AQA A LEVEL BIOLOGY Paper 1 Latest Update
Cell vacuole (plants) - ANSWER-Found in cytoplasm.
Contains cell sap.
Membrane surrounding this is called the tonoplast.
Maintains pressure inside the cell, keeping cell rigid/stops wilting.
Cell wall - ANSWER-Made of murein (glycoprotein).
Cell vacuole (plants) - ✔✔✔ANSWER-Found in cytoplasm.
Contains cell sap.
Membrane surrounding this is called the tonoplast.
Maintains pressure inside the cell, keeping cell rigid/stops wilting.
Cell wall - ✔✔✔ANSWER-Made of murein (glycoprotein).
,Cell wall (plants) - ✔✔✔ANSWER-Usually made of cellulose (chitin, fungi).
Support cells and prevents them from changing shape.
Chloroplast (plants) - ✔✔✔ANSWER-Double membrane.
Site of photosynthesis.
Define biodiversity. - ✔✔✔ANSWER-The variety of living organisms in an area.
Describe the 'induced fit' model. - ✔✔✔ANSWER-The substrate doesn't only have
to be the right shape to fit the active site but also has to make the active site change
shape in the right way.
Describe the 'lock and key' model. - ✔✔✔ANSWER-This is where the substrate
fits into the enzyme in the same way the key fits into a lock.
Describe the gas exchange system in dicotyledonous plants. - ✔✔✔ANSWER-
Mesophyll cell surface, large surface area, are inside the leaf, gases move into and
out of the leaf via stomata. Guard cells control the opening/closing of stomata.
Describe the gas exchange system in fish. - ✔✔✔ANSWER-Countercurrent (blood
flows through the lamellae in one direction and water flows over in the opposite
direction, maintains a high concentration gradient).
Water enters the fish through its mouth and passes through the gills.
Each gill is made of lots of thin plates called gill filaments which are covered in
lots of lamellae, which increase the surface area.
, Lamellae have lots of blood capillaries and a thin surface layer of cells to speed up
diffusion.
Describe the gas exchange system in insects. - ✔✔✔ANSWER-Use tracheae.
Air moves into tracheae through spiracles.
Oxygen travels down the concentration gradient towards the cells.
The tracheae branch off into smaller tracheoles which have thin permeable walls
and go to individual cells.
Carbon dioxide moves down its concentration gradient towards the spiracles to be
released into the atmosphere.
Insects use rhythmic abdominal movements to move air in and out of the spiracles.
3.1.2 Carbohydrates - ✔✔✔ANSWER-
3.1.4 Proteins - ✔✔✔ANSWER-
3.2.1 Cell Structure - ✔✔✔ANSWER-
3.3.2 Gas Exchange - ✔✔✔ANSWER-
3.3.4 Mass Transport - ✔✔✔ANSWER-
3.4.4 Genetic Diversity and Adaptation - ✔✔✔ANSWER-
3.4.6 Biodiversity - ✔✔✔ANSWER-
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