasis is false? a) in epistasis one gene masks the expression of another gene b) the fur of Labrador retrievers is an example for epistasis c) epistasis only occurs in canines such as dogs, wolves and coyotes d) epistasis leads to an F2 generation with a variation of the 9:3:3:1 phenotypic ratio of a dihybrid cross e) epistasis can occur when two genes control the expression of one phenotype
c) epistasis only occurs in canines such as dogs, wolves, and coyotes
At high altitude, people who are heterozygous for the sickle cell allele (genotype A/S) have more blood cells than people with sickle cell anemia (genotype S/S), but fewer red blood cells than people with normal hemoglobin (genotype A/A). This is an example of a) codominance b) dominance of one allele over the other c) incomplete dominance d) epistasis e) pleiotropy
c) incomplete dominance
Which of the following phenomena can NOT be demonstrated with monohybrid crosses? a) incomplete dominance b) the segregation of alleles c) independent assortment of alleles d) dominance of an allele over another one e) all of the above
c) independent assortment of alleles
Which of the following statements about fermentation is FASLE? a) it produces less energy per glucose molecule than aerobic respiration b) it produces a net gain of ATP c) it produces a net gain of NADH d) it is an anaerobic process e) none of the above
c) it produces a net gain of NADH
To which structure of a cell do the spindle microtubules attach during mitosis? a) centriole b) central vacuole c) kinetochore d) centrosome e) cell membrane
c) kinetochore
During respiration H2O is formed. Where do the oxygen atoms in the H2O come from? a) lactate b) glucose c) molecular oxygen (O2) d) pyruvate e) carbon dioxide (CO2)
c) molecular oxygen (O2)
Gregor Mendel discovered a) the cell nucleus b) chromosomes c) the segregation of alleles d) DNA e) crossing over
c) the segregation of alleles
Describe the structure of eukaryotic chromosomes and distinguish between chromosome and chromatin
chromatin makes up chromosomes. Structure of eukaryotic chromosomes: "colored bodies" visible during nuclear division
Describe the oxidative decarboxylation of pyruvate
coenzyme A attaches to pyruvate then NAD+ attaches to that combination and pyruvate dehydrogenase multi enzyme complex is released forming CO2 and then NADH is formed and released leaving us with acetyl-CoA to go into the Krebs cycle next
For each six molecules of carbon dioxide fixed in the light-independent reaction, how many molecules of glucose are produced? a) 2 b) 3 c) 6 d) 1 e) 30-32
d) 1
Linked genes a) are located on the same chromosome b) may recombine by crossing over c) cannot recombine d) a and b, but not c e) a and c, but not b
d) a and b, but not c
The actual assembly of sugars during photosyntheis a) occurs during light-independent reactions b) takes place in the stroma of the chloroplast c) involves the fixation of O2 d) a and b, but not c e) b and c, but not a
d) a and b, but not c
Which of the following metabolites, formed by the oxidative removal of CO2 from a molecule of pyruvate enters the Krebs cycle? a) citric acid b) lactate c) oxaloacetate d) acetyl-CoA e) glyceraldehyde 3-phosphate
d) acetyl-CoA
The role of oxygen in respiration is to a) combine with lactic acid to form pyruvic acid b) combine with carbon, forming CO2 c) yield energy in the form of ATP as it is passed down the respiratory chain d) act as an acceptor for electrons and hydrogen ions, forming water e) catalyze the final reaction of glycolysis
d) act as an acceptor for electrons and hydrogen ions, forming water
Which of the following statements about fertilization is FALSE? a) it occurs during sexual reproduction b) it leads to zygote formation c) it involves the fusion of gametes d) it reduces the number of chromosomes e) none of the above
d) it reduces the number of chromosomes
Which of the following statements about glycolysis is FALSE? a) glycolysis encompasses a redox reaction b) glycolysis can operate in the complete absence of O2 c) the enzyme of glycolysis are located in the cytoplasm of the cell d) the end products of glycolysis are CO2 and H2O e) glycolysis makes ATP exclusively through substrate-level phosphorylation
d) the end products of glycolysis are CO2 and H2O
Assume that the thylakiod membranes of a chloroplast are somehow punctured so that the interior of the thylakoids is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? a) the absorption of light by chlorophyll a b) the splitting of water c) the reduction of NADP+ d) the synthesis of ATP e) the flow of electrons from photosystem II to photosytem I
d) the synthesis of ATP
The reaction-center chlorophyll of photosystem II is known as P680 because a) it absorbs 680 photons per second b) there are 680 chlorophyll molecules in the center c) there are 680000 photosystem II components in each chloroplast d) this pigment is best at absorbing light with a wavelength of 680 nm e) it evolved approximately 680 million years ago
