Cell Biology: Chapter 1

• What are the stages of Mitosis ?

  DNA condenses to form chromosomes. Chromosomes line up along the center of the cells. Cell fibres pull the two arms of each chromosomes to opposite sides of the cell (also known as poles). The entire cell divides to form two identical daughter cells.
• Culturing Microorganisms (REQUIRED PRACTICAL) 1

  Clean the bench with disinfectant to kill microorganisms that could enter the culture. The inoculating loop is sterilised before use by placing it under a bunsen burner until it turns red hot. Open the sterile agar plate near a bunsen burner as the flames kill the bacteria in the air.
• Culturing Microorganisms (REQUIRED PRACTICAL) 2

  Then the steralised inoculating loop is dipped into the flask containing the bacteria culture. The inoculating loop spreads the chosen bacteria onto the agar plate. The lid of the petri dish is secured preventing contamination and is placed into an incubator at 25 degrees celcius
• what is the role of the cell membrane

  controls the type and amount of substances that can enter the cell
• plasmids

  small circular DNA molecules
• chlorophyll

  green substance that absorbs light energy for photosynthesis
• vacuole

  supports the shape of the cell and contains a watery solution of sugars and salts called cell sap
• cell wall

  made of cellulose and is strong and maintains the shape of the cell
• chloroplast

  where photosynthesis takes place
• nucleus

  contains genetic material and controls activity of a cell
• mitochondria

  were aerobic respiration happens to release energy for the cell to use
• cytoplasm

  gel - like substance were chemical reactions take places
• prokaryotic cell

  cell that doesn't have a nucleus (bacterial cell)
• eukaryotic cell

  cell that does have a nucleus (animal and plant cell)
• what is found in a plant cell that is not found in an animal cell

  cell wall, permanent vacuole and chloroplast
• ribosomes

  were protein synthesis takes place, were proteins are made
• difference between prokaryotes and eukaryotes

  prokaryotes are smaller than eukaryotes, prokaryotes don't have a nucleus and eukaryotes have a nucleus
• what do prokaryotes not have that eukaryotes have

  chloroplasts, mitochondria, nucleus
• process of binary fission

  two circular strands of DNA move to opposite sides of the cell. New cell from down the middle of the cell. Two halves pull apart from the two cells
• diffusion

  spreading out of particles from an area of higher concentration to an area of lower concentration
• the bigger the concentration gradient the faster the diffusion rate
• the higher the temperature the faster the diffusion rate as particles have more energy to move faster
• the larger the surface area of the membrane the faster the diffusion rate because more particles can pass through at once
• osmosis

  movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
• what is differentiation ?

  the process by which a cell changes to become specialised for its function
• what are undifferentiated cells called ?

  Stem cells
• what are sperm cells specialised for ?

  Reproduction. The function of the sperm cell is to get the male DNA to the female DNA. It has a long tail and a stream lined head to help it swim to the egg. There are a lot of mitochondria to provide the energy needed. It also carries enzymes in its head to digest through the cell membrane.
• what is nerve cells specialsation ?

  Rapid Signaling. The function of the nerve cell is to carry electrical impulses from one part of the body to another. These cells are long to cover more distance and have branched connections at their ends to connect with other nerve cells and form a network throughout the body
• What is the function of a muscle cell ?

  Contraction. The function of the muscle cell is to contract quickly. These cells are long and have lots of mitochondria to generate energy needed for contraction.
• What is the function of the root hair cell ?

  Absorption of water and minerals. Root hair cells are cells on the surface of plant roots which grow into longer ''hairs'' that stick out into the soil, This gives the plant a big surface area for absorbing water and mineral ions from the soil.
• What is the function for the xylem and phloem ?

  Transporting substances. Phloem and Xylem form phloem and xylem tubes which transports substances like food and water around the plants. To form tubes the cells are long and joined end to end. Xylem are hollow in the centre and phloem cells have very few subcellular substances so that stuff can flow through them
• what is the process of binary fission ?


  The circular DNA an plasmids replicate. The cell gets bigger and the circular DNA strands move to opposite poles of the cell. The cytoplasm begins to divide and new cell walls form. The cytoplasm divides and two daughter cells are produced. Each daughter cell has one copy of circular DNA but can have variable number of copies of plasmids