Which of the following macromolecules describe a )p 2:pi30ei2lw3 injs w ;albrtypical enzyme?

  What type of reaction is p4h6n*4 hzeo .4pie:yrsx cix,2v qzw+hotosynthesis?

  What is the substrate for third;ofi +f5 v. u-e .nc.z: 3yxswnwy0e enzyme lactase?

  Which of the following stages of cellular respiration takes place in t8zo do qpb,; ollo/+x .)8mhchhe cytoplasmzhlco+/ ,h ;)ob.qmo pxd 88lo?

  Which of the followinv m5 beppnq47q *3og1hg would not be useful in determining the rate of an enzyme-catalyzed reactigp73qv5 o1*mpqbne h4on?

  Which of the following proces)v; vtrok)cw. etq(,w ses may be described as catabolism?

  Which of the following statements is best depicted by the u3a 6jnfypbjxd48 .)rv0y b -xfigure below?

  Which statement aboun)os,hls9cv 8 t enzymes is not true?

  Which of the following graphs best illustrates the rx) 0r ep.2 -fnoy.tlkuelationship between temperature and the activity of enzymes such au)e f 0pny..-lto2rx ks lipase?

1.Sketch a graph to show how 8a 3 5w)eeblnbincreasing concentrations of substrate affect enzyme activity w583le)nea bb.
2.Explain how the addition of a competitive inhibitor changes the activity of an enzyme.

  The Calvin cycle is a series of enzyme catalysed reactions9p2wk dup 9yf4. A diagram outlining the Caw249f p9 ypkdulvin cycle is shown below.

The image below shows the catalytic site of an enzyme. The substrat 9wm1v;z vynq(;j4 jhwe is shown in black and is bo(4n9v;w ymqwjz;1hj vund to the active site.





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 ,bza/ s1qji8gpathways shown belowa,s bgqji/1z8? Letters represent various products of individual reactions.

  Which of the following describes the role of inhibitors in enzyme-catn7 n3.qk(i nk9jtj -wualysed reactin7jtnku-3 .i9k q j(nwons?

  Which of the following correctly describes photosynthesis or respir.yxrp w0ga o wc.tc2rzp.9+ 2kation?

Many enzymatic reactions happen as pathways invo6w;ir du2co;rlving multiple steps and multiplecwd;2iou; 6rr enzymes.

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

  Which of the following best describes the inhibitor iml2f)u . f8 -ru7jsr-2bkwzyxwy03zsn the image below?

  Which of the following statements are true regarding ooua*u7 bnb.g+f6uu+)q ;ofrregulation by end-product inhibit*o7)f +ur;uon +bq.fu u gao6bion?
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 ovsqp.zm *5 dc*f the lysozyme enzyme. The darkened structure in black is the sds5*pmcv.* qz ubstrate and is bound at the active site.

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

The equipment below can be.q c(rghld(+1 np:zjp used to study the effect of temperature on the activity of the enzyhl+q dj gr(pn.(p1z: cme amylase.



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 following st5jgrd 1 6q xj2gto;*moatements describes how enzymes interact with substrates to catalyze reactions? *16mto ;g2xjdrg5 qjo
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 enzymt/iw aw+9-+b oi1/ihugx job/ ;h xfw8e catalysed reactions can be measured.

  How does denaturation change the prorf j4zd +7j ss)fc: ylb8.+yzfperties of an enzyme?

  Enzymes play a role in catalysing reayau;pq3hyu3; .d xm- wctions. Which of the following statements are tr phyax;3u qwm;u -3y.due?
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 sepa:xwcljur ivz/ens (+za3789f rates mammals or endotherms from ectotherms that have fluctuating body temperat s:u8/wznvcexa9rl7+z3 (ij f ures?

  A metabolic pathway that converts th;v ul dm4-)yebreonine to the end-product isoleucine consists of five reactions. Threonine is c duby)m ;4vl-eonverted to various intermediate products sequentially by different enzymes before it is converted to isoleucine by the last enzyme in the pathway.
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 effect of increasing pH on dh(.lfzqrg-6: w vnnb84wc 6wd pq7h(the rate of an enzymatic reaction. What is occurring during 6v:- ghr.nh ( dq8w4 (wbcfw6dz7pqnlthe phase labelled section X in the graph?

  An experiment tests the v0 *y0tg9:f5f(ld nz 0jm8ou d fyyvt0effect of changing substrate concentration on an enzymatic reaction. What could be the independent and dependent variableyfvd5u:f0dgtn z9 j 08o0yl(0*mvy tf s in this experiment?

  The diagram shows the pathway tha80bvy st6j5a yc0, nwpt converts 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 i 0v:ldzvxxcz2 1l5b/ ats activity was compared with that of a free enzyme in solution. The graph shows the relative enzyme activity (y-axis) with varying pH (x-axis). /5v za:z2lbvxlcxd 01



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 bes b39 s9m:/g;,( dwbyczp trsbxnpt v9;t way to keep enzymes active for a longer period of tim93smptx v;s/b:p, 9grdby9w ct (;nbze?

  Which of the following describes some type gs (o6jc ktk a4b y-ec.trj*/wmj)m;9s of extracellular enzymes?

  The enzyme pepsin hydrolyses proteins to reletkp7-;gqzu e; 3kdc*mase peptides in the stomach. A study was carried out to determine the effect of increasing substr;kt*-dke;cm g qp3z7uate concentration on enzyme activity at a constant temperature 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 enzyme with increasing sul1/id*/txsqkk6/mco o( fi/q9 y3 a eibstrate ccsd/ q io 6/i*1qty9k/x(ei/alfm3 okoncentration. Similar concentrations of chemicals A, B, C 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 tu,j7hklq;k (rc )q2 tslrnip root into small cubes. They measured approximately 5 g in a 7qrjc l, lhkk;2q)s (tweighing 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 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 enzymfpk,u c3/on8w *l7 iake HMG- CoA reductase can l8f3 akpk7 *,/w oinuclower the production of cholesterol.


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 invo1x*eh+ n; ro/n c6jkeklved 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 reactions/oris .m1za p3fs o9+rt,t;tp in the classroom and were given +o9rt/som; s pr a.1t,ftpiz3 an experiment which demonstrated 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 increasingm3oc; 2do *k 9 zxu,f 0aqn8u(;worddc temperature on the efficiency of lactase activity is tested. Which is an appropriate dependent variable for td2ao c*fuqu( n;or3zm8 d9oc,w 0xdk;his experiment?

  A study has been conducted on the activi 9n5 z)1 j4;c;eaffvbepvo7bm ty of a specific lactase (Bg10), analysing the effect of pH, temperature and glucose concentration, as it may potent;cee; fm) zfbjvopbn54971 a vially be used as a commercial lactase to produce 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 treating patient,aq;g aok ci,6s with malaria. Describe aa,i6c goq;k, 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 concentration of and v)viehsi( hp87zd3;0kyw) va.r+sb enzyme affects the rate of reaction.aih)vi kr 3wh7+(z;yv e p vdd)0.sb8s
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 ;dbkyu 7m -.2ckxmvx8broken down or synthesized through metabolic reactions. Which type(s) of metabolic reactions a8x; udmkc-2x.mkv y7bre condensation reactions?
I. Hydrolysis
II. Catabolic
III.Anabolic

1.Outline the different ways the rate of eny)9r :e jy-2e4szjz2hc xi pc7zyme catalyzed reactions can be measure7y29jc4ezpyx hsze : 2cj-i )rd.
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:h-qn 8dk(3e+j miwto chemical reactions, given one example of each type of reactioqnh3j-:mto k (wie 8+dn.
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.