Biology 9700/11 October/November 2021: question paper and mark scheme

Question

A student observes a cell using a light microscope. The student then draws the cell. Which items will the student need to calculate the magnification of the drawing? 1 eyepiece graticule 2 ruler 3 hand lens 4 stage micrometer scale A 1, 2, 3 and 4 B 1, 2 and 4 only C 1 and 3 only D 2 and 4 only

Question

Which equations correctly show the relationship between magnification, image size and actual size in microscopy? image size 1 magnification = actual size actual size 2 magnification = image size image size 3 actual size = magnification magnification 4 actual size = image size A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

In which cell structures does DNA transcription occur? chloroplast A D mitochondrion nucleus C B

Question

Which rows could correctly identify the nucleic acids present in two different virus particles in a sample of air? DNA RNA 1 key 2 = nucleic acid present 3 = nucleic acid not present 4 A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

Question

Tests on four samples from a mixture of biological molecules gave the results shown in the table. boiled with boiled with excess excess Benedict’s solution after biuret iodine test Benedict’s acid hydrolysis and reagent solution solution neutralisation result blue red purple yellow Which biological molecules were in the mixture? A reducing sugar and protein B reducing sugar, non-reducing sugar and starch C non-reducing sugar and protein D non-reducing sugar and starch only

Question

One molecule of X is formed by a single condensation reaction releasing one molecule of water. What is molecule X? A a disaccharide B a phospholipid C a polysaccharide D a triglyceride

Question

The table shows some information about carbohydrate polymers. Which row describes glycogen? α-1,4 α-1,6 shape of function of glycosidic glycosidic molecule molecule bonds bonds A branched storage key B helical storage = present C branched structural = not present D helical structural

Question

The diagrams show four phospholipid molecules. Which molecule could contribute most to the fluidity of a cell surface membrane? A B C D

Question

Which properties of phospholipids explain why single layers of phospholipids added to water immediately form bilayers? 1 The hydrophobic fatty acid chains repel water molecules so the tails pack together. 2 The non-polar fatty acid chains are attracted to each other by hydrophobic interactions. 3 Hydrogen bonds form between the phosphate groups and water. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The diagrams show three examples of different bonds. bond 2 bond 1 bond 3 O NH O C C N CH2 S S CH2 H Which bonds hold the tertiary structure of proteins together? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which feature of collagen enables it to fulfil a structural role in skin and in tendons? A Adjacent collagen molecules are linked by ester bonds. B Collagen fibres form layers with the fibres in different directions. C Collagen molecules are formed as a triple helix of polypeptide chains. D Polypeptide chains of collagen are tightly folded into compact shapes.

Question

The graph shows how the concentrations of four components, 1, 2, 3 and 4, of an enzyme-catalysed reaction change with time. 1 concentration 2 3 4 time Which component is the enzyme–substrate complex? A 1 B 2 C 3 D 4

Question

The table shows the Michaelis–Menten constant, Km, for three enzymes. enzyme Km / mmol dm–3 C 1.5 × 10–2 P 3.0 × 10–4 F 5.0 × 10–6 Which interpretation of the information is correct? A Enzyme C has a Vmax which is half that of enzyme P. B Enzyme C will reach Vmax in the shortest time interval. C Enzyme F has the greatest affinity for its substrate. D Enzyme P has a Vmax of 6.0 × 10–3 mmol dm–3.

Question

What explains how a signal molecule produced by one cell can be detected by a target cell? A A signal molecule can bind to any type of cell surface receptor. B A signal molecule has a complementary shape to a cell surface receptor. C Signal molecules enter the cell by diffusion. D Signal molecules enter the cell by endocytosis.

Question

Some enzymes are produced in the cells of the pancreas. The enzymes are secreted when required. Which process is used to transport these enzymes out of the cells of the pancreas? A active transport B facilitated diffusion C endocytosis D exocytosis

Question

Plant cells were submerged in a solution with a water potential less negative than that found inside the cells. What describes the condition of the plant cells after 20 minutes? A burst B incipient plasmolysis C plasmolysed D turgid

Question

What will be present in each chromosome at the end of the G2 phase of the cell cycle? A two centrioles B two centromeres C two molecules of DNA D two telomeres

Question

Which events listed are part of the cell cycle? 1 interphase 2 metaphase 3 cytokinesis A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which features of an organism are affected by a drug that kills cells that are dividing mitotically? 1 cell repair 2 cell replacement 3 number of stem cells 4 tissue repair 5 tumour formation A 1, 2, 3, 4 and 5 B 1, 2 and 3 only C 1, 4 and 5 only D 2, 3, 4 and 5 only

Question

The graph shows how the distance between sister chromatids (curve P) and the distance between chromatids and centrioles (curve Q) changes during part of mitosis. 40 curve P distance / μm 20 curve Q 0 T V W X time Which statements could be correct? 1 T to V represents interphase. 2 T to W represents metaphase. 3 W to X represents anaphase. A 1 and 3 B 2 and 3 C 1 only D 2 only

Question

Which statement helps to explain why the two sugar-phosphate chains in a DNA molecule are a constant distance apart? A Adenine and thymine are held together by the same number of hydrogen bonds as cytosine and guanine. B Each nucleotide molecule is the same size. C Each purine base is linked to a pyrimidine base. D The sugar-phosphate strands of the helix are held together by sulfur bridges.

