biology paper 1 quiz

• Electron microscopes


  Have higher resolving power or resolution, allowing finer details to be visualized
• 5 micrometers


  5 * 10^-6 meters
• Subcellular structures/organelles only found in plant cells


  • Chloroplasts
  • Permanent vacuole
  • Cell wall
• Eukaryotic cells


  DNA is found in the nucleus
• Prokaryotic cells


  DNA is not found in a nucleus
• Stages of mitosis


  1. Nucleus dissolves

  2. Genetic material is duplicated

  3. Two sets of chromosomes move to opposite sides

  4. Organelles are duplicated

  5. Cell divides producing two genetically identical diploid cells
• Diploid cells


  Have two sets of chromosomes
• Haploid cells


  Have one set of chromosomes
• Diffusion


  Movement of particles from high to low concentration, down the concentration gradient, passive
• Osmosis


  Diffusion of water through a semi-permeable membrane to balance the concentration of solutions
• Active transport


  Movement of molecules from low to high concentration, against the concentration gradient, requires energy
• Factors that increase rate of diffusion/osmosis

  • Increase temperature
  • Increase concentration difference
  • Increase surface area
• Finding sugar concentration in potato using osmosis practical

  Interpolate using line of best fit where it crosses x-axis, this is the concentration at which no osmosis occurs, which is the same as inside the potato cells
• Bile


  Made by liver, stored in gallbladder, emulsifies lipids in small intestine to increase surface area for enzyme action
• Amylase


  Enzyme secreted by salivary glands and pancreas that breaks down starch into glucose
• Villi


  Cells in small intestine with large surface area to absorb nutrients
• Enzymes


  Biological catalysts that facilitate crucial processes in the body
• Enzyme specificity


  Enzymes only break down certain molecules due to their lock and key nature
• Factors that affect enzyme activity

  • Increasing temperature increases activity until denaturation
  • Optimum pH range
• What enzymes break down

  • Carbohydrases break down carbohydrates into sugars
  • Proteases break down proteins into amino acids
  • Lipases break down lipids into glycerol and fatty acids
• Determining if amylase has broken down all starch

  Solution no longer turns black/changes colour when added to iodine
• Tests for biological molecules

  • Starch - iodine turns black
  • Sugars - Benedict's solution turns orange/green
  • Proteins - Biuret reagent turns purple
  • Lipids - ethanol turns cloudy
• Alveoli


  Air sacs in lungs with large surface area for gas exchange
• Red blood cells


  Biconcave shape maximizes surface area for oxygen binding to hemoglobin
• Blood flow through the heart

  1. Enters through vena cava

  2. Right atrium

  3. Right ventricle

  4. Pulmonary artery

  5. Lungs

  6. Pulmonary vein

  7. Left atrium

  8. Left ventricle

  9. Aorta
• Differences between left and right sides of the heart

  Left side has thicker walls to deal with higher pressure pumping blood to whole body, right side only pumps to lungs
• Differences between arteries, veins and capillaries

  • Arteries - carry blood away from heart, thick walls, small lumen
  • Veins - carry blood towards heart, thin walls, large lumen, contain valves
  • Capillaries - very small, one cell thick walls for gas/nutrient exchange
• Risk factors for non-communicable diseases

  • Diabetes - poor diet, obesity
  • Heart disease - poor diet, lack of exercise
  • Liver disease - alcohol
  • Lung disease - smoking
• Cancer


  Autoimmune disease where cells mutate and divide uncontrollably, forming tumors
• Benign vs malignant cancers

  Benign does not spread, malignant will spread through the body
• Xylem


  Tubes that carry water up the plant by transpiration
• Phloem


  Tubes that transport sugars and other molecules up and down the plant
• Factors that increase transpiration rate

  • Increase temperature
  • Increase air flow
  • Increase leaf surface area
• Meristem


  Where new cells are made, stem cells that then differentiate
• Leaf structures and functions

  • Waxy cuticle - prevents water loss
  • Palisade mesophyll - site of most photosynthesis
  • Spongy mesophyll - allows gas exchange
  • Guard cells - control stomata
• Balanced equations for respiration and photosynthesis

  Respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O

  Photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2
• Anaerobic respiration in animals and plants

  Animals - glucose → lactic acid

  Plants - glucose → ethanol + CO2
• Uses of glucose from photosynthesis

  • Respiration
  • Starch/fat storage
  • Cellulose production
  • Amino acid synthesis
• Factors that increase photosynthesis rate

  • Increase temperature
  • Increase light intensity
  • Increase CO2 concentration
• Light intensity and distance

  Light intensity decreases by inverse square of distance