bio paper 1

• What can be seen with a normal light microscope?

  Cells and possibly the nucleus
• What advantage does an electron microscope have over a light microscope?

  It allows us to see finer details of organelles
• How can you calculate the actual size of a cell using a microscope?

  By dividing the image size by the magnification
• What are the two main groups of cells?

  Eukaryotic cells and prokaryotic cells
• What is a characteristic of eukaryotic cells?


  They have a nucleus containing DNA
• Where is DNA found in prokaryotic cells?

  In a ring called a plasmid
• What is the function of the cell membrane?

  It keeps everything inside the cell and is semi-permeable
• What do plant cells and most bacteria have that provides a rigid structure?

  A cell wall made of cellulose
• What is the cytoplasm?

  The liquid that makes up the cell where most chemical reactions occur
• Where does respiration take place in a cell?

  In the mitochondria
• What is the role of ribosomes in a cell?

  They assemble or synthesize proteins
• What do chloroplasts contain and what is their function?

  They contain chlorophyll and are where photosynthesis takes place
• What is a permanent vacuole in plant cells used for?

  To store sap
• How do bacteria multiply?

  By binary fission
• What is the purpose of using aseptic technique in culturing bacteria?

  To prevent contamination of the culture
• What is the process of incubating bacteria at 25°C used for?

  To allow the culture to grow
• How do you calculate the area of a circle in a bacterial culture?

  Using the formula $\frac{\pi d^2}{4}$
• What is the genetic material in eukaryotic cell nuclei stored as?

  In several chromosomes
• How many pairs of chromosomes do humans have?

  23 pairs
• What type of cells are gametes?

  Haploid cells
• What is the process by which new cells are made for growth and repair?

  By mitosis
• What happens to the genetic material during mitosis?

  It is duplicated and divided into two identical cells
• What are stem cells?

  Cells that haven't yet specialized
• Where are stem cells found in humans and animals?

  In embryos and bone marrow
• How can stem cells be used in medicine?

  To combat conditions like diabetes and paralysis
• What is diffusion?

  The movement of molecules from high to low concentration
• What is osmosis specifically?

  The diffusion of water across a semi-permeable membrane
• How does a higher concentration of glucose outside a cell affect water movement?

  Water moves out of the cell, decreasing its mass
• What factors can increase the rate of diffusion and osmosis?

  Higher concentration differences, increased temperature, and larger surface area
• What is the practical method for investigating osmosis using potatoes?

  Cut equal-sized cylinders, weigh them, and place them in sugar solutions
• How do you calculate percentage change in mass after osmosis?

  By using the formula $\frac{\text{final mass} - \text{initial mass}}{\text{initial mass}} \times 100$
• What does it mean when the percentage change in mass crosses the x-axis in an osmosis experiment?

  It indicates the concentration inside the potato is equal to the external concentration
• What is active transport?

  The movement of substances against a concentration gradient using energy
• How do carrier proteins function in active transport?

  They use energy to move substances through the membrane
• What is a tissue?

  A group of similar cells working together
• How do tissues form organs?

  By grouping together to perform specific functions
• What is the role of the digestive system?

  To break down food into useful nutrients
• What is the function of bile?

  To neutralize stomach acid and emulsify fats
• What are enzymes?

  Biological catalysts that speed up chemical reactions
• What is the function of amylase?

  To break down starch into glucose