BIOLOGY PAPER 1

• lungs gaseous exchange 


  Occurs in the alveoli which is in the lungs

  when air is inhaled , oxygen diffuses from the alveoli to the blood through the capillaries for respiration
• Alveoli adaptations 


  Good blood supply which ensures oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken in the lungs

  large surface area

  thin walls- one cell thick which provides gases with a short diffusion distance
• What are chromosomes made up of?

  Chromosomes consist of DNA molecules combined with proteins. They contain genes which provide the instructions for protein synthesis.
• What are the three main stages of the cell

  cycle?

  1. Replication of DNA and synthesis of organelles
  2. Mitosis
  3. Division of cell
• Substances that enter cells by diffusion

  Carbon dioxide

  oxygen
• things that affect rate of diffusion

  Temperature

  surface area

  concentration
• Name the organ where gas takes place as a fish

  Gills
• Where is protein digested in the human digestive system ?

  Stomach
• Cell cycle 


  Stage one - cell growth, replicate DNA , more sub cellular structures are made

  stage two- chromosomes are pulled to each end of the cell

  stage 3 - two identical daughter cells are made
• pondweed investigation - describe how the student could change the method to investigate the effect of CO2 conc on the effect of photosynthesis 


  Use different conc of sodium carbonate

  different light intensity
• The heart 


  Pumps blood in a double circulatory system
• What is the function of the atria 


  blood enters the heart through the atria . The atria contracts and forces blood out the heart
• What is the function of the valves

  They make sure the blood flows in the correct direction
• What is The natural resting heart rate Controlled by?

  a group of cells in the right atrium which is a pacemaker
• right atrium function

  recieves deoxygenated blood from the body
• Left atrium

  Sends oxygenated blood to the right ventricle
• Left ventricle 


  Pumps oxygenated blood to the rest of the body
• Right ventricle 


  Pumps deoxygenated blood to the lungs to pick up a fresh supply of oxygen
• What is Translocation?


  movement of food through phloem tissue

  Phloem tissue transports dissolved sugars from the leaves to the rest of the plant
• uses of stem cells 


  Stem cells are not rejected by the patient so it can be used for medical treatment

  can help paralysis
• Disadvantages of therapeutic cloning 


  Ethical reasons

  transfer viral infections
• Villi functions 


  Villi increases surface area in the small intestine

  thin walls, short distance,short diffusion gradient so diffusion takes place quicker
• Small intestine functions and adaptations

  9metres long

  where all the small molecules get absorbed into the blood

  all enzymes are here to break up big molecules
• Graphs on enzymes 


  The optimum is the best temperature for the enzyme to work

  rate of reaction is increasing meaning there’s more temperature, more particles abd they’re going to move a lot quicker

  after 40 degrees enzyme is denatured

  the temperature is on the x axis whereas the rate of reaction is on the y axis
• Respiration after exercise 


  Blood flowing through the muscles transports lactic acid to the liver where is broken down Oxygen debt is the amount of oxygen the body’s needs after doing exercise
• How can the spread of malaria pathogen be reduced

  Drain water from swamps
• Where in the cell do mutations happen?


  Nucleus
• How can a person with lung cancer develop secondary tumours in other parts of the body

  Cancer cells can be transported in the blood
• Why won’t nhs offer lung transplant to a person who smokes?

  smoking will damage the new lung
• Why are males under the age of 13 less prone to skin cancer

  Little exposure to ionising radiation
• Why did the concentration of bacteria continue to increase after starting the course of antibiotics

  Only a few bacteria was killed so bacteria continued to reproduce
• Why are fungal infections more common in toe nails?

  Because less air gets to the feet
• Equation for fermentation 


  Glucose—-> ethanol+ carbon dioxide
• Why is fermentation used when making beer and wine 


  It’s used when making beer and wine because it’s contains ethanol
• Why is fermentayion used when making bread

  It produces with carbon dioxisde which make the bread rise
• anaerobic respiration equation 


  Glucose—-> lactic acid
• How is the palisade layer adapted for photosynthesis

  Cells contain many chloroplasts
• What 2 measurements should the student make when calculating rate of photosynthesis?


  amount Bubbles of gas

  the time
• Variables student should keep the same (pondweed practical)

  distance of the light

  light intensity
• How can the spread of malaria be reduced

  Drain water from swamps