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Cell Biology Flashcards

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1
Q

Magnification Equation

A

Size of image over actual size

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2
Q

Four differences between theories and laws

A
  1. Theories provide the most logical explanation for what happens while laws explain what happens
  2. Theories can be proposed, challenged, revised while laws resist change
  3. Multiple theories compete to best explain a phenomenon while there is only a single law for a single phenomenon
  4. Theories need to be proven and are subject to tests while laws don’t need to be proven
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3
Q

7 Criteria of Life

A
  1. Metabolism
  2. Homeostasis
  3. Nutrition
  4. Excretion
  5. Sensitivity
  6. Reproduction
  7. Growth
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4
Q

Cell Theory

A
  1. The cell is the smallest unit of life
  2. All living things are made of cells
  3. Cells come form pre-existing cells
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5
Q

Three Exceptions to Cell Theory

A
  1. The striated muscle: cells have multiple nuclei, challenges that which makes up a cell
  2. Aseptate fungi: without septa (cell walls), one cell with several nucleii
  3. Giant algae: the foot, step and cap considered to be a single cell: is the cell the smallest unit of life?
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6
Q

Why do cells divide instead of keep growing larger and larger?

A

If the cell’s surace area becomes too small compared to the volume, the cell memrbane won’t be able to transport nutrients inside the cell fast enough to support the whole cell, nor will it be able to expel waste fast enough to make space for everything else

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7
Q

Nine Differences: Prokaryotes and Eukaryotes

A

Prokaryotes are…
1. Small and simple
2. Have no nucleus (nucleoid region)
3. No membrane bound organelles
4. Unicellular but may form colonies
5. One circular chromosome
6. DNA is circular
7. Mainly asexual reproduction
8. Many are anaerobic
9. 70s ribosomes

Eukaryotes are…
1. Larger and more complex
2. Have a nucleus
3. Membrane bound organelles
4. Multicellular
5. More than one chromosome
6. DNA is linear
7. Mainly sexual reproduction
8. Mainly aerobic
9. 80s ribosomes

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8
Q

Bacteria are too small to be seen with a …

A

Light microscope

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9
Q

Bacteriophage

A

Viruses that specifically target and kill bacteria

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10
Q

Phage therapy

A

Modifying viruses to attack bacteria

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11
Q

The nucleoid region isn’t called the nucleus because…

A

It’s not membrane bound

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12
Q

Prokaryotic pili

A

Attach to things and communicate with other cells and for bacterial conjugation.

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13
Q

Bacterial flagella

A

Allow for movement

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14
Q

Prokaryotic plasmid

A

Separate piece of DNA

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15
Q

Binary Fission vs. Mitosis

A

Bacteria cannot undergo mitosis because they don’t have nucleii

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16
Q

Two advantages of binary fission

A
  1. Can be done over and over again
  2. Fast and efficient
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17
Q

4 ways in which genetic diversity is created by bacteria

A
  1. Genetic mutations
  2. Errors that occur during the course of evolution
  3. Bacteria can swap plasmids with different species
  4. Plasmid gets copied alongside the DNA
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18
Q

Process of Plasmid Sharing (4 Steps)

A
  1. A factor triggers a bacterium to extend its conjugation pilus
  2. The pilus extends then pulls F- closer
  3. F+ donates the plasmid
  4. F- receives the plasmid
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19
Q

Two Possibilities during Plasmid Sharing

A
  1. The F- extends its own pilus and send plasmid back
  2. 2 bacteria exchange genetic information
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20
Q

Eukaryotic ribosomes

A

Have two subunits, one large and one small. SIze: 80s (Svedberg unit)

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21
Q

Endoplasmic Reticulum

A

Double layered, connected to the nucleus

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22
Q

Rough ER

A

Protein synthesis and modification

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23
Q

Smooth ER

A

Lipid synthesis

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24
Q

Golgi Apparatus

A

Made from membrane, fused together to make the cell membrane. Transports protein out of the cell

