Chapter 3 Flashcards

1
Q

Cell Theory 3 parts

A
  • Cells are the smallest unit of life
  • All organisms are made of one or more cells
  • All cells come from preexisting cells
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2
Q

Properties of cells

A
  • Differ in size, shape, and subcellular components (organelles)
  • Differences in structure lead to difference in function
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3
Q

Generalized cell (3 main parts)

A

-Plasma Membrane) separates cell from environment
Cytoplasm) Thick ICF, contains organelles
Nucleus) Contains DNA

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4
Q

Plasma Membrane (structure)

A
  • Made of a double layer of phospholipids (lipid bilayer)
  • Called fluid mosaic model because it it made of many pieces
  • Is selectively permeable.
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5
Q

Intracellular Fluid

A

-Fluid inside the cell (cytoplasm)

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6
Q

Extracellular fluid

A

-Fluid outside cells
ex:
Interstitial Fluid: Submersed cells
Blood Plasma
Cerebrospinal Fluid.
Cellular secretions
Extracellular matrix

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7
Q

Membrane Lipids

A

Phospholipids) Form lipid bilayer. have hydrophobic tail and a hydrophilic head.

Glycolipids: Lipids with polar sugar groups on membrane surface

Cholesterol) Increases membrane stability

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8
Q

Integral Proteins

A
  • Inserted into the membrane (Most are transmembrane)
  • Have Hydrophobic and Hydrophilic areas
    a) Hydrophobic region interact with lipid tails
    b) Hydrophilic areas interact with water
  • Function as transport proteins
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9
Q

Peripheral Proteins

A
  • Loosely attached to integral proteins. Include filaments on the intracellular surface for plasma membrane support.
  • Function as Enzymes
  • Some are motor proteins involved in mechanical functions
  • Responsible for cell to cell connections
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10
Q

6 Functions of Membrane Proteins

A

1) Transport) transport molecules across the membrane.
2) Receptors) Sense signals from hormones and relay information
3) Attachment) to the cytoskeleton or extracellular matrix.
4) Enzymatic Activity)
5) Intercellular Joining
6) Cell Cell recognition

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11
Q

Glycocalyx

A
  • Consists of sugars sticking out of the cell surface.
  • Some are attached to lipids (glycolipids) and some are attached to proteins (glycoproteins)
  • the coating is different for each cell and it provides specific markers for each cell, Allows recognition for self vs nonself.
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12
Q

Homostatic Imbalance

A

-Damaged cells are able to continue reproducing because the immune system cannot recognize the glycocalyx as incorrect.

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13
Q

Cell Juntions

A

-Binds cells into communities

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14
Q

Tight Junctions

A
  • Adjacent integral proteins form an impermeable junction around the cell which prevents fluids from moving between cells
  • useful in places like digestive tract.
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15
Q

Demosomes

A
  • Zipper like cell junction formed with liker proteins (cadherins) of neighboring cells.
  • Linker protein is anchored in a thickened part of the membrane called plaque
  • Allows for flexibility under tension
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16
Q

Gap Junction

A

-Transmembrane proteins form pores (called Connexons) which allow molecules (such as ions/electrical signals) to move around.

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17
Q

Active Transport

A
Uses energy (ATP) to move a particle across a selectively permeable membrane
- Moves particles across a selectively permeable membrane.
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18
Q

Passive Transport

A

Does not use energy to transport a particle across a selectively permeable membrane

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19
Q

Filtration

A

Diffusion across a capillary wall not plasma membrane

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20
Q

Diffusion

A
  • Molecules move from areas of high concentration to low concentration (down concentration gradient).
  • The speed of diffusion is influenced by concentration of molecules, size of the molecules, and temperature.
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21
Q

Simple Diffusion

A
  • Unassisted Diffusion of a Non Polar, Lipid Soluble (hydrophobic) molecule. These substances diffuse directly through the lipid bilayer.
    ex) O, CO2, Steroids, Fatty acids, and some very small substances.
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22
Q

