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63 Cards in this Set
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3:1 cells are the basic units of the body |
. the cell is the basic unit of structure and function in the body . cells are measured and micrometers (microns, um) . cells that have developed specialize characteristics are said to be Differentiated . cells vary in size and shape; structure and functions are inter-related |
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3:2 A composite cell |
. There is no typical cell but a composite cell shows the components found in most cells |
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About how many cells are there in the human body? |
There are 50 to 100 trillion cells in the human body |
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What are the 3 major parts of the cell? |
1. Nucleus 2. Cytoplasm 3. Cell membrane |
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What is cytoplasm and what does it consist of? |
. Cytoplasm consists of organelles, with specific functions suspended in a liquid called Cytosol |
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. Outer boundary of the cell . Maintain integrity of cell . Selectively permeable: regulates entry and exit of substance . Signal transduction: permits cell to receive and respond to messages . Consists mainly of lipids and proteins, with some carbohydrates |
Cell (plasma) membrane |
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. What structure of the cell membrane framework is phospholipid bilayer: - water-soluble (hydrophilic) heads form surfaces - water-insoluble (hydrophobic) tails form interior
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Cell membrane structure |
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Cell membrane structure
What substances are permeable and impermeable to phospholipid bilayer? |
Lipid-soluble substances: permeable
Water-soluble substances: impermeable |
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Cell membrane structure
What stabilizes the membrane and helps keep it impermeable to water-soluble substances? |
Cholesterol |
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Cell membrane structure
Membrane proteins have many functions: |
. Pores, channels, receptors, enzymes, cell contact and identification, CAMs ( Cell Adhesion Molecules) |
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Cell membrane structure
What role do carbohydrates play in the cell membrane? |
- cell recognition and interaction - self markers |
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. Guide cells on the move . Selectins: coat White blood cells and anchor them by providing friction . Integrins: Direct white blood cells through capillary walls toward infectious site . Guide embryonic cells toward material cells to form placenta . Establish connections between nerve cells |
Cellular adhesion molecules (CAMs) |
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Consists of networks of membrane and organelles suspended in cytosol |
Cytoplasm |
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Cytoplasm
Define cytosol & organelles |
. Cytoplasm = cytosol + organelles . Cytosol: fluid portion of the cytoplasm . Organelles: tiny solid structures with specific functions in the cell |
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Cytoplasm contains the _____, a supporting framework of protein rods and tubules |
Cytoskeleton |
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Cytoplasmic organelles
. Composed of protein and RNA . Free in cytoplasm or on RER . Provide structural support and enzyme activity to link amino acid proteins synthesis |
Ribosomes |
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. Membrane-bound sacs, canals, and vesicles . Tubular transport system . Rough ER contains ribosomes, conduct protein synthesis . Smooth ER does not have ribosomes: conduct lipid synthesis |
Endoplasmic reticulum |
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. Membranous sacs . Store or transfer substances |
Vesicles |
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. Sacs flattened, membranous sacs . Refines, packages, and delivers proteins made on the RER |
Golgi Apparatus |
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. Membrane-bound fluid filled sacs . House chemical reactions that extract energy from nutrients (cellular respiration, which produces ATP) . Called the "powerhouse of the cell" |
Mitochondria |
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. Small membranous sacs . Contain enzymes that digest proteins, carbohydrates, nucleic acid, bacteria, debris, worn out cell parts . "Garbage disposals" of cells |
Lysosomes |
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. Membranous sacs similar to lysosomes . Contain enzymes that's digest lipids, alcohol, hydrogen peroxide |
Peroxisomes |
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. "Central body", consists of 2 centrioles . In cytoplasm, near nucleus . Centrioles are cylindrical, composed of microtubules . Centrioles produce spindle fibers during cell division, which distribute chromosomes to form daughter cells |
Centrosomes |
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. Motile extensions of cell membrane . Consist of microtubules in cylindrical pattern . Form a "fringe" on the surface of certain epithelial cells . Shorter than flagella, but very abundant when present . Beat back and forth in coordinated matter . Propel muscles in respiratory tract, propel eggs toward uterus |
Cilia |
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. Another type of motile extension from cell membrane . Similar in structure to cilia, but much longer . Flagellum causes the entire cell to move . Tail of sperm is the only flagellum in a human cell . Each cell only has 1 flagellum |
Flagella |
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. Controls genetic material and controls cell activities |
Cell Nucleus |
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. Porous, double-layered membrane . Separates nucleoplasm from cytoplasm . Nuclear pores allow passage of certain substances |
Nuclear Envelope |
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. Dense body of RNA and protein . Site of ribosome production |
Nucleolus |
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. Consists of cell's chromosomes, each containing DNA wound around proteins . Stores information for protein synthesis |
Chromatin |
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3.3 movements into and out of the cell
. Do not require ATP . Diffusion . Osmosis . Facilitated diffusion . Filtration |
Physical (Passive) Processes |
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3.3 movements into and out of the cell
. Require ATP . Active Transport . Endocytosis . Exocytosis . Transcytosis
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Physiological (Active) Processes |
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. Movement of atoms, molecules, or ions from region of higher concentration to region of lower concentration . Occurs due to constant motion of atoms, molecules, or ions . Only substances that the cell membrane is permeable to: oxygen, carbon dioxide, and other lipid-soluble substances . A dissolving sugar cube is an example of the diffusion |
