Topic 1: Key Concepts in Biology

• What is the function of the acrosome in a sperm cell?

  It contains enzymes that digest the egg cell membrane.
• What is the active site of an enzyme?

  A specific region where the substrate binds and the reaction occurs.
• What is active transport?

  It is the movement of substances from low to high concentration using energy.
• What does Benedict’s test detect?

  Reducing sugars.
• What color does the Biuret test produce when protein is present?

  Purple.
• What is calorimetry used for?

  Measuring heat transfer during a chemical reaction.
• What do carbohydrases do?

  They break down carbohydrates into simple sugars.
• What is a carbohydrate?

  A large molecule synthesized from simple sugars.
• What is the basic building block of all living organisms?

  The cell.
• What is the function of the cell membrane?

  It acts as a partially permeable barrier surrounding the cell.
• What is the cell wall made of?

  Cellulose.
• What is the role of chloroplasts?

  They are the site of photosynthesis.
• What is a chromosome?

  A long, coiled molecule of DNA carrying genetic information.
• What are cilia?

  Hair-like structures that waft substances across tissue surfaces.
• What type of cell lines the respiratory tract and uterus?

  Ciliated epithelial cell.
• What is a concentration gradient?


  The difference in concentration between two areas.
• What is denaturation in enzymes?

  A permanent change in the shape of an enzyme's active site due to high temperature or pH.
• What is diffusion?

  The net spreading out of particles from high to low concentration.
• What is a diploid cell?

  A cell that contains two copies of each chromosome.
• What is an egg cell?

  A specialized female sex cell involved in reproduction.
• What is an electron microscope?

  A microscope that uses a beam of electrons for high magnification and resolution.
• What does the emulsion test detect?

  It detects lipids.
• What is an enzyme?

  A biological catalyst that increases the rate of reactions.
• What are the two main types of cells?

  Prokaryotic and eukaryotic
• What is a eukaryotic cell?

  A cell that contains a nucleus.
• What type of cells are animal and plant cells?

  Eukaryotic
• What are flagella?

  Long hair-like structures used for cell movement.
• What are the main organelles found in eukaryotic cells?

  • Cell membrane
  • Cytoplasm
  • Nucleus containing DNA
• What is a haploid cell?

  A cell that contains a single copy of each chromosome.
• What type of cells are bacterial cells?

  Prokaryotic
• What does the iodine test detect?

  It detects starch.
• What are the main organelles found in prokaryotic cells?

  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Single circular strand of DNA
  • Plasmids
• What is a light microscope?

  A microscope that uses lenses to magnify visible light reflecting off a specimen.
• What are organelles?

  Structures in a cell that have different functions
• What is the function of the nucleus in eukaryotic cells?

  • Contains DNA coding for proteins
  • Enclosed in a nuclear membrane
• What do lipases do?

  They break down lipids into fatty acids and glycerol.
• What is the function of the cytoplasm in eukaryotic cells?

  • Liquid substance for chemical reactions
  • Contains enzymes and organelles
• What is a lipid?

  A large molecule synthesized from fatty acids and glycerol.
• What is the function of the cell membrane in eukaryotic cells?

  Controls what enters and leaves the cell
• What is the lock and key hypothesis?

  It describes how substrates must fit the active site of an enzyme.