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25
Q

Vesicle

A

Any membrane bound organelle

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26
Q

Mitochondrion

A

Conducts cellular respiration, double membraned

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27
Q

Peroxisome

A

Breaks things down

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28
Q

Microtubule

A

Internal support system, maintains the shape of the cell

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29
Q

Cytoplasm

A

Everything inside the cell except for the nucleus

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30
Q

Cytosol

A

The jelly like substance suspending all the organelles mid - aor

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31
Q

Endosymbiotic Theory

A

Eukaroytic cells theorized to have evolved from early prokaryotes that were engulfed through phagocytosis. The engulfed cell remained undigested as it contributed new functions to the larger cell, forming an endosymbiont. Over time the engulfed cell evolved to become an organelle, as the cell provides it with nutrients and it with cellular respiration/photosynthesis

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32
Q

Endosymbiont

A

Mitochondrium, chloroplast. Possesses its own cell membrane, contains its own set of DNA and ribosomes, similar to bacteria in size.

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33
Q

Two Functions of the Cell Membrane

A
  1. Separate and dinstinguish a cell from its surroundings
  2. To allow certain substances in and out to supplt the cell with needed nutrients and to expel waste
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34
Q

Two Cell Membrane Models

A

Davson - Danielli (two protein layers sandwhiching tow phospholipid layers) and Singer and Nicholson (proteins are embedded within the bilayer)

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35
Q

Two Types of Proteins in the Singer and Nicholson Model

A

Both types are mobile
1. Integral: embedded within the membrane
2. Peripheral: attached to the inner (fatty acid chains) or outer surface

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36
Q

Three Proofs of the Singer Nicolson Model

A
  1. Freeze - etched electron micrograph: cell is frozen in liquid nitrogen, cleaved along the bilayer’s fracture plane: proteins were found to be embedded
  2. Structure of the membrane proteins: extracted and observed to be globular in shape; they are less likely to gorm continuous layers than fibrous proteins
  3. Fluorescent antibody tagging: two cells with red and green markers attached to antibodies binding to membrane proteins were fused; both colors spread throughout the cell
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37
Q

Structure of the Cell Membrane

A

Phospholipids, cholesterol and proteins

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38
Q

Structure of Phospholipids

A

The hydrophilic components: the phosphate group and glyverol molecule.
The hydrophobic component: fatty acid tails

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39
Q

Properties of Phospholipids

A

Amphipathic: prevent random materials from entering or leaving the cell and allows the membrane to spontaneously form a bilayer

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40
Q

Hydrophobic tail regions face x while hydrophilic head region associate with the y and z environments

A

X: inwards
Y: Cytosolic
Z: Extracellular

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41
Q

Phospholipid Movement Types

A
  1. Lateral (swap places with a phospholipid beside it)
  2. Flip - flop: swap places with a phospholipid on the layer opposite it)
42
Q

Role of Cholesterol in Cell Membrane

A

Regulates membrane fluidity. At warmer temperatures, cholesterol restraints movement of the phospholipids; at colder temperatures, it increases movement

43
Q

Transmembrane integral proteins

A

Stretch across the entirety of the phospholipid layers

44
Q

5 Functions of the Proteins in Cell Membranes

A
  1. Intercellular joinings and anchorage
  2. Enzymatic activity
  3. Transport
  4. Cell - cell recognition
  5. Signal transduction
45
Q

Fluidity created by the Phospholipid Bilayer allows for the…

A

Breaking and remaking of membranes during exocytosis and endocytosis

46
Q

Three Main Goals of Intramembrane Transport

A
  1. Take in nutrients
  2. Expel waste
  3. Keep the internal environment within certain parameters (homeostasis)
47
Q

Passive transport is driven by x and requires no y

A

X: Diffusion: the tendency of molecules within a closed space to spread out evenly among it
Y: Expenditure of cellular energy

