GCSE Biology paper 1
Topic 1. Cell biology
There are two types of cells, prokaryotic cells and eukaryotic cells.
Cells are tiny units of life that replicate independently. The sub cellular
structures (organelles) makeup a cell.
Animal cells and plant cells are eukaryotic cells, and a bacterial cell is a
prokaryotic cell.
Animal and plant cells are multicellular which means that they contain
loads of cells. However bacterial cells are unicellular and are much
simpler.
The table below shows what the two eukaryotic cells (animal and plant
cells) contain.
Animal cells Plant cells
Cell membrane (controls what comes Cell membrane
in and goes out of the cell)
Nucleus (contains all the genetic Nucleus
material and controls the cell)
Cytoplasm (where all the chemical Cytoplasm
reactions in a cell happens)
Mitochondria (provides the cell with Mitochondria
energy. Aerobic respiration happens
here)
Ribosomes (for protein synthesis) Ribosomes
No cell walls Cell wall (gives a rigid structure to the
cell. It's for support and it's made of
cellulose)
No chloroplasts Chloroplasts (contains chlorophyll and
this is where photosynthesis happens)
No vacuole Vacuole (contains cell sap which is
made up of salt and water and sugar)
,Here is the animal cell.
Here is the plant cell.
Bacterial cells don’t contain any ribosomes or mitochondria. They do have
a cytoplasm and a cell membrane in addition to a cell wall. They don’t
have a nucleus. The genetic material in a bacterium is stored in a form of
a single strand of DNA in the cytoplasm. Bacteria cells also contain
plasmids (eukaryotic cells don’t contain plasmids). They sometimes, also
have a flagellum which is used to move around with.
, Here is a bacterial cell.
Microscopy
Microscopes are used to magnify objects and create a detailed image with
high resolution for us.
There are two types of microscopes. Light microscopes and electron
microscopes. Electron microscopes are more advanced and are newer.
Resolution is the maximum level of details and clarity.
Magnification is how much larger the image is than the actual object.
Higher magnification makes the image larger. It may not make the image
clearer because it could be limited by a low resolution.
To calculate magnification, you use the equation below.
Magnification = image size ÷ real size.
Image size is what we see under the microscope and the real size is the
actual size of the object.
Here is the comparison between light and electron microscopes.
Light microscopes Electron microscopes
cheaper More expensive
Small Larger
Easy to use More complex and harder to use
Relies on light Works with electrons
Resolution is limited to 0.2 Maximum resolution of 0.1
micrometres. nanometre.
Can't view subcellular structures. Can view subcellular structures such
Topic 1. Cell biology
There are two types of cells, prokaryotic cells and eukaryotic cells.
Cells are tiny units of life that replicate independently. The sub cellular
structures (organelles) makeup a cell.
Animal cells and plant cells are eukaryotic cells, and a bacterial cell is a
prokaryotic cell.
Animal and plant cells are multicellular which means that they contain
loads of cells. However bacterial cells are unicellular and are much
simpler.
The table below shows what the two eukaryotic cells (animal and plant
cells) contain.
Animal cells Plant cells
Cell membrane (controls what comes Cell membrane
in and goes out of the cell)
Nucleus (contains all the genetic Nucleus
material and controls the cell)
Cytoplasm (where all the chemical Cytoplasm
reactions in a cell happens)
Mitochondria (provides the cell with Mitochondria
energy. Aerobic respiration happens
here)
Ribosomes (for protein synthesis) Ribosomes
No cell walls Cell wall (gives a rigid structure to the
cell. It's for support and it's made of
cellulose)
No chloroplasts Chloroplasts (contains chlorophyll and
this is where photosynthesis happens)
No vacuole Vacuole (contains cell sap which is
made up of salt and water and sugar)
,Here is the animal cell.
Here is the plant cell.
Bacterial cells don’t contain any ribosomes or mitochondria. They do have
a cytoplasm and a cell membrane in addition to a cell wall. They don’t
have a nucleus. The genetic material in a bacterium is stored in a form of
a single strand of DNA in the cytoplasm. Bacteria cells also contain
plasmids (eukaryotic cells don’t contain plasmids). They sometimes, also
have a flagellum which is used to move around with.
, Here is a bacterial cell.
Microscopy
Microscopes are used to magnify objects and create a detailed image with
high resolution for us.
There are two types of microscopes. Light microscopes and electron
microscopes. Electron microscopes are more advanced and are newer.
Resolution is the maximum level of details and clarity.
Magnification is how much larger the image is than the actual object.
Higher magnification makes the image larger. It may not make the image
clearer because it could be limited by a low resolution.
To calculate magnification, you use the equation below.
Magnification = image size ÷ real size.
Image size is what we see under the microscope and the real size is the
actual size of the object.
Here is the comparison between light and electron microscopes.
Light microscopes Electron microscopes
cheaper More expensive
Small Larger
Easy to use More complex and harder to use
Relies on light Works with electrons
Resolution is limited to 0.2 Maximum resolution of 0.1
micrometres. nanometre.
Can't view subcellular structures. Can view subcellular structures such
