IGCSE Biology Cells Identify the key features of plant and animal cells 22 May 2019

Learning Objectives Identify the main structures found in plant cells Identify the main structures found in animal cells Compare plant cells with animal cells 22 May 2019

Cells – The Building Blocks Of Life All living organisms are composed of cells. The simplest organisms are made of one single cell. More complex organisms like animals and plants are made of many cells and are called multicellular organisms. In multicellular organisms there are many different types of cells that are specialised to carry out particular functions. 22 May 2019

The Light Microscope 22 May 2019

Animal Cell 3 22 May 2019

Animal Cell Cell Membrane Cytoplasm Nucleus 22 May 2019

A general animal cell Cell membrane Cytoplasm Nucleus Mitochondria 22 May 2019

Plant Cell 6 22 May 2019

A general plant cell Cell wall Cell membrane Mitochondria Vacuole Cytoplasm Chloroplast Nucleus 22 May 2019

Additional features found in plant and animal cells Ribosomes Ribosomes Ribosomes are important for the manufacture of proteins 22 May 2019

Additional features found in plant and animal cells Rough endoplasmic reticulum Ribosomes Ribosomes Rough endoplasmic reticulum Rough endoplasmic reticulum-involved in the modification and transport of proteins 22 May 2019

Additional features found in plant and animal cells Rough endoplasmic reticulum Ribosomes Ribosomes Vesicles Rough endoplasmic reticulum A membrane bound bag that contains fluid 22 May 2019

Nucleus Largest organelle. Controls the activities of the cell. Contains chromosomes. Chromosomes carry genes. The genes determine which proteins the cell can make. Nucleus 22 May 2019

Cell Surface Membrane Forms a boundary between the cytoplasm and the outside of the cell. Some chemicals can pass through this barrier and the cell can control what comes in and out. It is selectively permeable. Cell membrane 22 May 2019

Cytoplasm Jelly like substance which contains all of the organelles (e.g. nucleus and mitochondria). Many of the cell’s chemical reactions take place in the cytoplasm. These are called metabolic reactions. Cytoplasm 22 May 2019

Mitochondria Carry out some of the reactions of aerobic respiration. Therefore releasing energy for the cell. Cells that have a high demand for energy usually have many mitochondria, such as muscle cells. Mitochondria 22 May 2019

Cell Wall Found only in plant cells. It is made of a non-living material called cellulose. Helps the cell keep its shape. It is freely permeable. Cell wall 22 May 2019

Chloroplast Found in some plant cells. Contains chlorophyll. Chlorophyll is a green pigment. It absorbs light energy to make food in the process of photosynthesis. Chloroplast 22 May 2019

Vacuole Found only in plant cells. Filled with cell sap. Cell sap is a store of dissolved sugars, mineral ions, and other solutes. Helps keep the cell’s shape. Vacuole 22 May 2019

Rough endoplasmic reticulum A membrane bound structure that is important for the modification and transport of proteins. The RER is encrusted with ribosomes Ribosomes Small organelles that can be free floating in the cytoplasm or bound to RER. Important for the synthesis of proteins Vesicles Membrane bound bags that contain fluids or chemicals 22 May 2019

Summary Cell structures and their functions Plant or animal cell Function Nucleus Both Controls the activity of the cell using genes Cell Membrane Cytoplasm Mitochondria Cell Wall Chloroplast Large Vacuole Endoplasmic reticulum Ribosomes Vesicles 22 May 2019

Summary Cell structures and their functions Plant or animal cell Function Nucleus Both Controls the activity of the cell using genes Cell Membrane Controls what enters and leaves the cell Cytoplasm Location of cell metabolic reactions Mitochondria Site of aerobic respiration- cells such as sperm and liver cells have lots of these Cell Wall Plant only Made of cellulose, gives cell strength Chloroplast Site of photosynthesis Large Vacuole Contains cell sap which helps keep cell’s shape Endoplasmic reticulum Modification ad transport of proteins Ribosomes Synthesis of proteins Vesicles Membrane bound bags containing fluids 22 May 2019

