Calderglen High School Higher Human Biology Unit 1: Human Cells Homework Questions
Contents Page Sub-Topic 1: Differentiation and stem cells 3-5 Sub-Topic 2: DNA and its replication 6-10 Sub-Topic 3: RNA, transcription and translation 11-19 Sub Topic 4: Proteins, mutations and genetic disorders 20-21 Sub topic 5: Human Genomics 22-24 Sub topic 6: Metabolism and Enzymes 26-29 Sub topic 7: Cellular respiration 30-39 2
---------------------- --------------------- Sub topic 1: Differentiation and stem cells 1. Which of the following is not a use of stem cells? A B C D Skin grafts Drug testing IVF treatment Bone marrow transplant 2. Which line in the table below describes correctly cell division in a specific cell type 5. Which of the following statements regarding stem cells is TRUE? A Stem cells are specialised cells that continue to divide. B Stem cells cannot differentiate into specialised cells C Stem cells are unspecialised cells that can differentiate into specialised cells. D None of the above Cell Type Type of cell division Chromosome number in cells produced A somatic meiosis diploid B somatic meiosis haploid C germline mitosis haploid D germline mitosis diploid 3. Which of the following statements about cancer cells is TRUE? A. Cancer cells respond to regulatory signals B. Cancer cells cannot spread through the body C. Cancer cells cannot divide excessively D. Cancer cells can form secondary tumours 4. Which of the following statements is TRUE? A. Blood cells and muscle cells are undifferentiated germline cells B. Blood cells and muscle cells are differentiated germline cells C. Blood cells and muscle cells are undifferentiated somatic cells D. Blood cells and muscle cells are differentiated somatic cells 6. Cancer cells can divide excessively to produce a mass of abnormal cells known as a tumour. A tumour cell can double every 40 minutes. If one tumour cell starts to divide how many tumour cells will be present after 12 hours? A 720 B 32768 C 131072 D 262144 7. The cell shown below is magnified six hundred times. What is the actual size of the cell? A 1080 μm B 108 μm C 30 μm D 3 μm 18 mm 3
8. The diagram below shows some stages in the development of blood cells and nerve cells. (a) What are stem cells? (1) (b) State the location of the tissue stem cells which develop into blood cells. (1) (c) Describe what is meant by the term differentiation. (1) 4
8. (continued) (d) Both embryonic stem cells and tissue stem cells are used in medical research. Give one reason why embryonic stem cells are potentially more useful than tissue stem cells. (1) (e) (i) Stem cells can be used in research and therapeutics (branch of medicine relating to the treatment of disease) because stem cells are able to develop into different types of cells. Explain why stem cells are able to develop into different types of cells. (1) (ii) List 3 therapeutic uses of stem cells. 1. 2. 3. (3) (f) Tumours can be found in patients suffering from cancer. (i) Describe what a tumour is: (1) (ii) Describe how a secondary tumour develops: (1) 5
Sub topic 2: DNA and it s replication 1. A DNA molecule consists of 4000 nucleotides of which 20% contain the base adenine. E. How many of the nucleotides in this DNA molecule will contain guanine? A 800 B 1000 C 1200 D 1600 2. A fragment of DNA was found to have 120 guanine bases and 60 adenine bases. What is the total number of sugar molecules in this fragment? A: 60 B: 90 C: 180 D: 360 3. If ten percent of the bases in a molecule of DNA are adenine, what is the ratio of adenine to guanine in the same molecule? A: 1:1 B: 1:2 C: 1:3 D: 1:4 4. A DNA nucleotide could be formed from a molecule of phosphate together with A. Ribose sugar and guanine B. Ribose sugar and uracil C. Deoxyribose sugar and guanine D. Deoxyribose sugar and uracil 6
5. DNA controls the activities of a cell by coding for the production of A B C D proteins carbohydrates amino acids bases 6. If a DNA molecule contains 8000 nucleotides of which 20% are adenine, then the number of guanine nucleotides present is: A 1600 B 2000 C 2400 D 3200 7. The table below refers to the mass of DNA in certain human body cells. Cell type Mass of DNA in cell (x10-12g ) liver 6.6 Lung 6.6 P 3.3 Q 0.0 Which of the following is most likely to identify correctly cell types P and Q? P Q A Kidney cell Sperm cell B Sperm cell Mature red blood cell C Mature red blood cell Sperm cell D Nerve cell Mature red blood cell 7
