Biology Paper 1

• What are cells?

  The basic unit of all living organisms
• Where do chemical reactions take place inside of a cell?

  The cytoplasm
• What is the function of the cytoplasm?

  To hold components in place, provide support, where chemical reactions occur
• What is the function of the nucleus?

  To hold DNA
• What is the function of ribosomes?

  Protein synthesis - making proteins
• What is the function of the mitochondria?

  The ‘powerhouse’ of the cell - releases energy
• What is the function of the cell membrane?

  Controls what enters/leaves the cell
• What is the function of chloroplasts? (Plant cells only)

  To release energy through photosynthesis
• What is the function of the vacuole? (Plant cells only)

  Stores cell sap and water to keep the cell ‘turgid’ also can help the plant to stop wilting.
• What is the function of the cell wall? (plant cells only)

  To provide structure and protection
• What are specialised cells?

  Cells that are adapted for a specific function.

  For example:

  Sperm cells (tail,acrosome)

  Egg cells (haploid nucleus)

  Ciliated epithelial cells (cilia)

  Red blood cells (bi-concave shape)
• What structures do bacterial cells contain?

  Plasmid DNA (small loops of extra DNA)

  Flagellum

  Chromosomal DNA (one long circular chromosome which controls cell activity and replication)
• What is the equation for Magnification?

  Objective lens x eyepiece lens
• What is the equation for ‘actual size’?

  Measured size $\div$ Magnification
• Which stain shows DNA in a cell?

  Methylene Blue
• What are enzymes?

  ’biological catalysts’ that speed up chemical reactions in cells
• What breaks down Fat into Glycerol + Fatty Acids?

  Lipase
• What breaks down Protein into Amino Acids?

  Protease
• What breaks down Starch into Sugar?

  Amylase
• What are digestive enzymes?

  Enzymes that break down large, insoluble food molecules into ones that are small enough to absorb.
• What is the test for starch?

  The iodine test.

  Adding iodine to a sample that contains starch will turn it from a ’yellow-brownish’ colour to a ‘blue-black’ colour.
• What is the definition of concentration?

  The number of particles in a set volume
• What is the definition of diffusion?

  The movement of particles from an area of high to low concentration.

  e.g oxygen from the lungs to the blood
• What is the definition of Osmosis?

  The diffusion of water particles across a partially permeable membrane. From an area of high concentration to low concentration.
• What is the definition of Active Transport?

  The movement of particles for an area of low concentration to high concentration.
• What is the core practical to investigate osmosis?

  Potatoes.

  Weigh each piece of potato,place each into a sucrose(sugar) solution of different concentrations, leave for 15 minutes, dry them, re-weigh them, calculate the percentage change.
• What is cell division?

  The process of making new cells.
• What are components of a diploid cell?

  23 pairs of chromosomes

  46 total chromosomes

  Most common type - nearly every cell
• What are components of a haploid cell?

  23 chromosomes Overall

  Only sperm and egg cells
• What is mitosis?

  Where one diploid parent cell creates two genetically identical diploid daughter cells. This is the process of making all cells (apart from sperm and egg)
• What are the phases of mitosis?

  Interphase-cell grows + replicates DNA to prepare

  Prophase-chromosomes condense + nuclear envelope breaks

  Metaphase-chromosomes line up along cells centre

  Anaphas-spindle fibres pull chromosomes to opposite ends of the cell

  Telophase-new nucleus/nuclear envelope begins to form

  Cytokinesis-new cell membrane forms (cells separate)
• What is meiosis?

  Where one diploid parent cell makes four genetically different haploid daughter cells. This process creates egg and sperm cells.
• What are stem cells?

  Undifferentiated cells that haven’t yet become specialised for a specific function. They have the potential to develop in the future.
• What is differentiation?

  The process where cells become specialised to perform specific functions.
• What is the nervous system?

  Nerves working together to gather information + make decisions.
• What is an impulse?

  An electrical message
• What is a neurone?

  A nerve cell with a dendron, cell body, and axon.
• What is a sensory neurone?

  A type of neurone which carries sense impulses to the CNS
• What is a relay neurone?

  A neurone in the CNS that makes decisions.
• What is a motor neurone?

  A neurone that carries impulsed from the CNS to the muscle.