BIOL1020 Mini Test 1 PDF

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Name: HUYEN TRAN LY

UQ email: [email protected] Tutor: Nicole Fortuna

BIOL1020 Mini Test 1 – Answer Sheet

P02

1. Dehydration reactions A. break down polymers. B. join monomers. C. add a water molecule. D. break bonds.

(1 mark)

2. What are the ends of chromosomes called? A. Histones B. Telomeres C. Origins of replication D. Centrosomes

(1 mark)

3. How do enzymes increase the rates of chemical reactions? A. Enzymes make the product energetically more favourable than the substrate. B. Enzymes provide the energy needed to overcome the activation energy barrier. C. Enzymes provide a lower-energy pathway to form the transition state. D. Enzymes serve as the substrates for chemical reactions. mark) 4. Which of the following processes occurs in the mitochondria? A. Glycolysis B. Glycolysis and citric acid cycle C. Citric acid cycle and oxidative phosphorylation D. Glycolysis, citric acid cycle and oxidative phosphorylation. mark) 5. At which stage of mitosis do the chromosomes start to condense? A. anaphase B. metaphase C. prophase D. prometaphase

(1

(1

(1 mark)

6. What type of shoes should you wear to come into the practical lab for a computer exercise? (1 mark) closed in shoes 7. Name three differences between eukaryotic and prokaryotic cells. marks)

(2

- eukaryotic cells have their genetic material enclosed by a membrane while prokaryotic do not - eukaryotic cells have many different membrane-bounded organelles while prokaryotic cells do not have - eukaryotic cells have linear DNA while prokaryotic cells have circle DNA

8. If there are 28 chromosomes in a cell: a) How many chromatids are there in metaphase? b) How many chromatids are there in each cell after mitosis? marks) a) 56 b) 28

(

2

9. What volume of 4.0 M Mg(OH)2 stock solution would you use to make 200 mL of 0.2 M Mg(OH)2? Show your calculations. (2 marks) V = The volume of 4.0 M Mg(OH)2 stock solution need to make 200 mL of 0.2 M Mg(OH)2 V = 0.2M x 200ml / 4.0M = 10ml

10. Imagine a new DNA polymerase is discovered that can synthesise DNA in the 3’ to 5’ direction. How would this change the mechanism of DNA replication as we currently understand it? Use the following terms in your explanation: Leading strand, lagging strand, 5’ to 3’, 3’ to 5’, DNA polymerase, replication fork, Okazaki fragments. (4 marks) Because two strands of a DNA molecule are oriented in opposite direction and DNA polymerase can only produce new DNA strand in the 5’->3’ direction, thus there are two different mechanisms in DNA replication. The new DNA strand which is continuously synthesized by DNA polymerase in the mandatory 5’ ->3’ direction is called the leading strand. The other new strand of DNA called the Lagging strand is synthesized discontinuously as a series of segment. These segments are called Okazaki fragments will be linked together by DNA ligase. If there is a new DNA polymerase that can synthesize DNA in the 3’ to 5’ direction, both new strand of DNA will have the same synthesize mechanism, which is being synthesized continuously.

11. Consider a ‘coupled reaction’ where ATP hydrolysis is used to power endergonic reactions (such as the production of e.g. proteins or amino acids, or similar compounds). Is the overall deltaG value of the reaction positive or negative? Would this coupled reaction be classified as spontaneous or non-spontaneous? Make sure you describe the basic principles of coupled reactions in your answer. Use terms such as positive deltaG value, spontaneous reaction, negative deltaG value, non-spontaneous reaction, coupled reactions, energy releasing, requiring energy input. (4 marks) ATP hydrolysis is an exergonic reaction, which is a reaction that can release energy, therefore its deltaG is negative. Endergonic reaction is a reaction that requires energy input to be able to occur, hence its deltaG is positive. In a coupled reaction the energy releasing from a exergonic reaction must be bigger than the requiring energy input that a endergonic reaction needs. As a result, the overall delta G value of the reaction is negative. This coupled reaction would be classified as non-spontaneous because it cannot occur without the providing energy from an exergonic reaction which is a spontaneous reaction....