Biology Revision 1 Solution

(a) Define respiration. [3] (b) State how aerobic and anaerobic respiration differ. [2]

Fig. shows a section through the heart.(a) (i) Identify blood vessels M, N and O in Fig. (ii) Name the type of tissue which forms the major part of the heart and name the blood vessel which supplies this tissue with oxygen unless it is blocked by heart disease. type of tissue ....................................blood vessel ...................................... [2] (b) The four statements below describe some of the events that occur during the flow of blood through the heart. Arrange the correct sequence of these events, starting immediately after deoxygenated blood has entered the heart and ending as the blood is sent to the lungs.     A    The right atrium contracts.     B    The semilunar valves open.     C    The right ventricle contracts.     D   The tricuspid valve closes.    [3]

Fig. shows a section through a small surface wound to the skin.a) Name structure O and the type of blood vessel P shown in Fig.b) State two features that are characteristic of the type of blood vessel P.c) Explain what is happening to the bacteria in Fig.(i) at M:(ii) at N: (d) Explain how the wound is being sealed in the region under the scab.  (a) (O) WBC/phagocyte, (P) capillary ; [2](b) walls + very thin/one cell thick ;microscopic/narrow/small bore/allow RBCs only in single file ;walls leaky/permeable /allow substances to pass through ;slow blood flow (c) (i) M - WBC/lymphocyte + antibodies ; clumping (of bacteria) ; [2](ii) N - engulfing/ingesting/phagocytosis (d) action of platelets, fibrinogen to fibrin ;  trapping of RBCs, prevention of further bacterial entry, blood clot

Fig. is a flow-diagram showing the pathways taken by oxygen and carbohydrate from their absorption into a mammal’s blood to their use in the liver. (a) By filling in the spaces, complete Fig.  to state • the structures involved • the blood vessels used • what happens in the liver cells. [8](b) State a waste product formed from proteins in the liver. (c) Suggest (i) a chemical element present in the waste product you mention in (b) that is also present in a fat. (ii) a chemical element present in the waste product that is not normally found in a fat.  (a) alveoli/capillaries/air sacs ; (micro) villi ; 1 pulmonary vein ;2 aorta (in any order)3 hepatic artery ;respiration/oxidation of glucose ; 1/2 respiration1/2. conversion from/to glycogen ; max. 8 (b) urea/uric acid (Ignore nitrogenous waste); 1(c) (i) H(hdrogen/C(arbon/O(xygen)(ii) N(itrogen)

Fig. shows some food just before it enters the stomach and the same food as it leaves the stomach four hours later. (a) On Fig., label structures K and L. [2] (b) The food consisted solely of meat and potatoes. By placing ticks ( ✓ ) in the appropriate boxes in Table, show how the major components of the food compare at positions M and N. Fig. shows the same food at O, and 24 hours later, at P. (c) (i) Explain what has happened to the protein between O and P. (ii) Name the region of the alimentary canal which will contain fibre in the highest proportion and give reasons for your answer. region of alimentary canal________________  reasons _____________________________a) K oesophagus ; L duodenum / small intestine ; [2](b) starch – almost the same ; protein – less ; fibre – almost the same ; [3](c) (i) digested / changed / broken down / ref. enzyme action ; to amino acids / (poly)peptides ;absorption (available only with ref. amino acids) ; [max 2](ii) colon / rectum / large intestine ; no suitable enzyme / not digested ; ref. cellulose / lignin ;therefore no absorption / egested as faeces

During heart transplant procedures, it is possible to keep the heart beating while it is being transported many miles from the donor to the patient. Fig. shows diagrammatically how the heart is kept beating during transportation.(a) Identify structures L and M on Fig. (b) Suggest two chemicals which must be added to the blood in the reservoir, and explain your suggestions. chemical   1 ... explanation ...................................................................................................................... chemical 2 .................. explanation___________ (c) Using your knowledge of the structure of the heart, explain why blood entering the aorta from the reservoir flows into the heart muscle and not into the left ventricle. a) (L) right + atrium / auricle ; (M) pulmonary vein ; [2](b) (chemicals) *glucose ; *oxygen ; [2](explanation max 2 – each mark available once only either under glucose or oxygen)for energy (R production) ; during respiration ;heart muscle / cells / tissue ; (max 2) [4](c) valve (if named, must be aortic / semi-lunar) ;closes (available with wrongly-named valve) ; sending blood through coronary blood vessel / artery(ies) (R vein) ; [3]

Fig.shows the structures involved in oxygen uptake in the lungs.(a) Identify structures A, B and C in Fig.(b) Describe what happens to a molecule of oxygen as it moves from D to E in Fig.(a) A - alveolus/air sac ;B - capillary ;C – RBC/erythrocyte (c) dissolves ; diffuses ;combines with haemoglobin/forms oxyhaemoglobin ;ref. any structure/substance which O2 passes through

Fig. shows human blood containing pathogenic (disease-causing) organisms. (a) (i) Name the liquid labelled Q in Fig.  ........................................................... [1] (ii) Name two mineral ions which may be found in liquid Q and, for each ion, state its function in the body. ion 1 ................................................. function ......................................................... ion 2 ................................................. function ....................................................[3](b) The pathogenic organisms were introduced into the blood by a mosquito while feeding. Suggest why the mosquito feeds from a capillary and not from an artery. (a) (i) (Q) plasma ; [1](ii) 2 named ions (iron and calcium on syllabus) ;iron + red blood cells/haemoglobin ;calcium + ref. bones or teeth/blood clotting ; [3](b) (capillary) close to surface ; thin/one cell thick ;low blood pressure ; [3]  

In living organisms, enzymes may be used in reactions to convert large molecules into smaller ones. (a) State the term used for all(i) molecules on which enzymes act, ................................................................... (ii) molecules that are formed in a reaction.  ........................................................[2] (b) For a chemical reaction that begins in the stomach, state (i) the original large molecule, .................................................................................... (ii) the stomach enzyme involved, .............................................................................. (iii) the smaller molecules formed. ...................................................................... [3] (c) Fig.  shows diagrammatically how an enzyme-controlled reaction may occur. (i) Identify region A on Fig.  ............................................................................ [1] (ii) State the hypothesis illustrated in Fig. (a) (i) substrate/s; (ii) product/s; [2](b) (i) protein (ii) protease/pepsin/proteolytic (iii) (poly)peptides/peptones/proteoses (A amino acids); [3]d) (i) active site/place where substrate fits AW (R lock / key); [1](ii) lock and key (A words in a description); [1]

Fig. 1.1 shows apparatus at the start of an experiment to investigate the digestion of an emulsion of fat droplets in water by enzyme A. The pH indicator is green in a pH of 7, blue when the pH is above 7 and red when it is below 7. The apparatus is kept at 40 °C for 20 minutes during which time the indicator changes from green to red. (a) (i) State the identity of enzyme A. ..................................................................... (ii) Explain why the apparatus was kept at 40 °C.[2] (b) Name the products of digestion of the emulsion by enzyme A [2](c) Describe the processes which led to the change in pH.(a) (i) lipase/steapsin 1(ii) optimum/best AW + for enzyme/lipase action (I ref. body temp) 1b) fatty acids ,glycerol/glycerine/  2(c) fatty acids/ref. smaller molecules(can) pass through membrane/Visking tubingconcentration gradient/diffusionref acidity of or lowers pH of water/ref acidity of molecules max 3