Presentation on theme: "Cells: The Basic Units of Life"— Presentation transcript:
1 Cells: The Basic Units of Life Ms. Samuelian 2011
2 Cells: Starting out small Most cells are too small to be seenNot all of your cells look and act the sameEach type is specialized to do a particular job (e.g. bone cells, blood cells, skin cells)The first cell of a chicken is one of the largest cells in the world.
3 Tissues: Cells Working in Teams When you look closely at your clothes, you can see that threads have been grouped together (woven) to make cloth that has a functionCells are the basic units of life. They are grouped together to make a tissue that has a functionA tissue is a group of cells that work together to perform a specific job in the body.
4 Organs: Teams Working Together When two or more tissues work together to perform a specific job, the group of tissues is called an organExamples: stomach, intestines, heart, lungs, and skinThe skin is the body’s largest organ.
5 Organ Systems: A Great Combination Organs work together in groups, called organ systems, to perform particular jobs.The organs in an organ system depend on each other – If any part of the system fails, the whole system is affected.Your body has several organ systems (e.g. nervous system, digestive system)
6 Did you know…?Your digestive system’s job is to break down food into very small particles so it can be used by all of your body’s cells.Your nervous system’s job is to transmit information back and forth between your brain and the other parts of your body.There are 11 main organ systems.
7 Organisms: Independent Living Anything that can live on its own is called an organismAll organisms are made up of at least one cellIf a single cell is living on its own, it is called a unicellular organismYou are a multicellular organism because you can exist only as a group of cells and most of your body cells can survive only is they remain a part of your body
8 The Big PictureA group of organisms that are of the same kind and that live in the same area make up a populationTwo or more different populations living in the same area make up a communityThe community and all of the nonliving things that affect it (water, soil, rocks, temperature, light) make up an ecosystem
9 The Cell Theory All living things are composed of one or more cells The cell is the basic unit of life in all living thingsNew cells are produced from existing cells
10 Cell SimilaritiesAll cells are surrounded by a cell membrane, which acts as a barrier between the inside of the cell and the cell’s environment.All cells have organelles, which are chemicals and structures that enable the cell to live, grow, and reproduce.
11 Two Types of CellsProkaryotic cells (also called bacteria) are the world’s smallest cells and they do not have a nucleus or any other membrane- covered organelles.Eukaryotic cells are 10 times larger than prokaryotic cells. They have a nucleus and many other membrane-covered organelles. All living things that are not bacteria are made of one or more eukaryotic cells. This includes plants, animals, and fungi.
12 Prokaryotic Cells Eukaryotic Cells No nucleusNucleusNo membrane-covered organellesMembrane-covered organellesCircular DNALinear DNABacteriaAll other cells (not bacteria)
13 Eukaryotic Cells- Cell membrane All cells are covered by a cell membrane. The job of the cell membrane is to keep the cytoplasm inside, to allow nutrients in and waste products out, and to interact with things outside the cell.
14 Cell Wall The cell wall provides strength to support the cell membrane For example, the strength of billions of cell walls in plants enables a tree to stand tall and its limbs to defy gravity
15 Nucleus: The Cell’s Library The largest and most visible organelle in a eukaryotic cell is the nucleusIt is the control center of the cellIt stores the DNA
16 Protein Proteins are the building blocks of all cells They are made of chemicals known as amino acidsThese amino acids are hooked together to make proteins at very small organelles called ribosomesAll cells have ribosomes because all cells need protein to live
17 Cells need energy, too! Mitochondria Chloroplasts Cells need energy to function and liveWhere do they get it from?MitochondriaChloroplasts
18 MitochondriaInside all cells, food molecules are “burned” (broken down) to release energyThe energy is transferred to ATP (a special molecule that the cell uses to get work done)ATP is mostly made in a bean-shaped organelle called mitochondriaMitochondria need oxygen to workThe reason you breathe air is to make sure your mitochondria have the oxygen they need to make ATP
19 ChloroplastsPlants and algae have an additional kind of energy-converting organelle called a chloroplastThe word chloroplast means “green structure”They contain an important chemical called chlorophyllChlorophyll is what makes chloroplasts green and also what makes a chloroplast a power plant for the cellThe energy of sunlight is trapped by chlorophyll and used to make sugar (photosynthesis)The sugar produced is usedby mitochondria to make ATP
20 The Cell’s Packaging Center When proteins and other materials need to be processed and shipped out of a eukaryotic cell, the job goes on to an organelle called the Golgi complexThe Golgi complex processes, packages, and transports material
21 Organelles and Their Functions NucleusContains the cell’s DNA and is the control center of the cellRibosomeThe site where amino acids are hooked together to make proteinsMitochondriaBreak down food molecules to make ATPChloroplastMake food using the energy of sunlightGolgi complexProcesses and transports materials out of the cell
22 Plant or Animal?They both have a cell membrane, nuclei, ribosomes, mitochondria, endoplasmic reticula, Golgi complexes, and lysosomesBut plant cells have things that animal cells don’t have: a cell wall, chloroplasts, and a large vacuole
23 Review How does the nucleus control the cell’s activities? Which of the following would not be found in an animal cell: mitochondria, cell wall, chloroplast, ribosome, endoplasmic reticulum, Golgi complex, vacuole, DNA, chlorophyll?Use the following words in a sentence: oxygen, ATP, breathing, and mitochondria.
24 Discussion QuestionsWhat is the structure of the nucleus? What is the function of the nucleus?Why do cells divide?Describe the process of mitosis.What is cytokinesis?What is the role of mitochondria?What is the role of chloroplasts?Describe the process of photosynthesis.