2 Marker question

• At the end of the menstrual cycle progesterone concentration decreases

  Describe the process that leads to this decrease(2 Marks)


  A decrease in concentration of LH which leads to the degeneration of the corpus luteum
• Suggest why statins are prescribed to individuals to reduce the risk of a heart attack

  They Reduce blood cholesterol build-up

  reduce the chances of clots like thrombus
• Describe how type 2 diabetes affects liver cells.

  There is a decrease in the number of insulin receptors

  less glucose is converted into glycogen
• During exercise, stimulation by sympathetic neurons increases heart rate and causes vasoconstriction of arteries in the small intestine. Explain the importance of increased heart rate and vasoconstriction of arteries in the small intestine during exercise

  Increased heart rate:

  Vasoconstriction of arteries in small intestine:

  Increased heart rate: Increases blood flow to muscles

  Vasoconstriction of arteries in small intestine: Decreases blood flow to small intestine
• Explain why lactate concentration increases as the intensity of exercise increases

  The muscles do not get enough oxygen.

  Pyruvate is converted to lactate
• When bacteria enter the body, phagocytes often destroy them. Describe how phagocytes destroy bacteria.

  phagocytes engulf bacteria

  Lysosomes release
• A number of hormonal changes occur in a woman’s body during the menstrual cycle

  State one function of each of the following hormones in the menstrual cycle

  FSH:

  Oestrogen:

  FSH: Stimulates the growth of the follicle

  Oestrogen: prepares the endometrium for implantation
• A woman took a daily oral contraceptive pill.

  Explain how taking this pill would affect the FSH concentrations in her blood during her menstrual cycle

  The pill has a negative feedback effect on the pituitary gland

  FSH decreases and remain low do not increase during menstruation
• Name organ Y and Hormone X

  Organ Y: Liver

  Hormone X: Glucagon

  
• Name the parts labelled X and Y.

  X – cell body

  Y – axon

  
• Neurons connect with other neurons at a synaptic cleft

  State one way that neurotransmitters are removed from a synaptic cleft

  Broken down by enzymes
• Explain why neurotransmitters must be removed from a synaptic cleft.

  To prevent continuous simulation
• Explain why the surface proteins of the virus used in the vaccine must remain undamaged


  The surface proteins acts as antigens

  Formation of memory cells

  They trigger the immune response
• Antibodies inactivate viruses, which are then removed by phagocytosis. Describe the process of phagocytosis

  Phagocytes engulf the pathogen

  Lysosome release

  enzymes destroys the pathogen
• State the location of blood stem cells in the body


  None Marrow

  
• Describe one therapeutic use and one research use of stem cells

  Therapeutic use: Corneal repair/regeneration of damaged skin.

  Research use: (Used as model cells) to study how diseases develop, for drug testing, used to study cell processes
• Describe the role of primers in allowing DNA replication to start.

  Primers bine to the 3'end of the DNA

  Primers allow DNA polymerase to start replicating

  
• The diagram represents a reaction in a metabolic pathway

  Name the type of reaction shown in the diagram and give a reason for your answer.

  Type of reaction:

  Reason:

  Type of reaction – Anabolic

  Reason - The reaction involves the build-up of molecules

  
• Describe the role of induced fit in this enzyme-catalysed reaction

  When the substrate binds the shape of the active site changes

  (1 mark)
• Use the diagrams to describe how this proton pump inhibitor drug works

  drug inhibitor binds to the proton and changes the shape of the proton

  This means that the protons cannot attach to the proton pump

  
• Apart from their role in making the stomach more acidic, hydrogen ions are required for ATP synthesis in the mitochondria. Describe the role of hydrogen ions in ATP synthesis

  Hydrogen ions are pumped across the inner mitochondrial membrane

  They flow back through ATP synthase generating ATP
• Describe how a decrease in LH concentration leads to menstruation

  Lack of LH causes degeneration of the corpus luteum

  This leads to a decrease in progesterone levels triggering menstrution
• Explain why non-functional LDL receptors can lead to an individual having high blood pressure.

  Cholesterol is deposited in the arteries (by LDL)

  Atherosclerosis occurs increasing blood preassure
• Explain the benefit of regular physical activity to individuals suffering from high blood cholesterol.

  decreases the ratio of LDL to HDL

  this lowers blood cholesterol levels
• Name A and B.

  A: Dendrite

  B: Synapse

  
• Name the divisions of the nervous system labelled X and Y.

  X: Peripheral Nervous System

  Y: Autonomic Nervous System

  
• Describe an effect of the parasympathetic nervous system on breathing and the digestive system.

  Breathing: Decreases heart and breathing rate

  Digestive system: Increases peristalisis and intestinal secretions
• Describe an effect of the parasympathetic nervous system on breathing and the digestive system

  Breathing: Decreases breathing rate

  Digestive system: increases peristalsis
• Use information from the diagram to explain how alcohol can be used as a substrate in respiration.

  Acetyl group is produced

  Acetyl group combines with oxaloacetate to form citrate.

  
• Describe two functions of testosterone

  Simulates sperm production

  triggers the prostate gland and seminal vesicles to produce secretions

  
• Describe how negative feedback control raises the concentration of testosterone in the blood if it has fallen to a low level.

  Low levels of testosterone fail to inhibit the pituitary gland

  An increased concentration of ISCH is released by the pituitary gland
• Describe an advantage and a disadvantage of using amniocentesis rather than chorionic villus sampling (CVS)

  Advantage: Lower risk of miscarriage

  Disadvantage: Is carries out later in pregnancy
• The glucose tolerance test indicated that this man had type 2 diabetes.

  Explain why production of insulin did not lower his blood glucose concentration in the first hour of the test.

  Cells have lower insulin receptors

  less glucose is taken into cells
• Explain why having a lower LDL concentration in the blood decreases the risk of death from CVD

  Less cholesterol is deposited in arteries

  Less chance of atherosclerosis
• Name the parts of the brain and heart which are linked by the nerves shown in the diagram

  Brain: Medulla

  Heart: SAN

  
• Explain how the sympathetic and parasympathetic nerves control heart rate

  Sympathetic nervous system increases heart rate while parasympathetic system decreases it.

  Sympathetic system releases noradrenaline the parasympathetic system releases acetylcholine.
• Mast cells initiate the inflammatory response. Name the chemical which they release and explain how it increases the supply of fluid into the infected tissue.

  Chemical: Histamine

  Explanation: Cases of vasodilation
• Name the process by which a stem cell develops into a specialised body cell and explain how this process occurs

  Process: Differentiation

  explanation: only the genes for producing proteins for the type of cell are expressed

  
• The nucleus of a germline stem cell divides twice during meiosis. Describe what happens to chromosomes during each division.

  First division – Homologous chromosomes are separated.

  Second division – Chromatids are separated.
• Phase 1 is the energy investment stage of glycolysis while phase 2 is the energy pay-off stage of glycolysis. Describe what happens during the energy investment and energy pay-off phases of glycolysis

  Energy investment - ATP molecules are broken down

  Energy pay-off - ATP molecules are produced.