In This Section We Will Be Studying The Following Topics: CELLS In This Section We Will Be Studying The Following Topics: Is it alive? The tiny parts of life. What are cells? Do cells have special jobs? What is a microscope and how do we use one? Why do we need to magnify cells? What do cells look like? Are plant and animal cells different? What jobs can cells do? What can these tiny things build up into? How do new cells get made?

OUT OF THIS WORLD We could ask some questions! You are a Chief Scientist for NASA. How can you work out if an object is alive? We could ask some questions! Could you work out if a newly found object was living or not?

Living or Non-living? That is the question! Sort the objects into the table: Living Non-Living Car table pen fire book bones Fly fish tree When you are doing this think about the ways that objects give clues. This helps us place them in the right box.

LIFE PROCESSES MRS NERG ‘REMEMBER’. Can it Move all or part of its body? Can it Reproduce to make offspring? Is it Sensitive – can it respond to its surroundings? Does it need to feed - is Nutrition vital for it? Does it need to Excrete waste products? Does it need to Respire to produce energy? Does it need to Grow?

MATCH THE PICTURE TO THE PROCESS BEING CARRIED OUT Movement. Reproduction. Sensitivity. Growth. Respiration. Excretion. Nutrition. Excretion means getting rid of waste. Movement means Running. Sensitivity means feeling the heat of the bottle. Reproduction means having a baby. Respiration means using oxygen and food to make our cells produce energy. Growth means getting bigger and making new cells. Nutrition means eating food to make our bodies work.

THE TINY PARTS OF LIFE Cells are the smallest parts of living things. All living things are made of cells. For example, the human body is made up of more than 10 million, million cells. All cells respire this means they take in oxygen and give out carbon dioxide. Cells take in food, get rid of waste, grow, reproduce and die. Big living things don’t have bigger cells, they just have more cells.

MICROSCOPES Microscopes enable us to see things that are very small. We need to use a microscope to see cells. Animal cells are smaller than plant cells and we cannot see them without MAGNIFYING them. The parts of the microscope are shown below. Objective lens. There can be more than one of these. Eyepiece lens. Focussing knob. This moves the stage up and down. Stage. This is where we place the object we want to look at. Safety – always carry your microscope with two hands

WHO INVENTED THE MICROSCOPE? Read the information about the scientists below, then put them into the correct order on the timeline. You may need to do more research to do this. Robert Hooke: This English chemist built the first compound microscope and used it to observe cork. He saw tiny compartments in it and named them cells. Flea Glasses: The earliest microscopes were a tube with a plate for the object at one end and a magnifying lens at the other end. Theodor Schwann: This German zoologist said that all animals were made of cells. Matthias Schleiden: This German botanist said that all plants were made of cells. Zacharias and Hans Janssen: They invented the forerunner to the compound microscope. It had a magnifying lens at both ends of the microscope tube. Antony van Leeuwenhoek: This Dutchman invented a microscope that could magnify things more than 200 times. 1500 1600 1700 1800 1900

ANIMAL CELLS These are the three main parts of an Animal Cell: Important: An animal cell does not have a Cell Wall Controls all cell activity. This is where the genetic information is stored. This is where all of the chemical reactions take place. It is a jelly-like substance. This controls what enters and leaves the cell.

These are the parts of a plant cell: PLANT CELLS These are the parts of a plant cell: This contains the green pigment ‘chlorophyll’. It absorbs sunlight for photosynthesis. This controls what enters and leaves the cell. This controls all cell activity. This is a bag-like structure that contains cell sap. This keeps the cell rigid. It is made of cellulose. This is a jelly-like substance and all of the chemical reactions take place here.

PLANT AND ANIMAL CELLS Some parts of the cell are the same in both plant and animal cells: Plant Cells. Animal Cells. Nucleus. Cell Membrane. Cytoplasm. Chloroplast. Cell Wall. Why are animal cells not green in colour? They do not have any chloroplasts with chlorophyll in them.

CELLS AS BUILDING BLOCKS Cells cannot do very much on their own. They need to join with other cells to make bigger structures. Cells join with other cells to make tissues. The heart is an organ Tissues join together to make an organ. Your body contains lots of different organs and these organs work together in organ systems. Can you think of examples to go with each of these statements?

