Paper 1 - B1-B9

• Eukaryotes are cells that have its DNA enclosed in a nucleus. Examples of eukaryotic cells are animal and plant cells.
• Prokaryotes are cells that don't have their genetic material in a nucleus. An example of prokaryotic cell are bacteria cells.
• Prokaryotic cells are much smaller than eukaryotic cells.
• Bacteria Cell:

  A) slime capsule

  B) cell wall

  C) plasmids

  D) cell membrane

  E) cytoplasm

  F) genetic material

  G) flagella

  H) 1

  
• Slime capsule

  Protects the cell from physical and chemical attacks.
• Flagella


  Assists the cell in movement.
• Plasmids


  Small rings of DNA that can give antibiotic resistance.
• Nucleus


  Controls all activities in the cell, carries instructions for making proteins.
• Cytoplasm


  Liquid gel where chemical reactions occur.
• Cell membrane


  Controls the movement and passage of substances.
• Mitochondria


  Where aerobic respiration occurs to produce energy.
• Ribosomes


  Where protein synthesis occurs.
• Cell wall


  Strengthens and supports the cell, made of cellulose.
• Chloroplasts 


  Has chlorophyll (green pigment that absorbs sunlight) to photosynthesise.
• Permanent vacuole


  Filled with cell sap to make the cell rigid for support.
• Most animal cells are specialised. They have adaptations which help them to carry out their particular function. When cells become specialised, scientists call that differentiation.
• Sperm cell:

  A) tail

  B) middle section

  C) acrosome

  D) nucleus

  
• Sperm cells contain half the genetic information of a normal adult cell in its nucleus. The tail helps the cell to move to the ovum/egg for fertilisation. The mitochondria provides energy needed for it to swim. The acrosome, an enzyme, digests the outer layer of the egg/ovum.
• Nerve cell:

  A) dendrite

  B) nucleus

  C) cell body

  D) axon

  E) axon terminal

  F) synapse

  G) myelin sheath

  
• The job of the nerve cell is to send electrical impulses around the body.
• Muscle cells:

  A) mitochondria

  B) nucleus

  C) Protein fibres

  
• The axon carries electrical impulses. The myelin sheath insulates the axon and speeds up the transmission of nerve impulses. The synapse allows the impulse to pass from one nerve cell to another. The dendrites increases the surface area so that other cells can connect more easily.
• Muscle cells can contract (get shorter). They do this by using protein fibres that can change their length. When a muscle cell contracts these protein fibres shorten, decreasing the length of the cell. Mitochondria provides the energy needed for the muscle to contract. Muscle cells work together which forms muscle tissue.
• Root hair cells increases the surface area of the root which means that it absorbs water and minerals more effectively.
• Root hair:

  A) root hair

  B) nucleus

  C) permanent vacuole

  D) mitochondria

  
• In the root hair cell, the large permanent vacuole speeds up the movement of water by osmosis from the soil and the mitochondira supports active transport to transfer mineral ions.
• Xylem cell:

  A) hollow tube

  B) cell wall

  C) lignin spirals

  
• Phloem Cell:

  A) sieve plates

  B) companion cells

  C) phloem vessel

  D) mitochondria

  
• A typical human cell = 10 - 20 μm
• Haemoglobin (protein found in red blood cells) molecule = 5 nm
• Same magnitude = similar size
• 1 order of magnitude means that something is 10 x another.
• 2 orders of magnitude = 100 x
• Every order of magnitude is 10 x greater than the one before.
• Centi means 1/100th.
• 1cm = 0.01m
• Milli means 1/1,000th.
• 1mm = 0.001m
• Micro means 1/1,000,000th.
• 1μm = 0.000001m