Transcript Cells
Chapter 5 Inside the Cell Measuring Cell Size: • Most cells are too small to see with the naked eye • Cells are usually measured in micrometers because they are so small – Ex: Red Blood Cells 10 micrometers Unicellular Organisms • 1 Cell Organisms, this single cell performs all functions necessary for life • These organisms use cellular respiration to generate energy from food • Some algae can also use photosynthesis as a process to make their own food using sunlight Ex: Bacteria, Amoeba, Paramecium, Algae Multicellular Organisms • Made of many cells • Most likely evolved from unicellular organisms • Cells are specialized to perform specific tasks – Ex: not all plant cells can perform photosynthesis • Different cells come in different shapes and sizes Levels of Organization Cells Tissues Organs Systems Organisms Cells- the basic unit of all living things Tissues- similar cells working together to perform a specific function Ex: muscle tissue, brain tissue, blood, skin Organs- many tissues combined together that perform a specific function Ex: stomach, brain, kidney, leaf Systems- groups of organs working together Ex: Digestive System, Nervous System Organism- a group of organ systems working together Common Features of All Cells • Cell Membrane- encloses the cell and separates it from the outside environment • Cytoplasm- the material inside the cell membrane • Cytoskeleton- a system of microscopic fibers that support cell structures • Ribosomes- make proteins for the cell Prokaryote Cells • Prokaryotes are the smallest & simplest type of single celled organisms • Prokaryotes are single celled and have NO NUCLEUS • Prokaryotes are believed to be the 1st living things on earth – Ex: Bacteria Characteristics of Prokaryotes • Prokaryotes live in a wide range of conditions Ex: in the soil, water, animals • Cytoplasm- everything on the inside of the cell membrane • DNA- prokaryotes have a single circular loop of DNA • Cell Wall- protective outer layer that provides structure and support • Cell Membrane- thin, flexible layer just beneath the cell wall • Flagella- long threadlike tails that allow movement Prokaryotes Eukaryote Cells • Eukaryotes are more complex single and multicellular organisms • Eukaryotes have internal cell structures and have a nucleus • Eukaryotes are thought to have evolved from prokaryotes Characteristics of Eukaryotes • Eukaryotes contain many specialized structures called organelles • Cytoplasm- the fluid & organelles inside the cell membrane • Nucleus- contains the DNA in the cell, controls cell functions • Cell Membrane- surrounds the cell and controls movement of things into and out of the cell • Flagella- tail-like structure used for movement • Cilia- short hair-like structures used for movement Eukaryotes Cell Structures • The Cytoskeleton- provides an interior framework for an animal cell – Has a similar function to the skeleton in the human body – The Cytoskeleton is made of 3 types of fibers: • Actin Fibers- long slender strands of protein • Microtubules- hollow tubes made of tubulin, that transmit information from the nucleus to different parts of the cell • Intermediate Filaments- thick ropes of protein that provide structural support inside the cell and hold cell parts in place The Cytoskeleton The Cell Membrane • The cell membrane surrounds the cell and acts as a barrier between the inside and outside of a cell • Selectively Permeable- only certain substances are allowed to enter and leave the cell through the cell membrane Cell Membrane Cell Parts • Organelles- structures inside the cell that perform specific functions The Nucleus • Control center of the cell • Instructs all other cell parts what to do • Contains chromosomes made of DNA • Nuclear Envelope- membrane that surrounds the nucleus – Contains pores“holes” that allow substances into and out of the nucleus • Nucleolus- central core of the nucleus that makes ribosomes The Nucleus Ribosomes • Ribosomes make proteins for the cell – Free Ribosomes: are scattered throughout the cytoplasm – Attached Ribosomes: are located on the surface of the rough endoplasmic reticulum Endoplasmic Reticulum(ER) • The ER is a system of folded membranes found near the nucleus • The ER transports proteins throughout the cell • Smooth ER- has no ribosomes on it’s surface • Rough ER- has ribosomes on it’s surface Endoplasmic Reticulum Golgi Apparatus • The Golgi is a flattened membrane of sacs found in the cytoplasm • The Golgi packages & distributes materials inside the cell using vesicles • Vesicles- small sacs that hold and carry substances in the cell Golgi Apparatus Processing Proteins Lysosomes • Lysosomes are small, spherical organelles containing digestive enzymes • Lysosomes break down food molecules & toxins inside the cell Mitochondria • The mitochondria is a bean shaped organelle found throughout the cytoplasm • The mitochondria produces energy(ATP) • The “Powerhouse” of the cell * Mitochondria have their own DNA inside Centrioles • Animal cells contain 2 pairs of centioles • Centrioles are responsible for coordinating cell division(mitosis) Plant Organelles • Cell Wall- protective outer membrane – Supports and maintains cell shape – Made of a material called cellulose Plant Organelles • Chloroplasts- use light(solar) energy to make food for plants – Contain a green pigment called chlorophyll Plant Organelles • Central Vacuole- a large water, mineral, and waste storage chamber in plant cells – The vacuole takes up a very large area in a plant cell Plant Organelles END OF CHAPTER 5 NOTES!!!