8.How many adenine molecules are present in a DNA molecule of 4000 bases, if 20% of the base molecules are cytosine? A 400 B 600 C 800 D 1200 9. Which of the following statements about DNA replication is correct? A Polymerase adds nucleotides to the 3 end of a DNA strand B Polymerase adds nucleotides to the 5 end of a DNA strand C D Ligase adds nucleotides to the 3 end of a DNA strand Ligase adds nucleotides to the 5 end of a DNA Strand 10.Thirty percent of bases in a DNA molecule are adenine. The percentage of cystosine bases in the same molecule is A 20% B 30% C 40% D 70% 8
11. Which of the following diagrams correctly represents part of a DNA molecule? The letters A, T, U, C and G represent bases. A. 3 B. 3 C. 5 D. 3 A C T A T T A C U A C G 5 3 5 5 12. The two components which make up the backbone of each DNA strand are A B C D Ribose and phosphate group Deoxyribose and phosphate group Deoxyribose and base pairs Phosphate group and thymine 13. Which of the following statements about the structure of DNA is TRUE? A. In DNA the base pairs are held together by peptide bonds. B. Fragments of DNA are joined together by ligase C. Fragments of DNA are joined together by polymerase D. DNA contains the bases represented by the letters A, U, C and G. 9
14.The diagram below shows part of a DNA molecule. T A X Y T (a) (i) Copy the diagram and then, on your diagram, draw a circle around one nucleotide. 1 (ii) Name parts X and Y X Y (b) Name the two DNA bases not shown in the diagram. 1 and 1 (c) A DNA molecule was found to contain 15000 nucleotides. What is the maximum number of amino acids which could be coded for by this molecule? 1 10
Sub topic 3: RNA, transcription, translation 1. The function of trna in cell metabolism is to A B C D transport amino acids to be used in synthesis of proteins carry codons to the ribosomes synthesise proteins transcribe the DNA code 2. The following information refers to protein synthesis. trna anticodon G U G C G U G C A A U G U A C U G U amino acid carried by trna Histidine (his) Alanine (ala) Arginine (arg) Tyrosine (tyr) Methionine (met) Threonine (thr) What order of amino acids would be synthesised from the base sequence of DNA shown? Base sequence of DNA A arg - tyr - his B ala - met - his C ala - tyr - his D arg - tyr - thr C G T T A C G T G 3. The table below contains statements which may be TRUE or FALSE with regard to DNA replication and mrna synthesis. Which line in the table is correct? A B C D Statement Occurs in the nucleus Involved in protein synthesis Requires free DNA Replication TRUE TRUE mrna synthesis FALSE TRUE nucleotides TRUE FALSE Involves specific base TRUE TRUE pairing 11
4. The diagram represents part of a molecule of DNA on which a molecule of RNA is being synthesised. What does component X represent? A B C D Ribose sugar Deoxyribose sugar Phosphate Ribose phosphate 5. The diagram shows a stage in the synthesis of part of a polypeptide. Tyrosine Amino acid trna mrna T A T DNA Identify the triplet codes for the amino acid tyrosine. mrna trna A ATA UAU B UAU AUA C AUA UAU D ATA TAT 12
6.The diagram below illustrates the two main stages of protein synthesis. (a) Describe three differences between DNA and mrna. 1. 2. 3. 2 13
6(continued) (b) Name bases 3, 8 and 11.,, 2 (c) Where in the cytoplasm does stage 2 take place 1 (d) Name molecules X and Y. X Y 1 7(a) The diagram shows part of an mrna molecule being formed on a strand of DNA. A C A T G A C A C G A G m RNA (i) In which part of the cell is mrna formed? 1 (ii) Copy the diagram above and then, on your diagram, complete the mrna molecule by filling in the correct base sequence. (iii) How many amino acids are coded for by this section of mrna? 1 14
8.(a) The diagram below shows a section of a messenger RNA (mrna) molecule. Phosphate= Sugar = guanine uracil adenine (i) Name the sugar that is present in mrna 1 (ii) Which base found in mrna is not shown in the diagram? (iii) Name two parts of a cell where mrna is found. 1. 2. 1 (b) DNA templates are used to produce mrna molecules. (i) (ii) (iii) Copy the table below and insert the names of the DNA bases which pair with the RNA bases shown. DNA base RNA base adenine uracil guanine 1 Apart from free RNA nucleotides and a DNA template, name one other molecule that is essential for mrna synthesis. 1 Describe the part played by a mrna molecule in the manufacture of a cell protein. 3 15
9.The formation of a mrna strand on a section of a chromosome is shown in the diagram below. (a) Give the names of bases 1, 2 and 3. 1. 2. 3. 1 (b) The mrna strand is constructed from free nucleotides. Name the two molecules which combine with a base to form a mrna nucleotide. 1. 2. 1 (c) Once completed, the mrna strand moves into the cytoplasm. What is its destination? 1 (d) Explain why the formation of mrna strands is essential to cell metabolism. 2 16
