Please note: these are not confirmed answers and are not necessarily correct or the only possible answers.
Higher Human Biology Answers: Section B 1)a) Meiosis b) A46 B23 C23 c) The chromosomes in cell B will be larger & more visible than those in cell C d) Independent assortment and Crossing over at chiasmata e) Seminiferous Tubules 2)a) Stage Name Location A Glycolysis Cell cytoplasm B Krebs/citric acid cycle Matrix of mitochondrion C Cytochrome system Cristae of mitochondrion b) Pyruvic acid – 3 Citric acid – 6 c) R is NAD and its function is to accept the hydrogen and transport it to the cytochrome system S is oxygen and its function is to act as the final acceptor of hydrogen. d) Situation Respiratory substrate Explanation Prolonged Muscular tissue/protein The glycogen and fat/lipid Starvation stores will have been used up in respiration. Towards Lipids/Fat The glucose will have been the end of used up in respiration and the a glycogen stores would be marathon exhausted race 3)a)i) P – Antigen/protein coat/antigenic marker Q – Antibody ii) B Cell iii) (A) Tlymphocyte: starts an immune response or actively works to attack and destroy foreign substances (antigens). (B) Macrophage: engulfs (and destroys) microorganisms/bacteria b)i) Underline active and naturally ii) Underline active and artificially c) An immune response by the body against its own tissue or cells. 4)a) The information above shows lactose being broken down into its constituent monosaccharides – glucose & galactose b) Mass/quantity of lactase enzyme Temperature of milk/ room temperature Volume of milk used 4)c) Graph d) Human milk contains more lactose than cow milk 1
e) There may be a limiting factor such as active sites on enzymes f) Repeat the experiment/ use a control g)i) Inborn error of metabolism ii) No change in blood glucose level 5)a)i) Prolactin ii) Milk contains protein and the ribosome is the site of protein synthesis b)i) Colostrum ii) It has more antibodies iii) The baby cannot verbally communicate so nonverbal communication is the only means of communication. It allows a bond to be formed between mother and child. 6)a) They emulsify lipids from the meal increased the surface area for the action of enzymes/ they neutralise the stomach acid/products from the stomach b) The fatty acids & glycerol are absorbed into the lymphatic system via the lacteal in the villi in the small intestine. The lymph fluid enters the blood stream near the heart and the products of fat digestion suspended in the lymph enters the bloodstream, c) Blood vessel Substance Glucose Urea
Hepatic Portal Vein Higher Low
Hepatic vein Low High
d) Detoxification 7)a)i) 1.4 beats/min ii) 7.2nMol/l iii) Approx 8.4 nMol/l b)i) As the speed increases, the rate of respiration in the muscle cells increases to produce more ATP, and therefore more oxygen is used up. In the absence of oxygen, anaerobic respiration takes place producing lactic acid ii) The rubber could use the graph to see when the lactic acid concentration would become high and adjust here running speed/heart rate accordingly to prevent muscle fatigue. 8)a)i) P has a high glucose concentration at 0 hours P’s blood glucose concentration remains high (even after 5 hours) ii) (A) Insulin (B) Glucagon b)i) Pituitary gland (in brain) ii) Dehydration as it results in excessive urination/ diabetes insipidus 9)a)i) The vesicle fuses with the membrane of cell X, the neurotransmitter is released during exocytosis. The neurotransmitter diffuses across the synapse to cell Y ii) Many impulses merge together so it increases the force/power of the it so the threshold is more likely to be reached for sufficient Neurotransmitter to be released to have an effect on the receptors or membrane of cell Y. b)i) Limbic system 2
ii) Alzheimer’s disease 10) This allows genetics to be discounted in the case of any behavioural differences or variations. b)i) Enviromental – A lower percentage of the monozygotic twins share this condition. ii) Genetic A higher percentage of the monozygotic twins share this condition. 11) Improved health care provision for the elderly/ medical advances so more people Are living longer b) The number of those aged 75 and over would be lower The number of those ages 0 to 14 would be higher c) Prepare for the future in terms of food for the population Plan ahead for the increasing ageing population 12)a)i) Nonaggressive man and Girls ii)1770% b) Imitation c) A video with no adults but just the clown could be shown to the children/ the children could be placed in a room with the clown before being shown any videos. 13)a) Similarity the application of both increased up until 1994 and decreased after This year. Difference The application of phosphorus increased quicker than nitrogen up until 1994, after which its application decreased slower than that of nitrogen. b) 3:1 c)i) It might prevent eutrophication/pollution of nearby rivers and lochs. ii) It might decrease crop yield. 14)a)i) 0.28m ii) It will reduce the area of land available for farming Increase in disease Increase in mortality rates in coastal communities b)i) Methane and Carbon Dioxide ii) Carbon Dioxide: • Increasing use/combustion of fossil fuels • Deforestation Or Methane: • Increased intensive livestock farming • Use of landfill sites