d) this pigment is best at absorbing light with a wavelength of 680 nm
The oxygen released in photosynthesis comes from a) carbon dioxide b) glucose c) ribulose bisphosphate d) water e) none of the above
d) water
Which of the following events contributes to the new combination of maternal and paternal alleles during meiosis? a) crossing over during prophase I b) cytokinesis at the end of telophase I c) random distribution of non-homologous chromosomes during anaphase I d) relaxation of chromosomes in telophase I e) a and c, but not b or d
e) a and c, but not b or d
The oxygen consumed during cellular respiration is directly involved in a) glycolysis b) the citric acid cycle c) the oxidation of pyruvate to acetyl CoA d) the phosphorylation of ADP e) accepting electrons from the mitochondrial electron transport chain
e) accepting electrons from the mitochondrial electron transport chain
Which of the following statements about alleles is NOT true? a) a homozygous organism possesses identical alleles of a particular gene b) a heterozygous organism possesses different alleles of a particular gene c) in a population there are typically more than two alleles of a particular gene d) a diploid organism contains two alleles of a particular gene e) an oocyte gets both alleles of a particular gene, a polar body none
e) an oocyte gets both alleles of a particular gene, a polar body none
Glycolysis is believed to be one of the most ancient of metabolic processes. Which statement below LEAST supports this idea? a) Glycolysis neither uses nor needs O2 b) glycolysis is found in all eukaryotic cells c) bacteria, the most primitive of cells, make extensive use of glycolysis d) the enzymes of glycolysis are found in the cytoplasm rather than in a membrane-enclosed organelle e) glycolysis comprises 10 reaction steps
e) glycolysis comprises 10 reaction steps
Where in a plant cell is chlorophyll found? a) in the outer chloroplast membrane b) in the inner mitochondrial membrane c) in the stroma of the chloroplast d) in the cell membrane e) in the thylakoid membrane of the chloroplast
e) in the thylakiod membrane of the chloroplast
Describe the cyclic flow of electrons from and back to photosystem I
electrons may flow back to the antenna complex; energy is picked up then lost to the electron acceptor
Describe how crossing over increases the possible number of different gametes
ex: 8 different haploid combinations of the maternal and paternal chromosomes are possible in the forthcoming gametes
Summarize the energy metabolism of food molecules other than carbohydrates
food gets broken down into fats and proteins. fats get broken down to either fatty acids or glycerol. glycerol goes into making PGAL and fatty acids go into making acetyl-CoA. proteins break down into amino acids which are then broken into NH3 then urea, or carbon backbones which will go into one of three things: formation of pyruvate, formation of acetyl-CoA, or the Krebs cycle
Define glycolysis and distinguish between its "preparatory phase" and its "pay-off phase"
glycolysis- break down of glucose to pyruvate preparatory phase requires energy and the pay-off phase releases energy
Justify why meiosis is necessary and advantageous for sexually reproducing organisms
guarantees no two cells are genetically identical
Explain how the oxygenase function of Rubisco causes photorespiration and under which condition this process becomes relevant
photorespiration is caused when the concentration of O2 in leaves is too high. this will form phosphoglycerate and glycolate, glycolate falls apart and generates CO2 in a reduced sugar formation (plant loses CO2 instead of co-operating)
Name plants representing each metabolism and weigh advantages and disadvantages of C3 metabolism verus C4 or CAM metabolism under different climate conditions
plants with C3 metabolsim use photorespiration to decease the CO2 uptake. ex: sunflower, tomato, and rice plants with C4 metabolism use the Calvin-Benson cycle to enhance the level of CO2 in the leaves. ex: corn and sugar cane plants with CAM metabolism are found in warmer climates so their stromas open at night. ex: pineapple and cacti
Elaborate on the chi-square test and perform the test on paper and with MS-Excel on a computer
the chi-square test helps determine if your results are actually reasonable and not occurring based on chance
Justify the necessity for chromosome condensation and decondensation during the cell cycle
the chromosomes need to be relaxed in order for the DNA to read it
Explain ATP formation in the chloroplast (photophosphorylation) via chemiosmosis
this is done in the chloroplast because if there was a hole in the thylakoid membrane, the hydrogen molecules would escape and ATP would not be made. 2 water molecules absorb the light in the chloroplast and go through a series of channels which creates NADPH.