topic 1- cell biology

• A) objvective lense

  B) Eye piece

  C) mirror

  D) Coarse focus

  E) fine focus

  F) stage clip

  G) slide

  
• Magnification of the microscope = magnification of eyepiece × magnification of objective
• The formula to calculate magnification is:

  Magnification= size of image ÷ real size of image
• A) cell membrane: controls what enters and leaves the cell,eg oxygen, carbon

  B) nucleas: a large structure that contains genes that control the activities in the cell

  C) cytoplasm: jelly-like substance that fills the cell

  D) mitochondria: tiny structures where respiration takes place, releasing energy for cell processes

  E) ribosome: where proteins are made

  
• A) cell wall

  B) permanent vacuole

  C) chloroplasts

  D) plant cell

  E) cytoplasm

  F) nucleus

  G) cell membrane

  H) ribosome

  
• The three structures which are only present in plant cells are :

  • vacuole-filled with cell sap to keep cell rigid
  • cell wall-made of cellulose which strengthens the cell
  • Chloroplast is where photosynthesis takes place to make food for the cell
• Animal and plant cells are eukaryotic. They have:

  • nucleus containing DNA
  • Cytoplasm
  • cell membrane
• Bacterial cells are much smaller and prokaryotic:

  • cell wall
  • cell membrane
  • cytoplasm
  • Singular strand of DNA and plasmids
• The prefix centi is multiply unit of 0.01
• the milli prefix has a multiply unit of 0.001
• the prefix micro has a multiply unit of 0.000,001
• the prefix Nano has a multiply unit of 0.000,000,001
• Chloroplast is :

  • where photosynthesis takes place providing food for the plant
  • contains chlorophyll pigiment which makes the leaf green and harvests the light needed for phototynthesis
• Permanent Vacuole:

  • contains cell sap
  • found within the cytoplasm
  • improves cell ridgety
• The single strand of DNA in a bacterial cell is found floating within the cytoplasm
• 7.9 x 10"3 = 7900
• Specialized cells undergo differentiation a process where the cell gains new sub-cellular structures to fit its role (Stem cells)
• A specialized cell in animals is : sperm cell
• Sperm cells: Specialised to carry male DNA to the egg cell for reproduction

  • long tail and streamlined head to help swimming
  • lots of mitochondria which provides reparation and helps cell to move
  • the top of the head has enzymes which help break down outer layers of the egg cell
• Nerve cells are stem cells that carry an electrical signal/ impulse from one part of the body to another:

  • a long axon to connect distant parts
  • having dendrites that connect with other nerve cells
  • mylein sheath speeds up impluses
• Muscle cells are specialized quickly to move bones or squeeze , causing movement:

  • Special proteins (myosin and actin) slide over each other and cause the muscle to contract
  • lots of mitochondria to provide energy from respiration from contact
  • can store glycogen thats used in respiration in the mitocondria
• Osmosis is the movement of water across a partially permeable membrane from a high concentration of water to a low concentration
• The diagram shows Osmosis

  A) water

  B) sugar

  
• Diffusion is the movement of molecules from a high to low concentration.
• What are the two types of cells?

  Prokaryotic - bacteria

  Eukaryotic - animal and plant cells
• What are the differences between Prokaryotic and Eukaryotic cells?

  Prokaryotic cells are much smaller

  Eukaryotic contain a membrane and contain genetic material
• How is genetic material stored in the Procaryotic cell?

  free within the cytoplasm

  • plasmid DNA
  • Chromosomial DNA
• What are plasmids?

  • small circular loops of DNA found free in the cytoplasm and separate from main DNA
  • carry genes with genetic advantages
• what is a centimetre?

  1 x 10-2 metres
• what is a micrometre(um)?

  1 x 10 -6 metre
• what is a nanometre (nm)?

  1 x 10 -9
• What is the function of cytoplasm?

  first stage of respiration
• Function of cell membrane?

  control the exit and entry of materials in and out of cell
• what is the function of the mitocondria?

  where aerobic respiration occurs
• Function of the ribisome?

  joins amino acids in specific order for synthesis of protein
• what is the plant cell made out of?

  cellulose
• Function of plant cell wall?

  • for strength
  • protect bursting by osmosis
• function of chloroplast in cell?

  site of photosynthesis
• How are root hair cells in plants adapted to their function?

  • large surface area
  • thin walls
• How are xylem cells adapted in plant cells?

  • no upper or lower margins between cells to allow route for water to flow
  • Thick woody side walls for strength