IGCSE Biology (S2) 2 Specialized Cells 22 May 2019

Learning Objectives Can you explain the organisation of an organism using the following terms: organelles, cells, tissues, organs and organ systems? 22 May 2019

Cell Division Multicellular organisms begin life as a single fertilised egg cell called a ZYGOTE. It then divides over and over again by MITOSIS Zygote Embryo 22 May 2019

Differentiation As the developing embryo grows, cells become specialised to carry out particular roles. This is called differentiation and is controlled by genes. As all cells have the same genes, some must be switched on and some switched off for this to work. This is discussed further in the IGCSE course. 22 May 2019

Specialised cells Here are a few examples of specialised cells that you will meet throughout the IGCSE Biology course. They will be mentioned briefly here as they will be explained fully in each relevant section. 22 May 2019

Specialized cells 22 May 2019

Specialized cells Ciliated cell Found in trachea and oviducts Specialised by its cilia- tiny hairs that move in waves Function- to move mucus along the trachea and to waft the ovum along the oviduct 22 May 2019

Specialized cells 22 May 2019

Specialized cells Root hair cell Found on the roots of plants Specialized by its protrusion that increases surface area Function- To absorb water and minerals 22 May 2019

Specialized cells 22 May 2019

Specialized cells Muscle Cell Found in muscles Specialized by its protein fibers found in the cytoplasm and their ability to contract Function- muscle contraction 22 May 2019

Specialized cells 22 May 2019

Specialized cells Red Blood Cell Found in plasma Specialized by a flattened disc shape, large surface area, lack of nucleus and haemoglobin content Function- to transport oxygen 22 May 2019

Specialized cells Xylem Found in the roots and stem of plants Specialized hollow tubes with no end plates, thickened with lignin (lignified) Function- to transport water and dissolved minerals 22 May 2019

Nerve cell (Neurone) Very long cell for carrying impulses around the body along its axon. Insulated by a myelin sheath to make the signal travel quicker. Dendron Cell body Axon Myelin sheath Dendrites Muscle 22 May 2019

Sperm cell Sperm cells have a tail for swimming. The head contains the genes from the father in the nucleus. The acrosome digests its way into the egg for fertilisation. Acrosome 22 May 2019 Tail Nucleus

Palisade cell This cell is found in the leaves of plants. It is packed full of chloroplasts for photosynthesis. It is a regular shape in order to pack many into the leaf. 22 May 2019

Tissues and organs Organelles are the individual parts that make up a cell, e.g. Membrane, nucleus Similar cells that are grouped together are called tissues- skin, muscle, blood Similar tissues working together form an organ- heart, lung, leaf Organs that work together to share the workload are called organ systems- circulatory, reproductive, digestive 22 May 2019

Organelles Cells Tissues Organs Organ Systems 22 May 2019

Some of the key major human organs 22 May 2019

These will all be covered in detail in the rest of IGCSE The 7 main organ systems Digestive Respiratory Circulatory Excretory Nervous Endocrine Reproductive These will all be covered in detail in the rest of IGCSE 22 May 2019

Division of Labour By working together organs are able to share the workload, we often refer to this as division of labour 22 May 2019

IGCSE Biology Magnification Calculate the magnification of an image 22 May 2019 Calculate the magnification of an image

Learning objectives Use the formula M= I/A Draw an image as seen under a microscope and calculate the mahgnification 22 May 2019

Magnification Calculate magnification if A is 10mm in width and B 30mm in width B A 22 May 2019

Magnification 1mm - 1000µm Calculate the magnification in micrometres of image B if it is 20cm at its longest point and the actual organism is 4.5cm B A 22 May 2019

Calculating magnification Draw an image as seen under a microscope and calculate the magnification 22 May 2019