2024 AQA AS BIOLOGYPAPER 2 2022 / 2024 AQA AS BIOLOGY Paper 2 Question Paper & Mark scheme (Merger)
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2024 AQA AS BIOLOGYPAPER 2 2022 / 2024 AQA AS BIO
Institution
2024 AQA AS BIOLOGYPAPER 2 2022 / 2024 AQA AS BIO
2024 AQA AS BIOLOGYPAPER 2 2022
/ 2024 AQA AS BIOLOGY Paper 2
Question Paper & Mark scheme
(Merger)
Glycolipid - ANS-A carbohydrate covalently bonded with a lipid.
They act as recognition sites, help maintain stability of the
membrane and help cells attach to one another.
Cholesterol -...
2024 AQA AS BIOLOGYPAPER 2 2022
/ 2024 AQA AS BIOLOGY Paper 2
Question Paper & Mark scheme
(Merger)
Glycolipid - ANS-A carbohydrate covalently bonded with a lipid.
They act as recognition sites, help maintain stability of the
membrane and help cells attach to one another.
Cholesterol - ANS-Lipid that is an important component of cell-
surface membranes because it adds strength. Excess in the blood
can lead to atheroma.
Permeability - ANS-How permeable a substance is depends on the
size, polarity and charge of the molecule. If it is small, non-polar
and fat soluble it is very permeable and can pass through the cell
membrane.
Fluid mosaic model - ANS-The arrangement of the various
molecules of the cell-surface membrane. Fluid because the
individual phospholipid molecules can move relative to one another
and mosaic because the proteins vary in shape, size and pattern.
Diffusion - ANS-Diffusion is the net movement of molecules (or
ions) from a region of high concentration to a region of low
concentration. It is passive.
Facilitated diffusion - ANS-Diffusion involving the presence of
protein carrier molecules to allow the passive movement of
, substances (normally large, polar or charged molecules) across
plasma membrane.
Osmosis - ANS-The passage of water from a region where there is a
higher water potential to a region where there is a lower water
potential through a partially permeable membrane.
Magnification - ANS-the number of times bigger the image/drawing
is compared to the object/real size
Resolution - ANS-the minimum distance needed to differentiate
between 2 adjacent objects
Micrometer - ANS-1x10-6 m
Nanometer - ANS-1x10-9 m
Light microscope - ANS-A type of microscope which has a
condenser, objective lens and eyepiece lens and light is passed
through the thin specimen an up through the objective and eyepiece
lenses to the eye.
Electron microscope - ANS-Beams of electrons are used to visualize
structures in a vacuum. Electrons have a smaller wavelength than
light so electron microscopes have a higher resolution than light
microscopes.
Scanning Electron Microscope (SEM) - ANS-A type of electron
microscope which bounces beams of electrons off the surface of an
object to develop a 3D image of the specimen (no need therefore for
thin sections).
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