Facilitated Diffusion

A

-Transport of hydrophobic molecules

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23
Q

Carrier Method Facilitated Diffusion

A
  • Transmembrane proteins (carriers) carry specific molecules that are too large for membrane channels
  • Carrier binds to a molecule which moves it across the membrane
  • Binding is limited to the number of carriers (when carriers are full they are saturated).
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24
Q

Channel-Mediated Diffusion

A
  • Transmembrane protein Channels with aqueous-filled cores
  • Transport Ions or Water (Osmosis) down the concentration gradient.
  • Water channel is called an aquaporin
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25
Q

Osmosis

A
  • Movement of solvent (Water) across a selectively permeable membrane
  • Water is moving from higher to lower concentration
  • Can diffuse through plasma membranes/lipid bilayer through channels called aquaporins.
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26
Q

Osmolarity

A
  • Measure of concentration of total number of solute particles in a solvent.
  • Water will move from areas of low solute (high water) concentration to areas with high solute (low water) concentration.
  • Moves through channels called aquaporins.
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27
Q

Hydrostatic Pressure

A

Outward pressure exerted on a cell due to osmosis

-Referred to as back

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28
Q

Osmotic Pressure

A

Inward pressure due to the tendency of water to be pulled into a cell with higher osmolarities.

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29
Q

Tonicity

A

-Ability of a solution to change shape or tone of cells by altering internal water volume.

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30
Q

Isotonic Solution

A

-Same osmolarity outside the cell as inside which leaves the volume of the cell unchanged.

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31
Q

Hypertonic Solution

A

-Higher osmolarity outside the cell then inside. Causes water to flow out of the cell which causes shrinking. crenation

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32
Q

Hypotonic Solution

A

-Has lower osmolarity inside the cell than outside the cell. Water will flow into the cell. Can lead to cell bursting known as lysing.

33
Q

Primary Active transport

A

Energy from hydrolysis (creation) of ATP causes the shape of a transport protein to change shape and pump solutes (ions) across the membrane.
-Pumps ions such as Na+, K-, Calcium, and Hydrogen

34
Q

Sodium Potassium pump

A
  • Located in excitable cells (nerve and muscle). Pumps Na+ out of cell and K- back into the cell because both elements will slowly diffuse across the membrane if not.
  • Pump works as an antiporter which moves ions back to original space. (maintains electrochemical gradient)
35
Q

Secondary active transport.

A
  • Depends on the ion gradient crated by Active Transport. This energy is used to drive the process.
  • Will transport more than one substance during transport.
36
Q

Antiporters

A

-Transport one substance into the cell while transporting another out.

37
Q

Symporters

A

Transport two substances in the same direction

38
Q

Vesicular transport

A

Transport of large molecules, macromolecules, and fluids across the plasma membrane in sacs called vesicles.
-Requires ATP.

39
Q

Endocytosis

A

Transport items into the cell.
-The tree types o endocytosis are phagocytosis (cell eating) pinocytosis (cell drinking) and receptor-mediated endocytosis.

40
Q

Resting Membrane Potential.

A
  • Electrical Potential Energy produced by the separation of oppositely charged molecules across a membrane in cells.
  • Inside of the cell is more negative than the outside of the cell. Difference in electrical charge is called voltage.
  • Cells that are charged are polarized
41
Q

Electrochemical Gradient

A

the combination of the concentration gradient and electrical charge. (Both gradients of cells)

42
Q

Generation of Resting Membrane Potential

Using K+

A

1) K+ diffuses out of the cell down its concentration gradient which creates a negative environment in the cell because of negative proteins which cannot leave.
2) K+ is pulled back into the negative interior because it is diffusing back down the concentration gradient.
3) When the drive for K+ to leave the cell is EQUAL to the drive for it to stay RMP is then established.

43
Q

Na+-K+ pump actions

A
  • Pumps 3Na+ out of the cell while pumping 2K+ into the cell.
  • Neuron and muscle cells will intentionally upset the balance of Na+ and K+ by opening gated channels.
44
Q

Plasma membrane receptors

A

-Serve as binding sites for several chemical signals.

