biology paper 1

• Chromosomes


  A strand of DNA containing hundreds or thousands of genes.
• Genes

  Pieces of DNA that contain the code to create different proteins.
• Proteins


  Created by the genes, they control which characteristics are developed.
• Two


  How many chromosomes are located in a cell?
• 23


  How many chromosome pairs do human have?
• Mitosis


  When a cell replicates sub-cellular structures, replicates its chromosome pair, moves the chromosome pairs to opposite poles, and the nucleus divides to form two identical daughter cells. Asexual form of reproduction.
• Undifferentiated cells


  Stem cells aka. cells that have not become specialised.
• Human embryos, the umbilical cord, some organs, and some tissues.


  Locations of stem cells
• Embryonic stem cells


  Cells found from a human embryo, umbilical cord, organs, or tissues that can differentiate into any cell.
• Bone Marrow


  Location of adult stem cells
• Diabetes and paralysis


  Diseases that can be cured by stem cell use
• 0.1mm diameter


  size of a plant cell
• 0.2mm diameter


  animal cell size
• 0.002mm diameter


  prokaryote cell size
• size of image / size of real object

  formula for magnification
• Therapeutic cloning


  When cells from a cloned embryo are used as a source of stem cells.
• Meristems


  Areas in a plant that contain stem cells. Used to create new cells for growth.
• Uses of meristems


  To clone rare plants, and create lots of identical crop plants with disease resistance.
• Alleles


  Different forms of the same gene.
• Two alleles

  Number of alleles inherited from the parents in total.
• Genotype


  Combination of alleles present in a gene.
• Phenotype


  The characteristic that appears to represent the allele.
• Homozygous gene


  Two identical alleles
• Heterozygous genes


  Two different alleles.
• Monohybrid inheritance


  When only one type of gene is involved in inheritance.
• Polydactyl


  Having extra toes or fingers caused by a dominant allele.
• Cystic fibrosis


  A disorder of cell membranes caused by a recessive gene.
• Sex chromosomes


  A single pair of chromosomes that determine sex.
• Female chromosomes


  Two X chromosomes
• Male chromosomes


  X and Y chromosome
• Enzyme


  Biological catalyst that speeds up the digestive process. Large proteins with an active site for a substrate.
• The optimum


  The ideal pH and temperature for an enzyme.
• Denaturation


  When an enzyme changes shape and becomes unusable due to a high temperature or extreme pH.
• Lipase


  An enzyme made in the pancreas and small intestine that turns lipids into fatty acids and glycerol.
• Amylase


  A carbohydrase that turns starch into sugar (aka. maltose) that is made in the salivary glands and pancreas.
• Protease


  An enzyme made in the stomach that breaks down proteins into amino acids.
• Bile


  An alkaline liquid made by the liver that is stored in the bladder, which neautralises hydrochloric stomach acid and emulsifies fat into droplets with a high surface area for enzymes to break down fat faster.
• Diffusion


  The net movement of particles from an area of high to low concentration along the gradient.
• Examples of diffusion


  Lungs, gills, plant leaves, and the movement of urea from cells to plasma and food molecules into the blood.
• Osmosis


  Movement of water from an area of low to high concentration, along the gradient, across a semi-permeable membrane.