Which of the following macromolecules describe a typical tpwb za6*kroy5; /cqm/r gr3) enzyme?

  What type of reaction i)r1*hcumywo3 s photosynthesis?

  What is the substrate for the enzyme lati.nxbvx+v *: ctase?

  Which of the following stages of cellular respi1vimqfet3 5 ja* z3,qgration takes place in the cytoplasmj5a3zt mi,3 vg*1 qqfe?

  Which of the following would not be useful in determining the rate of bq2yw)2 ge ln(an enzyme-cy nl)w2(2qb egatalyzed reaction?

  Which of the following processes may be described as catabolisr,we7 3x2b (*xws+gv9h tqz vdm?

  Which of the following statements is best depicted by the hqn;ac nvx: n8v:gc-1figure below?

  Which statement about enzymea,) e)wgt7ci i bky6d)s is not true?

  Which of the following graphs -wio0 a o(n r95g0wh9*apoavg7 p,skabest illustrates the relationship between temperature and the a ka,wra(g* -as5nov gphwiooa900p 7 9ctivity of enzymes such as lipase?

1.Sketch a graph to show how increasing concentrations ofuix9xv x) ik+3 substrate affect enzyme actik9ix3+vxx )ui vity.
2.Explain how the addition of a competitive inhibitor changes the activity of an enzyme.

  The Calvin cycle is wuqv9 x//z) qeq6s)ata series of enzyme catalysed reactions. A diagram outlining the Calvin cy )s/q)q6zu/a9vtx qe wcle is shown below.

The image below show)gx0ma njm 34za-fv9ds the catalytic site of an enzyme. The substrate is shown in black and is bound to the active si0m43v)a d-ajn9mfg zx te.





1.State how the activation energy is changed by adding an enzyme to a reaction.
2.Distinguish between anabolic and catabolic pathways.

  Which are correct descriptions of the enzyme catalysed metabolic,/xny u+nqjd,,2i ulz pathways shown below?, ,izjnu uy,+nl/ qdx2 Letters represent various products of individual reactions.

  Which of the following describes the role of inhibitors in enzyme-catalysqc5 c,qd87fp58e mvx ned reactioncq8mvpn5q7 x5 d,f8ecs?

  Which of the following correctly describes photosy(jje0 vl ;l:avp00lu .0mwx tanthesis or respiration?

Many enzymatic reactions happen as pat (6oqmd/5jqh nebms7 4hways involving multiple steps and multiple enzymes. q e64 bm7s5(jh/dnoqm

1.Describe how enzymes catalyze reactions.
2.Outline the advantages of enzyme-substrate specificity.

  Which of the following best describes the inhibitor in the image bel/ 2:cgvw8djpq:6m s xoow?

  Which of the following statements are true regarding regulation gjgq hb p/t(4c; ua2u8by end-product inhibition?8(q j;gbhuug2a/p 4tc
I. The end product binds to the allosteric site of the enzyme.
II. The binding of the end product is reversible.
III.End product inhibition is an example of negative feedback regulation.

  The following image shows the structure of the lysozy );kqx(f sji;ume enzyme. The darkened structure in black is the substrate and is bound at th sq;fxk();ui je active site.

Which of the following characterizes the active site of an enzyme?

The equipment below can be used to yz7hs(x2 2jb.msub i5w c6trj4.p4uostudy the effect of temperature on the activity of the enzyme amylase.uj2z(.x46 hyjo tub2s icp7.w5m 4rbs



1.Outline how this equipment could be used to set up a study into the effect of temperature on amylase activity, up to the point of getting the results.
2.Outline how the rate of reaction of the breakdown of starch by amylase could be measured using the equipment given.
3.Describe a suitable control experiment for this study.
4.Suggest one way to increase the reliability of the data that can be gathered from this experiment.
5.Using the axis below draw a graph of the expected results from the study in part (a).

