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Combined Science: Biology

GCSE · Edexcel · foundation

QuestionsFlashcards

Disease
Defence Against Disease
Development of Medicines
- Antibiotics
  4
- Discovery & Development of New Drugs
  3
Non-Communicable Diseases
- Lifestyle & Non-Communicable Disease
  7
- Cardiovascular Disease
  6

The Organism in the Environment
Human Influences on the Environment
- Human Impact on Biodiversity
  6
- Benefits of Maintaining Biodiversity
  4
Cycles within Ecosystems

DNA & the Genome Flashcards

All 5 cards in this deck

Describe the structure of a DNA molecule.: A polymer of two strands of nucleotides coiled into a double helix; each nucleotide is a sugar, a phosphate group and one of four bases, and the strands are linked by complementary base pairs joined by weak hydrogen bonds.
Which bases pair together in a DNA molecule?: A pairs with T, and C pairs with G (complementary base pairs, joined by weak hydrogen bonds).
What is meant by the genome, and what is a gene?: Genome = the entire DNA of an organism. Gene = a section of a DNA molecule that codes for a specific protein.
When extracting DNA from fruit, why are detergent and ice-cold alcohol used?: Detergent breaks down the cell membranes to release the DNA. DNA is insoluble in ice-cold alcohol, so it comes out of solution as white strands.
When extracting DNA from fruit, why is salt added?: It makes the DNA clump together, so it is easier to separate out.