CELLS AS BUILDING BLOCKS Nerve cell Can you think of other examples to go with each of these statements? Nerve tissue The Brain is an organ made of nervous tissue What about muscle tissue? What is it made of? The nervous system contains our brain and spinal cord

Different tissues make organs We need our hands to move. Hands are made up of different kinds of tissues. Can you think of at least three types of tissue in a hand ? Nerves Bone Muscles Tendon Skin TASK. Use the Internet or books to explain what each tissue does in this organ.

OTHER SPECIAL CELLS Task Look at the microscope images. Read the following information then complete the statements. Microscope slide A B Animals have a special layer of cells that protects organs. These are usually flat and fit together in large blocks. This protects the surfaces they cover. Plants have surface cells to protect the leaves. These are also in blocks. The animal cells are called epithelial cells. The plant cells are called epidermal cells. Plant cells have a much more regular shape because of the cell walls. Plants cells are usually much bigger than animal cells. B A The plant cell = slide ____ The animal cell = slide ___

OTHER SPECIAL CELLS Discuss this ….. This sphere is an egg cell, it contains half of the information and all of the food stores to make a baby. What do you think the very small cell that is moving towards the egg cell is? A sperm cell The round purple circle we see is a plant egg cell. Around it are pollen grains. They are the male sex cells in plants. Discuss this ….. Why are plant and animal sex cells similar in all living things?

CELLS AND THEIR JOBS Which one is which? B C A D E F Cells come in different shapes and sizes. They have to be the right shape for the job they have to do. Here are some pictures of different cells. On the next slide you will have a list of job descriptions to choose from and you may need to look at the pictures again to help you. B C A D E F Which one is which?

WHAT’S MY JOB? Job Description 1. A - root hair cell I can absorb water from the soil. I am very long and can stretch a long way through the soil. I am only found in plants. Job Description 1. A - root hair cell Job Description 2. I am a very long cell. In a human I can stretch from the hip right down to the feet. I carry messages around the body very quickly. Job Description 2. D – the nerve cell Job Description 3. My shape is very bendy so that I can travel around the body quickly and easily. I carry oxygen and take it to the cells. My shape is like a doughnut. I have dents in both of my sides. These make my surface even bigger. Job Description 3. B – the red blood cell

WHAT’S MY JOB? Job Description 4. E- the sperm cell Job Description 5. I carry the information needed to make a baby. I have a large head and a very long tail. My tail helps me to move quickly. I have a large nucleus. Job Description 4. E- the sperm cell Job Description 5. I am a large cell with a large nucleus. I am used to protect your body from infection. I can get rid of bacteria by digesting them. Job Description 5. F – the white blood cell Job Description 6. I am a tall cell. I have lots of chloroplasts and they trap sunlight for photosynthesis. I have a nucleus, a cell membrane and a cell wall and a big, bag-like structure in the middle of me called a vacuole. I am only found in plants. Job Description 6. C – the plant cell

Look at the things listed below. Can you make any links between them? LET’S THINK! Look at the things listed below. Can you make any links between them? Nerve. Sperm. Root hair cell. Has a long tail. Carries messages around the body. Absorbs water and minerals. Very long, stretches throughout the body. Swims to meet the egg for fertilisation. Long and thin, can stretch into the soil.

MAKING NEW CELLS Cells can divide to make new cells. The cells in the nucleus make a copy of themselves and then divide. The divided nucleus moves apart and the cell splits across the middle to make two new cells. The two new cells are identical to the starter cell.

MAKING NEW CELLS Two sex cells can join to make new organisms. There is a lot more about this in the next topic 7B. Sperm and (Ovum) Egg cell. Pollen and Egg cell. There are lots of egg cells in the plant. They are all in a place called the ovule. This is one egg cell with lots of sperm cells around it.

CHECK YOUR LEARNING Have you met you learning targets? Is a fossil alive? What are cells? Can you name five special cells? What is a microscope? Why do we need to magnify cells? Can you put organs, cells, tissues and organ systems in the right order?

CHECK YOUR LEARNING ANSWERS A fossil is non-living. They are the tiny building block of living things. Plant cell, blood cell, nerve cell, sperm cell, egg cell, root hair cell, pollen and many more! A microscope is used to magnify very small objects. Cells are too small to see with our eyes so we need to magnify them so that they are large enough to see. The correct order is CELLS TISSUES ORGANS ORGAN SYSTEMS.