1 Marker question

• Name the repeating units that makes up DNA ?

  (DNA) Nucleotides

  
• Name the parts of these units, joined by strong bonds, that make up the backbone of DNA

  Sugar/deoxyribose and phosphate

  
• Identify one letter from the diagram that labels the 3′ end of a DNA strand

  X or Y

  
• The first stage in the production of a protein involves the synthesis of mRNA from a section of DNA. Name this stage

  Transcription
• Describe how alternative RNA splicing can produce different proteins from one gene

  Different exons are retained/ removed.

  OR

  Different mature transcripts are produced.
• Use the diagram to explain why this reaction can be described as catabolic

  A (large) molecule is broken down (to smaller molecules)

  A) enzyme catalysed reaction

  
• The diagram shows induced fit occurring between the enzyme and its substrate molecule. Describe what happens during induced fit

  The active site changes to (better) fit the substrate

  
• Once the reaction is complete the products are released from the active site and the enzyme can be reused. Explain why the products leave the active site

  The products have low affinity for the active site

  
• Many enzymes are used in commercial processes. When using enzymes in these processes the end-product is regularly removed. Suggest why end-products are removed during production processes.


  To prevent feedback/end-product inhibition.
• State the exact location of the citric acid cycle in a cell.

  Matrix of the mitochondria
• Describe the role of dehydrogenase enzymes in the citric acid cycle.

  To remove hydrogen ions)/electrons.
• Name the substance that combines with an acetyl group to form citrate during the citric acid cycle.

  Oxaloacetate
• Suggest how changing one amino acid could cause the haemoglobin S protein to function less effectively than haemoglobin.

  The shape/structure of the protein is changed.

  OR

  The protein does not fold properly.
• Explain why the inheritance of sickle cell trait is an example of incomplete dominance.


  Both types of haemoglobin are found in their red blood cells

  
• Suggest why individuals with sickle cell disease have an increased risk of having a stroke

  Their red blood cells could stick together blocking the arteries to the brain
• State which of the numbered stages represents ovulation

  4

  
• Name Structure X


  Corpus luteum

  
• Describe one effect of the decrease in progesterone concentration

  Menstruation starts

  endometrium starts to break down

  Pituitary gland secrets FSH
• One treatment for infertility in women is to administer drugs to stimulate ovulation. Describe the action of these drugs

  prevents negative feedback

  Mimic the action of FSH/LH
• Blood vessel X is an artery and Y is a vein. Describe one feature shown in the diagram that confirms this.

  Lumen is smaller in arteries

  connective tissue is thicker in arteries

  
• Name Layer Z 


  endothelium

  
• Name blood vessel X

  Coronary artery

  
• Explain how the formation of a thrombus in blood vessel X results in heart muscle damage

  Muscles are deprived of oxygen

  
• Obesity is a major risk factor in the development of cardiovascular disease. BMI can be used to measure obesity.

  State the minimum BMI value that indicates obesity.

  30
• Calculate the mass of an individual who is 1.8 m tall with a BMI of 35.8

  115.992/115.99/116
• Name the test used to diagnose diabetes.

  Glucose tolerance (test).
• Describe how untreated diabetes may damage the retina

  the endothelium are damaged
• Name structure X


  Axon

  
• State why it is important that structure X is insulated by the myelin sheath

  It increases the speed of impulses

  
• Name the type of cell that produces the myelin sheath.

  Glial
• Explain how the structure of motor neurons causes a one year old child to be less coordinated than an adult

  myelination is incomplete and impulses are slower
• Motor neurons are often part of diverging neural pathways. State one advantage of neurons being arranged in a diverging pathway

  neurotransmitters can be sent to more than one destination
• Name the system identified by X

  Central Nervous System

  
• State the term that describes the opposing effect of the sympathetic and parasympathetic nervous systems on body organs.


  Antagonistic
• State one activity, other than exercise, that may increase endorphin levels

  Eating/sex.
• Tetanus is a disease caused by a type of bacteria. Tetanus bacteria live in soil and enter the body from the soil through wounds in the skin

  State the term that describes disease-causing organisms such as tetanus bacteria

  Pathogen
• Phagocytes release chemicals called cytokines at the wound site. Describe one function of cytokines


  Signal more phagocytes/Lymphocytes to the wound
• Tetanus bacteria produce a toxin. One of the actions of this toxin is to bind to pre-synaptic membranes in synapses between neurons and muscle fibres. Suggest why binding of this toxin to pre-synaptic membranes would decrease the transmission of impulses to muscle fibres.

  reduces the releases of neurotransmitters
• Explain why herd immunity would NOT protect unvaccinated individuals against tetanus.

  it is not spread from person to person
• Name the type of cells that divide to form sperm and eggs

  Germline (stem cell)