Subject Reference Biology 2.7
Title Demonstrate understanding of gene expression
Level 2 Credits 4 Assessment External
Achievement

Demonstrate understanding of gene expression.
1
Achievement with Merit

Demonstrate in-depth understanding of gene expression.
Achievement with Excellence

Demonstrate comprehensive understanding of gene expression.
Gene expression involves a selection from the following biological ideas and processes:
 nucleic acid structure and nature of the genetic code
 significance of proteins
 protein synthesis
 the determination of phenotype via metabolic pathways
 effect of environment on genotype through mutations
 effect of environment on expression of phenotype.
2 Biological ideas and processes relating to nucleic acid structure and nature of the genetic code must be selected from:
 molecular components and their role in carrying the genetic code: nucleotide monomers, deoxyribose and/or ribose sugar, phosphate,
nitrogenous bases, complementary base pairing resulting in coding and template strand
 nature of the genetic code including triplets, codons and anticodons
 redundancy due to degeneracy within the code.
3
4
5
Biological ideas and processes relating to the significance of proteins must be selected from:
 proteins as the products of gene expression: DNA  mRNA  polypeptide or protein
 significance of proteins is limited to their structural and catalytic role in living things.
Biological ideas and processes relating to protein synthesis must be selected from:
 the role of DNA sequence in determining the structure of a protein and how that protein is produced (transcription and translation)
 the role of enzymes in controlling the process (specific names of enzymes are not required).
Biological ideas and processes relating to the determination of phenotype via metabolic pathways must be selected from:
 biochemical reactions are catalysed by specific enzymes and every enzyme is coded for by a specific gene(s)
 biochemical reactions do not occur in isolation but form part of a chain reaction so that the product of one becomes the substrate of another
step in metabolism
 phenotype is determined by the presence, absence, or amount of specific metabolic products.
 identification of one gene one polypeptide relationship)
6 Biological ideas and processes relating to the effect of the environment on genotype through mutations must be selected from:
 mutagens (specific mutagens are recognised but their effect at molecular level is not required)
 the potential effect of a point mutation on genotype and phenotype.
7 Biological ideas and processes relating to the effect of environment on expression of phenotype must involve ways that environmental factors may change phenotype without changing genotype.
Students will:
Life processes

Explore the diverse ways in which animals and plants carry out the life processes.
Ecology

Explore ecological distribution patterns and explain possible causes for these patterns.
Evolution

Understand that DNA and the environment interact in gene expression.
Ecology and evolution

Explain how the interaction between ecological factors and natural selection leads to genetic changes within populations.

Key concepts: Biology (Teaching and
Learning Guide)
Key concepts are the big ideas and understandings that we hope will remain with our students long after they have left school.
The following are key concepts/big ideas in biology:
All organisms share a common set of essential life processes
Because of their shared evolutionary history, all organisms share a common set of essential life processes (movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition) and use the same genetic system to maintain continuity.
Organisms interact with each other and with their environment
Living systems are organised and regulate themselves at the cell, organism, and ecosystem levels. Each of these dynamic systems maintains stability in response to a changing environment and their responses impact in turn upon the environment.
Species arise, change, and become extinct over time
Evolution results in diverse adaptations to ensure survival. This diversity allows organisms to occupy different niches within an ecosystem.
Genetics maintain continuity plus allow for change
The inherited sequence of DNA underlies an organism's phenotype such as shape or blood type.
Heritable mutations allow evolution or genetic change over time.
Progression in biology
Students’ progress in biology is demonstrated by their increasingly sophisticated ability to identify, apply, and reflect on biological concepts, patterns, and processes.
As they progress, students:
 focus less on how specific groups of organisms carry out their life processes and more on how the diversity of strategies across species enables organisms to occupy differing niches in an ecosystem
 move from recognising the common life processes to appreciating those life processes at the cell level and then at a homeostatic systems level
 move from recognising that the environment affects the life processes of organisms, to explaining distribution patterns of organisms in terms of environmental factors and gradients, to applying in novel situations their understanding of the complex interactions that take place between organisms and their environment
 move from a focus on simple patterns of genetic inheritance to appreciating the mechanisms by which genes express themselves and the ways in which humans use their understanding of biotechnology to manipulate living organisms
 move from recognising that genetic variation is important in a changing environment to focusing on the processes by which allele frequencies alter in response to environmental changes
 move from understanding the species concept to focusing on the processes by which new species arise;
 move from identifying the impact of humans on a specific ecosystem to appreciating how humans can also affect evolutionary processes via genetic manipulation
 from identifying human impacts on a biological situation to developing a reasoned personal viewpoint based on critical thinking around the ethical, social and biological implications of human activities.
Indicators
Indicators are examples of the behaviours and capabilities that a teacher might expect to observe in a student who is achieving at the appropriate level. Teachers may wish to add further examples of their own.

Students will:
Life processes

Explore the diverse ways in which animals and plants carry out the life processes.
Ecology

Explore ecological distribution patterns and explain possible causes for these patterns.
Evolution

Understand that DNA and the environment interact in gene expression.
Ecology and evolution

Explain how the interaction between ecological factors and natural selection leads to genetic changes within populations.
Be able to describe DNA structure and explain mechanism and purpose of DNA replication.
(Central Dogma ideas)
Understand and explain the processes of mitosis and meiosis and rcognise their purpose in living things.
Explain the link between DNA, genetic code and proteins through protein synthesis.
Describe the different function of proteins in living things. (especially enzymes)
Be able to explain what mutations are, role of mutagens and the significance of new alleles.
Understand potential effect of point mutations on genotype and phenotype. (Pleiotropy)
Recognise some simple metaboilc pathways and how they can determine phenotype. Include the role of enzymes in controlling these pathways.
Be able to solve problems involving basic epistasis interactions.
Discuss the effect of environment on phenotype eg. Nutrition in-utero, exposure to wind/altitude on plants, island habitats environments
• Understand that scientists have an obligation to connect their new ideas to current and historical scientifi c knowledge and to present their findings for peer review and debate.
• Develop and carry out investigations that extend their science knowledge, including developing their understanding of the relationship between investigations and scientific theories and models.
• Use accepted science knowledge, vocabulary, symbols, and conventions when evaluating accounts of the natural world and consider the wider implications of the methods of communication and/or representation employed.
• Use relevant information to develop a coherent understanding of socio-scientific issues that concern them, to identify possible responses at both personal and societal levels.
Note: This unit of work lends itself to time spent on the history of DNA discovery and past research on metabolic disorders.
Also, thinking about current areas of research such as nutrigenomics and epigenetics.