Which of the following macromolecu 6mxx(qy 3iaw)les describe a typical enzyme?

  What type of reaction isn3+./sq kkh2.xmwut+lzv2z d photosynthesis?

  What is the substrate for the enzyme lactij),z ojo *8;oerb8dx ase?

  Which of the following stages of cellular respiration takes place in the cyto)0;9flqxxfg7 x/yi yuplasm?u)/xy0lf g 7if ;9yxqx

  Which of the following would not)6 s cg0m0xuca be useful in determining the rate of an enzyme-catalyzed reactioag)u6 x smc00cn?

  Which of the following processes may be described as ca(0g8lxyt l8(1phm nhy:jt -bftabolism?

  Which of the followigwig tl)w8pl vqdv1o,lmjz6 -5q7k(fm7 t:e2 ng statements is best depicted by the figure below?

  Which statement about enzymes is not t+n4,-vr5uq j c*nn41jdxnt(ngkh vua bg 3w1;rue?

  Which of the following gra4rh k-6mmjo;j 4qkk9f 5 8lgug3(wwvcphs best illustrates the relationship between temperature an q6w-cml;k5 h3kfjjwg rku4o4 (mg89vd the activity of enzymes such as lipase?

1.Sketch a graph to show how increasing conktsq146sih. geeoe 9e- k 2/iscentrations of substrate affect enzyme activity. 1i 6i.s/e gtehk9eq2sesk4o -
2.Explain how the addition of a competitive inhibitor changes the activity of an enzyme.

  The Calvin cycle is a series of enzyme catalysed reactions. A diagram out5w3v t0(- jprzcfv5eo lining t 5 fortecwz(vjpv-350 he Calvin cycle is shown below.

The image below shows the: qe9s zpcf(:e catalytic site of an enzyme. The substrate is shown in black and is bou:s(fez eq:cp9nd 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 t2c/n9c zch v:jb6cb0y he enzyme catalysed metabolic pathways shown below?nj96h/ c 0b:czcyv2cb Letters represent various products of individual reactions.

  Which of the following describes the role of inhibi d.5k,xxh2xq itors in enzyme-catalysed reactions?x xx ,q5dh.ik2

  Which of the following correctly describes photosynthn-ek8)632r5 b botdys sybj(pcdw( 5cesis or respiration?

Many enzymatic reactions happen as pathways involvi (oedk dd+nf+wqd8+k,ng multiple steps and multiple enzymes.n, f++kd(oeqdw8k+ dd

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

  Which of the following best describes the inhibitor in thaqg7ka-rlb k (1( 1bkge image below?

  Which of the following statements are true regarding regulation bysgwec++rffj ( 5em+z)-/zb lo end-product inhi+e 5g+e(rloz -m/)c sw ffz+jbbition?
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 op moaqt0 bn2+.f the lysozyme enzyme. The darkened structure in black is the substrate and is bound at the active si+oa t qbp02.mnte.

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

The equipment below c27ip jtn)-jhf0a w+fzan be used to study the effect of temperature on the activity of the ehz)pn +wfi2tj f0aj-7nzyme 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 statements describes how enzymes interact with shvb ,g w+1 ljy8*6dfiuubstrates to cat+fl b,gd*1vj u6 yiwh8alyze reactions?
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 catalysed reactiot(77udef8 y7 -sdqjwxns can be measured.

  How does denaturation change the propenocu83 w+* ciwrties of an enzyme?

  Enzymes play a role in catalysing reactions. Which of the fol)dx13xmw n2 zplowing statements are truez)ndx x3p2 1mw?
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 p:4 lpcna-zq; u u*4bnendotherms from ectotherms that ha4qb*luan:4u pcpn- ;zve fluctuating body temperatures?

  A metabolic pathway that converts threonine to the end-product isoleucine consis0 :edjwuwm;z4mbu pi/ z39h e,r)cg(2gt b2ists of five reactions. Threonine is converted to various intermediate products sequentially by different enzymes before it is converted to isoleucine by the lasb0z)grhdtwb g(;mw4/uz9e 3p 2mseii 2ju :c,t 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 inpc;hfjje : mx)ay11w)creasing pH on the rate of an enzymatic reaction. What is occurring during the phase labe:aw1)1 fj cexy) ;mhpjlled section X in the graph?

  An experiment tests the effect of changing substratez c.qw3 4ujy+e concentration on an enzymatic reaction. What could be the independenwqzj.y4+u ce3t and dependent variables in this experiment?

  The diagram shows the pathway that converts threb:+p p3pkrw.(oao m(k onine 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 ag b-400 ,nmkgb vxq gqdt70jniwk723f nd its activity was compared with that of a free enzyme in solution. The graph shows the relative bid q-fq34nx0bw2gvgknm7tg,7 00 jkenzyme 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 easi08 ghc /63afbaiz5qhd ly denatured. Which of the following is the best way to keep enzymes active for a lodh igabaq 6fhc/803z 5nger period of time?

  Which of the following describes some types of extravt7(mc dk ar:h0q9 /awcellular enzymes?

  The enzyme pepsin hydrolyses 5v clw3azi e5w+ ttf5gu78oj5 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 5 8lwet5+z35wt5auo 7f ijvcgconstant 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 enzy4r 7 amru7dh-rtuv 0w(h),nmlme with increasing substrate concentration. 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 o duv04r7lrt ,wa)n ru7hm -(mhf 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 into smalc)qn(rx b)9nm l cubes. They measured approximately 5 g in a weighing dish, added 50 ml water q m)rbc(n 9)nxand 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 enzyme HMG- CoA reductai zw72uf 9a-uvse can lower the production of cholesteroluiw27 v 9uaz-f.


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 inl0t7w a+-;zc 6pdxlsgvolved 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 in the class90kbkdk-nr y -0uo;cfroom and were given an experiment which demonstrated the effect of temperaturbcoky 0 0kr 9kud;--fne 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 vb g xg1; i09am5 ;*/pdby*cff1jh)y7cgvoew effect of increasing temperature on the efficiency of lactase activity is tested. Whb7yv5w/ i;g0fcdc1vxeg fy; g *oj)m9a1pb*h ich is an appropriate dependent variable for this experiment?

  A study has been conducted on the activity of a specifid9*2kj * 1v ;7acha5f nesdlpsc lactase (Bg10), analysinpjlsd;7 1dc*e ak52a*9v sfhn g the effect of pH, temperature and glucose concentration, as it may potentially 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 find6vxixf,age+i0 e0 olo2m j1n 3 new drugs for treating patients with malaria. Describe how anti-m02 g, lv 1 oxjfe+xn0oeimai36alarial 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 increasingr*.lf.x4r0ikai/ h v x the concentration of an enzyme affects the rate of reaction. lik*rairf0 4 hxx.v/.
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 broke102a, oc:pxid ene;zqn down or synthesized through metabolic reactions. Which type(s) of meqdex2:an;z o,0 pcei1tabolic reactions are condensation reactions?
I. Hydrolysis
II. Catabolic
III.Anabolic

1.Outline the different ways the rate of enzyme cataly,z2p 6fu f/6ukv a5zxiwtp2 8wzed reactions can be measured ku5z 2wv8ppxuwa/62fzti f,6.
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 chemical reactions, 2tpmi:2 w:fz hgiven one example of each type m w2pfhi:zt2:of reaction.
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.