  Which of the followib6 ,s 4lin lde8)b6dyyng statements describes how enzymes interact with substrates to catalyze reacd el6bid,8sy 6bln)4ytions?
I. Enzymes and substrates in solutions collide with one another, and the substrate is bound at the active site.
II. There is more movement of the substrate in a reaction because the substrate is usually smaller than the enzyme in size.
III.When the substrate binds to the active site, the shape of the enzyme changes slightly so it can accommodate the substrate.

Outline two ways enzyme c-;csr: /; 5heljh d0 fdja( h8idhf0inatalysed reactions can be measured.

  How does denaturation change the properties of an enzw29vc8t.ky9 gn3s0 a1yfmfn vyme?

  Enzymes play a role in catalysing tj 3v1b ix1 k*im)yi;freactions. Which of the following statements are truy)tiv*fi kbj1m; i1x3e?
I.The substrate is temporarily provided with energy before being converted to a product.
II. Enzymes reduce the activation energy needed for the reaction.
III.The active site binds to the substrate making it easier for bonds to be broken or formed.

  What is a characteristic that separates mammals or - sp,qjjp9g z6endotherms from ectotherms that have fluctuating bo9g jq-jpz,p s6dy temperatures?

  A metabolic pathway that convert-9xgb2oe4 hhg s;u(dr s threonine to the end-product isoleucine consists of five reactions. Threonine is converted to various intermediate products sequentially by different enzymes before it is converted to isoleucine by the last enzyme in the pat h u;h(2g9sb-4eodgxr hway.
In the following diagram, the enzymes have been labelled as E1, E2, E3, E4 and E5.


Which of the following shows how this pathway is regulated?

  The graph shows the 3// 6xuqt ko/rqnhpr,6w f-5l-kfgzxeffect of increasing pH on the rate of an enzymatic reaction. What is occurring during the phase labelled section fknp- xr6lk wxft/z5/ q,3h-6r/ ouq gX in the graph?

  An experiment tests the effect of chah ;lii5y1 ,caez2 rmf2sjw21lnging substrate concentration on an enzymatic reaction. What could be the independent and dependent va , i 5syl acemrh;21zi212fjwlriables in this experiment?

  The diagram shows the pathway that contq0-(y zez*ut verts threonine to isoleucine.



What is the name and mechanism of the process through which isoleucine interacts with threonine dehydratase?

  Enzyme A (Enz A) was immobilized on a matrix and its activity waso c8n4o1xf9:i p rjpa( compared with that of a free enzyme in solution. The grapjo: a8fi(xpn1 9ocpr4 h shows the relative enzyme activity (y-axis) with varying pH (x-axis).



Which of the following statements is true?
I. Both soluble and immobilized enzymes are inactive at higher pH values of 8.
II. The immobilized Enz A is more resistant to pH changes showing more activity than the soluble enzyme at most tested pH values.
III. Immobilizing Enz A did not decrease its catalytic activity.

  Purified enzymes are easily denatured. Which of the following is the p)(fm: w 5gaiytewi 38best way to keep ew tfim a3 w:8pegyi)5(nzymes active for a longer period of time?

  Which of the following describes some types otwt8ci upw,yk((0kik- t,-fp f extracellular enzymes?

  The enzyme pepsin hydrolyses r 9p: mk0 7b.tpcq ,y,fzfndj(proteins to release peptides in the stomach. A study was carried out to determine the effect of increasing substrate concentration on enzyme activity at a constant tempera,k7, n .jpcf9t fzpmb:yq(0rd ture of $30{\circ}C.

1.Describe the trends shown by the graph.
2. 1.Outline why it is important that temperature is kept constant in this experiment.
2.State one factor other than temperature that would need to be controlled in this experiment.
3.Suggest a method that can be used to maintain a constant temperature in this experiment.
3.Calculate the rate of reaction during the first 4 minutes when the enzyme pepsin is exposed to 5 mM of protein. Make sure you show your working. ----待选择----+-   
4.Explain the observed results.

