Biology — Modular 2024, Unit 1

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All 54 specification statements from the official Pearson Edexcel specification, as printed — filter by paper, unit or tier exactly as Pearson Edexcel assesses them.

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1. The nature and variety of living organisms

1. Characteristics of living organisms

1.1
understand how living organisms share the following characteristics:
- they require nutrition
- they respire
- they excrete their waste
- they respond to their surroundings
- they move
- they control their internal conditions
- they reproduce
- they grow and develop.
Unit 1

2. Variety of living organisms

1.2describe the common features shown by eukaryotic organisms: plants, animals, fungi and protoctists Plants: these are multicellular organisms; their cells contain chloroplasts and are able to carry out photosynthesis; their cells have cellulose cell walls; they store carbohydrates as starch or sucrose. Examples include flowering plants, such as a cereal (for example, maize), and a herbaceous legume (for example, peas or beans). Animals: these are multicellular organisms; their cells do not contain chloroplasts and are not able to carry out photosynthesis; they have no cell walls; they usually have nervous co- ordination and are able to move from one place to another; they often store carbohydrate as glycogen. Examples include mammals (for example, humans) and insects (for example, housefly and mosquito). Fungi: these are organisms that are not able to carry out photosynthesis; their body is usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products; this is known as saprotrophic nutrition; they may store carbohydrate as glycogen. Examples include Mucor , which has the typical fungal hyphal structure, and yeast, which is single-celled. Protoctists: these are microscopic single-celled organisms. Some, like Amoeba , that live in pond water, have features like an animal cell, while others, like Chlorella , have chloroplasts and are more like plants. A pathogenic example is Plasmodium , responsible for causing malaria.Unit 1
1.3describe the common features shown by prokaryotic organisms such as bacteria Bacteria: these are microscopic single-celled organisms; they have a cell wall, cell membrane, cytoplasm and plasmids; they lack a nucleus but contain a circular chromosome of DNA; some bacteria can carry out photosynthesis but most feed off other living or dead organisms. Examples include Lactobacillus bulgaricus , a rod-shaped bacterium used in the production of yoghurt from milk, and Pneumococcus , a spherical bacterium that acts as the pathogen causing pneumonia.Unit 1
1.4understand the term pathogen and know that pathogens may include fungi, bacteria, protoctists or viruses Viruses: these are not living organisms. They are small particles, smaller than bacteria; they are parasitic and can reproduce only inside living cells; they infect every type of living organism. They have a wide variety of shapes and sizes; they have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA. Examples include the tobacco mosaic virus that causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts, the influenza virus that causes ‘flu’ and the HIV virus that causes AIDS.Unit 1

2. Structure and functions in living organisms: Part

1. Level of organisation

2.1describe the levels of organisation in organisms: organelles, cells, tissues, organs and systemsUnit 1

2. Cell structure

2.2describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuoleUnit 1
2.3describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuoleUnit 1
2.4know the similarities and differences in the structure of plant and animal cellsUnit 1
2.5Bexplain the importance of cell differentiation in the development of specialised cellsUnit 1
2.6Bunderstand the advantages and disadvantages of using stem cells in medicineUnit 1

3. Biological molecules

2.7identify the chemical elements present in carbohydrates, proteins and lipids (fats and oils)Unit 1
2.8describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugars, protein from amino acids, and lipid from fatty acids and glycerolUnit 1
2.9practical: investigate food samples for the presence of glucose, starch, protein and fatUnit 1
2.10understand the role of enzymes as biological catalysts in metabolic reactionsUnit 1
2.11understand how temperature changes can affect enzyme function, including changes to the shape of active siteUnit 1
2.12practical: investigate how enzyme activity can be affected by changes in temperatureUnit 1
2.13understand how enzyme function can be affected by changes in pH altering the active siteUnit 1
2.14Bpractical: investigate how enzyme activity can be affected by changes in pHUnit 1

4. Movement of substances into and out of cells

2.15understand the processes of diffusion, osmosis and active transport by which substances move into and out of cellsUnit 1
2.16understand how factors affect the rate of movement of substances into and out of cells, including the effects of surface area to volume ratio, distance, temperature and concentration gradientUnit 1
2.17practical: investigate diffusion and osmosis using living and non-living systemsUnit 1

5. Nutrition

2.18understand the process of photosynthesis and its importance in the conversion of light energy to chemical energyUnit 1
2.19know the word equation and the balanced chemical symbol equation for photosynthesisUnit 1
2.20understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesisUnit 1
2.21describe the structure of the leaf and explain how it is adapted for photosynthesisUnit 1
2.22understand that plants require mineral ions for growth, and that magnesium ions are needed for chlorophyll and nitrate ions are needed for amino acidsUnit 1
2.23practical: investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyllUnit 1
2.24understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibreUnit 1
2.25identify the sources and describe the functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, the mineral ions calcium and iron, water and dietary fibre as components of the dietUnit 1
2.26understand how energy requirements vary with activity levels, age and pregnancyUnit 1
2.27describe the structure and function of the human alimentary canal, including the mouth, oesophagus, stomach, small intestine (duodenum and ileum), large intestine (colon and rectum) and pancreasUnit 1
2.28understand how food is moved through the gut by peristalsisUnit 1
2.29understand the role of digestive enzymes, including the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipasesUnit 1
2.30understand that bile is produced by the liver and stored in the gall bladderUnit 1
2.31understand the role of bile in neutralising stomach acid and emulsifying lipidsUnit 1
2.32understand how the small intestine is adapted for absorption, including the structure of a villusUnit 1
2.33Bpractical: investigate the energy content in a food sampleUnit 1

6. Respiration

2.34understand how the process of respiration produces ATP in living organismsUnit 1
2.35know that ATP provides energy for cellsUnit 1
2.36describe the differences between aerobic and anaerobic respirationUnit 1
2.37know the word equation and the balanced chemical symbol equation for aerobic respiration in living organismsUnit 1
2.38know the word equation for anaerobic respiration in plants and in animalsUnit 1
2.39practical: investigate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organismsUnit 1

7. Gas exchange

2.40Bunderstand the role of diffusion in gas exchangeUnit 1
2.41Bunderstand gas exchange (of carbon dioxide and oxygen) in relation to respiration and photosynthesisUnit 1
2.42Bunderstand how the structure of the leaf is adapted for gas exchangeUnit 1
2.43Bdescribe the role of stomata in gas exchangeUnit 1
2.44Bunderstand how respiration continues during the day and night, but that the net exchange of carbon dioxide and oxygen depends on the intensity of lightUnit 1
2.45Bpractical: investigate the effect of light on net gas exchange from a leaf, using hydrogen- carbonate indicatorUnit 1
2.46describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea, bronchi, bronchioles, alveoli and pleural membranesUnit 1
2.47understand the role of the intercostal muscles and the diaphragm in ventilationUnit 1
2.48explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillariesUnit 1
2.49understand the biological consequences of smoking in relation to the lungs and the circulatory system, including coronary heart diseaseUnit 1
2.50practical: investigate breathing in humans, including the release of carbon dioxide and the effect of exerciseUnit 1