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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

Specialised Cells Flashcards

All 6 cards in this deck

What is the acrosome of a sperm cell and what does it do?: A sac of enzymes in the head; the enzymes digest the membrane around the egg so the sperm can enter.
Why does a sperm cell have many mitochondria?: To release energy by respiration so the tail can move and the sperm can swim to the egg.
What does it mean that the nucleus of a sperm cell or egg cell is haploid?: It contains half the number of chromosomes of a body cell – 23 in a human gamete.
Why does the cytoplasm of an egg cell contain nutrients?: To provide food for the developing embryo after fertilisation.
What happens to the cell membrane of an egg cell straight after fertilisation?: It changes so that no more sperm can enter the egg.
How are ciliated epithelial cells in the airways adapted to their function?: They have cilia that beat to move (waft) mucus, with trapped dust and bacteria, along the airway.