  The graph below shows the rate of reaction of an enzym:)i e(+lzxdcs e with increasing substrate concentration. Similar concentrations of chemicals A, B, + edxlzi(c): sC and D were added independently to the reaction, and the activity was monitored for each of the reactions. The curve marked A coincides with the activity of the enzyme with no inhibitor added.
Which of the chemicals is likely to be a non-competitive inhibitor?

  To study catalase enzyme activity, a student cut a turnip root infy )ynmqy o/*or ui88.to small cubes. They measured approximately 5 g in a weighing dish, added 50 ml water and used a blender to homogenize the turnip root. The homogenate was filtered and the liquid extract was stored in a test)8/youfm i8royny*q. tube at room temperature.


The turnip extract and water were added to the conical flask first. Then 3% hydrogen peroxide solution was added to the conical flask, as shown in the image above. The oxygen produced is collected over 1 minute and measured in an inverted measuring cylinder, as shown.
The student wanted to conduct an experiment to see the effect of increasing enzyme concentration on the reaction. She made up the different concentrations as shown in the table below and added 1 ml of 3% hydrogen peroxide to each.

1.Suggest why the process of grinding the turnip root and extracting the filtrate was carried out.
2.State the dependent variable.
3.Explain why the volume of water was varied, as shown.
The following graph was obtained when the student varied the substrate (hydrogen peroxide) concentration, keeping the enzyme concentration constant.



4.From the graph shown above, calculate the percentage increase in volume of oxygen gas produced when using 1% hydrogen peroxide compared to 0.5% hydrogen peroxide.  %
5.Outline the reasons for the shape of the curve obtained.
The student repeated the same experiment but added an inhibitor along with the enzyme to the reaction mix. She got the following results.


6.Deduce, with an explanation, whether a competitive or non-competitive inhibitor was used in the investigation.
7.Other than the factors already mentioned, state one other factor that can lower the rate of an enzyme controlled reaction.

  The mevalonate pathway is shown below. Inhibitors to the enzyme HMG- CoA rede2ka r, k+ei* 5zst6suuctase can lower the production of choleste6e +*kk iar5szsu2te ,rol.


Statins lower cholesterol, reduce the risk of heart attacks, and prevent strokes. They are known to inhibit HMG-CoA reductase, which is the rate-limiting enzyme of cholesterol biosynthesis in the mevalonate pathway (image above).
Which of the following describes the mechanism of action of statins in lowering cholesterol?

  Which of the following are invotf,f 1i,df7s ds tf,(alved in denaturation?
I.A change to the three dimensional structure of the protein
II. A change in the amino acid sequence of the protein
III. Changes in the properties of the protein

  Students were investigating metabolic k7gfjng; z7m5 reactions in the classroom and were given an experiment which demonst57k 7 ;nzfmgjgrated the effect of temperature on a catabolic reaction.
A sample of fat was added to a beaker, which contained 150ml of a 1% sodium chloride solution.


The beaker and its contents were then added to a water bath, which was set at 15
o
C. The beaker was given 5 minutes to equalise with the temperature of the water bath. After 5 minutes, 5 ml of a 2 % lipase solution, at the same temperature as the water bath, was added to the beaker.


5 ml of 2 % sodium hydroxide (NaOH), pH 8.4, was added to a test tube and phenolphthalein, a colourless solution which turns pink in basic environments, was then added. The intensity of the pink colour is proportionate to the strength of the basic solution.
At exactly 20 minutes, a 5ml sample was taken from the beaker incubated in the water bath and added to the test tube.

The contents of the test tube were then immediately transferred into a cuvette and placed in a spectrophotometer set at 420 nm. The percentage transmission of light able to pass through the sample was measured and recorded.

The procedure was then repeated using water baths set at a range of different temperatures. The measurements were recorded in a table and presented in a graph.