45
Q

Contact Signaling

A

Cells touch and are able to recognize each other by the unique surface of the other cell (glycocalyx)
-Used in development and immunity

46
Q

Chemical Signaling

A

Interactions between receptors and ligands (chemical messengers) that cause changes in cells.
-Ligands bind to receptors. They can be neurotransmitters, hormones (endocrine system transmitter), and paracrines (chemical messages that occur over short distances)

47
Q

G Protien-Linked Receptors

A

Chemical message (ligand) is received by a receptor on the plasma membrane called the G-Protien Linked receptor. The chemical message then causes the G protein of a cell to be activated and relay the message to ions channels, enzymes, or release another internal message.

48
Q

Cytoplasm

A
  • All cellular material between the plasma membrane and the nucleus
  • Cytosol) Gel-like solution made of water and soluble molecules (proteins, salts, sugars, etc.)
  • Inclusions) Insoluble materials (Glycogen granules, pigments, lipid droplets, vacuoles crystals)
  • Organelles) machinery of cell. Either membranous or non mebranous.
49
Q

Organelles

A

Specialized cellular compartments/ structures. Each performs its own job to maintain cell life.

50
Q

Membranous Organelles.

A

-Mitochondria, Endoplasmic Reticulum, Golgi Apparatus, Peroxisomes, and Lysosomes

51
Q

Nonmembranous Organelles

A

Cytoskeleton, Centrioles, and Ribosomes.

52
Q

Mitochondria

A
  • Power Plant of the cell because it produces ATP (via aerobic cellular respiration)
  • Enclosed in double membrane. Inner membrane is called cristae which contains proteins important for cellular respiration.
  • Have their own DNA, RNA, and ribosome (only organelle besides nucleus.)
  • Capable of dividing (fission)
53
Q

Ribosomes

A
  • Site of protein synthesis
  • Free Ribosomes) Float in cytosol. Synthesise protein in cytosol for organelles or cytosol
  • Membrane Bound Ribosomes) Attached to membrane of the Endoplasmic Reticulum (ER). Proteins synthesized are incorporated into membranes or lysosomes or exported from the cell.
54
Q

Endoplasmic Reticulum (Structure)

A
  • Series of parallel, interconnected tubes and parallel sacs called cisterns (enclose fluid interiors.)
  • Continuous with the outer nuclear membrane.
55
Q

Rough ER

A
  • Has Ribosomes for Protein synthesis.
  • Protein enters cisterns where is is modified as they pass through ER. Final protein is enclosed in a vesicle and sent to the Golgi apparatus.
56
Q

Smooth ER

A

-No Ribosomes. Synthesizes Lipids, Detoxifies. Coverts glycogen into free glucose. Storage of calcium.

57
Q

Golgi Apparatus

A
  • Formed by stacked and flattened cistern membranous sacs.
  • Modifies, concentrates, and packages proteins/lipids from ER.
  • Three steps
    1) Transport Vesicle From ER fuses with membrane of the Golgi
    2) Proteins/ Lipids are modified, tagged, sorted and packaged.
    3) Figures out where the products are going and packages protein/lipid accordingly (Can be sent somewhere in the cell or released via exocytosis.)
58
Q

Three Pathways Packages from Golgi apparatus are sent to

A

Pathway A) Secretory Vesicles containing protein to be used outside the cells are exocytosis.

Pathway B) Vesicles Containing Lipids/Transmembrane proteins fuse directly with the organelles or plasma membrane.

Pathway C) Inactive digestive enzymes (proteins) are packaged into vesicles that will become lysosomes.

