Brown's Biology AQA GCSE Additional Science-BIOLOGY
Biology Unit B2.1 Cells and simple cell transport
for GCSE Additional Science or GCSE Biology
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AQA GCSE Science BIOLOGY 2 Unit
B2.1 Cells and simple cell transport
All living things are made up of cells.
Know that the structures of different types of
cells are related to their functions.
Know the similarities and
differences between animal cells, bacteria and plant cells.
Know that to get
into or out of cells, dissolved substances have to cross the cell membranes.
You need to be able to use your skills, knowledge
and understanding to relate the structure of different types of cells to
AQA GCSE Science BIOLOGY Unit B2.1.1 Cells and cell structure
a) Know that most
human and animal cells
have the following parts:
soft cell membrane 'wall'
holding the contents together
a nucleus, which controls the activities of the
cell and contains the genetic material - genes-DNA
cytoplasm, in which most of the chemical reactions take place
usually via enzyme catalysts
cell membrane, holds the cytoplasm together and controls the passage of substances into and out of the
mitochondria, which is where
most energy is released in respiration - eg 'burning' glucose to release
ribosomes, where protein synthesis
from amino acids occurs.
b) Know that
plant and algal cells also have a
rigid cell wall made of
cellulose, which strengthens the cell and therefore the plant's structure.
chloroplasts, which absorb light energy to
make food via chlorophyll in photosynthesis
a permanent vacuole filled with cell sap
containing sugars and mineral salts.
c) Know that a
bacterial cell consists of cytoplasm and a
membrane surrounded by a cell wall; the
genes are not in a distinct nucleus - a sort of jumbled cluster.
d) Know that yeast is a single-celled organism.
e) Know and understand that cells may be specialised to carry out a
particular function e.g.
Red blood cells to carry oxygen
via their haemoglobin molecules.
White blood cells of the immune
Gamete cells ie egg cells and
sperm cells are the sexual reproduction cells.
Palisade leaf cell structure is
adapted to support the sites of photosynthesis.
Guard cells can open and close
the pores (stomata) in leaves - they must allow oxygen and carbon dioxide to
pass in and out.
AQA GCSE Science BIOLOGY Unit B2.1.2 Dissolved substances
a) Know that dissolved substances can move into and out of
cells by diffusion through the cell membrane.
b) Know that diffusion is the spreading of the particles of a gas,
or of any substance in solution, resulting in a net
movement from a region where they are of a
higher concentration to a region with a lower
Diffusion occurs spontaneously
due to the random movement of fluid particles - all gas, liquid or dissolved
particles have kinetic energy of movement.
Know that the greater the difference in
concentration, the faster the rate of diffusion, due to the steeper
Only relatively small molecules
can diffuse through cell membranes eg amino acids but not proteins, sugars
like glucose but not large carbohydrate molecules like starch.
c) Know that oxygen required for respiration passes
through cell membranes by diffusion.
Diffusion occurs in all mixtures
of gases, liquids or solutions.
Anything dissolved in a solution
can spread or diffuse if there is a difference in concentration ie a net
transfer of the substance from one place to another eg through a cell
keywords: gcse AQA human animal cell structure function
nucleus cytoplasm membrane mitochondria ribosomes chloroplasts permanent vacuole
sap diffusion Unit B2.1 Cells and simple cell transport Cell structure Dissolved
substances additional science Unit 2 BIOLOGY 2
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