SBI3UI Genetics - Cell Structure and Function PDF

SBI3UI: Genetics - Review: Cell Structure and Function Biology – The study of living things. How do we know that something is living? All Living Things: 1) Grow and Reproduce 5) Respond to the Environment 2) Respire 6) Can Heal and R...

SBI3UI: Genetics - Review: Cell Structure and Function Biology – The study of living things. How do we know that something is living? All Living Things: 1) Grow and Reproduce 5) Respond to the Environment 2) Respire 6) Can Heal and Repair Themselves 3) Produce and Excrete 7) Have a Limited Lifespan Waste 4) Require Food for Energy What is the basic, self-contained unit of living organisms? ​ the cell How and when did we learn of the cell? ​ Only a few hundred years ago, it was believed that living things spontaneously generated from non-living matter. We now know better… The Cell theory lays out the basic rules that apply to the smallest unit of life. The classical interpretation of the Cell Theory states: ​ All living organisms are composed of cells. Organisms may be unicellular or multicellular. ​ The cell is the structural and functional unit of life. ​ Cells arise from pre-existing cells. The modern version of the Cell Theory includes the ideas that: ​ Energy flow occurs within cells. ​ Heredity information (DNA) is passed from cell generation to cell generation. ​ All cells have the same basic chemical composition. SBI3UI: Genetics - Review: Cell Structure and Function What else should we recall about cells? ​ Cells come in many sizes, types, lengths, shapes etc. ​ Cells are made up of tiny structures (organelles) that work together to form tissues, organs and organ systems and organisms. Cells are of 2 Major Types: Prokaryotes & Eukaryotes ​ Prokaryotes (Bacteria & Archaea) – Have ribosomes but do not have membrane-bound organelles like a nucleus. They evolved earlier and have simpler cellular machinery. ​ Eukaryotes (Animals, Plants, Fungi & Protists) – Have membrane-bound organelles. They evolved later and have more complex cellular machinery. ​ Humans are eukaryotes → made up of 10 trillion body cells → 100 trillion prokaryotic cells live on your skin and in your digestive system Cells are limited to how large they can grow. The cell size to volume ratio determines how efficiently materials nutrients and waste can travel in and out of a cell to support the function of each organelle. The larger the cell, the more volume of organelles that must be supported and the surface area cannot support it. Transport of materials like glucose (for energy), amino acids (to build proteins), oxygen and carbon dioxide across a cellular membrane is a complex process. Cells are protein factories. It is these proteins that make all living things different. Each living thing can make thousands of different types of proteins. Remember, the recipes for making the proteins are all stored in the genes in a cell’s nucleus. Our cells make hair, haemoglobin, antibody, melanin, enzyme and eye colour proteins. SBI3UI: Genetics - Review: Cell Structure and Function The Structure of a Typical Eukaryotic Cell Instructions: Use the information below and your resourcefulness to colour the animal cell correctly on the next page. Every cell in your body has at least one special function (job to do). A few examples: the cells in the outer layers of your skin are designed to protect you from your external environment (epithelial cells); certain cells in your stomach make chemical substances to digest the food you eat (parietal cells make HCl), and other cells are specially designed to carry electrochemical impulses that make your muscles contract (neurons). Even though your body cells have different functions, certain aspects of their internal anatomies (structures) are similar. While completing this worksheet, you will learn the internal anatomy/function of a generalized cell. The function of the nucleus is to act as the control center of the cell. The nucleus of each somatic human cell contains 46 chromosomes, which store instructions for the cell’s activities. For most of the cell cycle, the chromosomes look like threads, called chromatin. The nucleus is the most obvious structure in the generalized cell. The following diagram shows the nucleus and the chromatin. Colour the nucleus brown. Colour the chromatin blue. One of the ways the nucleus directs cellular activity is by sending instructions through mRNA to the ribosomes, where proteins are assembled. Colour the ribosomes dark green. Ribosomes receive instructions from the chromosomes by molecules called ‘messenger RNA’ (mRNA). A round structure found within the nucleus assists in the production and storage of RNA. This round structure is called the nucleolus. The diagram on the next page shows the nucleolus. The mRNA exits the nucleus through pores (holes) in the nucleus and travels to the ribosomes in the cytoplasm. Colour the nucleolus yellow. Colour the nuclear pores pink. Once proteins are made, they are sometimes transported through the cells by a system of tubules called the endoplasmic reticulum (ER). There are 2 types of endoplasmic reticulum. The walls of the rough endoplasmic reticulum are studded with ribosomes. Picture the rough ER as a subway tunnel with ribosomes mounted on the inner walls of the tubes. (Colour the ribosomes dark green here too!) Colour the endoplasmic reticulum(s) blue and the ribosomes dark green. SBI3UI: Genetics - Review: Cell Structure and Function The endoplasmic reticulum delivers many types of proteins to the Golgi body. (The Golgi body is also known as the Golgi apparatus or the Golgi complex.) The function of the Golgi body is to coat the protein with a special molecular layer that allows the protein to leave the cell. Once it leaves the cell it will be transported through the bloodstream to other places in the body to help the body to perform the functions necessary for life. Colour the Golgi body yellow. Lysosomes contain chemical substances called ‘enzymes’. Lysosomes use these enzymes to break proteins down into their building blocks, the amino acids. As protein enters the cell, it attaches to a lysosome. The amino acids that results from the breakdown of the protein are used by ribosomes to make new proteins. Colour the lysosome purple. Vacuoles are large storage sacs where incoming nutrients are stored before they are broken down by lysosomes. The following diagram shows what a vacuole looks like. Colour this vacuole orange To assemble proteins and to perform other functions, the cell uses energy. The mitochondria acts like a power house: that is, they produce energy in the form that the cell can use. The following diagram shows what a mitochondrion looks like. (singular= mitochondrion; plural= mitochondria) Colour the mitochondria red. Plant cells have a few extra organelles. Cell walls allow plants to have strength and structure and to allow certain molecules in and out. Chloroplasts are the site of photosynthesis and allow plants to capture the energy of the Sun to create energy-rich molecules – to make their own food! Colour the cell wall grey Colour the chloroplasts light green SBI3UI: Genetics - Review: Cell Structure and Function SBI3UI: Genetics - Review: Cell Structure and Function Formative Questions: Answer the questions below to check your understanding 1. The cell is the functional and structural building block of the body. 2. How are certain cells of your stomach specialized? Specialized to break down food → release enzymes and hydrochloric acid (HCl) 3. The nucleus is the control center of the cell. 4. How many chromosomes are in each human cell? 46 5. What is one function of the chromosomes? hold hereditary information, get copied [correctly], instructions 6. Where are proteins assembled (made)? ribosomes 7. Where is RNA manufactured? nucleolus 8. Describe the function of messenger RNA. transport DNA instructions to ribosomes for protein synthesis 9. What structure transports proteins? Why? endoplasmic reticulum (ER) 10. What is the function of the Golgi body? modify and package proteins for transport out of the cell 11. Lysosomes contain chemical substances called enzymes. 12. Lysosomes use their enzymes to break proteins into amino acids. 13. The ribosomes use these amino acids to assemble new proteins. 14. Vacuoles are storage sacs. 15. Incoming nutrients are stored in vesicles or vacuoles before they are broken down. 16. To assemble proteins and perform other functions the cell uses/needs energy (ATP). 17. Mitochondria produce energy in the form that the cell can use. (ATP) 18. Create a Venn Diagram of the organelles, similarities and differences of a Plant and Animal Cell. ​ Animals Both Plants SBI3UI: Genetics - Review: Cell Structure and Function 19. Create a chart to summarize the structures and functions of cell organelles. Organelle Function/Location Found In Nucleus Control centre of the cell (directs all the cells activities) Both Holds the genetic information (DNA) Enclosed in a double membrane Nuclear pores Holes in the nuclear membrane that allow materials to move in/out of the nucleus Both Selectively permeable - only lets some material enter/leave Nucleolus Structure found inside the nucleus that is responsible for making ribosomes Both Cell Membrane Controls the movement of materials into and out of the cell Both Thin - easier/faster to move material across the membrane Selectively permeable - only lets some material enter/leave Cell Wall Controls the movement of materials into and out of the cell Plant Cells Provides support for the cell Allows for turgor pressure (pressure from water) Cytoplasm Supports all cell organelles Both Jelly-like to allow for fluidity of cell organelles Mitochondria Provides energy from the glucose molecules within the cell to fuel cell activities Both CELLULAR RESPIRATION (convert food → energy) Golgi Assembles, packages, and stores proteins Both Apparatus Composed of several tubes that can pinch off to enclose proteins Cytoskeleton Framework for the cell, helps maintain structure and provides “tracks/highways” for Both vesicles to move Endoplasmic Series of canals connected to nucleus that carries materials through the cell Both Reticulum Rough ER has ribosomes on it & smooth ER lacks ribosomes (ER) Ribosomes Produce proteins Both Small dots, some float in cytoplasm, some are attached to the ER Vesicles Transport and/or stores materials inside the cell; sometimes helps materials cross the cell Both membrane -​ Fuse to the membrane and release contents to inside or outside of cell Have a membrane (similar to a cell membrane) which is what allows it to fuse to the membrane Lysosome Contains enzymes that break down large molecules and old cell parts Both Chloroplast PHOTOSYNTHESIS: Use the sun’s energy to make food (in the form of sugar) for the plant Plant Cells Contains chlorophyll - a colour pigment that is responsible for trapping the sun's energy Vacuole Storage container for water, waste, and food Both May be used to transport molecules (but Plant cells have 1 large vacuole different) Animal cells have many smaller vacuoles Centrioles Involved in animal cell reproduction Animal Cell They grow spindle fibres that pull chromosomes apart (but few Two of them in each cell - their movement to opposite poles of the cell start mitosis (cell plant) reproduction)