Bio P1 quiz

• Electron microscopes


  Have higher resolving power or resolution, allowing finer details to be visualized like cell organelles and subcellular structures
• 5 micrometers into metre (in standard form)

  5 * 10^-6 meters
• Subcellular structures or 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 of the cell

  4. Organelles are duplicated

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


  Have 23 pairs or 46 chromosomes
• Haploid human cells


  Have 23 chromosomes
• Diffusion


  Movement of particles from an area of high concentration to an area of low concentration, down the concentration gradient, passive and doesn't require energy
• Osmosis


  Diffusion of water through a semi-permeable membrane to balance the concentration of solutions on either side, water moves into the higher concentration solution to dilute it
• Active transport


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

  • Increase temperature
  • Increase difference in concentrations
  • Increase surface area
• Finding concentration of sugar inside potato in osmosis practical

  Interpolate using a line of best fit where it crosses the x-axis, this concentration is the same as inside the potato cells
• Role of bile


  Made by the liver, stored in the gallbladder, then goes to the small intestine where it emulsifies lipids/fats to form small droplets, increasing surface area for enzymes to break them down
• Amylase


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


  Cells in the small intestine that absorb nutrients into the bloodstream, have a large surface area to increase absorption rate
• Enzymes


  Biological catalysts that facilitate crucial processes in the body, such as breaking down polymers into monomers
• Enzyme specificity


  Enzymes only break down certain molecules due to their lock and key nature, only specific substrates can bind to the active site
• Factors affecting enzyme activity

  Increasing temperature increases activity until it denatures, optimum pH range
• What enzymes break down

  • Carbohydrases break down carbohydrates into sugars
  • Proteases break down proteins into amino acids
  • Lipases break down lipids/fats into glycerol and fatty acids
• In enzyme practical, solution no longer turns black/changes color with iodine when all starch has been broken down
• Tests for biological molecules

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


  Air sacs in the lungs where gas exchange takes place, have a large surface area to maximize diffusion of oxygen and carbon dioxide
• Red blood cells


  Transport oxygen around the body via the bloodstream, their biconcave shape maximizes surface area for oxygen binding to hemoglobin
• Path of blood through the heart

  1. Enters through vena cava

  2. Right atrium

  3. Right ventricle

  4. Pulmonary artery to lungs

  5. Pulmonary vein to left atrium

  6. Left ventricle

  7. Aorta to body
• Difference between left and right side of 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, oxygenated, thick walls, small lumen
  • Veins - carry blood towards heart, deoxygenated, thin walls, large lumen, contain valves
  • Capillaries - very small blood vessels, one cell thick walls, facilitate 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, resulting in tumors. Benign cancers don't spread, malignant cancers do.
• Xylem


  Long unbroken tubes that carry water up the plant by transpiration
• Phloem


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

  • Increase temperature
  • Increase air flow (decrease water concentration)
  • Increase leaf surface area
• Meristem


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

  • Waxy cuticle - prevents water evaporation
  • Palisade mesophyll - most photosynthesis occurs here
  • Spongy mesophyll - gaps for gas exchange
  • Guard cells - control size of stomata
• Respiration


  Glucose + Oxygen -> Carbon Dioxide + Water + Energy
• Photosynthesis


  Carbon Dioxide + Water + Light Energy -> Glucose + Oxygen
• Anaerobic respiration in animals

  Glucose -> Lactic Acid
• Anaerobic respiration in plants

  Glucose -> Ethanol + Carbon Dioxide
• Uses of glucose from photosynthesis

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

  • Increase temperature
  • Increase light intensity
  • Increase carbon dioxide concentration