59
Q

Lysosomes

A
  • Spherical Membranous bags containing digestive enzymes
  • Digest bacteria, virus, and toxins.
  • Break down glycogen and release Ca2+ from the bone.
60
Q

Peroxisomes

A
  • Contain powerful detoxifying substances that neutralize toxins. Free radicals are toxic, highly reactive molecules.
  • Oxidase uses oxygen to convert toxin to H2O2.
  • Catalase) turns H2O2 into harmless H2O
  • There are a lot of peroxisomes in liver/kidney cells
61
Q

Endomembrane System

A
  • Made of ER, golgi apparatus, secretory vesicles, lysosomes and nuclear and plasma membranes.
  • TWO FUNCTIONS
    1) Produce, Degrade, Store, and Export Biological molecules
    2) Degrade potentially harmful molecules.
62
Q

Cytoskeleton

A

-Network of Filament Proteins. Support Cell Structure.

63
Q

Microfilaments

A
  • Thinnest of Cytosol elements
  • Semiflexible strand of protein actin
  • Dense crosslink network
  • Strengthens cell surface to resist compression
  • Most are involved in cell movement, changes in cell state, or exocytosis or endocytosis.
64
Q

Intermediate Filaments

A
  • Medium size
  • Tough, insoluble, ropelike protein fibers.
  • Composed of tetramer (4 fibers twisted together.)
  • Help cell resist pulling forces.
65
Q

Microtubules

A
  • Largest element of cytoskeleton.
  • Composed of Tubulins.
  • Determine cell shape and organelle distribution
66
Q

Centrosome

A
  • Cell Center

- Generates microtubules and organizes mitotic spindle

67
Q

Centrioles

A
  • Come in pairs
  • Organized at right angles to each other.
  • Form the base of Cilia and Flagella known as basal bodies.
68
Q

Cilia and Flagella

A

Cilia) are whiplike extensions on cell surface. Move substances across cell surface
Flagella) Long extension that propels the whole cell (sperm)
-Cilia and Flagella have a 9+2 pattern of microtubules (9 sets of doubles surrounding 2)
-Centrols has 9 +0 pattern (9 pairs of triplets with nothing middle)

69
Q

Microvili

A
  • Plasma membrane protrusions
  • Increases surface area
  • Have core of actin filaments
70
Q

Nucleus

A
  • Largest Organelle
  • Contains DNA
  • The three main structures are nuclear envelope, nucleoli, and the chromatin.
71
Q

Nuclear Envelope

A
  • Double-membrane barrier that encloses nucleoplasm
  • Connects to ER
  • Maintains shape of nucleus.
  • Pores allow some substances to pass.
72
Q

Nucleoli

A
  • Involved in rRNA synthesis (Contains DNA to do so) and ribosome subunit assembly.
73
Q

Chromatin

A
  • Consists of DNA, RNA, and Histone proteins.
  • arranged in nucleosomes (DNA wrapped around 8 histone proteins)
  • When cell divides chromatin condenses and makes chromosomes. This state protects the chromatin threads.
74
Q

Cell Cycle

A

-Series of changes a cell undergoes in preparation to divide.
Interphase) cell grows and carries on normal activities.
Cell division) cell divides in two.

75
Q

Interphase

A

G1 phase) Vigorous cell growth and metabolism.
S (synthetic) phase) DNA replication occurs.
G2) Preparation for division.

76
Q

DNA Replication

A

(You have to study and understand the process and be able to describe it.)

  • Leading strand is synthesized continuously
  • Lagging strand is made in fragments.
  • Process is called semiconservative replication because it retains one original DNA strand in each replicated pair.
77
Q

Cell Division

A

-Consists of two distinct events called mitosis and cytokinesis.

78
Q

Mitosis

A

1) Prophase)
-Early Prophase) Chromatin condenses to form chromosomes. Chromosomes (two sister chromatids) are held together by a centromere.
-Late Prophase) Nuclear envelope breaks up and microtubules attach to the centromere (kinetochore).
2) Metaphase) Centromeres of chromosomes are aligned on the equator of the cell.
3) Anaphase) Chromosomes split and are pulled to each pole by a microtubule.
Telophase) Chromosomes detach from spindle and begin reforming into the chromatin.

79
Q

Cytokinesis

A
  • Cleavage furrow appears to split cells in half

- Ends cell division