Topic Summaries
Punnett squares and family trees
Transport Systems
Blood and heart disease
Stem cells, microscopy, and microorganisms
Transport in cells
Human health and enzymes
Plant transport systems
Pathogens and non-specific immunity
The immune system and drugs
Plant disease and monoclonal antibodies
Photosynthesis and respiration
The nervous system and homeostasis
The brain and the eye
Hormone regulation and waste excretion
Reproductive hormones and plant hormones
Cell division, reproduction, and DNA structure
DNA synthesis and inheritance
Genetic engineering and modification
Evolution and natural selection
Species and classification
Resource cycles and environmental change
Biodiversity and environmental management
Biomass and trophic levels
Food supply and biotechnology
Science skills: Experimental procedures
Science skills: Presenting and using data
Science skills: Measuring results
Transport Systems
Blood and heart disease
Stem cells, microscopy, and microorganisms
Transport in cells
Human health and enzymes
Plant transport systems
Pathogens and non-specific immunity
The immune system and drugs
Plant disease and monoclonal antibodies
Photosynthesis and respiration
The nervous system and homeostasis
The brain and the eye
Hormone regulation and waste excretion
Reproductive hormones and plant hormones
Cell division, reproduction, and DNA structure
DNA synthesis and inheritance
Genetic engineering and modification
Evolution and natural selection
Species and classification
Resource cycles and environmental change
Biodiversity and environmental management
Biomass and trophic levels
Food supply and biotechnology
Science skills: Experimental procedures
Science skills: Presenting and using data
Science skills: Measuring results
- A Punnett square is a grid used to determine the probability of an offspring’s genotype based on the genotype of the parents, showing the potential allele combinations offspring can inherit.
- For example, when determining the inheritance of eye colour if both parents have the brown eye phenotype and the genotype Bb:
| Parent 1 | |||
| B | b | ||
| Parent 2 | B | BB | Bb |
| b | Bb | bb | |
-
- Genotype ratio BB:Bb:bb = 1:2:1
- Probability of offspring: BB = 25%, Bb = 50%, bb = 25%
- Probability of offspring: Brown eyes = 75%, blue eyes 25%
- Family trees show the inheritance of characteristics over several generations. The oldest members of a family are at the top of a tree, and each new tier represents a new generation. People with XY chromosomes are represented by squares and people with XX chromosomes are represented by circles. Individuals with a specific characteristic will have their shape coloured in, unless shown otherwise with a key.
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