B1 (Cell Biology) Combined Science

1.1

Microscopes- Used to view small objects like cells that cannot be seen by the naked eye

Magnification- The number of times an object seems larger

Resolution- The ability to distinguish between 2 points that are close together 

Magnification = image size (mm) / actual size (mm) 

=              I               (HINT- I am magnification)

            A      M

micrometres (μm)= from mm multiply by 1000

1.2

Eukaryotes- cells characterised by containing a nucleus and large organelles examples are plant and animal cells

Algae- single celled organisms  that have the same components of a plant cell but are not plants

Cell membrane- Controls passage of substances in and out of the cell

Cytoplasm- Where chemical reactions take place

Nucleus- Controls all of the activities of the cell and holds the genetic information

Mitochondria- Release energy from respiration

Ribosome- Where protein synthesis takes place

Cell wall (plant)- Strengthens cell and gives it support

Vacuole (plant)- Filled with cell sap keeps cell rigid 

Chloroplast (plant) Contains chlorophyll to carry out photosynthesis

1.3

Prokaryote- small single-celled organisms with no true nucleus

DNA loop- Loop of DNA, controls activities of the cell

Slime Capsule- Used for protection

Flagellum- Rotates helping the bacterium to move

Plasmids- Holds additional genes that may be useful for the bacterium

Pili- Help bacterium attach to surfaces

1.4

Specialised cells- cells that have adaptations to help them carry out a particular function

Nerve Cells:

Adaptations-

-Lots of dendrites to make connections to other nerve cells

-Axon to carry the nerve impulse from one place to another 

-Synapses to pass impulses between nerve cells and muscle cells using a chemical 

-Many mitochondria to release energy for making transmitter chemicals

Muscle Cell:

Adaptations-

-Special proteins help fibres contract 

-Many mitochondria to release energy for muscle contraction

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