48
Q

Factors Affecting Diffusion

A
  1. Concentration gradient
  2. Size of particles
  3. Temperature
49
Q

The concentration gradient is always naturally…

A

From high to low concentration

50
Q

Dynamic Equilibrium

A

No net movement: the amount of particles traveling in either direction is equal

51
Q

Osmosis

A

Diffusion of water across a selectively permeable membrane

52
Q

Tonicity

A

The ability of a solution to cause a cell to gain or lose water

53
Q

Hypotonic Solution

A

Cell gains water, becoming lysed

54
Q

Isotonic Solution

A

No net water movement across the membrane

55
Q

Hypertonic Solution

A

Cell loses water, becomes shriveled

56
Q

Plant cells require more x than animal cells

A

X: water

57
Q

Plant cells are x in a hypotonic solution, y in an isotonic solution, z in a hypertonic solution

A

X: turgid (normal)
Y: flaccid
Z: plasmolyzed

58
Q

Only x and Y can cross the cellular membrane through diffusion

A

Small hydrophobic molecules and uncharged polar molecules

59
Q

Facilitated diffusion is passive or active?

A

Passive

60
Q

Facilitated Diffusion Mechanism

A

Transport proteins allow passage of hydrophilic substances across the membrane

61
Q

Channel proteins are hydrophilic or hydrophobic?

A

Hydrophilic

62
Q

An example of a channel protein

A

Aquaporin

63
Q

Carrier Proteins Mechanism

A

Bind to molecules, then undergo conformational change and shuttle them across the membrane. Specific to the type of molecule it binds to

64
Q

Active transport is the result of the cell’s need to…

A

Gain more control over its internal environment

65
Q

Active transport requires energy in the form of…

A

ATP

66
Q

Energy for primary active transport comes from…

A

The direct hydrolysis of ATP

67
Q

Secondary Active Transport

A

Indirectly coupling transport with another molecule moving along its gradient

68
Q

The Sodium Potassium Pump

A

A form of secondary active transport
1. Three Na ions bind to intracellular sites on the pump
2. A phosphate group is transferred to the pump through hydrolysis
3. The pump undergoes conformational change as it translocates Na across the membrane
4. 2 K binding sites are exposed outside
5. A catalyzed reaction releases the phosphate group, causing the pump to return to its original conformation
6. The potassium is pumped through the membrane

69
Q

Proton Pump

A

Relies on an electrochemical gradient, also uses ATP to pump hydrogen ions from the negatively charged cytoplasm to the positively charged extracellular fluid

70
Q

Co - Transport Types

A

Symport (same direction) and antiport (opposite directions)

71
Q

Bulk Transport

A

For large molecules that need to travel in bulk through vesicles, which are moved by microtubules

72
Q

2 Types of Bulk Transport

A

Endocytosis and Exocytosis

73
Q

Endocytosis

A

The cell takes in a macromolecule by forming vesicles form the plasma membrane

74
Q

Phagocytosis

A

The cell engulfs a particle in a vacuole, which then fuses with a lysosome to digest the particle

75
Q

Pinocytosis

A

Molecule are taken up in tiny vesicles alongside extracellular fluid

76
Q

Receptor - mediated endocytosis

A

Binding of ligands, a molecule that binds specifically to a receptor site of another molecule to receptors triggers vesicle formation. Restricts the type of substances allowed inside

77
Q

Exocytosis

A

Transport vesicles migrate to the membrane, fuse with it, then release the contents

78
Q

Types of Stem Cells

A
  1. Totipotent: can form ANY cell type
  2. Pluripotent: Can form any type except for extra - embryonic tissue
  3. Induced pluripotent: pluripotent that comes from an adult stem cell
  4. Multipotent: can form closely related types
  5. Unipotent: cannot differentiate
79
Q

