Biology Paper One

• Eukaryotic cells contain their genetic material (DNA) enclosed in a nucleus
• Eukaryotic cells contain a cytoplasm
• In Eukaryotic cells, the cytoplasm is enclosed in a cell membrane
• In eukaryotic cells, the genetic material is found in the nucleus
• The genetic material in a prokaryotic cell are the loop of DNA and the plasmids
• Difference between eukaryotic cells and prokaryotic cells is the location of the DNA.
• In eukaryotic cells, the genetic material is found in the nucleus but in prokaryotic cells do not have a nucleus
• In both prokaryotic cells and eukaryotic cells their genetic material (both the loop of DNA and the plasmids) are located in the cytoplasm
• Prokaryotic cells are much smaller than eukaryotic cells
• Animal cells are eukaryotic meaning their DNA is enclosed in a nucleus. The whole cell is enclosed within a cell membrane which controls which molecules can enter and leave the cell.
• The cytoplasm in a watery solution where chemical reactions take place (e.g 1st stage of respiration). Animal cells contain mitochondria and ribosomes .
• Aerobic respiration takes place in the mitochondria. Ribosomes are where proteins are synthesised
• Ribosomes are extremely small which mean that they are too small to be seen with a light microscope. They can only be seen with an electron microscope (has a much greater magnification than a light microscope)
• Mitochondria are also small but they can be seen under a good light microscope, if the sample is prepared correctly
• Cell Membrane- this controls the molecules that enter and leave the cell
• Cytoplasm- this is a watery solution where chemical reactions take place.
• Ribosomes- this is where proteins are synthesised takes place.
• mitochondria-there are where aerobic respiration takes place in the cell
• Most animal cells do not have a rigid, fixed shape. this is because animal cells do not have a cell wall
• Plant cells are eukaryotic because they contain DNA enclosed within the nucleus
• In a typical plant cell which organelle is the site of aerobic respiration 


  Mitochondria
• In a typical plant cell which organelle is the site of protein synthesis

  Ribosomes
• In a typical plant cell which organelle is the site of photosynthesis

  Chloroplast
• Sperm cells are specialised cells. Explain how the acrosome helps the sperm cell to carry out its function

  The acrosome contains enzymes that digest through the egg cell membrane
• What are 'embryonic' stem cells?

  Undifferentiated cells found in the ealry embryo
• Name 2 medical conditions that could be treated with embryonic stem cells in the future

  Diabetes Spinal injuries/ paralysis
• why do cells undergo mitosis 


  to produce new cells for growth and repair
• In mitosis... what has to happen before the cell divides 


  the cell grows and increases the amount of organelles, and it replicates its DNA
• what happens to the cell during mitosis

  1. chromosomes line up in the centre of the cell and copies are pulled apart by spindle fibres to opposite end of the cell 2. Nuclear membranes form around the chromosomes to make two nuclei 3. Finally, the cell splits into two identical 'daughter' cells
• Name the tubes that transport the food around the plant

  phloem
• Name three substances that are transported into, or out of, animal cells by diffusion 


  oxygen, carbon dioxide, amino acids
• What is osmosis 


  the movement of water molecules from an area of high wtaer concentration to an area of lower water concentration across a partially permeable membrane
• light microscopes have objective lenses. What is the purpose of the objective lens?

  to form and magnify an image of the specimen
• what is diffusion 


  the spreading out of the particles of any gas or liquid from an area of high concentration to an area of lower concentration
• How many chromosomes does: 1.a human skin cell contain? 2. a human gamete contain

  1..46/23 pairs (diploid) 2..23 single (haploid)
• name the tubes that transport water up the stem of a plant

  xylem
• In a typical animal cell which organelle is the site of aerobic respiration

  mitochondria
• in a typical animal cell, which organelle controls the movement of substance in and out of the cell

  cell membrane
• in a typical animal cell which organelle contains the genetic information

  nucleus
• what is the equation for calculating the magnification of an image?

  magnification= image size = ------------- = real size