Year 12 Biology Test Autumn 2023 Flashcards
Describe how monomers join to form the primary structure of a protein
Formed between a condensation reaction between amino acids
Form peptide bonds between amino acids
Primary structure is the number or order of amino acids in the sequence
A competitive inhibitor decreases the rate of an enzyme controlled reaction. Explain how
Similar shape to substrate
Binds to active site
Prevents enzyme substrate complexes from being formed
When bread becomes stale the structure of some of the starch is changed. This changed starch is called retrograded starch. Scientists have suggested that retrograded starch is a competitive inhibitor of amylase in the small intestine
Assuming the scientists are correct, suggest how eating stale bread could help reduce wait gain
Less hydrolysis of starch to maltose so less absorption of glucose
Raffinose is a trisaccharide of three monosaccharides: galactose, glucose and fructose. The chemical formulae of these monosaccharides are:
galactose C6H12O6
glucose C6H12O6
fructose C6H12O6
Give the number of carbon atoms, hydrogen atoms and oxygen atoms in a molecule of raffinose
Number of carbon atoms 18
Number of hydrogen atoms 32
Number of oxygen atoms 16
A biochemical test for reducing sugar produces a negative result with raffinose solution.
Describe a biochemical test to show that raffinose solution contains a non-reducing sugar
Heat sample with dilute hydrochloric acid
Neutralise with sodium hydrocarbonate
A red precipitate will form
U marinum cells ingest bacteria and digest them in the cytoplasm
Describe the role of one organelle in digesting this bacteria
Lysosomes contain lysozymes which ingest bacteria
They fuse with vesicles and release hydrolytic enzymes
In large cells of U marinum most mitochondria are found close to the cell-surface membrane. In smaller cells the mitochondria are evenly distributed throughout the cytoplasm. Mitochondria use oxygen during aerobic respiration
Use the information and your knowledge of surface area to volume ratios to suggest an explanation for the position of mitochondria in large U marinum cells
Larger cells have a smaller SA:VOL ratio so it takes longer for oxygen to diffuse
The scientist joined DNA molecules together to make tiny cages. The cages are exactly 20 nm long, 20 nm and 17 nm deep.
He trapped one GOx molecule and one HRP molecule together tin each cage . The GOx molecule and HRP molecule fill 9% of the cage volume.
The volume of the GOx molecule is eight times larger than the HRP molecule
Use this information to calculate the volume of a GOx molecule
Cage volume = 20 x 20 x 17 = 6800
6800 x 0.09 = 612nm occupied by enzymes
544 nm