10. The diagram shows the synthesis of a peptide chain. (a) Name bond X and molecule Y. Bond X Molecule Y 2 (b) What term is used to describe the triplet code on the trna molecules? 1 (c) Give the abbreviated names of the next four amino acids which will be attached to complete the peptide chain. Iso 1 (d) What sequence of bases on a DNA molecule will code for the amino acid labelled thr? 1 (e) Amino acids are added to the peptide chain at the rate of 15 per second. How long will it take for the complete synthesis of the peptide shown in the diagram above? s 1 17
11. The diagram below shows a section through a nucleus and associated cell structures. (a) (i) Name organelle X. 1 (ii) What type of substance is manufactured by organelle X? 1 (iii) Give an example of such a substance. 1 12. The diagram below shows one gene within a chromosome. non coding region of the gene coding region of the gene (a) State what non-coding regions of a gene are called. 1 (b) Explain why it is important that non-coding regions are removed from the primary transcript of this gene before translation. 1 18
(c) The diagram below shows part of one coding region of the mrna from this gene. U G U C G G A C A U G U C A C U U G How many different types of amino acid are coded for by this region of the mrna strand? 1 19
Sub topic 4: Proteins, mutations and genetic disorders 1. Which type of gene mutation occurs when a codon for an amino acid is replaced by a stop codon? A Nonsense B Missense C Frameshift D Splice-site 2. Individuals with Cri-du-chat syndrome have a shortened chromosome 5. No other chromosomes are affected Which type of mutation causes Cri-du-chat syndrome? A Deletion B Insertion C Duplication D Translocation 3. In Duchenne Muscular Dystrophy (DMD) one amino acid codon is substituted with a stop codon. What type of gene mutation is this? A. Missense B. nonsense C. frameshift D. splice-site 4. In cystic fibrosis (CF) one base pair is deleted. This is an example of A: Missense B: nonsense C: frameshift D: splice-site 20
5. Copy and complete the table below about gene mutations: Type of mutation Missense Description Substituted nucleotide results in a stop codon, so the polypeptide is shorter. This is the result of a deletion or insertion mutation and the entire sequence of triplets after this point will be wrong. (3) 6.Whole sections of chromosomes can be altered by mutation, affecting several genes. Give an account of the three types of chromosome mutations. (3) 21
Sub topic 5: Human Genomics 1. During the polymerase chain reaction (PCR) samples of DNA are repeatedly heated and cooled. Why are the samples cooled? A B C D To denature DNA polymerase To slow the reaction down To allow primers to bind to target sequences To separate the DNA strands 2. What is the function of a DNA probe? A B C D To replicate a particular region of DNA To join fragments of DNA together To remove non-coding sections of DNA To detect the presence of specific DNA sequences 22
3. The diagram below shows the results of a paternity test. It compares DNA samples from five individuals. Woman S is the mother of child X and child Y. Men P and Q are possible fathers of these children. Woman S Man P Man Q Child X Child Y Which of the following conclusions can be drawn from these results? A B C D Man P could be the father of child X Man P could be the father of child Y Man Q could be the father of child X Man Q could be the father of child Y 4. Which of the following lines regarding DNA amplification is TRUE? Melting Annealing Extending Primers bind at two ends of the region to be amplified A. Heating the DNA to separate the strands B. Complementary strands of target 23 Heating the DNA to separate the Complementary strands of target DNA are made Primers bind at two ends of the region
DNA are made strands to be amplified Heating the DNA to Complementary separate the strands of target strands DNA are made C. Primers bind at two ends of the region to be amplified D. Heating the DNA to separate the strands Complementary strands of target DNA are made Primers bind at two ends of the region to be amplified 5. How many cycles of PCR have been completed if 128 molecules of DNA were produced from one double DNA helix? A. 5 B. 6 C. 7 D. 8 24
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Sub topic 6 Metabolism and Enzymes 1. The diagram below shows a metabolic pathway that is controlled by end product inhibition. Substance 1 Substance 2 Substance 3 Substance 4 Enzyme 1 Enzyme 2 Enzyme 3 For Substance 4 to bring about end product inhibition, with which of the following would it interact. A. Enzyme 1 B. Enzyme 3 C. Substance 1 D Substance 3 2. The graph shows the effect of substrate concentration on the rate of an enzyme-catalysed reaction. At what substrate concentration is the reaction rate equal to 75% of the maximum rate? A. 6 units B. 8 units C. 12 units D. 18 units 26