1. 1.State the independent variable in this experiment.
2.Identify two factors, not already mentioned, that would need to be controlled in this experiment
2. 1.Explain how the spectrophotometer is able to measure the breakdown of fat.
2.Explain the effect of increasing the temperature from 15
o
C to 35
o
C on the rate of the catabolic reaction.
3.Predict the percentage transmission for a sample incubated at 20
o
C.  %
4.Evaluate the claim that based on the data, the optimum temperature for lipase activity is 35
o
C.

  In an experiment, the effect of increasing temperatureo:n5vnxlp qajb.lpx;; * y0e* on the efficiency of lactase activity is tested. Which is an appropriate dependenyjn:aop p;qeb* v0nl;.5xl* x t variable for this experiment?

  A study has been conducted on the activity of a specific lacta( j0pj 2g,s2 e6qz+4yeb kmjulse (Bg10), analysing the effect of pH, temperature and glucose concentration, as it may potentially be used as a commercial lactase to prj pyj0bk mqju, 2g+l6s(4 z2eeoduce lactose-free milk.



1.Deduce which temperature used in this experiment was the optimum one for the enzyme Bg10. Give a reason for your answer.
2.Explain the change in enzyme activity at temperatures above $40^{\circ}C$.
3.Evaluate whether the data supports the claim that the optimum pH for the lactase enzyme Bg10 is 7.

4.Calculate the percentage difference in relative activity of the enzyme Bg10 when treated with 500 mM of glucose compared to 50 mM of glucose. Make sure you show your working.  %

Further studies have been conducted on other lactase enzymes to test their thermal stability at an optimum temperature of 60°C, when they are immobilised on graphene nanosheets, in comparison to lactase enzymes floating freely in milk.

5.Compare the trend shown by the immobilised enzyme to that of the soluble enzyme.
6.Calculate the range of data for the soluble enzyme over 10 minutes.  log %

The storage stability at room temperature of the immobilised enzymes has also been compared to lactase enzymes floating freely in milk.


7.Compare and contrast the storage stability of the immobilised and free soluble enzyme.

The reusability of the immobilised enzyme was tested, by analysing the activity of the immobilised enzyme over 10 uses.


8.State one advantage of being able to reuse immobilised enzymes.
9.Using the data provided, and your own knowledge, suggest why immobilised enzymes should be used to make lactose free milk.

1.There is a continuous need to find new drugs for treatinwyuv (ck7fg(q 6w *l3pg patients with malariaqp(76kg yw* lcufw(v3 . Describe how anti-malarial drugs are being discovered with new technologies.
2.Enzymes are regulated by inhibitors that are classified as competitive or non-competitive. Distinguish between these two types of inhibitors.
3.Describe, using an example, how metabolic pathways can be regulated by end-product inhibition.

1.Explain how increasing the concentk(m ..)y(t;hrk qad ycration of an enzyme affects the rate of reaction. arkhq .k )y;c(.d(yt m
2.Lactase converts lactose to glucose and galactose. Outline how lactase is used in the food industry.
3.Discuss the industrial use of immobilized enzymes using a named example.

  Biomolecules can be broken down or synthesized through metabolic reactions. Whiv)uo.h2wstkrg 9 qbg *av/ p3(ch type(s) of metabolic reactio u3 a2ptr)gsb(gwq*vv/9.h k ons are condensation reactions?
I. Hydrolysis
II. Catabolic
III.Anabolic

1.Outline the different ways the rate of es yue7yhgvl*tm* v/ 2,nzyme catalyzed reactions can be measu/ *l,gvv*uyy 7seh2 mtred.
2.Draw a graph to show the effect of temperature on the reaction rate of an enzyme.


3.State how the optimum temperature can be determined using the graph drawn in part b.

1.Compare and contrast intracellular and extracellular chem pd,e1gra y;oodp g(89ical reactions, given one example of each type of reactio1rdgyeagdo o,pp98 ;(n.
2.Enzymes are regulated by inhibitors that are classified as competitive or non-competitive. Distinguish between these two types of inhibitors.
3.Describe, using an example, how metabolic pathways can be regulated by end-product inhibition.