Disadvantages of stem cell therapy

A

Possibility of tumors forming, the body rejecting the foreign cells

80
Q

Stargardt’s Disease

A

Macular degeneration, causing progressive vision loss. Stem cells can replaced compromised photoreceptor cells

81
Q

3 purposes of mitosis

A

Cell/organism growth, asexual reproduction, tissue repair

82
Q

Three Stages of Interphase

A
  1. G1: occurs in the cytoplasm, involves regular processes, growth, rapid protein synthesis, replication of mitochondria and chloroplasts
  2. S: occurs in the nucleus, proteins made during G1 used for DNA synthesis and replication
  3. G2: occurs in the cytoplasm, protein synthesis for components used during mitosis, like spindle fibers
83
Q

Prophase Summary

A

Chromosomes, spindle fibers and centrosomes form, membranes dissolve

84
Q

Metaphase Summary

A

Chromosomes line up along the equator of the cell

85
Q

Anaphase Summary

A

Spindle fibers attach to the centromeres of the chromosomes and pull apart the sister chromatids

86
Q

Telophase Summary

A

Cleavage furrow forms, the nucleus and the nuclear membrane reform

87
Q

Cytokinesis Summary

A

In animal cells: microfilaments constrict to form a cleavage furrow, which pinches the cell into two. In plant cells: carbohydrate rich vesicles around the center of the cell fuse, forming a plate

88
Q

Cyclins

A
  • A protein that regulates mitosis
  • Undergoes a cycle of synthesis and decomposition during cell division
89
Q

How Cyclin Regulates Mitosis

A

Cyclins accumulate during G2 of interphase. The mitosis promoting factor (MPF) forms, signaling the cell to enter mitosis. Once the cyclin degrades, the MPF is deactivated, signaling the cell to exit mitosis, dividing into two

90
Q

Three Factors that Control Cyclin Levels

A

Cell size, completion of DNA replication and the cellular environment

91
Q

Cyclin Dependent Kinase

A

Enzyme that adds phosphates to molecules, activated by cyclin

92
Q

Activation of G1/S Cyclin

A

Cyclin activates CdK, which phosphorylates targets, beginning the S phase, activating DNA replication enzymes

93
Q

Mitotic Index Equation

A

NUmber of cells in mitosis over total number of cells

94
Q

Mitotic indices differ due to…

A

Different cells’ differing locations and functions

95
Q

Mitotic Index Usage

A

Cancer diagnosis

96
Q

Cancer Definition

A

Abnormally fast growth of cells caused by multiple gene expression changes. The rate at which cells are forming is faster than that which they are dying off.

97
Q

Pasteur’s Experiment

A
  1. A growth medium was boiled to kill any microorganisms already present
  2. Placed the medium in different containers
  3. It was observed that bacterial growth only occurred in the medium if the flask was exposed to the air
  4. Proved that bacterial growth came from external contaminants and is incapable of self - generation
98
Q

Abiogenesis Process (5 Steps)

A
  1. Simple organic molecules are formed
  2. The simple organic molecules form more complex polymers
  3. The polymers must have the ability to self - replicate
  4. The polymers are eventually cut off from the environment by the formation of a cell membrane around them
  5. The polymers develop a different internal chemistry from their surroundings by becoming protobionts
99
Q

Urey Miller Experiment (5 Steps)

A
  1. Water is boiled to vapor to mimic the high temperatures present on Earth during primordial times
  2. The vapor is mixed with gases like hydrogen, methane and ammonia to create a reducing atmosphere, where oxygen is limtied
  3. The mixture is exposed to an electrical discharge to mimic the effects of lightning as an energy source
  4. The mixture is allowed to cool and left alone for about a week
  5. The mixture is analyzed after the week and found to contain traces of simple organic molecules like amino acids and carbohydrates
100
Q

Since the conditions of primordial earth no longer exist, cells can no longer…

A

Undergo abiogenesis and can only come from pre - existing cells

Biology (7 decks)

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