Question

During DNA replication, what must happen before a newly added nucleotide is bonded to the next nucleotide in the strand? 1 complementary base pairing 2 hydrogen bond formation 3 phosphodiester bond formation A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

An antibiotic enters bacterial cells through a membrane channel protein, P. Some bacterial cells have shown resistance to this antibiotic by acquiring a mutation which alters P. This mutation prevents the entry of the antibiotic into the cell. Which conclusions can be drawn about how resistance to this antibiotic developed in these bacteria? 1 The mutation changed the order of the amino acids in the gene coding for P. 2 The mutation resulted in the production of P with an altered tertiary structure. 3 The antibiotic is a hydrophobic molecule and so cannot cross the phospholipid bilayer to enter the cell. A 1, 2 and 3 B 1 and 3 only C 2 and 3 only D 2 only

Question

What is the correct tRNA anticodon coding for the amino acid proline? DNA triplet code amino acid on transcribed strand alanine CGT histidine GTG proline GGT A CCA B CCU C GGT D GGU

Question

The table shows the observations made by a student about three different cell types, P, Q and R, seen in a transverse section of a plant stem, using a light microscope. ratio of cell wall width to whole structures observed in cell contents cell width P 1 : 10 none Q 1 : 20 regular pattern of circles in some cells R 1 : 20 granular appearance of all cells What type of cells are P, Q and R? P Q R A companion cell phloem sieve tube element xylem vessel element B companion cell xylem vessel element phloem sieve tube element C xylem vessel element companion cell phloem sieve tube element D xylem vessel element phloem sieve tube element companion cell

Question

Water molecules are attracted to each other. This property is important in the upward movement of water in xylem. Which term is used to describe the attraction of water molecules to each other? A adhesion B cohesion C hydrophilic D polar

Question

The diagram shows a model to demonstrate mass flow. W water concentrated dilute sucrose solution sucrose solution Y X Z partially permeable partially permeable membrane membrane In a plant, what are the structures W, X, Y and Z and what is the direction of flow of solution along W? phloem xylem roots leaves direction of flow along W A W X Y Z from Z to Y B W X Z Y from Y to Z C X W Y Z from Y to Z D X W Z Y from Z to Y

Question

The parts of the heart that control heart action are listed. ● sinoatrial node (SAN) ● atrioventricular node (AVN) ● Purkyne tissue Which row is correct for atrial contraction and ventricular contraction? atrial contraction ventricular contraction A AVN produces SAN produces waves of excitation waves of excitation B Purkyne tissue carries AVN produces waves of excitation waves of excitation C SAN and AVN produce Purkyne tissue carries waves of excitation waves of excitation D SAN produces Purkyne tissue carries waves of excitation waves of excitation

Question

The diagram shows part of the circulatory system in a mammal. 1 2 3 4 direction of direction of blood flow vena cava blood flow aorta Where is the blood pressure and the speed of flow the lowest? lowest blood lowest speed pressure of flow A 1 4 B 2 3 C 3 2 D 4 1

Question

The photomicrograph shows human blood cells. X What type of blood cell is X? A B-lymphocyte B monocyte C phagocyte D T-lymphocyte

Question

The diagram shows some of the reactions of carbon dioxide when it enters the blood from cells in a metabolically active tissue. Which reaction is catalysed by the enzyme carbonic anhydrase? CO2 plasma A B CO2 + H2O H2CO3 H+ + HCO3− C D CO2 + H2O H2CO3 H+ + HCO3− red blood cell

Question

The graph shows the oxygen dissociation curves for haemoglobin in animals that live at high altitude and animals that live at low altitude. 100 high altitude percentage saturation of haemoglobin low with oxygen altitude 0 partial pressure of oxygen / kPa What explains the oxygen dissociation curve at high altitude? A Haemoglobin has a higher affinity for oxygen. B Haemoglobin releases oxygen more readily. C The change in partial pressure of carbon dioxide causes a Bohr effect. D The decrease in percentage of carbon dioxide causes the curve to shift to the left.

Question

The diagram shows three features found in the mammalian gas exchange system. ciliated goblet epithelium cells X cartilage Which structures of the gas exchange system could be represented by X in the diagram? A small bronchiole only B small bronchiole and bronchus C trachea only D trachea and bronchus

Question

What are short-term effects of nicotine on the cardiovascular system? 1 constriction of small arteries 2 increase in heart rate 3 increase in blood pressure A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Some features of a disease are listed. ● It can be transmitted by animals to other animals, including humans. ● One mode of transmission is by transfusion with contaminated blood. ● The causative organism can show multiple drug resistance. ● The majority of humans who die from the disease are children. Which disease has all these features? A cholera B HIV / AIDS C malaria D tuberculosis

Question

The following advice was given to a person travelling to a country where there had been an outbreak of an infectious disease. ● Cook food well and eat it hot. ● Peel fruit and vegetables. ● Drink only cool, boiled water. ● Wash hands often with soap and cool, boiled water. Which infectious disease would this advice help to protect against? A cholera B malaria C measles D tuberculosis

Question

Which description of multiple drug resistance in bacteria is correct? A Bacteria have DNA with resistant genes for several different types of antibiotic. B Different species of bacteria have DNA with resistant genes for one type of antibiotic. C Large numbers of one species of bacteria are immune to several different types of antibiotic. D Many different species of bacteria are immune to one type of antibiotic.

Question

Which description of a T-lymphocyte is correct? A They are only found in blood and secrete cytokines in response to infection. B They can leave the blood and accumulate at sites of inflammation. C They can leave the blood and secrete cytotoxins when exposed to bacteria. D They circulate in the blood and always present antigens in response to infection.

Question

Where are antibodies found during an immune response? on the surface in blood of memory cells plasma A key B = antibodies found C = antibodies not found D

Question

Monoclonal antibodies are used in the diagnosis and treatment of disease. They are produced using a technique known as cell fusion. Which two structures are fused together in this technique? A antigens and hybridoma cells B T-lymphocytes and cancer cells C cancer cells and plasma cells D hybridoma cells and antibodies