CELL BIOLOGY CELL STRUCTURE FUNCTION Chapter 4 CELL
CELL BIOLOGY
CELL STRUCTURE & FUNCTION Chapter 4
CELL (Plasma) MEMBRANE • Holds contents inside
CELL MEMBRANE • Controls what enters and leaves cell
FLUID MOSAIC MODEL Image from: http: //bio. winona. msus. edu/berg/ILLUST/memb-mod. jpg
CELL MEMBRANES are mainly PHOSPHOLIPIDS POLAR HEAD“hydrophillic” 2 NON-POLAR TAILS“hydrophobic”
WATER INSIDE CELL Water WATER OUTSIDE CELL
Cell membranes form because the hydrophobic tails are trying to stay away from water!
CELL MEMBRANE BILAYER Made of PHOSPHOLIPIDS & PROTEINS
MEMBRANE PROTEINS Image modified from: http: //bio. winona. msus. edu/berg/ILLUST/Bil&mem 3. jpg PERIPHERAL ________ stick only on the SURFACE of the membrane Can be on inside or outside of cell
MEMBRANE PROTEINS INTEGRAL _______ proteins that stick into the membrane Can go part way OR all the way through Image modified from: http: //bio. winona. msus. edu/berg/ILLUST/Bil&mem 3. jpg
OTHER MOLECULES in MEMBRANES GLYCOPROTEINS ___________ Proteins with carbohydrates attached Function in cell recognition Organ donors Foreign invader ID
OTHER MOLECULES in MEMBRANES STEROIDS ___________ Lipids made with carbon rings STRUCTURAL Fit between hydrophobic tails of phospholipids
SELECTIVELY PERMEABLE “Semi-permeable” Let’s some kinds of molecules pass through, but keeps others OUT!
Passive Transport • Moves from an area of greater concentration. to and area of lesser concentration • Move “down a concentration gradient”
Passive Transport - Osmosis • Moves water from area where it is most pure to area where it is less pure • Hypotonic • Hypertonic • Isotonic (Equilibrium)
Osmosis • Hypertonic = less pure (more solute) • Hypotonic = more pure (less solute) • Isotonic = equal
Passive Transport – Ion Channels • Integral proteins form channels that allow substances to pass through
Passive Transport – Facilitative Diffusion • Proteins “carry” substances across the cell membrane
Active transport - endocytosis • Movement of large substances into the cell
Active Transport - exocytosis • Large particles leave the cell
CYTOPLASM = cytosol + organelles CYTOSOL ________ Fluid portion of the cytoplasm ORGANELLES _________ small structures with a special function
CYTOSKELETON = the support system of the cell A. Microtubules B. microfilaments
NUCLEUS = the “control center” of the cell
NUCLEUS A. Contains genetic material
CHROMATIN (DNA & proteins) Thin form of DNA
CHROMOSOMES (DNA & proteins) Thick form of DNA
NUCLEUS B. Surrounded by a nuclear envelope 1. contains pores for materials to enter and leave the nucleus
NUCLEUS C. Contains the nucleolus = area of densely-packed DNA 1. makes ribosomes
MITOCHONDRIA = the “powerhouse” of the cell A. Converts glucose into ATP 1. occurs during the process of respiration
MITOCHONDRIA 2. Reaction occurs on the inner membrane of the mitochondria known as the cristae Increases surface area for more chemical reactions to happen
MITOCHONDRIA B. Contains its own DNA = mt. DNA 1. mother is only person to pass mt. DNA to offspring
-used to identify bodies Jesse James
Ribososmes = make proteins(attach amino acids into long chains) A. Some ribosomes are found floating in the cytoplasm - make proteins for inside the cell B. Some ribosomes are found attached to endoplasmic reticulum - make proteins for outside of cell
ROUGH ENDOPLASMIC RETICULUM (ER) = carries proteins through the cell (highway system)
ROUGH ENDOPLASMIC RETICULUM (ER) A. Has ribosomes attached
SMOOTH ENDOPLASMIC RETICULUM (ER) = detoxifies the cell A. Has no ribosomes attached
CENTRIOLES = • Appear during cell division to pull chromosomes apart
CENTRIOLES
GOLGI BODY (APPARATUS) = • “Packaging centers” of the cell • Packages molecules for transport out of cell. Puts proteins into vesicles.
All the cell membranes interconnect
It’s ALL connected!
VACUOLES • Storage for enzymes and waste
LYSOSOMES = Contain enzymes use to help break down food or break down tissues
Peroxisomes = bags of enzymes used to help break down chemicals A. Used to break down hydrogen peroxide in cells
Cilia/Flagella= move the cell or move substances past the cell • Many • short * one or two * long
How are Bacteria and Plant Cells Different from Animal Cells?
WHICH IS BIGGER? Plant cell Small Animal Cell Bacteria Smaller Smallest
2 KINDS OF CELLS _________ PROKARYOTES “No nucleus or membrane bound organelles” They have a cell membrane around outside. No membranes around their DNA NO organelles surrounded by membranes inside EXAMPLE: Bacteria
BACTERIA • No nuclear membrane • No membrane bound organelles • Cell wall • Single loop of DNA • Few organelles
2 KINDS OF CELLS EUKARYOTES _________ “Nucleus with membrane bound organelles” They have a cell membrane around outside. They have a nuclear membrane around their DNA and organelles surrounded by membranes inside EXAMPLE: Animal & plant cells
CELL WALL Supports and protects cell Outside of cell membrane Made of cellulose Different than bacteria cell wall
Plasmodesmata • Connect adjacent plant cells
Plasmodesmata
Vacuole • large • Water –filled • Provides support for the plant (turgor)
Chloroplasts • Green pigment • Most numerous
Chromoplast • Additional pigments (red, orange, yellow)
Leucoplasts • Store starch
PLANT CELLS • • Cell wall Plastids Bigger vacuoles No centrioles
2 KINDS OF ORGANISMS ___________ AUTOTROPHS Can make their own food Example: Green Plants _________
2 KINDS OF ORGANISMS HETEROTROPHS ___________ Can’t make their own food Get energy by eating other organisms Animals & YOU Examples: ________
ALL LIVING THINGS ARE MADE OF…. . CELLS ______
CELL WALL Supports and protects cell Outside of cell membrane Made of different molecules than plant cell wall
CHLOROPLASTS • Use energy from sun to make glucose for food
CHLOROPLASTS • Surrounded by DOUBLE membrane • Thylakoid stacks contain enzymes for photosynthesis • Contain own DNA
VACUOLES Storage for enzymes and waste Vacuoles are much larger in plants
NO CENTRIOLES in Plants
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