AQA AS Biology questions

Multiple copies of the AMY1 gene is an adaptation

- More mRNA

- More enzyme

- Reaction is faster

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Describe how the student could use an eyepiece gra

- Measure stomata using eyepice graticule

- Calibrate eyepice graticule against stage micrometer

- Take a number of measurements (for mean)

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NMO is a disease that leads to damage to the nerve

- Anti-AQP4 antibody has a specific tertiary structure

- Has binding site / variable region that only binds to / complementary to one antigen

- Antigen to this antibody only found on these nerve cells

- So, antibody only binds to / forms antigenantibody complex with these nerve cells, causing damage

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Explain why all the cells of the body will have th

- Mutation / extra chromosome in gamete/egg/sperm

- All cells derived from a single cell/zygote by mitosis

- Mitosis produces genetically identical cells / a clone

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Describe the cohesion-tension theory of water tran

-Water lost from leaf because of transpiration

- Lowers water potential of mesophyll / leaf cells

-Water pulled up xylem, creating tension

-Water molecules cohere / ‘stick’ together by hydrogen bonds

-Forming continuous water column; 6.

-Adhesion of water molecules to walls of xylem

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Describe how mRNA is produced in a plant cell

-The DNA strands separate by breaking the H bonds/ H bonds broken between complementary DNA bases;Only one of the strands/template strand is used (to make mRNA/is transcribed)

- Complementary base pairing so A→U, T→A, C→G, G→C

- RNA nucleotides joined by RNA polymerase

- Pre-mRNA formed

- Splicing / introns removed to form mRNA

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Investigating Rates of Enzyme-Controlled Reactions

Changing pH

Changing the pH changes the number of hydroxide ions and hydrogen ions (OH− and H+) surrounding the enzyme.
These interact with the charges on the enzyme’s amino acids, affecting hydrogen bonding and ionic bonding, so resulting in changes to the tertiary structure.

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