3. The graph shows the effect of substrate concentration on the rate of an enzyme-controlled reaction. X Y Rate of reaction Substrate concentration The graph levels out between points X and Y because the A. enzyme is denatured B. active sites are saturated with substrate C. enzyme is inhibited D enzyme is activated 4. The following table gives information on the control of metabolic pathways using inhibitors. Which line in the table is CORRECT? Competitive Non-competitive Feedback inhibition Changes shape of active site of enzyme A. Binds to active site of the enzyme B. End product binds to an enzyme that catalyses a reaction early in the pathway C. Changes shape of active site of enzyme D. Binds to active site of the enzyme Type of inhibitor Changes shape of active site of enzyme Binds to active site of the enzyme End product binds to an enzyme that catalyses a reaction early in the pathway End product binds to an enzyme that catalyses a reaction early in the pathway Binds to active site of the enzyme End product binds to an enzyme that catalyses a reaction early in the pathway Changes shape of active site of enzyme 27
5. The diagram below represents a reaction catalysed by an enzyme in the cytochrome system. (a) What name is given to the part of the enzyme where this reaction occurs? 1 (b) Name the product of this reaction. 1 (c)cyanide is a poison which inhibits this enzyme. Suggest how cyanide is able to do this. 1 28
6.The graph shows the effect of increasing substrate concentration on the rate of this reaction. Rate of reaction Substrate concentration (i) Explain why the graph levels out at high substrate concentration. 1 (ii) Assuming that the enzyme is operating at its optimum ph and temperature, suggest how the rate of reaction could be increased at high substrate concentrations. 1 29
Sub topic 7: Respiration 1. During which of the following chemical conversions is ATP produced? A B C Amino acids protein Glucose pyruvic acid Haemoglobin oxyhaemoglobin energy 5.The diagram below shows energy transfer within a cell. Compound X + phosphate energy Cellular Processes D Nucleotides mrna Compound Y 2. The following statements relate to respiration and the mitochondrion. 1 Glycolysis takes place in the mitochondrion. 2 The mitochondrion has two membranes. 3 The rate of respiration is affected by temperature. Which of the above statements are correct? A. 1 and 2 B. 1 and 3 C. 2 and 3 D. All of them 3.In the absence of oxygen the breakdown of glucose splits from the aerobic pathway of respiration A after the formation of pyruvate B after the formation of acetyl CoA C after the formation of citric acid D at the start of glycolysis. 4.In respiration, the products of the electron transfer system are A hydrogen and carbon dioxide B water and ATP C oxygen and ADP D pyruvate and water. Which line in the table below identified correctly compounds X and Y? X Y A glucose ATP B glucose ADP C ADP ATP D ATP glucose 6.The following chart shows stages in the complete breakdown of glucose in aerobic respiration. Glucose Pyruvate Stage X Stage Y Citric acid cycle Stage Z At which stage or stages is hydrogen released to be picked up by hydrogen acceptors? A. Stages X, Y and Z B. Stages X and Y only C. Stages Y and Z only D. Stage Z only 30
7.In respiration, the sequence of reactions resulting in the conversion of glucose to pyruvare is called A. the cytochrome system B. the TCA cycle 11. The graph below shows changes which occur in the masses of protein, fat and carbohydrate in a person s body during seven weeks without food. C. the Krebs cycle D. glycolysis. 8. The diagram shows part of a liver cell with four parts labelled. In which part is most ATP produced? Weeks without food 9. Glycolysis takes place in the F. nucleus G. Inner membrane of mitochondria H. matrix of mitochondria I. cytoplasm. 10. The following diagram represents stages in the complete breakdown of glucose in aerobic respiration. Glucose Stage X The person s starting weight was 60kg. Predict their weight after two weeks without food. A. 57kg B. 54kg C. 50kg D. 43kg 12.The diagram below represents stages in tissue respiration. oxygen ADP+P D A + Pyruvate Stage Y Krebs cycle Stage Z At which stage, or stages, is carbon dioxide released? A. Stages X and Z B. Stages X and Y C. Stages Y and Z D. Stage Z only. B + carbon dioxide Which box represents ATP? C relaxed muscle 31
