Which of the following macromolecules describe a typical en. pk;xj0bfvqgn f761 9rtwt;xzyme?

  What type of reaction is photogv x*k;val mb:p6:0r-sq4smb synthesis?

  What is the substrate for the enzymev7zh k*t6t-i q lactase?

  Which of the following stages of cellular respiration takes place iluc;yu i6w9s:+5kwjqz 3d /eqn the cytoplasme/3c9yws;d+: jluquwq i5 k6 z?

  Which of the following would not be useful in determining the rate of an enzyme w*x;nvmnul,2 -catalyu*v;, mlwnx2 nzed reaction?

  Which of the following process;xg4 je1 f/ysses may be described as catabolism?

  Which of the following statements is besty *ek(g(jz vb: depicted by the figure below?

  Which statement about enzymes is no o 9(br+ij-ecaqc2it8t true?

  Which of the following c)b,u(hi x/n. oo;pam ped5)s;o5hpwgraphs best illustrates the relationship between temperature and the activ5,udbhp ( o )wo phso ;ea.i)xm5p;n/city of enzymes such as lipase?

1.Sketch a graph to show how increasing concentrations of substrap bo;whf98mn2ypfvi /(w0-a wte affect enzyme a wiw 92ovmh-f(a ypw;f nb80p/ctivity.
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 6:cs1zsl 1dca)mbz: q. A diagram outlining the Calvin cycle is shown below qdzssm:bcz16)ca1l: .

The image below show+1 c1:v+3n ofqmh tmnls the catalytic site of an enzyme. The substrate is shown in black and is bound to the active sit+3t nm+: mo1fvh1lnqce.





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 pathways e8*)ti78s/kcy p-vk r7 ddbu yshown below? Letters represy-cptiyr *7 vbe7kddk8)8/ su ent various products of individual reactions.

  Which of the following describes the role of inhibitors in enzyme-catalyse0h1: rsdnsn3od reactionso0ds hn1r3n s:?

  Which of the following correctly describ. o/gaji.p e3zes photosynthesis or respiration?

Many enzymatic reactions happen as pathways involvine- /zcu. puu qjak:u,7g multiple steps and multiple e u q.7u:,- z/acejukpunzymes.

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 belowjzcf6;2gc8 s s?

  Which of the following statemenca6ahdynwr l*r56;d+azh: w8u .: cnzts are true regarding regulation by end-product inh 5rahnadrz+a6;.:6 ld*: c8n uzcwwyhibition?
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 lysozyme +l9xiqmo(78: pdgf dt enzyme. The darkened structure in black is t(7gt 8qifdd+m lp: x9ohe substrate and is bound at the active site.

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

The equipment below can by5k c0+srsr8p e used to study the effect of temperature on the activity of the enzymy8 +rs0 c5pksre 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 s o5wrg k.:xn z xs;2i19nivj3lubstrates to cataly.1l 9n2xi5gxkj;sz:iv r3 n woze 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 catal37:bfs+p6h jib f/ixlysed reactions can be measured.

  How does denaturation change the properties of a7;gi/o2.edppnwq7 ge ixl9dd 4m:y,t2 dk 5ls n enzyme?

  Enzymes play a role in catao;cmi, 5f*ky +tw0lxv lysing reactions. Which of the following statements are t0ft+ic; owmyv5,xlk* rue?
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 thatxmyz1udt cjo303( n :s separates mammals or endotherms from ectotherms that have fluctuating body temperatu:13uyz sxcd n(to0 3jmres?

  A metabolic pathway v-nw6,l (c . xeel:p+,euwqlh that converts 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 v w:wqlhc- l(l 6+ue, x.,epneenzyme 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 increasingyxm,b/o 3bvxwmn( 5(h pH on the rate of an enzymatic reaction. What is occurring during the phase labelled sectionxb/ym, (mvx3(obnw5h X in the graph?

  An experiment tests theqb k(b1yh ,qb1mo .,c1sgq0e q effect of changing substrate concentration on an enzymatic reaction. What could be the independent and dependent variables in this experimentge q.b1yo1 q0hk b, 1b(s,mqcq?

  The diagram shows the path* 4cchiyfz-* qway that 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 its activity was comparet33dielw7mn,0 inq zj/,v.mgd with that of a free enzyme in 3ei,gni07l z3.tjv /dq n ,wmmsolution. The graph 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 fv,j/ e px 71v3aoyu gywsrj437ollowing is the best way to keep en 3a ex31v,4/7oyyjp sg w7jruvzymes active for a longer period of time?

  Which of the following describes som xad5sbdq*.ul vs9 b82e types of extracellular enzymes?

  The enzyme pepsin hydrolyses proteins to release peptides in the stomach. A : t.ugqm.xk192nk ga 2i yg0bnstudy was carried out to determine the effect of increasing substrate concentration on enzym2 .2gg ut9im x:kag.k0byq1 nne 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 increasl1+bhd0+aqn3q: f gj6q jerk zz9:ti)ing 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 of theq nza:hb l0)ji6e+z:jr+ fk q3q9dtg1 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 small c84o ;srryb y0y ot)795ffm sznubes. nyo ) rsr y9mbof857z04y tsf;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 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.gen h;a: wacy1)q/lv reductase can lowereach ; )avl1w: .ngqy/ 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 involved in denat ,eq mr4ob- xuuf sv0r b.:5pa+e3uxw)uration?
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 classroom and w, n/3u jke5xg;10wcu 2lkyvxe ere given an experi wjxu uke ,ygn0vx3k 25;c1/lement 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 in bruhwsl;6 x:e):t. etcreasing temperature on the efficiency of lactase activity is tested. Which is an appropriate dependent variable for this experimb.xt:wehu6 trs; e)l:ent?

  A study has been conducted on the activb4usada j9*1 dity of a specific lactase (Bg10), analysing the effect of pH, temperature and glucose concb9 aajdu*d 14sentration, 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 net: z(s r( wx9sw;z0axbd alu ,2,yeru)ed to find new drugs for treating patients with malaria. Describe how anti-malarir a)( xwsru0,zb( :9tus;zwya2,xdel al 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 coniv2 ;vc p l+u8wk0ny,zcentration of an enzyme affects the rate of reaction wl8iun0;z cpy +2vvk,.
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 r-kfxr9pt n l 9 vzx+nv.s8qr2/eactions. Which type(s) of metabolic reactions are condensation sf.rv2k qz+/9nn9xtr p-l8 xvreactions?
I. Hydrolysis
II. Catabolic
III.Anabolic

1.Outline the different ways the rate of enzyme catalyzed rc :r4va ova.y;eactions can be measured vyva:;a o4.rc.
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 exj0u 4stu*gz 7ttracellular chemical reactions, given one example of each type of reaction. ut* gu 0jz7ts4
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.