Science mid year assesment year9

• What does the cell membrane control?

  Things going in and out of the cell
• What do chloroplasts contain for photosynthesis?

  Chlorophyll
• What is the function of the cell wall in plant cells?

  It gives the plant cell a strong shape
• What is the role of the nucleus in a cell?

  Controls the cell
• Where are proteins made in the cell?

  Ribosomes
• What is the function of a vacuole?

  Stores cell sap
• Where is energy released by respiration?

  Mitochondria
• What does the term differentiate refer to in biology?

  Process in which cells become more specialised
• What are eukaryotic cells characterized by?

  True nucleus and many organelles
• What type of cells are prokaryotic cells?

  Bacteria, smaller and simpler cells
• What are chromosomes made out of?

  DNA
• What is a gene?

  Section of DNA that codes for characteristics
• What are homologous chromosomes?

  Matching pair of chromosomes
• What is mitosis?

  Type of cell division producing identical daughter cells
• What are the stages in mitosis?

  1. DNA replicated to form 2 copies of chromosomes
  2. Copied chromosomes pulled to each cell
  3. Nucleus, cytoplasm, and cell membrane divide
  4. Two identical cells formed
• What is cloning?

  Process of generating a genetically identical copy
• What is an atom?

  Smallest part of an element
• What is an element made of?

  Only one type of atom
• What is a molecule?

  Two or more non-metal atoms joined together
• What is necessary to show what's happening in a chemical reaction?

  Understanding chemical equations
• What is one way to show a chemical reaction?

  Using a word equation
• What happens when methane burns in oxygen?

  It turns into carbon dioxide and water
• What are the reactants in the equation for methane burning?

  Methane and oxygen
• What are the products of the combustion of methane?

  Carbon dioxide and water
• What does the single arrow in a chemical equation indicate?

  Reactants react completely to form products
• What is a symbol equation?

  An equation using chemical symbols of molecules
• What is the chemical symbol for methane?

  $CH_4$
• What is the chemical symbol for oxygen?

  $O_2$
• Why do we write $O_2$ instead of $O$ in chemical equations?


  Oxygen exists as a molecule of two atoms
• What is the first rule of balancing chemical equations?

  Do not change the small numbers in formulas
• Why can't we change $O_2$ to $O_3$ when balancing?


  It changes the actual type of chemical
• What do the big numbers in front of compounds represent?

  The quantity of that substance in the reaction
• How do you increase the number of oxygen atoms on the left side?

  Put a 2 in front of $O_2$
• Why can't we use one and a half molecules of oxygen?

  We need to keep whole numbers in balancing
• What is the common problem when balancing equations?

  Needing to adjust the number of atoms
• How do you balance the equation for sulfuric acid and sodium hydroxide?

  Start by balancing sulfur and sodium first
• What do we need to balance in the equation for sulfuric acid and sodium hydroxide?

  Hydrogens, sulfur, oxygens, and sodiums
• What happens when you put a 2 in front of sodium hydroxide?

  It gives two sodiums on the left side
• How do you fix the need for two more hydrogens and one more oxygen on the right side?

  Add one more water molecule to the right
• What should you do after balancing a chemical equation?

  Double-check to see if it's balanced