BSC 2010 Exam 3 Questions And Answers Verified Solutions| Graded A+

What is the primary function of cellular respiration? Why bother doing all this? - Correct Answers Cellular respiration converts food molecules into ATP, which is then used as energy How does aerobic glucose catabolism compare with processes like the burning of wood or gasoline? How is it different? - Correct Answers Glucose is oxidized similarly to the fuel while the oxygen is reduced. ATP is produced following aerobic glucose catabolism Explain what redox reactions are, and give examples. Explain the meaning of the terms: Oxidation Reduction Oxidizing Agent Reducing Agent - Correct Answers Redox reaction: chemical reaction that transfers electrons between reactants EX: Na + Cl - Na+ + Cl- Oxidation: substance loses electrons Reduction: substance gains electrons Oxidizing agent: electron receptor Reducing agent: electron donor What are the coenzymes that contribute to catabolism? - Correct AnswersNAD+ NAD+ is an OA, where NADH represents stored energy which passes electrons to the electron transport chain - energy yielded is used to regenerate ATP Between the inputs to cellular respiration and its products, trace where the energy is and how it's transferred. Describe how the energy stored in reduced coenzymes is used to create a hydrogen ion gradient, and then ultimately stored in ATP by chemiosmosis. - Correct Answers What is the electron transport chain, and what does it accomplish? - Correct AnswersA collection of molecules in the mitochondria that can lose potential energy as each component of the chain becomes reduced Energy released is used to pump H+ from matrix to the intermembrane space What roles do oxygen and water play in relation to the electron transport chain? - Correct AnswersOxygen is at the end of the ETC where it can accept electrons to form water and vice versa One phase of cellular respiration makes many times more ATP than the others. Which one? - Correct AnswersKrebs cycle In the absence of oxygen, some organisms and some cell types can make much smaller amounts of ATP by fermentation - Correct AnswersPyruvate is recycled to keep glycolysis running Types of fermentation: alcohol and lactic acid Alcohol: pyruvate is converted to ethanol Lactic acid: pyruvate reduced by NADH to form lactate Fermentation produces 2 ATP, aerobic respiration produces 32 Which food molecules, other than glucose, can be used in cellular respiration? Do they enter at the same point? - Correct AnswersCarbohydrates, proteins and lipids Some molecules enter at glycolysis, others at the citric acid cycle Beyond providing energy as ATP, what do catabolic pathways provide to anabolic pathways that enables them to build biomolecules? - Correct AnswersCatabolic pathways provide certain cofactors like NADH, NADP and FADH, etc for the building of new molecules What is the PRIMARY function of photosynthesis? Why bother doing all this? - Correct AnswersPhotosynthesis converts solar energy into chemical energy within chloroplasts A pigment absorbs some wavelengths/colors of light and reflects/transmits others. Which of these wavelengths/colors do we see, and why? - Correct AnswersWe see visible light (380 nm to 750 nm) The color we see that is reflected by leaves is green because chlorophyll reflects green light According to the absorption spectrum of chlorophyll: Which wavelengths/colors of visible light does it absorb? Which wavelengths are reflected and transmitted? Which of these power photosynthesis? - Correct AnswersAbsorbs blue and red Reflects green Light absorbed powers photosynthesis What is the original source of electrons for the manufacture of sugar? - Correct AnswersWater is split, providing a source of electrons and protons The light reactions generate ATP and increase the potential energy of electrons by moving them from water to NADPH What does the Calvin Cycle accomplish? - Correct AnswersThe Calvin cycle builds sugar from smaller molecules by using ATP and the reducing power of electrons carried by NADPH. The Calvin Cycle forms sugar from CO2 What types of structures and what principles are similar in photosynthesis and cellular respiration? - Correct AnswersBoth processes produce energy in differing forms. Photosynthesis occurs in the chloroplasts of plant cells, cellular respiration in the mitochondria of animal cells What's the relationship between photosynthesis and cellular respiration? Are they the same reactions, just run in opposite directions? - Correct AnswersThe two processes provide their counterpart with the necessary reactants needed for each reaction to take place A common misconception is that plants do photosynthesis and animals do cellular respiration. How is this not quite the whole picture? - Correct AnswersPhotosynthesis occurs in other organisms other than plants, such as algae, some unicellular eukaryotes, and some prokaryotes Compare and contrast sexual and asexual reproduction - Correct AnswersSexual reproduction: two parents, genetically unique offspring w/half as many chromosomes as the parent cell Asexual reproduction: one parent, genetically identical offspring For what reason(s) do cells of single-celled organisms divide? How about for multicellular organisms? - Correct AnswersSingle-celled organisms: reproduction Multicellular organisms: growth and maintenance What are the two phases of the cell cycle? - Correct AnswersMitosis and interphase Mitosis phase: mitosis (prophase, prometaphase, metaphase, anaphase, telophase) and cytokinesis Interphase: G1, S, and G2 Summarize what occurs during each phase of the cell cycle, and in what sequence. Think about how these fit in the larger picture of dividing a cell, and the purposes they serve in that process - Correct AnswersProphase: chromosomes condense and become visible Prometaphase: centrosomes move toward opposite poles Metaphase: mitotic spindle is fully developed, chromosomes are lined up in center w/sister chromatids attached to a spindle fiber Anaphase: sister chromatids pulled towards opposite poles, cell is elongated Telophase: chromosomes begin to decondense and mitotic spindle breaks down Cytokinesis: cleavage furrow separates cells if animal. A cell wall separates cells if plant G1: organelles and cytosolic components are duplicated S: DNA is replicated w/each chromosome replicating to form two sister chromatids held at a centromere G2: enzyme and protein synthesis w/large amounts of ATP being produced, centrioles are replicated The terms below are distinct ways of referring to specific aspects of genetic material. What does each term mean, and how do they relate to one another? At what points in the cell cycle are they relevant? DNA Gene Genome Chromosome Replicated Chromosome Sister Chromatids Chromatin - Correct AnswersDNA: polynucleotide chain containing protein making info Gene: sequence of nucleotides forming part of a chromosome Genome: complete set of genes of an organism Chromosome: threadlike structure of nucleic acids and proteins Replicated chromosome: identical double-strand DNA molecules Sister chromatids: identical copies of a single replicated chromosome connected by a centromere Chromatin: material that chromosomes are made of Mitosis is the division of the ______, while cytokinesis is the division of the ______ - Correct Answerscell; cytoplasm How is cytokinesis different between animals and plants? - Correct Answers What's the structure of the mitotic spindle? - Correct AnswersComposed of microtubules that control chromosome movement during mitosis Describe how the cell cycle control system works, in terms of: Checkpoints Which key events do checkpoints precede? The mechanism of cyclins and cyclin-dependent kinases - Correct AnswersG1 checkpoint (before G0 and S): checks nutrien