13. Which of the following statements about the role of dehydrogenase enzyme in respiration is TRUE? A. Dehydrogenase enzymes remove oxygen ions from a substrate B. Dehydrogenase enzymes add hydrogen ions to a substrate C. Dehydrogenase enzymes remove hydrogen ions from a substrate D. Dehydrogenase enzymes add oxygen ions to a substrate 14. The diagram below shows two stages of respiration Stage A Glucose Pyruvate Acetyl coenzyme A (a) (i) Identify stages A and B. Stage A Stage B (ii) Name Substance X. (b) During Stage A, glucose is converted to pyruvate. Name the molecule that provides phosphate for this conversion. 1 (c) The conversion of citrate to substance X in Stage B involves several reactions. 32
Name two molecules, apart from NADH, which are produced during these reactions. 1. 2. 1 (d) Phosphofructokinase is an enzyme involved in Stage A. The presence of excess citrate inhibits this enzyme. Explain why this is important in the conservation of resources in the cell. 1 33
15. The diagram below shows some of the reactions which occur during aerobic respiration. glucose Stage A Pyruvic acid acetyl CoA 4-carbon compound Stage B Citric acid reduced molecule R Molecule R water Stage C molecule S (a) Complete the table by naming stages A, B and C and indicating their exact location within cell. Stage Name Location A B C 3 (b) Complete the following sentences by naming molecules R and S and describing their function with respect to stage C. 34
R is and its function is S is and its function is 16.The diagram below represents two stages in the chemistry of respiration in a cell which is respiring aerobically. Glucose 3-carbon compound Coenzyme A (CoA) X Acetyl (2C) coenzyme A 4 carbon compound 6 carbon compound 5 carbon compound (a) Name the 3-carbon compound and the 6-carbon compound. 3C 6C 2 (b) Copy the diagram and draw a line across it to indicate where this series of reactions would stop if oxygen were not available. 1 (c) State the precise location of the Krebs cycle within the cell 1 (d) Complete the table below to name product X and to describe what happens to each of the products. Product Fate of product 35
X Hydrogen 17. Which of the following equations describes correctly the role of creatine phosphate? A ADP + phosphate + creatine B creatine phosphate + ADP C creatine phosphate + ATP D ATP + phosphate creatine phosphate + ATP ATP + creatine ADP + phosphate + creatine creatine phosphate + ADP 18.The diagram below shows three stages that occur during aerobic respiration. Stage X Reactions in the cytoplasm 1 Stage Y 2 Stage Z metabolic products Reactions in Reaction in matrix of Inner mitochondrion menbrane of mitochondrion (a).name each stage. X Y Z (b) Arrows 1 and 2 represent the transfer of molecules from one stage to another. Copy and complete the table to identify these molecules. Arrow Name of molecule 1 2 2 (c) Name the two metabolic products of stage Z. and 1 (d)the diagram below shows a mitochondrion from a skin cell. 36
Describe how the structure of mitochondrion from an active muscle cell would differ from the one shown. Give a reason for your answer. Structural difference 1 Reason 1 19.The diagram below shows the metabolism of three energy sources in a cell. proteins carbohydrates fats Intermediate compound glycerol X Gas Z pyruvate acetyl CoA Y (a) Name X, Y and Z X Y Z 2 (b) respiration? What term describes the breakdown of carbohydrate into pyruvate during 1 (c) Describe what happens to acetyl CoA after it enters the citric acid cycle. 1 37
20.The diagram shows the role of ATP in cell metabolism. glucose + oxygen + proteins Pathway X process Y + ATP (a)copy and complete the diagram by entering the names of the appropriate substances. 3 (b)name one stage of pathway X and state where it occurs in the cell. Stage Location 1 (c) Name the organelle where process Y occurs. 1 (d)name a respiratory substrate other than glucose. 1 21(a) The table below contains three statements about two stages of cellular respiration. Copy and complete the table to indicate whether the statements are True (T) or False (F) for each stage. Stages of Respiration Statement Glycolysis Cytochrome System Occurs in the mitochondrion T Releases carbon dioxide Uses oxygen F 38
2 (b)the diagram below summarises anaerobic respiration in a muscle cell. Glucose (6C) X (3C) Lactic acid (3C) Pathway Y (i) Name substance X 1 (ii) Which substance would need to be present for pathway Y to occur? 1 (iii) Why is anaerobic respiration considered to be a less efficient process than aerobic respiration? 1 (iv) Glucose is not stored in muscle cells. Name the carbohydrate which is stored in muscle cells. 1 39