Diffusion |
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. Diffusion occurs across the cell membrane through ion channels or transporters . Water-soluble substances (Na+, K+, Cl-, glucose, amino acids) . Passive process; no ATP required . Does not require energy but requires some form of chemical enegry |
Facilitated Diffusion |
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. Movement of water across a selectively permeable membrane from region of higher water concentration to region of lower water concentration . Water moves into region containing higher impermeant solute concentration . Passive process; no ATP required |
Osmosis |
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What's the difference between hypertonic & hypotonic? |
Hypertonic - more solid in water Hypotonic - less solid in water |
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Osmotic pressure
. Ability of osmosis to generate enough pressure to lift a volume of water . Osmotic pressure increase as the concentration of impermeant solutes increases |
Osmotic pressure |
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. Same osmotic pressure cells in an isotonic solution have no net gain or loss of water |
Isotonic Solution |
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. Higher osmotic pressure cells in a hypertonic solution lose water |
Hypertonic Solution |
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. Lower osmotic pressure cells in a hypotonic solution gain water |
Hypotonic Solution |
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. Process that forces molecules through membranes by exerting pressure . Used to separate solids from water, or small particles from large ones . Example: when blood plasma leave capillaries, water and small solutes are filtered; but large plasma proteins are not . Passive process; No ATP required |
Filtration |
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. Movement of substances across a membrane from region lower concentration to region of higher concentration (against concentration gradient) . Uses carrier molecules in cell membrane . Active process; require ATP energy . Examples; sugars, amino acids, Ca+2, H+, Na+/K+ pump |
Active Transport |
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. Movement of a substance into the cell inside a vesicles . Substances too large to enter by other methods can enter cell this way |
Endocytosis |
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3 Types of endocytosis: |
Pinocytosis - Membrane engulfs droplets of liquid
Phagocytosis - Membrane engulfs solid particles
Receptor-Mediated Endocytosis - Membrane engulfs specific substances, which have bound to receptor proteins on the membrane |
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. Release of substances/particles from the cell . Vesicle containing particles fuse with cell membrane and release contents . Example: release of neurotransmitters from nerve cells |
Exocytosis |
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. Involves receptor-mediated endocytosis followed by exocytosis . Quickly transports substances from one end of cell to the other . Moves substances across barriers formed by highly connected cells . Example: transport of HIV across lining of anus or vagina |
Transcytosis |
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3:4 the cell cycle
Series of changes a cell undergoes from the time it forms until the time it divides |
Cell Cycle |
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3:4 the cell cycle
Stages: |
- Interphase - Mitosis - Cytokinesis |
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. A very active period in cell cycle . Cell grows . Cell maintains normal functions . Cell replicates genetic material (DNA) to prepare for mitosis (Nuclear division) . Cell synthesizes organelles, membranes, and biochemicals to prepare for cytokinesis (Division of cytoplasm |
Interphase |
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phases:
What are the the stages of the cell cycle?
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S (synthesis) phase: DNA is replicated
G1 and G2 (growth or gap) phases: structures other than DNA are replicated and cell grows |
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. Produces two daughter cells from an original somatic cell |
Mitotic Cell Division |
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. Division of the nucleus |
Mitosis |
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. Division of the Cytoplasm and Division of Cytoplasmic division |
Cytokinesis |
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Phases of Mitosis:
Chromatin condenses to form chromosomes, nuclear envelope and nucleolus disperse |
Prophase |
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. Chromosomes attach to spindle fibers, and align midway between centrioles |
Metaphase |
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. Chromosomes separates and move in opposite directions, toward centrioles |
Anaphase |
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. Chromosomes return to chromatin structure, nuclear envelope forms, nucleoli become visible |
Telophase |
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3:5 control of cell division:
What 2 Frequency of cell division is strictly regulated, and varies by cell type: |
- skin cells, intestinal cells, and blood-forming cells divide often and continually
- neurons divide a specific number of times, then cease |
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3:5 control of cell division |
. Chromosomes tips (telomeres) that shorten with each Mitosis provide a mitotic clock . Fluctuating levels of certain proteins in cell control cell cycle . Cells divide to provide a more favorable surface area to volume relationship . Hormones and growth factors are external control for cell division |
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3:5 control of cell division:
Healthy cells stop dividing when they become crowded
Tumors can result from a loss of control over frequency of mitosis |
Contact Inhibition |
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Tumors
2 types of tumors: |
Benign: remains in local area
Malignant: invasive, cancerous, can spread or metastasize |
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Tumors:
2 major types of genes cause cancer: |
Oncogenes: abnormal forms of genes that control cell cycle, but are overexpressed
Tumor suppressor: normally limit mitosis, but if inactive/removed cannot regulate mitosis cancer cell called "immortal", since they do not stop dividing after 40 - 60 divisions |
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3:7 cell division
. Programmed cell death . Normal part of development . A continuous, stepwise process . Remove webbing between fetal fingers and toes . Protective peels away damaged skin cells after sunburn
This is called? |
Apoptosis |
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3:7 cell death
. Cell death from damage . Not a normal process
Example: gangrene |
Necrosis |