Biology Revision by Miriam

d) Movement of substances into and out of cells: 2.12 understand definitions of diffusion, osmosis and active transport Diffusion: the net movement of particles from an area of higher concentration to an area of lower concentration Osmosis: the net movement of water molecules across a partially permeable membrane, from a region of high water concentration (low solute concentration) to a region of lower water concentration (high solute concentration) Active transport: movement of substances against a concentration gradient, using energy from respiration. 2.13 understand that movement of substances into and out of cells can be by diffusion, osmosis and active transport. 2.14 understand the importance in plants of turgid cells as a means of support - TRIPLE SCIENCE ONLY: When plants are well watered, the cells take in water by osmosis and the cells become turgid (the contents of the cell push against the cell wall). This helps to support the plant. When there's not enough ...

c) Biological Molecules 2.5 identify the chemical elements present in carbohydrates proteins and lipids (fats and oils) Carbohydrates: Carbon Hydrogen Oxygen Proteins: Carbon Hydrogen Oxygen Nitrogen Lipids: Carbon Hydrogen Oxygen 2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units Carbohydrates: large molecules (eg. starch and glycogen) are made from simple sugars (eg. glucose) Proteins: large molecules are made up of amino acids Lipids: large molecules are made up of fatty acids and glycerol 2.7 describe the tests for glucose and starch Test for glucose/reducing sugar: Add Benedict's reagent to the sample of food Heat it (with out boiling) in a water bath If glucose is present it will form a coloured precipitate Test for starch: Add iodine solution to the sample If starch is present it will turn from an orange / brown colour to a blue /black colour 2.8 understand the role of enzymes ...

Section 2: Structures and functions in living organisms a) Levels of organisation 2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems. Organelles are tiny structures within cells For example: Nucleus Cell membrane  Cells can be specialised for a specific function For example: Red blood cells are adapted for carrying oxygen Tissues are a group of similar cells that work together to carry out a specific function For example: Xylem and phloem tissues in plants Organs are different tissues that work together to perform a function For example: Lungs Leaves Organ systems are organs working together For example: Digestive system (stomach, intestines, pancreas, liver) b) Cell structure: Nucleus - control cell's activities and contains genetic material Cell membrane - controls substances that go in and out of the cell Chloroplasts - contain chlorophyll for photosynthesis to happen Cell wa...

Section 1: The nature and variety of living organisms a) Characteristics of living organisms 1.1 Understand that living organisms share the following characteristics: M ovement R espiration S ensitivity G rowth R eproduction E xcretion N utrition b) Variety of living organisms 1.2 Describe the common features shared by organisms within the following main groups: plants, animals, fungi, bacteria, protoctists and viruses, and for each group describe examples and their features Plants: Multicellular Cells contain chloroplasts to carry out photosynthesis Have cellulose cell walls Store carbohydrates as sucrose or starch Examples: cereals (maize), herbaceous legumes (peas, beans) Animals: Multicellular No chloroplasts No cell walls Most have nervous coordination Able to move from place to place Store carbohydrates as glycogen Examples: mammals (humans), insects (mosquitoes) Fungi: Single celled or multicellular Have a body called a myce...