Edexcel A-level Biology A 2024 Topic 2
Exam Questions and Answers
Diffusion - Answer>>passive movement of molecules
what is diffusion dependent one? - Answer>>concentration,
thickness of diffusion pathway, surface area
how are lungs adapted for efficient gas exchange -
Answer>>Lots of alveoli - large surface area
capillary endothelial - one cell thick, short diffusion pathway
Breathing in and out maintains a concentration gradient
Fick's Law of Diffusion - Answer>>surface area x concentration
gradient / diffusion pathway
what are proteins made from? - Answer>>long chains of amino
acids
What is a polypeptide? - Answer>>long chain of amino acids
How does a polypeptide form? - Answer>>peptide bond and a
condensation reaction
What determines the shape of a protein? - Answer>>sequence
of amino acids and the size of the r group
Four structural levels of proteins - Answer>>primary,
secondary, tertiary, quaternary
what is a primary structure? - Answer>>sequence of amino
acids in a polypeptide chain
, what is a secondary structure? - Answer>>the polypeptide
chain folds and there is hydrogen bonds between amino acids in
chains
what are the two secondary structures - Answer>>alpha helix
and beta pleated sheet
Alpha helix - Answer>>the r group is small, the chain coils,
hydrogen bonds
beta pleated sheet - Answer>>r group is bulky, chain folds on
itself, hydrogen bonds between the amino acids
What is tertiary structure? - Answer>>secondary structure folds
into a unique shape
what are the different bonds that can occur in tertiary structure? -
Answer>>hydrogen, ionic, disulfide
What is quaternary structure? - Answer>>several different
polypeptide chains held together by bonds
what are examples of quaternary structures -
Answer>>Globular - haemoglobin (functional)
Fibrous - collagen (structural)
what is the arrangement of groups in a 3d+ structure -
Answer>>Hydrophobic place themselves on the inside and
hydophilic on the outside
Explain globular proteins. - Answer>>Round, compact,
hydophobic/philic arrange themselves
soluble
Exam Questions and Answers
Diffusion - Answer>>passive movement of molecules
what is diffusion dependent one? - Answer>>concentration,
thickness of diffusion pathway, surface area
how are lungs adapted for efficient gas exchange -
Answer>>Lots of alveoli - large surface area
capillary endothelial - one cell thick, short diffusion pathway
Breathing in and out maintains a concentration gradient
Fick's Law of Diffusion - Answer>>surface area x concentration
gradient / diffusion pathway
what are proteins made from? - Answer>>long chains of amino
acids
What is a polypeptide? - Answer>>long chain of amino acids
How does a polypeptide form? - Answer>>peptide bond and a
condensation reaction
What determines the shape of a protein? - Answer>>sequence
of amino acids and the size of the r group
Four structural levels of proteins - Answer>>primary,
secondary, tertiary, quaternary
what is a primary structure? - Answer>>sequence of amino
acids in a polypeptide chain
, what is a secondary structure? - Answer>>the polypeptide
chain folds and there is hydrogen bonds between amino acids in
chains
what are the two secondary structures - Answer>>alpha helix
and beta pleated sheet
Alpha helix - Answer>>the r group is small, the chain coils,
hydrogen bonds
beta pleated sheet - Answer>>r group is bulky, chain folds on
itself, hydrogen bonds between the amino acids
What is tertiary structure? - Answer>>secondary structure folds
into a unique shape
what are the different bonds that can occur in tertiary structure? -
Answer>>hydrogen, ionic, disulfide
What is quaternary structure? - Answer>>several different
polypeptide chains held together by bonds
what are examples of quaternary structures -
Answer>>Globular - haemoglobin (functional)
Fibrous - collagen (structural)
what is the arrangement of groups in a 3d+ structure -
Answer>>Hydrophobic place themselves on the inside and
hydophilic on the outside
Explain globular proteins. - Answer>>Round, compact,
hydophobic/philic arrange themselves
soluble
