biology paper 1

• what's the balanced equation for photosynthesise?

  6 CO2 + 6 H2O ➔ C6H12O6 + 6 O2
• Which part of a plant cell absorbs the energy needed for photosynthesis?


  chloroplasts/chlorophyll
• Explain why photosynthesis is considered an endothermic reaction


  it aborses light energy from the environment
• Describe the relationship between light intensity and the rate of photosynthesis.

  the rate of photosynthesis increases with light intensity

  above a certain light intensity/500 lux, the rate of photosynthesis increases at a much slower rate

  suggesting a limiting factor other than light intensity
• The lamp gives out heat as well as light.

  What could the students do to make sure that heat from the lamp did not affect the rate of photosynthesis?

  add a water bath

  heat screen

  use LED

  low energy bulb
• Identify and describe the role of two structures in the leaf that are involved in photosynthesis.

  Chloroplasts

  chloroplasts

  found mainly in the palisade layer

  where photosynthesis occurs

  contain chlorophyll, which absorbs light energy for photosynthesis

  Stomata/guard cells

  stomata/guard cells

  found on the lower epidermis

  responsible for gas exchange

  allow CO2 (reactant in photosynthesis) to enter the leaf, and oxygen (product of photosynthesis) to leave

  Waxy cuticle 

  waxy cuticle

  transparent

  helps the plant retain wate
• In a certain plant species, it is observed that the leaves have fewer stomata than a typical plant.

  Suggest how this could impact the rate of photosynthesis. 

  fewer stomata could limit the rate of gas exchange

  less carbon dioxide available for photosynthesis

  less reactant reduces the rate of photosynthesis
• Explain why root hair cells are considered specialised cells.

  they have undergone differentiation

  they have a specific role (in the plant)
• Explain how this adaptation helps the root hair cell to absorb water and mineral ions from the soil more effectively.


  there is more absorption of water and mineral ions

  increased surface area
• whats the four blood component?

  Plasma

  red blood cells

  white blood cells

  platelets
• What’s plasmas job ?


  Transporting carbon dioxid, digestived food molecule, urea and hormone ; distributing heat.
• What’s the job of a red blood cell?

  Transport of oxygen
• What’s the job of white blood cells?

  Ingesting pathogens and producing antibodies
• What’s the job of platelets?

  Involved in blood clotting
• What are the two types of cells ?

  eukaryotic (plant and anima)

  prokaryotic (bacteria)
• What’s the difference between the two types of cells

  eukaryotic has membrane bound organelles + nucleus contains genetic material.

  prokaryotic are a lot smaller
• Light microscope


  Developed in the mid 17th century, uses light to form an image, can view live specimens, relatively cheap and easy to use, can magnify up to 2,000 times, has a resolution of around 200 nanometers
• Electron microscope


  Developed in the 1930s, uses electrons to form an image, can only view dead specimens, very expensive and has many conditions, can magnify up to 2 million times, has a resolution of 0.2 nanometers
• The electron microscope is much better than the light microscope in terms of magnification and resolution
• Nucleus


  Controls the cell's activities and contains genetic material (DNA)
• Cell membrane


  Responsible for controlling the passage of substances in and out of the cell
• Cytoplasm


  Liquid gel that fills the entire cell and is where chemical reactions occur
• Mitochondrion


  Where aerobic respiration occurs, releasing energy for the cell
• Ribosome


  Site of protein synthesis
• Parts of an animal cell


  • Nucleus
  • Cell membrane
  • Cytoplasm
  • Mitochondrion
  • Ribosome
• Chloroplast


  Contains chlorophyll and is responsible for photosynthesis
• Permanent vacuole


  Filled with cell sap, helps keep the cell rigid
• Cell wall


  Made of cellulose, strengthens and supports the plant cell
• Parts of a plant cell


  • Nucleus
  • Cell membrane
  • Cytoplasm
  • Mitochondrion
  • Ribosome
  • Chloroplast
  • Permanent vacuole
  • Cell wall
• Eukaryotic cells


  Animal, plant, fungi and protista cells that have a cell membrane, cytoplasm and genetic material enclosed in a nucleus
• Prokaryotic cells


  Bacterial cells that have a cell membrane and cytoplasm but their genetic material is not enclosed in a nucleus
• Differences between eukaryotic and prokaryotic cells


  • Eukaryotes have a nucleus, prokaryotes do not
  • Eukaryotes may have chloroplasts and mitochondria, prokaryotes do not
  • Eukaryotes have a cell wall that is sometimes made of cellulose, prokaryotes have a cell wall made of different materials
• Specialised cells


  Cells that have developed different subcellular structures to carry out a particular function
• Sperm cell


  Has a tail to swim, a midpiece with many mitochondria to provide energy, an acrosome with enzymes to break down the egg, and a large nucleus to contain DNA
• Muscle cell


  Has many mitochondria to release energy for contraction, special proteins that cause contraction by sliding, and can store glycogen
• Nerve cell


  Has a long axon to carry electrical impulses, dendrites to connect to other nerve cells, and nerve endings that release chemical messengers
• Root hair cell


  Has a large surface area for absorption, a large permanent vacuole to speed up osmosis, and many mitochondria for active transport of mineral ions
• Xylem cell


  Forms long hollow tubes with spirals of lignin to allow easy movement of water and minerals up the plant
• Phloem cell


  Has sieve plates to allow easy movement of dissolved food up and down the plant, and companion cells that provide the energy for this
• Diffusion


  The spreading out of particles in a solution or gas from an area of higher concentration to an area of lower concentration