Cells and Microscopes

• What are the animal cells sub cellular structures and uses?

  -Nucleus-> Contains genetic information (which is arranged into chromosomes), and controls cells activities.

  -Cytoplasm-> Where chemical reactions take place. They contain enzymes which controls the chemical reactions.

  -Ribosomes-> Involved in the translation of genetic material in the synthesis of proteins. Site of protein synthesis.

  -Mitochondria-> Reactions for respiration takes place here. (Respiration transfers energy that cells need to work)

  -Cell Membrane-> Controls what goes in and out in the cell

  
• What are the plant cells sub cellular structures and uses?

  -Chloroplasts - photosynthesis occurs. Contains green substance called 'chlorophyll'. This absorbs light energy for photosynthesis. It makes leaves green. -Vacuole (contains cell sap) - storage, for the cell to use when needed. Maintains internal pressure to support the cell -Cell wall (made of cellulose) - provides support and structure to the cell

  
• What are the bacterial cells sub cellular structures and uses?

  -Chromosomal DNA-> controls cells activity and replication. Floats free in the cytoplasm. Contains genes needed to survive+reproduce

  -Plasmid DNA-> loops of extra DNA (antibiotic resistance)

  -Flagella-> Helps the bacterium to move. Can be used to move to beneficial things such as nutrient or oxygen or move away from harmful substances like toxins

  
• A cell is the smallest unit of life that can live on its own. Cells make up all living organisms+ their tissues.
• Difference between prokaryotic and eukaryotic cells:

  1. Prokaryotic are simpler and smaller
  2. Eukaryotic cells contains membrane-bound organelles, while prokaryotic cells do not
  3. Prokaryotic doesn't have nucleus (DNA floats in cytoplasm)
• Role of mitochondria:

  carry out aerobic respiration, so provides energy for the cell to use in chemical reactions
• Role of ribosomes:

  site of protein synthesis (when proteins are made)
• What is chlorophyll?

  A green pigment found in chloroplast that is responsible for photosynthesis. Absorbs sunlight for photosynthesis. Chlorophyll makes plants green.
• What is the prokaryotic cell wall composed of?

  Peptidoglycan.
• Role of Mitochondria

  site of aerobic respiration, so they release energy for the cell
• Chloroplasts carry out the process of photosynthesis, which involves using light energy from the sun to make glucose. The green pigment that absorbs the light energy is called chlorophyll. This is what makes plants green.
• The vacuole is a large sac in the middle of the cell that contains a watery solution of sugars and salts (cell sap). It helps maintain the structure and shape of the cell.
• Bacteria are unicellular (only consist of a single cell).
• Microscopy

  The use of microscopes
• How light microscopes work

  1. Light from the room hits the mirror

  2. Light reflected upwards through the object

  3. Light passes through the objective lens

  4. Light passes through the eyepiece lens

  5. Light enters the eye
• Object

  The real object or sample that you're looking at
• Image


  The image that we see when we look down the microscope
• Magnification


  How many times larger the image is than the object
• Magnification = image size / object size
• Resolution

  The shortest distance between two points on an object that can still be distinguished as two separate entities
• Higher resolution

  More details can be seen, less blurry the image
• Nanometers


  Smallest unit of length you need to know
• Units of length

  • Nanometers
  • Micrometers
  • Millimeters
  • Meters
  • Kilometers
• Each unit is 1,000 times bigger or smaller than the one next to it
• Converting between units

  1. Divide by 1,000 to convert to a larger unit

  2. Multiply by 1,000 to convert to a smaller unit
• Animal and plant cells are 10 to 100 micrometers across
• Electron microscopes can see down to about 0.1 nanometers
• Centimeters

  10 millimeters, 100 centimeters in a meter
• Converting centimeters

  1. Divide by 100 to get meters

  2. Multiply by 10 to get millimeters
• nm->um= divide by 1000
• um->mm= divide by 1000
• mm->m= divide by 1000
• m->km= divide by 1000
• km->m= x by 1000
• m->mm= x by 1000
• mm->um= x by 1000
• um->nm= x by 1000
• Specialised cells: Sperm

  Sperms function is to transport the males DNA to females egg.

  1. Long tail (and shape of head) -> aiding to swim
  2. (Lots of) Mitochondria -> carry out respiration to create energy for the sperm to swim
  3. acrosome -> this contains enzymes, which digests through the membrane of the egg cell
  4. haploid nucleus
• Specialised cells: Egg Cell

  Functions of the egg is to accept a single sperm cell and develop into an embryo

  1. nutrients in cytoplasm -> feed embryo
  2. haploid nucleus
  3. after fertilisation, membrane changes structure to stop and more sperm from getting in. => This means the offspring has enough amount of DNA
• Specialised Cells: Ciliated Epithelial Cells

  These are specialised to waft bacteria or move substances in one direction. (specialised to waft bacteria (trapped by mucus) to the stomach)

  1. Cilia -> cilia, hair like structures, on top of cell. It moves substances in one direction, along the surface of the tissue.
  2. These help mucus up to the throat so it can't be swallowed and doesn't reach the lungs.