Describe the structure of DNA

-DNA is a double-stranded helix-Two polynucleotide strands (that run antiparallel to each other), held together by hydrogen bonding between the complementary base pairs-Each nucleotide consists of deoxyribose sugar, a phosphate group and a base (adenine [A), thymine [T], cytosine [C] and guanine [G] in the case of DNA).-The two strands are equidistant and the double helix is stable due to complementary base pairing, which means that A+T always pair together, and C+G always pair together

Answered by Biology tutor

2157 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Describe how phagocytosis of a virus leads to presentation of its antigens and how presentation of this antigen leads to the secretion of an antibody against this virus antigen.


(a) (i) Give a biological molecule that contains: 1. nitrogen 2. phosphorous (ii) Describe the role of microorganisms in producing nitrates from the remains of dead organims.


Describe the steps of mitosis. (10 Marks)


Give examples of some factors that increase the rate of diffusion.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences