Notes for Unit 2: Cells - Cell Theory, Microscopes, and Organelles - PDF

UNIT 2: CELLS Main Idea: cells are the basic unit of LIFE Learning strands for unit 2: Appreciate the development of the CELL THEORY Types of microscopes, microscope parts and functions Cell structures and functions Prokaryotic vs Eukaryotic cells Cell specialization for ob...

UNIT 2: CELLS Main Idea: cells are the basic unit of LIFE Learning strands for unit 2: Appreciate the development of the CELL THEORY Types of microscopes, microscope parts and functions Cell structures and functions Prokaryotic vs Eukaryotic cells Cell specialization for obtaining nutrients through photosynthesis Harnessing the energy in nutrients through cellular respiration Sexual and asexual reproduction Unicellular vs multicellular organisms Life Unit B - p. 10-21 Science 11 Study You are responsible for guide reading this material and making your own notes. Cell Theory  All living things are composed of one or more cells Cells are the fundamental unit of life (building blocks) New cells arise from the division of pre- existing cells Cell Cells come in many shapes and sizes Theory – although most are microscopic Most cells are around 0.001 cm (1/100 of a mm or 10 μm) Humans are composed of about 50- 100 trillion cells Microscopes The study of cells is made possible by MICROSCOPY. The study of cell structure is called CYTOLOGY (for cells) and HISTOLOGY (for tissues). The study of the function of the cell is called cell physiology, biochemistry and cytogenetics. First microscope.. Was used by Antoine Van Leeuwenhoek to look at th animals in water 17 century, Dutch Types of Microscopes 1) Compound light microscope – maximum revolving power of 200nm (maximum magnification is around 1000x). Uses light rays to view specimens. REVOLVING POWER – is the ability to distinguish between 2 adjacent points 2) Transmission Electron Microscope: maximum resolving power of 0.5nm (around 30,000X). Uses electrons to view preserved tissue. Used to view the internal details of the cells. 3) Scanning Electron Microscope: gives vivid 3D images but has less magnification than transmission EM Coronavirus Difference between EM and SEM... Know how to use a microscope... Complete worksheet on microscope parts and function and learn how to do a proper microscope drawing. Activity: Use a microscope to find organisms on slides given Assignment: Draw proper microscope drawings of 2 organisms. (20 marks) Video to help with getting actual size … Video's on TOUR OF CELLS Make your own notes on the organelles. Cell structures … Cell Membrane Also known as plasma membrane A flexible boundary that controls the movement of substances into and out of the cell Cytoplasm: The environment inside the plasma membrane It is made up of semifluid material All of the chemical processes in the cell occur in the cytoplasm Cytoskeleton: Supporting network of long, thin protein fibers (microfilaments) that form a framework for the cell and provide and anchor for the organelles in the cells Helps with cell movement and other cellular activities  Found in Eukaryotic cells Directs the processes in the cell - managing structure Contains most of the cell's DNA (chromatin) - which stores information Nucleus to make proteins that are responsible for cell growth, function and reproduction Nuclear envelope is a double membrane that encloses the nucleus Nucleolus in the nucleus is responsible for making some ribosomes Ribosomes Used to make proteins that are used by the cell or by other cells Found attached to rough endoplasmic reticulum or free floating  A highly folded membrane that is the site of protein synthesis Endoplasmic reticulum Two types of ER Rough endoplasmic reticulum - has ribosomes attached to it Smooth endoplasmic reticulum - does NOT have any ribosomes attached to it  Some ERs are responsible for the production of specific molecules such as hormones. When the hormones are produced in large numbers, they are sent out in vesicles to the Golgi bodies Golgi bodies process the hormones before they are sent out of the cells by secretory vesicles. This is also known as exocytosis. The secretory pathway Golgi apparatus A flattened stack of tubular membranes that modifies proteins and packages them for distribution outside the cell Vacuoles A membrane bound vesicle for the temporary storage of materials Animal cells have a few smaller ones and plant cells have a large one called a central vacuole. Plant cell vs animal cell Lysosomes A vesicle that contains digestive enzymes (called hydrolytic enzymes) for the breakdown of excess or worn-out cellular substances Lysosomes Centrioles Organelles that occur in pairs and are important for cell division Only found in animal cells Mitochondria A membrane bound organelle that makes energy available to the rest of the cell Chloroplast A double membrane bound organelle that contains chlorophyll Photosynthesis occurs here Only found in plant cells Cell wall An inflexible barrier that provides support and protects the plant cell  Cilia and flagella Projections that aid in locomotion and feeding Compare and contrast animal and plant cells Prokaryotic vs Eukaryotic cells Prokaryotic cells - bacteria and archaea cells Do not have a NUCLEUS Lack membrane bound organelles All metabolic functions occur in the cytoplasm Are very tiny - around micrometer Eukaryotic cells All other cells from Animals, plants, fungi and protists Contain a true nucleus and membrane bound organelles A bit more efficient, diverse and specialized than prokaryotic cells 100 times larger than prokaryotic cells Prokaryotic vs Eukaryotic cells video...  What is the difference between autotrophic and heterotrophic organisms? How do Autotrophs – produce their own cells nutrients using energy in the environment (Sun light). For obtain example, plants produce glucose. Heterotrophs - rely on ingesting nutrients? or absorbing nutrients. Examples are fungi and you (and all other animals)  Nutrients come in by endocytosis – food particles become surrounded by cell How do membrane to form food vacuoles. heterotrophic Later, food vacuoles merge with cells "eat"? lysosomes that have digestive enzymes, and the food is broken down and the nutrients are kept and used in the cell.  Use sunlight and photosynthesis to produce sugar What are They contain chlorophyll in photosynthetic organelles called chloroplast autotrophs? There are many types of chlorophyll and plants use the ones that are useful to them  What happens during photosynthesis? Energy is absorbed by the chlorophyll and glucose molecules Photosynthesis: are built using carbon dioxide and water Photosynthesis  Do not rely on sunlight How do Live in harsh environments Chemosynthetic like a volcanic vent autotrophs get their energy? They can harness energy from sulfur-containing molecules Bacteria that undergo chemosynthesis  What is cellular respiration? Once cells have nutrients, they must be able to break them down to access the stored energy. Cellular Cellular respiration is a process Respiration that occurs in the mitochondria that produces ATP (adenosine triphosphate). When ATP is broken down, energy is available for the cell. Equation for cellular respiration Cellular respiration  During glycolysis, glucose is broken down into a 2-carbon molecule Then the 2-carbon molecule enters the mitochondria, and it is metabolized by enzyme complexes on the inner membrane to produce ATP (energy molecules) This is known as AEROBIC respiration as it needs oxygen. Carbon dioxide and water are released as waste.  Some Prokaryotic cells do not have mitochondria and function anaerobically. Obligate aerobes - need oxygen Obligate anaerobes - cannot live in the presence of oxygen Facultative anaerobes - can live in the presence or absence of oxygen  To replace dead or damaged cells Why do To grow cells need The two types of cell division to that occur in cells: reproduce? Mitosis Meiosis Asexual Reproduction Also known as binary fission During this process chromosomes replicate and then the cell divides into two genetically identical daughter cells  No contribution of genetic material from another cell/organism When environmental conditions are favorable, most unicellular organisms go through binary fission Can mass produce quickly  Involves the mixing of genes from two organisms which means it may take longer and may produce fewer offspring Sexual New cells are genetically different from each other and reproduction parents In unicellular organisms, this is called Conjugation Produces variants in structure, ability or appearance which can help their survival  Meiosis is required. At the end of meiosis, each gamete (sperm and egg) will have half the number of chromosomes (haploid). During fertilization, the gametes fuse and produce zygotes that are different Chances of mutations are high as the genes/chromosomes are replicated, there are many chances for incorrect base pairing. This is the reason for genetic variation. ○ Chances of mutations are high as the genes/chromosomes are replicated, there are many chances for incorrect base pairing. This is the reason for genetic variation. Sexual Vs Asexual Reproduction  Unicellular organisms: Prokaryotic – bacteria and Unicellular archaea bacteria vs - simple organisms and Multicellular their protoplasm are not Organisms compartmentalized – no membrane bound organelles and do not have a nucleus. Unicellular organisms  Eukaryotic – protists such as paramecia, amoeba and euglena a little bit more elaborate with a nucleus and have membrane bound organelles.  Made up of millions of eukaryotic cells Contain organelles and a nucleus Multicellular Cells are organized into tissue, organisms organs and organ systems Can grow very large and are highly complex Have more sophisticated adaptations and abilities  Organisms started living within another organism and eventually became an effective team that could not be separated UNIT 2 REVIEW Make sure you understand the cell theory Make sure you know who discovered the microscope and the three different types Make sure you know how to use a microscope, it's parts and functions and how to draw biological drawings Know the organelles found in animal and plant cells  Know the difference between Prokaryotic and Eukaryotic cells Know how different cells obtain energy – know difference between photosynthesis, chemosynthesis and cellular respiration Know why cells reproduce and the difference between sexual and asexual reproduction Know the difference between unicellular and multicellular organisms Know the endosymbiont hypothesis Try the review on p. 20/21 of workbook (#1-18) Make your own notes including the KEY TERMS