Search our library of Biology A Level questions

Top answers

Biology

A Level

Why is the oxygen dissociation curve shaped like it is?

At first, the shape of the Hb makes it hard for oxygen to bind to one of the polypeptide subunits so at low concentrations of oxygen, the saturation of oxygen is low too.
Once the first molecule of o...

Answered by • Biology tutor

1500 Views

What is meant by the term "tertiary structure" of a protein? Describe the forms of bonding that could be involved.

Tertiary structures in a protein refers to the overall three-dimensional structure of the protein. The tertiary structure is primarily generated by interactions between amino-acid R groups. There are five...

Answered by Henry H. • Biology tutor

1948 Views

Briefly describe the steps of DNA replication and the enzymes involved.

DNA helicase breaks the hydrogen bonds that bind the two strands of the DNA double helix.Free nucleotide complementary base pairs are added to the newly exposed single strands of DNA.Binding of the free n...

Answered by • Biology tutor

1514 Views

Use your knowledge of the humoral immune response to explain a vaccination programme

Interesting topic with regards to COVID-19A vaccine introduces a foreign pathogen into the body. This foreign body stimulates the innate immune response which occurs regardless. The process of phagocytosi...

Answered by Will A. • Biology tutor

2742 Views

Cells need mRNA molecules to create proteins. How are they created?

Protein synthesis is a convoluted process but, essentially, all the cell is doing is 'reading' the instructions contained within the base sequence in the correct gene or 'section' of the DNA and then doin...

Answered by Matthew J. • Biology tutor

1933 Views